Safety of e-cigarettes and nicotine patches as stop-smoking aids in pregnancy: Secondary analysis of the Pregnancy Trial of E-cigarettes and Patches (PREP) randomized controlled trial

AIMS

The aim of this study was to examine the safety of e-cigarettes (EC) and nicotine patches (NRT) when used to help pregnant smokers quit.

DESIGN

A recent trial of EC versus NRT reported safety outcomes in the randomized arms. We conducted a further analysis based on product use.

SETTING

Twenty-three hospitals in England and a stop-smoking service in Scotland took part.

PARTICIPANTS

The participants comprised 1140 pregnant smokers.

INTERVENTIONS

We compared women using and not using EC and NRT regularly during pregnancy.

MEASUREMENTS

Measurements included nicotine intake compared with baseline, birth weight, other pregnancy outcomes, adverse events, maternal respiratory symptoms and relapse in early abstainers.

FINDINGS

Use of EC was more common than use of NRT (47.3% vs 21.6%, P < 0.001). Women who stopped smoking (abstainers) and used EC at the end-of-pregnancy (EOP) reduced their salivary cotinine by 45% [49.3 ng/ml, 95% confidence interval (CI) = -79.8 to -10]. Only one abstainer used NRT at EOP. In dual users, cotinine increased by 19% (24 ng/ml, 95% CI = 3.5-68). In women reporting a reduction of at least 50% in cigarette consumption, cotinine levels increased by 10% in those using nicotine products and by 9% in those who did not. Birth weights in dual users and exclusive smokers were the same (3.1 kg). Birth weight in abstainers using either nicotine product was higher than in smokers [3.3 kg, standard deviation (SD) = 0.7] versus 3.1 kg, SD = 0.6; difference = 0.15 kg, 95% CI = 0.05-0.25) and not different from abstainers not using nicotine products (3.1 kg, SD = 0.8). Abstainers and smokers using nicotine products had no worse pregnancy outcomes or more adverse events than abstainers and smokers not using them. EC users reported more improvements than non-users in cough [adjusted relative risk (aRR) = 0.59, 95% CI = 0.37-0.93] and phlegm (aRR = 0.53, 95% CI = 0.31-0.92), controlling for smoking status. EC or NRT use had no association with relapse.

CONCLUSIONS

Regular use of e-cigarettes or nicotine patches by pregnant smokers does not appear to be associated with any adverse outcomes.

Effects of plant diversity on productivity strengthen over time due to trait-dependent shifts in species overyielding

Plant diversity effects on community productivity often increase over time. Whether the strengthening of diversity effects is caused by temporal shifts in species-level overyielding (i.e., higher species-level productivity in diverse communities compared with monocultures) remains unclear. Here, using data from 65 grassland and forest biodiversity experiments, we show that the temporal strength of diversity effects at the community scale is underpinned by temporal changes in the species that yield. These temporal trends of species-level overyielding are shaped by plant ecological strategies, which can be quantitatively delimited by functional traits. In grasslands, the temporal strengthening of biodiversity effects on community productivity was associated with increasing biomass overyielding of resource-conservative species increasing over time, and with overyielding of species characterized by fast resource acquisition either decreasing or increasing. In forests, temporal trends in species overyielding differ when considering above- versus belowground resource acquisition strategies. Overyielding in stem growth decreased for species with high light capture capacity but increased for those with high soil resource acquisition capacity. Our results imply that a diversity of species with different, and potentially complementary, ecological strategies is beneficial for maintaining community productivity over time in both grassland and forest ecosystems.

Efficacy of Electronic Cigarettes vs Varenicline and Nicotine Chewing Gum as an Aid to Stop Smoking: A Randomized Clinical Trial

Importance

Electronic cigarettes (ECs) are often used by smokers as an aid to stopping smoking, but evidence is limited regarding their efficacy compared with nicotine replacement therapy (NRT), and no evidence is available on how their efficacy compares with that of varenicline.

Objective

To evaluate whether ECs are superior to NRT and noninferior to varenicline in helping smokers quit.

Design, Setting, and Participants

This was a randomized clinical trial conducted at 7 sites in China and including participants who were smoking at least 10 cigarettes per day and motivated to quit, not using stop-smoking medications or EC, and willing to use any of the study products. Participants were first recruited in May 2021, and data analysis was conducted in December 2022.

Interventions

A cartridge-based EC (30 mg/mL nicotine salt for 2 weeks and 50 mg/mL after that), varenicline (0.5 mg, once a day for 3 days; 0.5 mg, twice a day for 4 days; and 1 mg, twice a day, after that), and 2 mg (for smokers of ≤20 cigarettes per day) or 4 mg (>20 cigarettes per day) nicotine chewing gum, all provided for 12 weeks and accompanied by minimal behavioral support (an invitation to join a self-help internet forum).

Main Outcomes and Measures

The primary outcome was sustained abstinence from smoking at 6 months as validated by an expired-air carbon monoxide reading (<8 parts per million). Participants lost to follow-up were included as nonabstainers.

Results

Of 1068 participants, 357 (33.5%) were female, and the mean (SD) age was 33.9 (3.1) years. A total of 409 (38.3%), 409 (38.3%), and 250 (23.4%) participants were randomized to the EC, varenicline, and NRT arms, respectively. The 6-month biochemically validated abstinence rates were 15.7% (n = 64), 14.2% (n = 58), and 8.8% (n = 22) in the EC, varenicline, and NRT study arms, respectively. The quit rate in the EC arm was noninferior to the varenicline arm (absolute risk reduction, 1.47%; 95% CI, -1.41% to 4.34%) and higher than in the NRT arm (odds ratio, 1.92; 95% CI, 1.15-3.21). Treatment adherence was similar in all study arms during the initial 3 months, but 257 participants (62.8%) in the EC arm were still using ECs at 6 months, with no further use in the 2 other study arms. The most common adverse reactions were throat irritation (32 [7.8%]) and mouth irritation (28 [6.9%]) in the EC arm, nausea (36 [8.8%]) in the varenicline arm, and throat irritation (20 [8.0%]) and mouth irritation (22 [8.8%]) in the NRT arm. No serious adverse events were recorded.

Conclusions and Relevance

The results of this randomized clinical trial found that when all treatments were provided with minimal behavior support, the efficacy of EC was noninferior to varenicline and superior to nicotine chewing gum.

Trial Registration

Chinese Clinical Trial Registry: ChiCTR2100048156.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol by heating an e-liquid. People who smoke, healthcare providers and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review.

OBJECTIVES

To examine the safety, tolerability and effectiveness of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence, in comparison to non-nicotine EC, other smoking cessation treatments and no treatment.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register to 1 February 2023, and Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 July 2023, and reference-checked and contacted study authors.

SELECTION CRITERIA

We included trials in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention as these studies have the potential to provide further information on harms and longer-term use. Studies had to report an eligible outcome.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Critical outcomes were abstinence from smoking after at least six months, adverse events (AEs), and serious adverse events (SAEs). We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in pairwise and network meta-analyses (NMA).

MAIN RESULTS

We included 88 completed studies (10 new to this update), representing 27,235 participants, of which 47 were randomized controlled trials (RCTs). Of the included studies, we rated ten (all but one contributing to our main comparisons) at low risk of bias overall, 58 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. There is high certainty that nicotine EC increases quit rates compared to nicotine replacement therapy (NRT) (RR 1.59, 95% CI 1.29 to 1.93; I2 = 0%; 7 studies, 2544 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6 more). There is moderate-certainty evidence (limited by imprecision) that the rate of occurrence of AEs is similar between groups (RR 1.03, 95% CI 0.91 to 1.17; I2 = 0%; 5 studies, 2052 participants). SAEs were rare, and there is insufficient evidence to determine whether rates differ between groups due to very serious imprecision (RR 1.20, 95% CI 0.90 to 1.60; I2 = 32%; 6 studies, 2761 participants; low-certainty evidence). There is moderate-certainty evidence, limited by imprecision, that nicotine EC increases quit rates compared to non-nicotine EC (RR 1.46, 95% CI 1.09 to 1.96; I2 = 4%; 6 studies, 1613 participants). In absolute terms, this might lead to an additional three quitters per 100 (95% CI 1 to 7 more). There is moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 5 studies, 1840 participants). There is insufficient evidence to determine whether rates of SAEs differ between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I2 = 0%; 9 studies, 1412 participants; low-certainty evidence). Due to issues with risk of bias, there is low-certainty evidence that, compared to behavioural support only/no support, quit rates may be higher for participants randomized to nicotine EC (RR 1.88, 95% CI 1.56 to 2.25; I2 = 0%; 9 studies, 5024 participants). In absolute terms, this represents an additional four quitters per 100 (95% CI 2 to 5 more). There was some evidence that (non-serious) AEs may be more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low-certainty evidence; 4 studies, 765 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 0.89, 95% CI 0.59 to 1.34; I2 = 23%; 10 studies, 3263 participants; very low-certainty evidence). Results from the NMA were consistent with those from pairwise meta-analyses for all critical outcomes, and there was no indication of inconsistency within the networks. Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons, hence, evidence for these is limited, with CIs often encompassing both clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain due to risk of bias inherent in the study design. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non-nicotine ECs nor between nicotine ECs and NRT. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but the longest follow-up was two years and the number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this review is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Effects of reduced-risk nicotine-delivery products on smoking prevalence and cigarette sales: an observational study

Background

It is not currently clear what impact alternative nicotine-delivery products (electronic cigarettes, heated tobacco products and snus) have on smoking rates and cigarette sales.

Objective

To assess whether access to these products promotes smoking in the population.

Design and data sources

We examined associations of alternative nicotine product use and sales with smoking rates and cigarette sales overall, and in different age and socioeconomic groups, and compared smoking prevalence over time in countries with contrasting regulations of these products. For electronic cigarettes, we examined data from countries with historically similar smoking trajectories but differing current electronic cigarette regulations (United Kingdom and United States of America vs. Australia, where sales of nicotine-containing electronic cigarettes are banned); for heated tobacco, we used data from countries with state tobacco monopolies, where cigarette and heated tobacco sales data are available (Japan, South Korea), and for snus we used data from Sweden.

Analysis methods

We pre-specified dynamic time series analyses to explore associations between use and sales of alternative nicotine-delivery products and smoking prevalence and cigarette sales, and time series analyses to compare trends of smoking prevalence in countries with different nicotine product policies.

Results

Because of data and analysis limitations (see below), results are only tentative and need to be interpreted with caution. Only a few findings reached statistical significance and for most results the Bayes factor indicated inconclusive evidence. We did not find an association between rates of smoking and rates of the use of alternative nicotine products. The increase in heated tobacco product sales in Japan was accompanied by a decrease in cigarette sales. The decline in smoking prevalence seems to have been slower in Australia than in the United Kingdom overall, and slower than in both the United Kingdom and the United States of America among young people and also in lower socioeconomic groups. The decline in cigarette sales has also accelerated faster in the United Kingdom than in Australia.

Limitations

Most of the available data had insufficient data points for robust time series analyses. The assumption of our statistical approach that causal interactions are more likely to be detected when longer-term changes are screened out may not apply for short time series and in product interaction scenarios, where short-term fluctuations can be caused by, for example, fluctuations in prosperity or product supplies. In addition, due to dual use, prevalence figures for smoking and alternative product use overlap. The ecological study design limits the causal inferences that can be made. Longer time periods are needed for any effects of exclusive use of the new products on smoking prevalence to emerge.

Conclusions

We detected some indications that alternative nicotine products are competing with cigarettes rather than promoting smoking and that regulations that allow their sales are associated with a reduction rather than an increase of smoking, but the findings are inconclusive because of insufficient data points and issues with the assumptions of the pre-specified statistical analyses.

Future work

As further prevalence and sales data emerge the analyses will become more informative. Accessing sales figures in particular is the current research priority.

Study registration

The project is registered on Open Science Framework https://osf.io/bd3ah.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme (NIHR129968) and will be published in full in Public Health Research; Vol. 11, No. 7. See the NIHR Journals Library website for further project information.

Helping pregnant smokers quit: a multi-centre randomised controlled trial of electronic cigarettes versus nicotine replacement therapy

Background

Some pregnant smokers try e-cigarettes, but effectiveness and safety of such use are unknown.

Objectives

To compare effectiveness and safety of nicotine patches and e-cigarettes in pregnancy.

Design

A pragmatic multi-centre randomised controlled trial.

Setting

Twenty-three hospitals across England, and a Stop Smoking Service in Scotland.

Participants

One thousand one hundred and forty pregnant daily smokers (12-24 weeks' gestation) motivated to stop smoking, with no strong preference for using nicotine patches or e-cigarettes.

Interventions

Participants in the e-cigarette arm were posted a refillable e-cigarette device with two 10 ml bottles of tobacco-flavoured e-liquid (18 mg nicotine). Participants in the nicotine patches arm were posted a 2-week supply of 15 mg/16-hour nicotine patches. Supplies were provided for up to 8 weeks. Participants sourced further supplies themselves as needed. Participants in both arms received support calls prior to their target quit date, on the quit date, and weekly for the next 4 weeks.

Outcome measures

The primary outcome was validated prolonged abstinence at the end of pregnancy. Participants lost to follow-up or not providing biochemical validation were included as non-abstainers. Secondary outcomes included self-reported abstinence at different time points, treatment adherence and safety outcomes.

Results

Only 55% of self-reported abstainers mailed back useable saliva samples. Due to this, validated sustained abstinence rates were low (6.8% vs. 4.4% in the e-cigarettes and nicotine patches arms, respectively, risk ratio = 1.55, 95% confidence interval 0.95 to 2.53; Bayes factor = 2.7). In a pre-specified sensitivity analysis that excluded abstainers using non-allocated products, the difference became significant (6.8% vs. 3.6%, risk ratio = 1.93, 95% confidence interval 1.14 to 3.26; Bayes factor = 10). Almost a third of the sample did not set a target quit date and the uptake of support calls was low, as was the initial product use. At end of pregnancy, 33.8% versus 5.6% of participants were using their allocated product in the e-cigarettes versus nicotine patches arm (risk ratio = 6.01, 95% confidence interval 4.21 to 8.58). Regular use of e-cigarettes in the nicotine patches arm was more common than use of nicotine replacement products in the e-cigarette arm (17.8% vs. 2.8%). Rates of adverse events and adverse birth outcomes were similar in the two study arms, apart from participants in the e-cigarette arm having fewer infants with low birthweight (<2500 g) (9.6% vs. 14.8%, risk ratio = 0.65, 95% confidence interval 0.47 to 0.90; Bayes factor = 10.3).

Limitations

Low rates of validation reduced the study power. A substantial proportion of participants did not use the support on offer sufficiently to test its benefits. Sample size may have been too small to detect differences in less frequent adverse effects.

Conclusions

E-cigarettes were not significantly more effective than nicotine patches in the primary analysis, but when e-cigarettes use in the nicotine patches arm was accounted for, e-cigarettes were almost twice as effective as patches in all abstinence outcomes. In pregnant smokers seeking help, compared to nicotine patches, e-cigarettes are probably more effective, do not pose more risks to birth outcomes assessed in this study and may reduce the incidence of low birthweight.

Future work

Routine monitoring of smoking cessation and birth outcomes in pregnant women using nicotine patches and e-cigarettes and further studies are needed to confirm these results.

Trial registration

This trial is registered as ISRCTN62025374 and Eudract 2017-001237-65.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 27, No. 13. See the NIHR Journals Library website for further project information.

Biomarkers of potential harm in people switching from smoking tobacco to exclusive e-cigarette use, dual use or abstinence: secondary analysis of Cochrane systematic review of trials of e-cigarettes for smoking cessation

AIMS

This study aims to compare biomarkers of potential harm between people switching from smoking combustible cigarettes (CC) completely to electronic cigarettes (EC), continuing to smoke CC, using both EC and CC (dual users) and using neither (abstainers), based on behaviour during EC intervention studies.

DESIGN

Secondary analysis following systematic review, incorporating inverse variance random-effects meta-analysis and effect direction plots.

SETTING

This study was conducted in Greece, Italy, Poland, the United Kingdom and the United States.

PARTICIPANTS

A total of 1299 adults smoking CC (nine studies) and provided EC.

MEASUREMENTS

Measurements were conducted using carbon monoxide (CO) and 26 other biomarkers.

FINDINGS

In pooled analyses, exhaled CO (eCO) was lower in EC versus EC + CC [mean difference (MD) = -4.40 parts per million (p.p.m.), 95% confidence interval (CI) = -12.04 to 3.24, two studies] and CC (MD = -9.57 p.p.m., 95% CI = -17.30 to -1.83, three studies). eCO was lower in dual users versus CC only (MD = -1.91 p.p.m., 95% CI = -3.38 to -0.45, two studies). Magnitude rather than direction of effect drove substantial statistical heterogeneity. Effect direction plots were used for other biomarkers. Comparing EC with CC, 12 of 13 biomarkers were significantly lower in EC users, with no difference for the 13th. Comparing EC with dual users, 12 of the 25 biomarkers were lower for EC, and five were lower for dual use. For the remaining eight measures, single studies did not detect statistically significant differences, or the multiple studies contributing to the outcome had inconsistent results. Only one study provided data comparing dual use with CC; of the 13 biomarkers measured, 12 were significantly lower in the dual use group, with no statistically significant difference detected for the 13th. Only one study provided data on abstainers.

CONCLUSIONS

Switching from smoking to vaping or dual use appears to reduce levels of biomarkers of potential harm significantly.

Summer temperatures reach the thermal tolerance threshold of photosynthetic decline in temperate conifers

Climate change-related environmental stress has been recognized as a driving force in accelerating forest mortality over the last decades in Central Europe. Here, we aim to elucidate the thermal sensitivity of three native conifer species, namely Norway spruce (Picea abies), Scots pine (Pinus sylvestris) and silver fir (Abies alba), and three non-native species, namely Austrian pine (Pinus nigra), Douglas fir (Pseudotsuga menziesii) and Atlas cedar (Cedrus atlantica). Thermal sensitivity, defined here as a decline of the maximum quantum yield of photosystem II (F_v /F_m ) with increasing temperature, was measured under varying levels of heat stress and compared with the turgor loss point (π_tlp ) as a drought resistance trait. We calculated three different leaf thermotolerance traits: the temperature at the onset (5%) of the F_v /F_m decline (T5), the temperature at which F_v /F_m was half the maximum value (T50) and the temperature at which only 5% F_v /F_m remained (T95). T5 ranged from 38.5 ± 0.8 °C to 43.1 ± 0.6 °C across all species, while T50 values were at least 9 to 11 degrees above the maximum air temperatures on record for all species. Only Austrian pine had a notably higher T5 value than recorded maximum air temperatures. Species with higher T5 values were characterized by a less negative π_tlp compared to species with lower T5. The six species could be divided into 'drought-tolerant heat-sensitive' and 'drought-sensitive heat-tolerant' groups. Exposure to short-term high temperatures thus exhibits a considerable threat to conifer species in Central European forest production systems.

Longer-term use of electronic cigarettes when provided as a stop smoking aid: Systematic review with meta-analyses

Moderate certainty evidence supports use of nicotine electronic cigarettes to quit smoking combustible cigarettes. However, there is less certainty regarding how long people continue to use e-cigarettes after smoking cessation attempts. We set out to synthesise data on the proportion of people still using e-cigarettes or other study products at 6 months or longer in studies of e-cigarettes for smoking cessation. We updated Cochrane searches (November 2021). For the first time, we meta-analysed prevalence of continued e-cigarette use among individuals allocated to e-cigarette conditions, and among those individuals who had successfully quit smoking. We updated meta-analyses comparing proportions continuing product use among individuals allocated to use nicotine e-cigarettes and other treatments. We included 19 studies (n = 7787). The pooled prevalence of continued e-cigarette use at 6 months or longer was 54% (95% CI: 46% to 61%, I2 86%, N = 1482) in participants assigned to e-cigarette conditions. Of participants who had quit combustible cigarettes overall 70% were still using e-cigarettes at six months or longer (95% CI: 53% to 82%, I2 73%, N = 215). Heterogeneity in direction of effect precluded meta-analysis comparing long-term use of nicotine e-cigarettes with NRT. More people were using nicotine e-cigarettes at longest follow-up compared to non-nicotine e-cigarettes, but CIs included no difference (risk ratio 1.15, 95% CI: 0.94 to 1.41, n = 601). The levels of continued e-cigarette use observed may reflect the success of e-cigarettes as a quitting tool. Further research is needed to establish drivers of variation in and implications of continued use of e-cigarettes.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol by heating an e-liquid. Some people who smoke use ECs to stop or reduce smoking, although some organizations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review.

OBJECTIVES

To examine the effectiveness, tolerability, and safety of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 July 2022, and reference-checked and contacted study authors.  SELECTION CRITERIA: We included randomized controlled trials (RCTs) and randomized cross-over trials, in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. Studies had to report abstinence from cigarettes at six months or longer or data on safety markers at one week or longer, or both.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow-up, adverse events (AEs), and serious adverse events (SAEs). Secondary outcomes included the proportion of people still using study product (EC or pharmacotherapy) at six or more months after randomization or starting EC use, changes in carbon monoxide (CO), blood pressure (BP), heart rate, arterial oxygen saturation, lung function, and levels of carcinogens or toxicants, or both. We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in meta-analyses.

MAIN RESULTS

We included 78 completed studies, representing 22,052 participants, of which 40 were RCTs. Seventeen of the 78 included studies were new to this review update. Of the included studies, we rated ten (all but one contributing to our main comparisons) at low risk of bias overall, 50 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. There was high certainty that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (RR 1.63, 95% CI 1.30 to 2.04; I2 = 10%; 6 studies, 2378 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6). There was moderate-certainty evidence (limited by imprecision) that the rate of occurrence of AEs was similar between groups (RR 1.02, 95% CI 0.88 to 1.19; I2 = 0%; 4 studies, 1702 participants). SAEs were rare, but there was insufficient evidence to determine whether rates differed between groups due to very serious imprecision (RR 1.12, 95% CI 0.82 to 1.52; I2 = 34%; 5 studies, 2411 participants). There was moderate-certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non-nicotine EC (RR 1.94, 95% CI 1.21 to 3.13; I2 = 0%; 5 studies, 1447 participants). In absolute terms, this might lead to an additional seven quitters per 100 (95% CI 2 to 16). There was moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 5 studies, 1840 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I2 = 0%; 8 studies, 1272 participants). Compared to behavioural support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.66, 95% CI 1.52 to 4.65; I2 = 0%; 7 studies, 3126 participants). In absolute terms, this represents an additional two quitters per 100 (95% CI 1 to 3). However, this finding was of very low certainty, due to issues with imprecision and risk of bias. There was some evidence that (non-serious) AEs were more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low certainty; 4 studies, 765 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 1.03, 95% CI 0.54 to 1.97; I2 = 38%; 9 studies, 1993 participants).  Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons, hence evidence for these is limited, with CIs often encompassing clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the effect size. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non-nicotine ECs nor between nicotine ECs and NRT. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but longest follow-up was two years and the number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates, but further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this review is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Evaluating the effectiveness of e-cigarettes compared with usual care for smoking cessation when offered to smokers at homeless centres: protocol for a multi-centre cluster-randomized controlled trial in Great Britain

BACKGROUND AND AIMS

Smoking is extremely common among adults experiencing homelessness, but there is lack of evidence for treatment efficacy. E-cigarettes are an effective quitting aid, but they have not been widely tested in smokers with complex health and social needs. Here we build upon our cluster feasibility trial and evaluate the offer of an e-cigarette or usual care to smokers accessing a homeless centre.

DESIGN, SETTING AND PARTICIPANTS

Multi-centre two-arm cluster-randomized controlled trial with mixed-method embedded process and economic evaluation in homeless centres in England, Scotland and Wales. Adult smokers (18+ years; n = 480) accessing homeless centres and who are known to centre staff and willing to consent.

INTERVENTION AND COMPARATOR

Clusters (n = 32) will be randomized to either an e-cigarette starter pack with weekly allocations of nicotine containing e-liquid for 4 weeks [choice of flavours (menthol, fruit and tobacco) and strengths 12 mg/ml and 18 mg/ml] or the usual care intervention, which comprises very brief advice and a leaflet signposting to the local stop smoking service.

MEASUREMENTS

The primary outcome is 24-week sustained carbon monoxide-validated smoking cessation (Russell Standard defined, intention-to-treat analysis).

SECONDARY OUTCOMES

(i) 50% smoking reduction (cigarettes per day) from baseline to 24 weeks; (ii) 7-day point prevalence quit rates at 4-, 12- and 24-week follow-up; (iii) changes in risky smoking practices (e.g. sharing cigarettes, smoking discarded cigarettes) from baseline to 4, 12 and 24 weeks; (iv) cost-effectiveness of the intervention; and (v) fidelity of intervention implementation; mechanisms of change; contextual influences and sustainability.

CONCLUSIONS

This is the first study, to our knowledge, to randomly assign smokers experiencing homelessness to an e-cigarette and usual care intervention to measure smoking abstinence with embedded process and economic evaluations. If effective, its results will be used to inform the larger-scale implementation of offering e-cigarettes throughout homeless centres to aid smoking cessation.

Mutually inclusive mechanisms of drought-induced tree mortality

Unprecedented tree dieback across Central Europe caused by recent global change-type drought events highlights the need for a better mechanistic understanding of drought-induced tree mortality. Although numerous physiological risk factors have been identified, the importance of two principal mechanisms, hydraulic failure and carbon starvation, is still debated. It further remains largely unresolved how the local neighborhood composition affects individual mortality risk. We studied 9435 young trees of 12 temperate species planted in a diversity experiment in 2013 to assess how hydraulic traits, carbon dynamics, pest infestation, tree height and neighborhood competition influence individual mortality risk. Following the most extreme global change-type drought since record in 2018, one third of these trees died. Across species, hydraulic safety margins (HSMs) were negatively and a shift towards a higher sugar fraction in the non-structural carbohydrate (NSC) pool positively associated with mortality risk. Moreover, trees infested by bark beetles had a higher mortality risk, and taller trees a lower mortality risk. Most neighborhood interactions were beneficial, although neighborhood effects were highly species-specific. Species that suffered more from drought, especially Larix spp. and Betula spp., tended to increase the survival probability of their neighbors and vice versa. While severe tissue dehydration marks the final stage of drought-induced tree mortality, we show that hydraulic failure is interrelated with a series of other, mutually inclusive processes. These include shifts in NSC pools driven by osmotic adjustment and/or starch depletion as well as pest infestation and are modulated by the size and species identity of a tree and its neighbors. A more holistic view that accounts for multiple causes of drought-induced tree mortality is required to improve predictions of trends in global forest dynamics and to identify mutually beneficial species combinations.

Electronic cigarettes versus nicotine patches for smoking cessation in pregnancy: a randomized controlled trial

Nicotine replacement therapy, in the form of nicotine patches, is commonly offered to pregnant women who smoke to help them to stop smoking, but this approach has limited efficacy in this population. Electronic cigarettes (e-cigarettes) are also used by pregnant women who smoke but their safety and efficacy in pregnancy are unknown. Here, we report the results of a randomized controlled trial in 1,140 participants comparing refillable e-cigarettes with nicotine patches. Pregnant women who smoked were randomized to e-cigarettes (n = 569) or nicotine patches (n = 571). In the unadjusted analysis of the primary outcome, validated prolonged quit rates at the end of pregnancy in the two study arms were not significantly different (6.8% versus 4.4% in the e-cigarette and patch arms, respectively; relative risk (RR) = 1.55, 95%CI: 0.95-2.53, P = 0.08). However, some participants in the nicotine patch group also used e-cigarettes during the study. In a pre-specified sensitivity analysis excluding abstinent participants who used non-allocated products, e-cigarettes were more effective than patches (6.8% versus 3.6%; RR = 1.93, 95%CI: 1.14-3.26, P = 0.02). Safety outcomes included adverse events and maternal and birth outcomes. The safety profile was found to be similar for both study products, however, low birthweight (<2,500 g) was less frequent in the e-cigarette arm (14.8% versus 9.6%; RR = 0.65, 95%CI: 0.47-0.90, P = 0.01). Other adverse events and birth outcomes were similar in the two study arms. E-cigarettes might help women who are pregnant to stop smoking, and their safety for use in pregnancy is similar to that of nicotine patches. ISRCTN62025374.

Mutually inclusive mechanisms of drought-induced tree mortality

Unprecedented tree dieback across Central Europe caused by recent global change-type drought events highlights the need for a better mechanistic understanding of drought-induced tree mortality. Although numerous physiological risk factors have been identified, the importance of two principal mechanisms, hydraulic failure and carbon starvation, is still debated. It further remains largely unresolved how the local neighborhood composition affects individual mortality risk. We studied 9435 young trees of 12 temperate species planted in a diversity experiment in 2013 to assess how hydraulic traits, carbon dynamics, pest infestation, tree height and neighborhood competition influence individual mortality risk. Following the most extreme global change-type drought since record in 2018, one third of these trees died. Across species, hydraulic safety margins (HSMs) were negatively and a shift towards a higher sugar fraction in the non-structural carbohydrate (NSC) pool positively associated with mortality risk. Moreover, trees infested by bark beetles had a higher mortality risk, and taller trees a lower mortality risk. Most neighborhood interactions were beneficial, although neighborhood effects were highly species-specific. Species that suffered more from drought, especially Larix spp. and Betula spp., tended to increase the survival probability of their neighbors and vice versa. While severe tissue dehydration marks the final stage of drought-induced tree mortality, we show that hydraulic failure is interrelated with a series of other, mutually inclusive processes. These include shifts in NSC pools driven by osmotic adjustment and/or starch depletion as well as pest infestation and are modulated by the size and species identity of a tree and its neighbors. A more holistic view that accounts for multiple causes of drought-induced tree mortality is required to improve predictions of trends in global forest dynamics and to identify mutually beneficial species combinations.

E-cigarettes versus nicotine replacement treatment as harm reduction interventions for smokers who find quitting difficult: randomized controlled trial

BACKGROUND AND AIMS

The majority of smokers accessing the current best treatments continue to smoke. We aimed to test if e-cigarettes (EC) compared with nicotine replacement treatment (NRT) can help such smokers to reduce smoking.

DESIGN

Randomized controlled trial of EC (n = 68) versus NRT (n = 67) with 6-month follow-up.

SETTING

Stop smoking service in London, UK.

PARTICIPANTS

A total of 135 smokers (median age = 40 years, 51% male) previously unable to stop smoking with conventional treatments.

INTERVENTIONS

Participants received either NRT of their choice (8-week supply) or an EC starter pack and instructions to purchase further e-liquids of strength and flavours of their choice themselves. Products were accompanied by minimal behavioural support.

MEASUREMENTS

Participants who reported that they stopped smoking or reduced their daily cigarette consumption by at least 50% at 6-month follow-up were invited to provide a carbon monoxide (CO) reading. The primary outcome was biochemically validated reduction in smoke intake of at least 50% at 6 months and the main secondary outcome was sustained validated abstinence at 6 months. Drop-outs were included as 'non-reducers'.

FINDINGS

Validated smoking reduction (including cessation) was achieved by 26.5 versus 6.0% of participants in the EC and NRT study arms, respectively [relative risk (RR) = 4.4, P = 0.005, 95% confidence interval (CI) = 1.6-12.4]. Sustained validated abstinence rates at 6 months were 19.1 versus 3.0% (RR = 6.4, P = 0.01, 95% CI = 1.5-27.3). Product use was high and equal in both study arms initially, but at 6 months allocated product use was 47% in the EC arm versus 10% in the NRT arm (χ2(1)  = 22.0, P < 0.001), respectively. Adverse events were minor and infrequent.

CONCLUSIONS

In smokers unable to quit using conventional methods, e-cigarettes were more effective than nicotine replacement therapy in facilitating validated long-term smoking reduction and smoking cessation when limited other support was provided.

The experience of tobacco withdrawal symptoms among current smokers and ex-smokers in the general population: Findings from nationwide China Health Literacy Survey during 2018-19

OBJECTIVE

To clarify the extent to which smokers in the general population experience tobacco withdrawal symptoms and whether such experience differs in those who continue to smoke and those who stopped smoking.

METHODS

We included relevant questions in the nationally-representative China Health Literacy Survey (CHLS) conducted in 2018-2019. Among 87,028 participants, there were 22,115 ever-smokers aged 20-69 years who provided information on their smoking history and their experience of tobacco withdrawal symptoms. Multivariate logistic regressions were conducted to explore the association between withdrawal symptoms and other variables.

RESULTS

Among ever-smokers, there were 19,643 (88.8%) current smokers and 2,472 (11.2%) ex-smokers. Among current smokers, 61.3% reported having tried to quit smoking in the past. Overall, 61.1% of current smokers reported experiencing withdrawal symptoms: 69.9% of those who tried to quit smoking in the past and 47.5% of those who did not. A lower proportion of ex-smokers experienced withdrawal symptoms (46.3%) and the difference remained significant after controlling for demographic characteristics (OR = 1.76, 95% CI 1.62-1.93, P < 0.001). The most commonly reported withdrawal symptoms in both current smokers and ex-smokers were craving, restlessness and anxiety. In the multivariable-adjusted analyses, those who experienced withdrawal symptoms when they tried to quit smoking (OR: 2.05, 95% CI: 1.86-2.27) were less likely to successfully quit.

CONCLUSIONS

The clinical picture of the tobacco withdrawal syndrome is the same in current smokers and in ex-smokers, but ex-smokers are less likely to have experienced it. The experience of discomfort when unable to smoke is common and seems likely to be a major factor contributing to maintaining smoking behavior not just among individuals seeking help with quitting smoking, but among smokers generally.

A randomised controlled trial of the 5:2 diet

Objective

The 5:2 diet is a popular intermittent energy restriction method of weight management that awaits further evaluation. We compared the effects of one-off 5:2 instructions with the effects of one-off standard multicomponent weight-management advice; and also examined whether additional behavioural support enhances 5:2 adherence and efficacy compared to one-off instructions.

Methods

Three hundred adults with obesity were randomised to receive a Standard Brief Advice (SBA) covering diet and physical activity (N = 100); 5:2 self-help instructions (5:2SH) (N = 100); or 5:2SH plus six once-weekly group support sessions (N = 100). Participants were followed up for one year.

Results

Adherence to 5:2SH was initially high (74% at 6 weeks), but it declined over time (31% at 6 months and 22% at one year). 5:2SH and SBA achieved similar weight-loss at six months (-1.8kg (SD = 3.5) vs -1.7kg (SD = 4.4); b = 0.23, 95%CI:-0.79–1.27, p = 0.7) and at one year (-1.9kg (SD = 4.9) vs -1.8kg (SD = 5.7), b = 0.20, 95%CI:-1.21–1.60, p = 0.79), with 18% vs 15% participants losing ≥5% of their body weight with 5:2SH and SBA, respectively at one year (RR = 0.83, 95%CI:0.44–1.54, p = 0.55). Both interventions received positive ratings, but 5:2SH ratings were significantly higher. 5:2SH had no negative effect on fat and fiber intake and physical activity compared to SBA. Compared to 5:2SH, 5:2G generated a greater weight loss at 6 weeks (-2.3kg vs -1.5kg; b = 0.74, 95%CI:1.37–0.11, p = 0.02), but by one year, the difference was no longer significant (-2.6kg vs -1.9kg, p = 0.37; ≥5% body weight loss 28% vs 18%, p = 0.10).

Conclusions

Simple 5:2 advice and multicomponent weight management advice generated similar modest results. The 5:2 diet did not undermine other health behaviours, and it received more favourable ratings. Adding initial group support enhanced 5:2 adherence and effects, but the impact diminished over time. Health professionals who provide brief weight management advice may consider including the 5:2 advice as an option.

Trial registration

ISRCTN registry (ISRCTN79408248).

Discovery and optimization of cyclohexane-1,4-diamines as allosteric MALT1 inhibitors

Inhibition of mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1) is a promising strategy to modulate NF-κB signaling, with the potential to treat B-cell lymphoma and autoimmune diseases. We describe the discovery and optimization of (1s,4s)-N,N'-diaryl cyclohexane-1,4-diamines, a novel series of allosteric MALT1 inhibitors, resulting in compound 8 with single digit micromolar cell potency. X-ray analysis confirms that this compound binds to an induced allosteric site in MALT1. Compound 8 is highly selective and has an excellent in vivo rat PK profile with low clearance and high oral bioavailability, making it a promising lead for further optimization.

Nicotine Delivery and User Ratings of IQOS Heated Tobacco System Compared With Cigarettes, Juul, and Refillable E-Cigarettes

INTRODUCTION

Reduced-risk nicotine products are more likely to replace smoking if they match cigarettes in nicotine delivery and user satisfaction.

AIMS AND METHODS

We examined the nicotine delivery profile and user ratings of IQOS heated tobacco system and compared it with own brand cigarettes (OBC), Juul, and refillable e-cigarettes (EC).Participants (N = 22) who were daily vapers smoking <1 cigarette per day on average, attended after overnight abstinence from smoking and vaping, to test at separate sessions OBC, IQOS, and Juul. Eight participants also tested two refillable EC using e-liquid with 20 mg/mL nicotine. At each session, a baseline blood sample was taken before participants used the product ad libitum for 5 minutes. Further samples were taken at 2, 4, 6, 8, 10, and 30 minutes. Maximum nicotine concentration (Cmax), time to Cmax (Tmax), and nicotine delivered over 30 minutes (AUC0->30) were calculated. Participants rated their urge to smoke and product characteristics.

RESULTS

IQOS delivered less nicotine than OBC (AUC0->30: z = -2.73, p = .006), and than Juul (AUC0->30: z = -3.08, p = .002; Cmax: z = -2.65, p = .008), and received less favorable ratings than Juul (effect on urges to smoke: z = -3.23, p = .001; speed of urge relief: z = -2.75, p = .006; recommendation to friends: z = -2.45, p = .014). Compared with refillable EC, IQOS delivered nicotine faster (Tmax: z = -2.37, p = .018), but received less favorable overall ratings (recommended to friends: z = -2.32, p = .021).

CONCLUSIONS

IQOS' pharmacokinetic profile suggests that it may be less effective than Juul for smoking cessation, but at least as effective as refillable EC; although participants, who were experienced vapers rather than IQOS users, preferred refillable EC.

IMPLICATIONS

Because IQOS provided less efficient nicotine delivery than cigarettes and Juul in this sample, and also had a weaker effect on urges to smoke than Juul, it could be less helpful than Juul in assisting such dual users, and possibly smokers generally, to switch to an alternative product. IQOS, however, provided nicotine faster than refillable EC products, although participants preferred EC.

Interventions for preventing weight gain after smoking cessation

BACKGROUND

Most people who stop smoking gain weight. This can discourage some people from making a quit attempt and risks offsetting some, but not all, of the health advantages of quitting. Interventions to prevent weight gain could improve health outcomes, but there is a concern that they may undermine quitting.

OBJECTIVES

To systematically review the effects of: (1) interventions targeting post-cessation weight gain on weight change and smoking cessation (referred to as 'Part 1') and (2) interventions designed to aid smoking cessation that plausibly affect post-cessation weight gain (referred to as 'Part 2').

SEARCH METHODS

Part 1 - We searched the Cochrane Tobacco Addiction Group's Specialized Register and CENTRAL; latest search 16 October 2020. Part 2 - We searched included studies in the following 'parent' Cochrane reviews: nicotine replacement therapy (NRT), antidepressants, nicotine receptor partial agonists, e-cigarettes, and exercise interventions for smoking cessation published in Issue 10, 2020 of the Cochrane Library. We updated register searches for the review of nicotine receptor partial agonists.

SELECTION CRITERIA

Part 1 - trials of interventions that targeted post-cessation weight gain and had measured weight at any follow-up point or smoking cessation, or both, six or more months after quit day. Part 2 - trials included in the selected parent Cochrane reviews reporting weight change at any time point.

DATA COLLECTION AND ANALYSIS

Screening and data extraction followed standard Cochrane methods. Change in weight was expressed as difference in weight change from baseline to follow-up between trial arms and was reported only in people abstinent from smoking. Abstinence from smoking was expressed as a risk ratio (RR). Where appropriate, we performed meta-analysis using the inverse variance method for weight, and Mantel-Haenszel method for smoking.

MAIN RESULTS

Part 1: We include 37 completed studies; 21 are new to this update. We judged five studies to be at low risk of bias, 17 to be at unclear risk and the remainder at high risk.  An intermittent very low calorie diet (VLCD) comprising full meal replacement provided free of charge and accompanied by intensive dietitian support significantly reduced weight gain at end of treatment compared with education on how to avoid weight gain (mean difference (MD) -3.70 kg, 95% confidence interval (CI) -4.82 to -2.58; 1 study, 121 participants), but there was no evidence of benefit at 12 months (MD -1.30 kg, 95% CI -3.49 to 0.89; 1 study, 62 participants). The VLCD increased the chances of abstinence at 12 months (RR 1.73, 95% CI 1.10 to 2.73; 1 study, 287 participants). However, a second study  found that no-one completed the VLCD intervention or achieved abstinence. Interventions aimed at increasing acceptance of weight gain reported mixed effects at end of treatment, 6 months and 12 months with confidence intervals including both increases and decreases in weight gain compared with no advice or health education. Due to high heterogeneity, we did not combine the data. These interventions increased quit rates at 6 months (RR 1.42, 95% CI 1.03 to 1.96; 4 studies, 619 participants; I² = 21%), but there was no evidence at 12 months (RR 1.25, 95% CI 0.76 to 2.06; 2 studies, 496 participants; I² = 26%). Some pharmacological interventions tested for limiting post-cessation weight gain (PCWG) reduced weight gain at the end of treatment (dexfenfluramine, phenylpropanolamine, naltrexone). The effects of ephedrine and caffeine combined, lorcaserin, and chromium were too imprecise to give useful estimates of treatment effects. There was very low-certainty evidence that personalized weight management support reduced weight gain at end of treatment (MD -1.11 kg, 95% CI -1.93 to -0.29; 3 studies, 121 participants; I² = 0%), but no evidence in the longer-term 12 months (MD -0.44 kg, 95% CI -2.34 to 1.46; 4 studies, 530 participants; I² = 41%). There was low to very low-certainty evidence that detailed weight management education without personalized assessment, planning and feedback did not reduce weight gain and may have reduced smoking cessation rates (12 months: MD -0.21 kg, 95% CI -2.28 to 1.86; 2 studies, 61 participants; I² = 0%; RR for smoking cessation 0.66, 95% CI 0.48 to 0.90; 2 studies, 522 participants; I² = 0%). Part 2: We include 83 completed studies, 27 of which are new to this update. There was low certainty that exercise interventions led to minimal or no weight reduction compared with standard care at end of treatment (MD -0.25 kg, 95% CI -0.78 to 0.29; 4 studies, 404 participants; I² = 0%). However, weight was reduced at 12 months (MD -2.07 kg, 95% CI -3.78 to -0.36; 3 studies, 182 participants; I² = 0%). Both bupropion and fluoxetine limited weight gain at end of treatment (bupropion MD -1.01 kg, 95% CI -1.35 to -0.67; 10 studies, 1098 participants; I² = 3%); (fluoxetine MD -1.01 kg, 95% CI -1.49 to -0.53; 2 studies, 144 participants; I² = 38%; low- and very low-certainty evidence, respectively). There was no evidence of benefit at 12 months for bupropion, but estimates were imprecise (bupropion MD -0.26 kg, 95% CI -1.31 to 0.78; 7 studies, 471 participants; I² = 0%). No studies of fluoxetine provided data at 12 months. There was moderate-certainty that NRT reduced weight at end of treatment (MD -0.52 kg, 95% CI -0.99 to -0.05; 21 studies, 2784 participants; I² = 81%) and moderate-certainty that the effect may be similar at 12 months (MD -0.37 kg, 95% CI -0.86 to 0.11; 17 studies, 1463 participants; I² = 0%), although the estimates are too imprecise to assess long-term benefit. There was mixed evidence of the effect of varenicline on weight, with high-certainty evidence that weight change was very modestly lower at the end of treatment (MD -0.23 kg, 95% CI -0.53 to 0.06; 14 studies, 2566 participants; I² = 32%); a low-certainty estimate gave an imprecise estimate of higher weight at 12 months (MD 1.05 kg, 95% CI -0.58 to 2.69; 3 studies, 237 participants; I² = 0%).

AUTHORS' CONCLUSIONS

Overall, there is no intervention for which there is moderate certainty of a clinically useful effect on long-term weight gain. There is also no moderate- or high-certainty evidence that interventions designed to limit weight gain reduce the chances of people achieving abstinence from smoking.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol formed by heating an e-liquid. Some people who smoke use ECs to stop or reduce smoking, but some organizations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit and if they are safe to use for this purpose. This is an update conducted as part of a living systematic review.

OBJECTIVES

To examine the effectiveness, tolerability, and safety of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 May 2021, and reference-checked and contacted study authors. We screened abstracts from the Society for Research on Nicotine and Tobacco (SRNT) 2021 Annual Meeting.   SELECTION CRITERIA: We included randomized controlled trials (RCTs) and randomized cross-over trials, in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. Studies had to report abstinence from cigarettes at six months or longer or data on safety markers at one week or longer, or both.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow-up, adverse events (AEs), and serious adverse events (SAEs). Secondary outcomes included the proportion of people still using study product (EC or pharmacotherapy) at six or more months after randomization or starting EC use, changes in carbon monoxide (CO), blood pressure (BP), heart rate, arterial oxygen saturation, lung function, and levels of carcinogens or toxicants or both. We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in meta-analyses.

MAIN RESULTS

We included 61 completed studies, representing 16,759 participants, of which 34 were RCTs. Five of the 61 included studies were new to this review update. Of the included studies, we rated seven (all contributing to our main comparisons) at low risk of bias overall, 42 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. There was moderate-certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (risk ratio (RR) 1.53, 95% confidence interval (CI) 1.21 to 1.93; I2 = 0%; 4 studies, 1924 participants). In absolute terms, this might translate to an additional three quitters per 100 (95% CI 1 to 6). There was low-certainty evidence (limited by very serious imprecision) that the rate of occurrence of AEs was similar (RR 0.98, 95% CI 0.80 to 1.19; I2 = 0%; 2 studies, 485 participants). SAEs were rare, but there was insufficient evidence to determine whether rates differed between groups due to very serious imprecision (RR 1.30, 95% CI 0.89 to 1.90: I2 = 0; 4 studies, 1424 participants). There was moderate-certainty evidence, again limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non-nicotine EC (RR 1.94, 95% CI 1.21 to 3.13; I2 = 0%; 5 studies, 1447 participants). In absolute terms, this might lead to an additional seven quitters per 100 (95% CI 2 to 16). There was moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 3 studies, 601 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 1.06, 95% CI 0.47 to 2.38; I2 = 0; 5 studies, 792 participants). Compared to behavioural support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.61, 95% CI 1.44 to 4.74; I2 = 0%; 6 studies, 2886 participants). In absolute terms this represents an additional six quitters per 100 (95% CI 2 to 15). However, this finding was of very low certainty, due to issues with imprecision and risk of bias. There was some evidence that non-serious AEs were more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low certainty; 4 studies, 765 participants), and again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 1.51, 95% CI 0.70 to 3.24; I2 = 0%; 7 studies, 1303 participants).  Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued use. Very few studies reported data on other outcomes or comparisons, hence evidence for these is limited, with CIs often encompassing clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that ECs with nicotine increase quit rates compared to NRT and compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the effect size. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non-nicotine ECs. Overall incidence of SAEs was low across all study arms. We did not detect  evidence of harm from nicotine EC, but longest follow-up was two years and the  number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates, but further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this review is now a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Exploring the uptake and use of electronic cigarettes provided to smokers accessing homeless centres: a four-centre cluster feasibility trial

Background

Smoking prevalence is extremely high in adults experiencing homelessness, and there is little evidence regarding which cessation interventions work best. This study explored the feasibility of providing free electronic cigarette starter kits to smokers accessing homeless centres in the UK.

Objectives

Seven key objectives were examined to inform a future trial: (1) assess willingness of smokers to participate in the study to estimate recruitment rates; (2) assess participant retention in the intervention and control arms; (3) examine the perceived value of the intervention, facilitators of and barriers to engagement, and influence of local context; (4) assess service providers’ capacity to support the study and the type of information and training required; (5) assess the potential efficacy of supplying free electronic cigarette starter kits; (6) explore the feasibility of collecting data on contacts with health-care services as an input to a main economic evaluation; and (7) estimate the cost of providing the intervention and usual care.

Design

A prospective cohort four-centre pragmatic cluster feasibility study with embedded qualitative process evaluation.

Setting

Four homeless centres. Two residential units in London, England. One day centre in Northampton, England. One day centre in Edinburgh, Scotland.

Intervention

In the intervention arm, a single refillable electronic cigarette was provided together with e-liquid, which was provided once per week for 4 weeks (choice of three flavours: fruit, menthol or tobacco; two nicotine strengths: 12 or 18 mg/ml). There was written information on electronic cigarette use and support. In the usual-care arm, written information on quitting smoking (adapted from NHS Choices) and signposting to the local stop smoking service were provided.

Results

Fifty-two per cent of eligible participants invited to take part in the study were successfully recruited (56% in the electronic cigarette arm; 50.5% in the usual-care arm; total n = 80). Retention rates were 75%, 63% and 59% at 4, 12 and 24 weeks, respectively. The qualitative component found that perceived value of the intervention was high. Barriers were participants’ personal difficulties and cannabis use. Facilitators were participants’ desire to change, free electronic cigarettes and social dynamics. Staff capacity to support the study was generally good. Carbon monoxide-validated sustained abstinence rates at 24 weeks were 6.25% (3/48) in the electronic cigarette arm compared with 0% (0/32) in the usual-care arm (intention to treat). Almost all participants present at follow-up visits completed measures needed for input into an economic evaluation, although information about staff time to support usual care could not be gathered. The cost of providing the electronic cigarette intervention was estimated at £114.42 per person. An estimated cost could not be calculated for usual care.

Limitations

Clusters could not be fully randomised because of a lack of centre readiness. The originally specified recruitment target was not achieved and recruitment was particularly difficult in residential centres. Blinding was not possible for the measurement of outcomes. Staff time supporting usual care could not be collected.

Conclusions

The study was associated with reasonable recruitment and retention rates and promising acceptability in the electronic cigarette arm. Data required for full cost-effectiveness evaluation in the electronic cigarette arm could be collected, but some data were not available in the usual-care arm.

Future work

Future research should focus on several key issues to help design optimal studies and interventions with this population, including which types of centres the intervention works best in, how best to retain participants in the study, how to help staff to deliver the intervention, and how best to record staff treatment time given the demands on their time.

Trial registration

Current Controlled Trials ISRCTN14140672; the protocol was registered as researchregistry4346.

Funding

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 9, No. 7. See the NIHR Journals Library website for further project information.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol formed by heating an e-liquid. Some people who smoke use ECs to stop or reduce smoking, but some organizations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit and if they are safe to use for this purpose. This is an update of a review first published in 2014.

OBJECTIVES

To examine the effectiveness, tolerability, and safety of using electronic cigarettes (ECs) to help people who smoke achieve long-term smoking abstinence.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 February 2021, together with reference-checking and contact with study authors.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and randomized cross-over trials in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. To be included, studies had to report abstinence from cigarettes at six months or longer and/or data on adverse events (AEs) or other markers of safety at one week or longer.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow-up, adverse events (AEs), and serious adverse events (SAEs). Secondary outcomes included changes in carbon monoxide, blood pressure, heart rate, blood oxygen saturation, lung function, and levels of known carcinogens/toxicants. We used a fixed-effect Mantel-Haenszel model to calculate the risk ratio (RR) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data from these studies in meta-analyses.

MAIN RESULTS

We included 56 completed studies, representing 12,804 participants, of which 29 were RCTs. Six of the 56 included studies were new to this review update. Of the included studies, we rated five (all contributing to our main comparisons) at low risk of bias overall, 41 at high risk overall (including the 25 non-randomized studies), and the remainder at unclear risk. There was moderate-certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (risk ratio (RR) 1.69, 95% confidence interval (CI) 1.25 to 2.27; I2 = 0%; 3 studies, 1498 participants). In absolute terms, this might translate to an additional four successful quitters per 100 (95% CI 2 to 8). There was low-certainty evidence (limited by very serious imprecision) that the rate of occurrence of AEs was similar) (RR 0.98, 95% CI 0.80 to 1.19; I2 = 0%; 2 studies, 485 participants). SAEs occurred rarely, with no evidence that their frequency differed between nicotine EC and NRT, but very serious imprecision led to low certainty in this finding (RR 1.37, 95% CI 0.77 to 2.41: I2 = n/a; 2 studies, 727 participants). There was moderate-certainty evidence, again limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non-nicotine EC (RR 1.70, 95% CI 1.03 to 2.81; I2 = 0%; 4 studies, 1057 participants). In absolute terms, this might again lead to an additional four successful quitters per 100 (95% CI 0 to 11). These trials mainly used older EC with relatively low nicotine delivery. There was moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 3 studies, 601 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 0.60, 95% CI 0.15 to 2.44; I2 = n/a; 4 studies, 494 participants). Compared to behavioral support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.70, 95% CI 1.39 to 5.26; I2 = 0%; 5 studies, 2561 participants). In absolute terms this represents an increase of seven per 100 (95% CI 2 to 17). However, this finding was of very low certainty, due to issues with imprecision and risk of bias. There was no evidence that the rate of SAEs differed, but some evidence that non-serious AEs were more common in people randomized to nicotine EC (AEs: RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low certainty; 4 studies, 765 participants; SAEs: RR 1.17, 95% CI 0.33 to 4.09; I2 = 5%; 6 studies, 1011 participants, very low certainty). Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued use. Very few studies reported data on other outcomes or comparisons and hence evidence for these is limited, with confidence intervals often encompassing clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that ECs with nicotine increase quit rates compared to ECs without nicotine and compared to NRT. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the size of effect, particularly when using modern EC products. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, though evidence indicated no difference in AEs between nicotine and non-nicotine ECs. Overall incidence of SAEs was low across all study arms. We did not detect any clear evidence of harm from nicotine EC, but longest follow-up was two years and the overall number of studies was small. The evidence is limited mainly by imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information, this review is now a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Nicotine delivery and user reactions to Juul EU (20 mg/ml) compared with Juul US (59 mg/ml), cigarettes and other e-cigarette products

RATIONALE

The degree to which the EU version of Juul with 20 mg/ml nicotine (Juul EU) delivers nicotine to users is likely to determine its treatment potential.

OBJECTIVES

To compare the pharmacokinetic profile and user ratings of Juul EU, Juul US (59 mg/ml nicotine), cigarettes and other e-cigarette (EC) products.

METHODS

In a within-subjects crossover design, 18 vapers used, at separate sessions, their own brand cigarette (OBC), Juul US and Juul EU for 5 min ad libitum, after overnight abstinence. Seven of the participants also tested eight other EC previously. Blood samples were taken at baseline and 2, 4, 6, 8, 10 and 30 min after initiating product use. Products were rated on a range of characteristics.

RESULTS

Juul EU delivered less nicotine than OBC (t(13) = -4.64 p < .001) and than Juul US (t(13) = -6.40, p < .001): AUC0 ≥ 30 77.3, 324.8 and 355.9, respectively. Maximum nicotine concentration (Cmax) was also much lower for Juul EU than Juul US (z = -3.59, p < .001): Cmax 3.8 ng/ml vs 21.1 ng/ml, respectively. Juul EU was perceived to relieve urges to smoke less than Juul US (z = -2.29, p = .022) and to provide less nicotine (z = -2.57. p = 0.010). Juul EU delivered less nicotine than refillable EC (Cmax: t(6) = 3.02, p = 0.023; AUC0 ≥ 30: z = -2.20, p = 0.028) and also less than cig-a-like EC, though the difference did not reach significance (Cmax: t(6) = 2.49, p = 0.047; AUC0 ≥ 30: z = -1.99, p = 0.046). Subjective ratings of Juul EU and other EC products were similar.

CONCLUSIONS

Juul EU delivers much less nicotine to users than Juul US, and also less than refillable EC products. It may thus have more limited potential to help smokers quit.

Time restricted eating as a weight loss intervention in adults with obesity

Objectives

Time-restricted eating (TRE) is a weight management approach in which food is consumed only within a specific period each day. The simplicity of this approach is appealing, but its efficacy is not known. The aim of this pilot cohort study was to assess adherence to TRE and its effects on weight and lipid profile.

Methods

Fifty participants with obesity attempted to follow TRE for 12 weeks. Surveys were conducted weekly over the phone to assess treatment adherence and ratings; and at 6 and 12 weeks, participants attended the clinic to be weighed, have their blood pressure taken and provide a blood sample for lipid profile. Treatment results were compared with data from previous comparable cohorts using other weight management methods.

Results

Mean age of the participants was 50 (SD = 12.0), mean weight 97kg (SD = 17.1), mean BMI = 35 (SD = 4.0) and most were female (74%). At weeks 6 and 12, 64% and 58% of participants continued to practice TRE on at least five days/week. Using the ‘last observation carried forward’ imputation, mean (SD) weight loss was 2.0 (1.7) kg and 2.6 (2.6) kg at 6 and 12 weeks. Among participants who provided follow-up data, those who adhered to the intervention for at least five days/week recorded greater weight loss than those with lower adherence (week 6: 2.5 (1.7) vs 1.0 (1.3), p = 0.003; week 12: 3.5 (2.7) vs 1.3 (2.0), p = 0.001). A total of 26% of the sample lost at least 5% of their body weight at 12 weeks. The intervention had no effect on blood pressure or lipid profile.

Conclusions

TRE results were modest, but at least on par with those achieved with more complex interventions, and weight loss did not decline at 12 weeks. A formal trial of the intervention is warranted.

A Qualitative Study of Factors Influencing Adherence among Pregnant Women Taking Part in a Trial of E-Cigarettes for Smoking Cessation

Use of e-cigarettes (vaping) has potential to help pregnant women stop smoking. This study explored factors influencing adherence among participants in the vaping arm of the first trial of vaping for smoking cessation in pregnancy. We conducted semi-structured telephone interviews (n = 28) with women at three-months postpartum. Interviews were analysed using thematic analysis, informed by the Theoretical-Domains Framework, Necessity-Concerns Framework and Perceptions and Practicalities Approach. Interviewees generally reported high levels of vaping. We found that: (1) intervention adherence was driven by four necessity beliefs-stopping smoking for the baby, and vaping for harm reduction, smoking cessation or as a last resort; (2) necessity beliefs outweighed vaping concerns, such as dependence and safety; (3) adherence was linked to four practicalities themes, acting as barriers and facilitators to vaping-device and e-liquid perceptions, resources and support, whether vaping became habitual, and social and environmental factors; and (4) intentional non-adherence was rare; unintentional non-adherence was due to device failures, forgetting to vape, and personal circumstances and stress. Pregnant smokers provided with e-cigarettes, and with generally high levels of vaping, had positive beliefs about the necessity of vaping for smoking cessation which outweighed concerns about vaping. Non-adherence was mainly due to unintentional factors.

Nicotine replacement treatment, e-cigarettes and an online behavioural intervention to reduce relapse in recent ex-smokers: a multinational four-arm RCT

BACKGROUND

Relapse remains an unresolved issue in smoking cessation. Extended stop smoking medication use can help, but uptake is low and several behavioural relapse prevention interventions have been found to be ineffective. However, opportunistic 'emergency' use of fast-acting nicotine replacement treatment or electronic cigarettes may be more attractive and effective, and an online behavioural Structured Planning and Prompting Protocol has shown promise. The present trial aimed to evaluate the clinical effectiveness and cost-effectiveness of these two interventions.

DESIGN

A randomised controlled trial.

SETTING

English stop smoking services and Australian quitlines, Australian social media and St Vincent's Hospital Melbourne, Fitzroy, VIC.

PARTICIPANTS

Ex-smokers abstinent for at least 4 weeks, with some participants in Australia also recruited from 1 week post quit date. The planned sample size was 1400, but the trial was curtailed when 235 participants were recruited.

INTERVENTIONS

Participants were randomised in permuted blocks of random sizes to (1) oral nicotine replacement treatment/electronic cigarettes to use if at risk of relapse, plus static text messages (n = 60), (2) the Structured Planning and Prompting Protocol and interactive text messages (n = 57), (3) oral nicotine replacement treatment/electronic cigarettes plus the Structured Planning and Prompting Protocol with interactive text messages (n = 58) or (4) usual care plus static text messages (n = 59).

OUTCOME MEASURES

Owing to delays in study set-up and recruitment issues, the study was curtailed and the primary outcome was revised. The original objective was to determine whether or not the two interventions, together or separately, reduced relapse rates at 12 months compared with usual care. The revised primary objective was to determine whether or not number of interventions received (i.e. none, one or two) affects relapse rate at 6 months (not biochemically validated because of study curtailment). Relapse was defined as smoking on at least 7 consecutive days, or any smoking in the last month at final follow-up for both the original and curtailed outcomes. Participants with missing outcome data were included as smokers. Secondary outcomes included sustained abstinence (i.e. no more than five cigarettes smoked over the 6 months), nicotine product preferences (e.g. electronic cigarettes or nicotine replacement treatment) and Structured Planning and Prompting Protocol coping strategies used. Two substudies assessed reactions to interventions quantitatively and qualitatively. The trial statistician remained blinded until analysis was complete.

RESULTS

The 6-month relapse rates were 60.0%, 43.5% and 49.2% in the usual-care arm, one-intervention arm and the two-intervention arm, respectively (p = 0.11). Sustained abstinence rates were 41.7%, 54.8% and 50.9%, respectively (p = 0.17). Electronic cigarettes were chosen more frequently than nicotine replacement treatment in Australia (71.1% vs. 29.0%; p = 0.001), but not in England (54.0% vs. 46.0%; p = 0.57). Of participants allocated to nicotine products, 23.1% were using them daily at 6 months. The online intervention received positive ratings from 63% of participants at 6 months, but the majority of participants (72%) completed one assessment only. Coping strategies taught in the Structured Planning and Prompting Protocol were used with similar frequency in all study arms, suggesting that these are strategies people had already acquired. Only one participant used the interactive texting, and interactive and static messages received virtually identical ratings.

LIMITATIONS

The inability to recruit sufficient participants resulted in a lack of power to detect clinically relevant differences. Self-reported abstinence was not biochemically validated in the curtailed trial, and the ecological momentary assessment substudy was perceived by some as an intervention.

CONCLUSIONS

Recruiting recent ex-smokers into an interventional study proved problematic. Both interventions were well received and safe. Combining the interventions did not surpass the effects of each intervention alone. There was a trend in favour of single interventions reducing relapse, but it did not reach significance and there are reasons to interpret the trend with caution.

FUTURE WORK

Further studies of both interventions are warranted, using simpler study designs.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN11111428.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 68. See the NIHR Journals Library website for further project information. Funding was also provided by the National Health and Medical Research Council, Canberra, ACT, Australia (NHMRC APP1095880). Public Health England provided the funds to purchase the nicotine products in England.

Assessment of internal carotid artery stenosis and results of carotid stenting by angiography compared with intravascular ultrasound

Background/Introduction

Intravascular imaging is commonly used in coronary interventions and improves outcomes. On the contrary, it is almost unrecognized for the guidance of carotid stenting (CAS).

Purpose

The aim of this study was to compare quantitative angiography (QA) and intravascular ultrasound (IVUS) in the assessment of the severity of carotid stenosis and residual stenosis in patients undergoing CAS and to provide reference values for IVUS measurements of the internal carotid artery (ICA) in the European population.

Methods

IVUS imaging was performed during 151 CAS procedures in 140 patients from April 2013 to December 2019. In total 162 self-expanding stents of different design were implanted (66% closed-cell, 22% open-cell, 8% hybrid, 4% double layer micromesh stents). IVUS was used to measure distal reference diameter and area of ICA, minimal luminal diameter (MLD) and minimal luminal area (MLA) before and after CAS. IVUS and QA were used to measure relative stenosis area (stenosis) at baseline and relative residual stenosis area (residual stenosis) after CAS. Relative stenosis area was calculated as [1 − (MLA / distal reference area)] x 100.

Results

Mean (±SD) distal reference diameter of ICA was 4.5±0.8 mm. MLD increased from 1.9±0.4 mm to 3.6±0.6 mm after CAS (p&lt;0.001). MLA increased from 3.9±1.7 mm2 to 12.0±3.4 mm2 after CAS (p&lt;0.001). Stenosis measured by QA and IVUS was 84±9% and 76±13% respectively (p=0.01). There was a moderate correlation (Pearson's correlation coefficient r=0.575; p=0.01) between QA and IVUS measurement of ICA stenosis severity. Residual stenosis measured by QA and IVUS was 12±10% and 40±16% (p&lt;0.001) respectively with only weak correlation (r=0.433; p&lt;0.001) between the two methods.

Conclusion

Angiography slightly overestimates stenosis of internal carotid artery and substantially underestimates residual stenosis after CAS compared to IVUS. Angiography alone is inaccurate in the assessment of ICA stenosis and results of carotid stenting.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): University Hospital Motol

A cluster feasibility trial to explore the uptake and use of e-cigarettes versus usual care offered to smokers attending homeless centres in Great Britain

Smoking rates in the UK are at an all-time low but this masks considerable inequalities; prevalence amongst adults who are homeless remains four times higher than the national average. The objective of this trial was to assess the feasibility of supplying free e-cigarette starter kits to smokers accessing homeless centres and to estimate parameters to inform a possible future larger trial. In this feasibility cluster trial, four homeless centres in Great Britain were non-randomly allocated to either a Usual Care (UC) or E-Cigarette (EC) arm. Smokers attending the centres were recruited by staff. UC arm participants (N = 32) received advice to quit and signposting to the local Stop Smoking Service. EC arm participants (N = 48) received an EC starter kit and 4-weeks supply of e-liquid. Outcome measures were recruitment and retention rates, use of ECs, smoking cessation/reduction and completion of measures required for economic evaluation. Eighty (mean age 43 years; 65% male) of the 153 eligible participants who were invited to participate, were successfully recruited (52%) within a five-month period, and 47 (59%) of these were retained at 24 weeks. The EC intervention was well received with minimal negative effects and very few unintended consequences (e.g. lost, theft, adding illicit substances). In both study arm, depression and anxiety scores declined over the duration of the study. Substance dependence scores remained constant. Assuming those with missing follow up data were smoking, CO validated sustained abstinence at 24 weeks was 3/48 (6.25%) and 0/32 (0%) respectively for the EC and UC arms. Almost all participants present at follow-up visits completed data collection for healthcare service and health-related quality of life measures. Providing an e-cigarette starter kit to smokers experiencing homelessness was associated with reasonable recruitment and retention rates and promising evidence of effectiveness and cost-effectiveness.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol formed by heating an e-liquid. People who smoke report using ECs to stop or reduce smoking, but some organisations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit and if they are safe to use for this purpose. This review is an update of a review first published in 2014.

OBJECTIVES

To evaluate the effect and safety of using electronic cigarettes (ECs) to help people who smoke achieve long-term smoking abstinence.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO for relevant records to January 2020, together with reference-checking and contact with study authors.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and randomized cross-over trials in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. To be included, studies had to report abstinence from cigarettes at six months or longer and/or data on adverse events (AEs) or other markers of safety at one week or longer.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow-up, AEs, and serious adverse events (SAEs). Secondary outcomes included changes in carbon monoxide, blood pressure, heart rate, blood oxygen saturation, lung function, and levels of known carcinogens/toxicants. We used a fixed-effect Mantel-Haenszel model to calculate the risk ratio (RR) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data from these studies in meta-analyses.

MAIN RESULTS

We include 50 completed studies, representing 12,430 participants, of which 26 are RCTs. Thirty-five of the 50 included studies are new to this review update. Of the included studies, we rated four (all which contribute to our main comparisons) at low risk of bias overall, 37 at high risk overall (including the 24 non-randomized studies), and the remainder at unclear risk. There was moderate-certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (risk ratio (RR) 1.69, 95% confidence interval (CI) 1.25 to 2.27; I2 = 0%; 3 studies, 1498 participants). In absolute terms, this might translate to an additional four successful quitters per 100 (95% CI 2 to 8). There was low-certainty evidence (limited by very serious imprecision) of no difference in the rate of adverse events (AEs) (RR 0.98, 95% CI 0.80 to 1.19; I2 = 0%; 2 studies, 485 participants). SAEs occurred rarely, with no evidence that their frequency differed between nicotine EC and NRT, but very serious imprecision led to low certainty in this finding (RR 1.37, 95% CI 0.77 to 2.41: I2 = n/a; 2 studies, 727 participants). There was moderate-certainty evidence, again limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non-nicotine EC (RR 1.71, 95% CI 1.00 to 2.92; I2 = 0%; 3 studies, 802 participants). In absolute terms, this might again lead to an additional four successful quitters per 100 (95% CI 0 to 12). These trials used EC with relatively low nicotine delivery. There was low-certainty evidence, limited by very serious imprecision, that there was no difference in the rate of AEs between these groups (RR 1.00, 95% CI 0.73 to 1.36; I2 = 0%; 2 studies, 346 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 0.25, 95% CI 0.03 to 2.19; I2 = n/a; 4 studies, 494 participants). Compared to behavioural support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.50, 95% CI 1.24 to 5.04; I2 = 0%; 4 studies, 2312 participants). In absolute terms this represents an increase of six per 100 (95% CI 1 to 14). However, this finding was very low-certainty, due to issues with imprecision and risk of bias. There was no evidence that the rate of SAEs varied, but some evidence that non-serious AEs were more common in people randomized to nicotine EC (AEs: RR 1.17, 95% CI 1.04 to 1.31; I2 = 28%; 3 studies, 516 participants; SAEs: RR 1.33, 95% CI 0.25 to 6.96; I2 = 17%; 5 studies, 842 participants). Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate over time with continued use. Very few studies reported data on other outcomes or comparisons and hence evidence for these is limited, with confidence intervals often encompassing clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that ECs with nicotine increase quit rates compared to ECs without nicotine and compared to NRT. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the degree of effect, particularly when using modern EC products. Confidence intervals were wide for data on AEs, SAEs and other safety markers. Overall incidence of SAEs was low across all study arms. We did not detect any clear evidence of harm from nicotine EC, but longest follow-up was two years and the overall number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information for decision-makers, this review is now a living systematic review. We will run searches monthly from December 2020, with the review updated as relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Combined percutaneous approach for aortic valve implantation in poor vascular access

Transcatheter aortic valve implantation (TAVI) is a well-established management option for symptomatic patients with severe aortic stenosis. The minimally invasive transfemoral approach is considered to be superior to non-transfemoral accesses; however, its use is often limited by concomitant peripheral artery disease (PAD). Percutaneous transluminal angioplasty with stent implantation (PTA) is a gold-standard therapy for symptomatic PAD. We present 2 cases from our cohort of patients with severe aortic stenosis and PAD previously contraindicated for TAVI because of poor peripheral vascular access. However, the patients were eventually treated either by staged PTA and TAVI through an endothelialized stent or PTA and TAVI though a newly implanted peripheral stent during one procedure. We provide recommendations based on our experience of how to select the optimal patients for such a combined minimally invasive transfemoral approach (Fig. 2, Ref. 9). Keywords: transcatheter valve implantation, peripheral arterial disease, aortic valve disease, percutaneous intervention, atherosclerosis.

Nicotine delivery and users' reactions to Juul compared with cigarettes and other e-cigarette products

AIMS

To assess the pharmacokinetic (PK) profile of, and users' reactions to, Juul (59 mg nicotine/ml) as an indication of its therapeutic and dependence potential.

DESIGN

Cross-over, within-subjects study in which participants attended after overnight abstinence on separate sessions and smoked a cigarette or used Juul or eight other types of e-cigarettes (EC) ad libitum for 5 minutes. The Juul product used was the version available in the United States that has more nicotine in the e-liquid than the one available in the European Union.

SETTING

Laboratory setting in the United Kingdom.

PARTICIPANTS

Twenty dual users (smokers who also vape) provided data on Juul and cigarettes, with eight also providing data on other EC products.

MEASUREMENTS

At each session, number of puffs taken was counted during the 5-minute product use period and blood samples were taken at baseline and at 2, 4, 6, 8, 10 and 30 minutes after starting smoking/vaping and analysed for nicotine. Participants also monitored their urges to smoke and rated the products on a range of characteristics.

FINDINGS

Juul's PK profile was close to the PK profile of cigarettes [maximum concentration (Cmax ) = 20.4 versus 19.2 ng/ml; time to maximum concentration (Tmax ) = 4 versus 6 minutes; area under the curve (AUC): 307.9 versus 312.6, respectively]. Compared with other EC products, Juul had shorter Tmax [4 minutes, (IQR = 2.5-4.0) versus 6.3 minutes, (IQR = 4.7 - 8.1), P = 0.012] and higher Cmax (28.9 (SD = 15.6) versus 10.6 (SD = 5.5), P = 0.013) despite a lower number of puffs (12.5 (SD = 4.2) versus 17.0 (SD = 4.2), P = 0.084). Compared with other e-cigarette products, it also provided faster reduction of urges to smoke and obtained more favourable subjective ratings.

CONCLUSION

Juul's PK profile and user ratings suggest that it could be more effective than other EC products in helping smokers to quit smoking, but it may also have a higher potential to generate regular use in non-smokers.

Varenicline: mode of action, efficacy, safety and accumulated experience salient for clinical populations

Objective: Varenicline, a selective partial agonist of the α4β2 nicotinic acetylcholine receptor, is a smoking cessation pharmacotherapy that more than doubles the chance of quitting smoking at 6 months compared with placebo. This article reviews salient knowledge of the discovery, pharmacological characteristics, and the efficacy and safety of varenicline in general and in specific populations of smokers and provides recommendations to support use in clinical practice.Methods: Literature searches for varenicline were conducted using PubMed, with date limitations of 2000-2018 inclusive, using search terms covering the discovery, mechanism of action, pharmacokinetics, efficacy and safety in different populations of smokers, alternative quit approaches and combination therapy. Selection of safety and efficacy data was limited to clinical trials, meta-analyses and observational studies.Results: Standard administration of varenicline is efficacious in helping smokers to quit, including smokers with cardiovascular disease and chronic obstructive pulmonary disease. Furthermore, varenicline efficacy may be improved with pre-loading, a gradual quitting approach for smokers unwilling or unable to quit abruptly, and extended treatment in smokers who have recently quit to help maintain abstinence. Initial concerns regarding the association of varenicline with increased risk of neuropsychiatric and cardiovascular adverse events have been disproven after extensive clinical evaluations, and the benefit-risk profile of varenicline is considered favorable.Conclusions: Varenicline is efficacious and safe for all adult smokers with a range of clinical characteristics. Evidence suggests that approaches offering greater flexibility in timing and duration of treatment may further extend treatment efficacy and clinical reach.

Cost-effectiveness of e-cigarettes compared with nicotine replacement therapy in stop smoking services in England (TEC study): a randomized controlled trial

AIM

To evaluate the cost-effectiveness of e-cigarettes as a smoking cessation aid used in routine stop smoking services in England.

DESIGN

Cost-effectiveness analysis was performed from the National Health Service (NHS) and Personal Social Services (PSS) perspective for 12-month periods and life-time. Costs, including that of both treatments, other smoking cessation help and health-care services, and health benefits, estimated from EQ-5D-5L and measured in quality-adjusted life-years (QALYs), for the 12-month analysis, came from a randomized controlled trial. Life-time analysis was model-based with input from both trial data and published secondary data sources. Cost-effectiveness was measured by an incremental cost-effectiveness ratio (ICER).

SETTING

Three stop-smoking service sites in England.

PARTICIPANTS

Adult smokers (n = 886) who sought help to quit in the participating sites.

INTERVENTION AND COMPARATOR

An e-cigarette (EC) starter kit versus provision of nicotine replacement therapy (NRT) for up to 3 months, both with standard behavioural support. A total of 886 participants were randomized (439 in the EC arm, 447 in the NRT arm). Excluding one death in each arm, the 1-year quit rate was 18.0 and 9.9%, respectively.

MEASUREMENTS

Cost of treatments was estimated from the treatment log. Costs of other smoking cessation help and health-care services and EQ-5D-5 L were collected at baseline, 6- and 12-month follow-ups. Incremental costs and incremental QALYs were estimated using regression adjusting for baseline covariates and their respective baseline values.

FINDINGS

The ICER was £1100 per QALY gained at the 12 months after quit date (87% probability below £20 000/QALY). Markov model estimated the life-time ICER of EC to be £65 per QALY (85% probability below £20 000/QALY).

CONCLUSION

Using e-cigarettes as a smoking cessation aid with standard behavioural support in stop-smoking services in England is likely to be more cost-effective than using nicotine replacement therapy in the same setting.

Relapse prevention interventions for smoking cessation

BACKGROUND

A number of treatments can help smokers make a successful quit attempt, but many initially successful quitters relapse over time. Several interventions have been proposed to help prevent relapse.

OBJECTIVES

To assess whether specific interventions for relapse prevention reduce the proportion of recent quitters who return to smoking.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group trials register, clinicaltrials.gov, and the ICTRP in May 2019 for studies mentioning relapse prevention or maintenance in their title, abstracts, or keywords.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of relapse prevention interventions with a minimum follow-up of six months. We included smokers who quit on their own, were undergoing enforced abstinence, or were participating in treatment programmes. We included studies that compared relapse prevention interventions with a no intervention control, or that compared a cessation programme with additional relapse prevention components with a cessation programme alone.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 81 studies (69,094 participants), five of which are new to this update. We judged 22 studies to be at high risk of bias, 53 to be at unclear risk of bias, and six studies to be at low risk of bias. Fifty studies included abstainers, and 30 studies helped people to quit and then tested treatments to prevent relapse. Twenty-eight studies focused on special populations who were abstinent because of pregnancy (19 studies), hospital admission (six studies), or military service (three studies). Most studies used behavioural interventions that tried to teach people skills to cope with the urge to smoke, or followed up with additional support. Some studies tested extended pharmacotherapy. We focused on results from those studies that randomised abstainers, as these are the best test of relapse prevention interventions. Of the 12 analyses we conducted in abstainers, three pharmacotherapy analyses showed benefits of the intervention: extended varenicline in assisted abstainers (2 studies, n = 1297, risk ratio (RR) 1.23, 95% confidence interval (CI) 1.08 to 1.41, I² = 82%; moderate-certainty evidence), rimonabant in assisted abstainers (1 study, RR 1.29, 95% CI 1.08 to 1.55), and nicotine replacement therapy (NRT) in unaided abstainers (2 studies, n = 2261, RR 1.24, 95% Cl 1.04 to 1.47, I² = 56%). The remainder of analyses of pharmacotherapies in abstainers had wide confidence intervals consistent with both no effect and a statistically significant effect in favour of the intervention. These included NRT in hospital inpatients (2 studies, n = 1078, RR 1.23, 95% CI 0.94 to 1.60, I² = 0%), NRT in assisted abstainers (2 studies, n = 553, RR 1.04, 95% CI 0.77 to 1.40, I² = 0%; low-certainty evidence), extended bupropion in assisted abstainers (6 studies, n = 1697, RR 1.15, 95% CI 0.98 to 1.35, I² = 0%; moderate-certainty evidence), and bupropion plus NRT (2 studies, n = 243, RR 1.18, 95% CI 0.75 to 1.87, I² = 66%; low-certainty evidence). Analyses of behavioural interventions in abstainers did not detect an effect. These included studies in abstinent pregnant and postpartum women at the end of pregnancy (8 studies, n = 1523, RR 1.05, 95% CI 0.99 to 1.11, I² = 0%) and at postpartum follow-up (15 studies, n = 4606, RR 1.02, 95% CI 0.94 to 1.09, I² = 3%), studies in hospital inpatients (5 studies, n = 1385, RR 1.10, 95% CI 0.82 to 1.47, I² = 58%), and studies in assisted abstainers (11 studies, n = 5523, RR 0.98, 95% CI 0.87 to 1.11, I² = 52%; moderate-certainty evidence) and unaided abstainers (5 studies, n = 3561, RR 1.06, 95% CI 0.96 to 1.16, I² = 1%) from the general population.

AUTHORS' CONCLUSIONS

Behavioural interventions that teach people to recognise situations that are high risk for relapse along with strategies to cope with them provided no worthwhile benefit in preventing relapse in assisted abstainers, although unexplained statistical heterogeneity means we are only moderately certain of this. In people who have successfully quit smoking using pharmacotherapy, there were mixed results regarding extending pharmacotherapy for longer than is standard. Extended treatment with varenicline helped to prevent relapse; evidence for the effect estimate was of moderate certainty, limited by unexplained statistical heterogeneity. Moderate-certainty evidence, limited by imprecision, did not detect a benefit from extended treatment with bupropion, though confidence intervals mean we could not rule out a clinically important benefit at this stage. Low-certainty evidence, limited by imprecision, did not show a benefit of extended treatment with nicotine replacement therapy in preventing relapse in assisted abstainers. More research is needed in this area, especially as the evidence for extended nicotine replacement therapy in unassisted abstainers did suggest a benefit.

Management of supragastric belching with cognitive behavioural therapy: factors determining success and follow-up outcomes at 6-12 months post-therapy

BACKGROUND

Supragastric belching (SGB) has a significant behavioural component. We recently used cognitive behavioural therapy (CBT) to treat SGB. We demonstrated that CBT significantly reduces symptoms and improves quality of life in 50% of patients who had completed treatment.

AIMS

To investigate factors associated with successful CBT for SGB and to assess symptoms 6-12 months after completion of CBT METHODS: Records of 39 patients who had completed the CBT protocol were analysed. Per cent pre- to post-treatment change in symptoms was assessed using a visual analogue scale (VAS) score. We evaluated the association between 'pre-treatment' factors and 'during-treatment' factors, and symptomatic outcomes. Symptoms were also assessed 6-12 months after treatment.

RESULTS

From 'pre-treatment factors', a lower number of SGBs (P < .01) and lower hypervigilance score (P < .04) were significantly associated with a better outcome. From 'during-treatment factors' a higher CBT 'proficiency score' ([a] acceptance of the explanation that SGB is a behavioural phenomenon [b] detection of a warning signal before belching [c] adherence to the exercises treatment) was associated with a better outcome (P = .001). Multiple regression analysis found that number of SGBs, hypervigilance score and CBT proficiency score were independently associated with outcome (P < .01, P = .01, P < .01). VAS score before CBT (267 ± 79) decreased to 151 ± 88 soon after CBT (P < .001), and the effect persisted at 6-12 months follow-up (153 ± 82).

CONCLUSIONS

Lower number of SGBs, lower hypervigilance score and higher proficiency during CBT were associated with better CBT outcome. CBT positive effect lasted for at least 6-12 months post-treatment.

E-cigarettes compared with nicotine replacement therapy within the UK Stop Smoking Services: the TEC RCT

BACKGROUND

Over the past few years, a large number of smokers in the UK have stopped smoking with the help of e-cigarettes. So far, UK Stop Smoking Services (SSSs) have been reluctant to include e-cigarettes among their treatment options because data on their efficacy compared with the licensed medications are lacking.

OBJECTIVE

The objective was to compare the efficacy of refillable e-cigarettes and nicotine replacement therapy (NRT) products, when accompanied by weekly behavioural support.

DESIGN

A randomised controlled trial comparing e-cigarettes and NRT.

SETTING

Three sites that provide local SSSs.

PARTICIPANTS

The participants were 886 smokers seeking help to quit smoking, aged ≥ 18 years, not pregnant or breastfeeding, with no strong preference to use or not to use NRT or e-cigarettes in their quit attempt, and currently not using NRT or e-cigarettes. A total of 886 participants were randomised but two died during the study (one in each study arm) and were not included in the analysis.

INTERVENTIONS

The NRT arm (n = 446) received NRT of their choice (single or combination), provided for up to 12 weeks. The e-cigarette arm (n = 438) received an e-cigarette starter pack and were encouraged to buy addtional e-liquids and e-cigarette products of their choice. Both arms received the same standard behavioural support. Participants attended weekly sessions at their SSS and provided outcome data at 4 weeks. They were then followed up by telephone at 6 and 12 months. Participants reporting abstinence or at least 50% reduction in cigarette consumption at 12 months were invited to attend for carbon monoxide (CO) validation. Participants/researchers could not be blinded to the intervention.

MAIN OUTCOME MEASURES

The primary outcome was CO-validated sustained abstinence rates at 52 weeks. Participants lost to follow-up or not providing biochemical validation were included as non-abstainers. Secondary outcomes included abstinence at other time points, reduction in smoke intake, treatment adherence and ratings, elicited adverse reactions, and changes in self-reported respiratory health. A cost-efficacy analysis of the intervention was also conducted.

RESULTS

The 1-year quit rate was 9.9% in the NRT arm and 18.0% in the e-cigarette arm (risk ratio 1.83, 95% confidence interval 1.30 to 2.58; p < 0.001). The e-cigarette arm had significantly higher validated quit rates at all time points. Participants in the e-cigarette arm showed significantly better adherence and experienced fewer urges to smoke throughout the initial 4 weeks of their quit attempt than those in the NRT arm, and gave their allocated product more favourable ratings. They were also more likely to be still using their allocated product at 1 year (39.5% vs. 4.3%, χ2 = 161.4; p < 0.001). Participants assigned to e-cigarettes reported significantly less coughing and phlegm at 1 year than those assigned to NRT (controlling for smoking status). A detailed economic analysis confirmed that, because e-cigarettes incur lower NHS costs than NRT and generate a higher quit rate, e-cigarette use is more cost-effective.

LIMITATIONS

The results may not be generalisable to other types of smokers or settings, or to cartridge-based e-cigarettes.

CONCLUSIONS

Within the context of multisession treatment for smokers seeking help, e-cigarettes were significantly more effective than NRT. If SSSs provide e-cigarette starter packs, it is likely to boost their success rates and improve their cost-efficacy.

FUTURE WORK

The efficacy of e-cigarettes provided with different levels of support will show whether smokers should be encouraged to switch to vaping within support services or whether e-cigarettes can be recommended with less intensive or no support.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN60477608.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 43. See the NIHR Journals Library website for further project information. The trial was supported by the Cancer Research UK Prevention Trials Unit (grant A16893).

Nicotine preloading for smoking cessation: the Preloading RCT

BACKGROUND

Nicotine preloading means using nicotine replacement therapy prior to a quit date while smoking normally. The aim is to reduce the drive to smoke, thereby reducing cravings for smoking after quit day, which are the main cause of early relapse. A prior systematic review showed inconclusive and heterogeneous evidence that preloading was effective and little evidence of the mechanism of action, with no cost-effectiveness data.

OBJECTIVES

To assess (1) the effectiveness, safety and tolerability of nicotine preloading in a routine NHS setting relative to usual care, (2) the mechanisms of the action of preloading and (3) the cost-effectiveness of preloading.

DESIGN

Open-label randomised controlled trial with examination of mediation and a cost-effectiveness analysis.

SETTING

NHS smoking cessation clinics.

PARTICIPANTS

People seeking help to stop smoking.

INTERVENTIONS

Nicotine preloading comprised wearing a 21 mg/24 hour nicotine patch for 4 weeks prior to quit date. In addition, minimal behavioural support was provided to explain the intervention rationale and to support adherence. In the comparator group, participants received equivalent behavioural support. Randomisation was stratified by centre and concealed from investigators.

MAIN OUTCOME MEASURES

The primary outcome was 6-month prolonged abstinence assessed using the Russell Standard. The secondary outcomes were 4-week and 12-month abstinence. Adverse events (AEs) were assessed from baseline to 1 week after quit day. In a planned analysis, we adjusted for the use of varenicline (Champix^®; Pfizer Inc., New York, NY, USA) as post-cessation medication. Cost-effectiveness analysis took a health-service perspective. The within-trial analysis assessed health-service costs during the 13 months of trial enrolment relative to the previous 6 months comparing trial arms. The base case was based on multiple imputation for missing cost data. We modelled long-term health outcomes of smoking-related diseases using the European-study on Quantifying Utility of Investment in Protection from Tobacco (EQUIPT) model.

RESULTS

In total, 1792 people were eligible and were enrolled in the study, with 893 randomised to the control group and 899 randomised to the intervention group. In the intervention group, 49 (5.5%) people discontinued preloading prematurely and most others used it daily. The primary outcome, biochemically validated 6-month abstinence, was achieved by 157 (17.5%) people in the intervention group and 129 (14.4%) people in the control group, a difference of 3.02 percentage points [95% confidence interval (CI) -0.37 to 6.41 percentage points; odds ratio (OR) 1.25, 95% CI 0.97 to 1.62; p = 0.081]. Adjusted for use of post-quit day varenicline, the OR was 1.34 (95% CI 1.03 to 1.73; p = 0.028). Secondary abstinence outcomes were similar. The OR for the occurrence of serious AEs was 1.12 (95% CI 0.42 to 3.03). Moderate-severity nausea occurred in an additional 4% of the preloading group compared with the control group. There was evidence that reduced urges to smoke and reduced smoke inhalation mediated the effect of preloading on abstinence. The incremental cost-effectiveness ratio at the 6-month follow-up for preloading relative to control was £710 (95% CI -£13,674 to £23,205), but preloading was dominant at 12 months and in the long term, with an 80% probability that it is cost saving.

LIMITATIONS

The open-label design could partially account for the mediation results. Outcome assessment could not be blinded but was biochemically verified.

CONCLUSIONS

Use of nicotine-patch preloading for 4 weeks prior to attempting to stop smoking can increase the proportion of people who stop successfully, but its benefit is undermined because it reduces the use of varenicline after preloading. If this latter effect could be overcome, then nicotine preloading appears to improve health and reduce health-service costs in the long term. Future work should determine how to ensure that people using nicotine preloading opt to use varenicline as cessation medication.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN33031001.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 41. See the NIHR Journals Library website for further project information.

Randomised controlled trial and economic evaluation of a task-based weight management group programme

BACKGROUND

Obesity is a rising global threat to health and a major contributor to health inequalities. Weight management programmes that are effective, economical and reach underprivileged groups are needed. We examined whether a multi-modal group intervention structured to cater for clients from disadvantaged communities (Weight Action Programme; WAP) has better one-year outcomes than a primary care standard weight management intervention delivered by practice nurses (PNI).

METHODS

In this randomised controlled trial, 330 obese adults were recruited from general practices in London and allocated (2:1) to WAP (N = 221) delivered over eight weekly group sessions or PNI (N = 109) who received four sessions over eight weeks. Both interventions covered diet, physical activity and self-monitoring. The primary outcome was the change in weight from baseline at 12 months. To indicate value to the NHS, a cost effectiveness analysis estimated group differences in cost and Quality-Adjusted Life-Years (QALYs) related to WAP.

RESULTS

Participants were recruited from September 2012 to January 2014 with follow-up completed in February 2015. Most participants were not in paid employment and 60% were from ethnic minorities. 88% of participants in each study arm provided at least one recorded outcome and were included in the primary analysis. Compared with the PNI, WAP was associated with greater weight loss overall (- 4·2 kg vs. - 2·3 kg; difference = - 1·9 kg, 95% CI: -3·7 to - 0·1; P = 0·04) and was more likely to generate a weight loss of at least 5% at 12 months (41% vs. 27%, OR = 14·61 95% CI: 2·32 to 91·96, P = 0·004). With an incremental cost-effectiveness ratio (ICER) of £7742/QALY, WAP would be considered highly cost effective compared to PNI.

CONCLUSIONS

The task-based programme evaluated in this study can provide a template for an effective and economical approach to weight management that can reach clients from disadvantaged communities.

TRIAL REGISTRATION

ISRCTN ISRCTN45820471 . Registered 12/10/2012 (retrospectively registered).

National survey of smoking cessation provision in China

INTRODUCTION

Treatment for smoking cessation is an important part of tobacco control and has been promoted within the Chinese health service for many years. The aim of this study was to assess the current status of smoking cessation treatment provision within the Chinese health service.

METHODS

A nationwide survey, sponsored by the National Health and Family Planning Commission, assessed smoking cessation activities in all 31 Provincial Health and Family Planning Commissions (PHFPCs) in China. Within the 31 provinces, 366 hospitals and primary care centers running smoking cessation clinics provided details of their activities.

RESULTS

Findings show that all PHFPCs took steps to promote smoking cessation, such as by conducting inspections and supervising local cessation clinics. Specifically, among the 366 health institutions,73% were based in general hospitals, with smoking cessation clinics predominantly located in respiratory departments. Furthermore, only 43% provided smoking cessation medications.

CONCLUSIONS

This was the first nationwide survey of smoking cessation support available to smokers in China. It provides the most comprehensive picture of the treatment arm of smoking cessation activities so far. The Chinese government has taken measures to support smoking cessation, however, further efforts are needed to address the imbalanced distribution of resources and the limited availability of medications. On-going monitoring of barriers and facilitators affecting treatment provision is needed, as well as an understanding of the importance of each hospital focusing on working priorities specific to their needs. This survey could be a reference for other countries starting to promote smoking cessation.

Are 'dual users' who smoke and use e-cigarettes interested in using varenicline to stop smoking altogether, and can they benefit from it? A cohort study of UK vapers

OBJECTIVES

Smokers who use e-cigarettes (EC) do so mostly to stop smoking, but many continue to use both products. It is not known whether these 'dual users' are interested in stop-smoking medications and whether they can benefit from them.

SETTING, PARTICIPANTS AND MEASURES

Dual users were recruited over social media and posted study questionnaire and saliva kits at baseline, 3 and 6 months. Those interested in varenicline were posted the medication and received weekly calls over the first 6 weeks, followed by three calls at fortnightly intervals.

RESULTS

Of 204 participants, 124 (61%, CI=54% to 68%) expressed interest in receiving varenicline and 80 (39%, CI=32% to 45%) started varenicline (varenicline users, VU). VU were more dependent smokers (F=6.2, p=0.01) with higher cigarette consumption (F=8.7, p<0.01) who were using stronger nicotine e-liquids (F=13.9, p<0.001) than dual users not opting for varenicline (varenicline non-users, VN). In terms of abstinence for at least 3 months at the 6-month follow-up, VU were more likely than VN to report abstinence from smoking (17.5% vs 4.8%, p=0.006, RR=3.6, CI:1.4 to 9.0), vaping (12.5% vs 1.6%, p=0.007, RR=7.8, CI:1.7 to 34.5) and both smoking and vaping (8.8% vs 0.8%, p=0.02, RR=10.9, CI:1.4 to 86.6). The differences were significant across sensitivity analyses (RRs=4.9 to 14.0; p=0.02 to p<0.001 at 3 months; RRs=3.0 to 14.0; p=0.01 to p<0.001 at 6 months). VU reported a greater reduction in enjoyment of vaping by the end of the varenicline use period (F=4.1, p=0.04) and recorded a significantly greater reduction in nicotine intake than VN at 3 months (F=13.9, p<0.001) and 6 months (F=26.5, p<0.001).

CONCLUSION

Varenicline offered to dual users is likely to promote successful abstinence from both smoking and vaping, although a randomised trial is needed to confirm this. Among dual users who want to stop smoking, there seems to be a high level of interest in smoking-cessation treatments.

Progressive nicotine patch dosing prior to quitting smoking: feasibility, safety and effects during the pre-quit and post-quit periods

BACKGROUND AND AIMS

Nicotine replacement therapy (NRT) may be more effective in aiding smoking cessation if higher doses of nicotine from it can be tolerated. We examined the responses to, and 4-week abstinence rates observed, when titrating the dose of transdermal nicotine patch up to 84 mg/day over 4 weeks prior to a target quit date and titrating down again over 4 weeks afterwards.

DESIGN

Clinical cohort study.

SETTING

Tobacco dependence clinic, Mar del Plata, Argentina.

PARTICIPANTS

Fifty smokers seeking help with stopping smoking.

INTERVENTION

Participants started on one 21-mg/24-hour patch 4 weeks prior to their target quit day (TQD). The dose was increased weekly by adding a 21-mg patch unless participants reported adverse effects and/or did not wish to increase the dose. The dose was reduced by 21 mg/day each week from 1 week post-TQD, until it reverted to the standard dose (21 mg/day) at 4 weeks post-TQD. Participants received weekly behavioural support and could also use oral NRT from the TQD. Participants were advised to smoke ad libitum during the pre-quit period.

MEASUREMENTS

Proportion of participants progressing through each stage of dosing, adherence, adverse effects, changes in cigarette consumption, smoke intake and enjoyment of smoking during the pre-quit period; withdrawal symptoms; carbon monoxide-validated abstinence during 4 weeks post-TQD.

FINDINGS

Of the 50 participants, 72.0% (n = 36) progressed to the 84-mg nicotine dose and 94.0% (n = 47) completed the trial. Adverse effects consisted primarily of nausea and were mild and well tolerated. Cigarette consumption, smoke intake and enjoyment of smoking declined significantly during the pre-quit period. Forty-one (82%) participants achieved 4 weeks validated abstinence. Abstainers experienced no detectable cigarette withdrawal symptoms.

CONCLUSIONS

Most smokers seeking help with stopping appear to be able to tolerate doses of transdermal nicotine patch up to 84 mg/day during a 4-week pre-quit up-titration period with minimal side effects.