The multiple risk factor intervention trial (MRFIT). V. Intervention on smoking

Strategies to improve smoking cessation rates in primary care

BACKGROUND

Primary care is an important setting in which to treat tobacco addiction. However, the rates at which providers address smoking cessation and the success of that support vary. Strategies can be implemented to improve and increase the delivery of smoking cessation support (e.g. through provider training), and to increase the amount and breadth of support given to people who smoke (e.g. through additional counseling or tailored printed materials).

OBJECTIVES

To assess the effectiveness of strategies intended to increase the success of smoking cessation interventions in primary care settings. To assess whether any effect that these interventions have on smoking cessation may be due to increased implementation by healthcare providers.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and trial registries to 10 September 2020.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and cluster-RCTs (cRCTs) carried out in primary care, including non-pregnant adults. Studies investigated a strategy or strategies to improve the implementation or success of smoking cessation treatment in primary care. These strategies could include interventions designed to increase or enhance the quality of existing support, or smoking cessation interventions offered in addition to standard care (adjunctive interventions). Intervention strategies had to be tested in addition to and in comparison with standard care, or in addition to other active intervention strategies if the effect of an individual strategy could be isolated. Standard care typically incorporates physician-delivered brief behavioral support, and an offer of smoking cessation medication, but differs across studies. Studies had to measure smoking abstinence at six months' follow-up or longer.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. Our primary outcome - smoking abstinence - was measured using the most rigorous intention-to-treat definition available. We also extracted outcome data for quit attempts, and the following markers of healthcare provider performance: asking about smoking status; advising on cessation; assessment of participant readiness to quit; assisting with cessation; arranging follow-up for smoking participants. Where more than one study investigated the same strategy or set of strategies, and measured the same outcome, we conducted meta-analyses using Mantel-Haenszel random-effects methods to generate pooled risk ratios (RRs) and 95% confidence intervals (CIs).

MAIN RESULTS

We included 81 RCTs and cRCTs, involving 112,159 participants. Fourteen were rated at low risk of bias, 44 at high risk, and the remainder at unclear risk. We identified moderate-certainty evidence, limited by inconsistency, that the provision of adjunctive counseling by a health professional other than the physician (RR 1.31, 95% CI 1.10 to 1.55; I2 = 44%; 22 studies, 18,150 participants), and provision of cost-free medications (RR 1.36, 95% CI 1.05 to 1.76; I2 = 63%; 10 studies,7560 participants) increased smoking quit rates in primary care. There was also moderate-certainty evidence, limited by risk of bias, that the addition of tailored print materials to standard smoking cessation treatment increased the number of people who had successfully stopped smoking at six months' follow-up or more (RR 1.29, 95% CI 1.04 to 1.59; I2 = 37%; 6 studies, 15,978 participants). There was no clear evidence that providing participants who smoked with biomedical risk feedback increased their likelihood of quitting (RR 1.07, 95% CI 0.81 to 1.41; I2 = 40%; 7 studies, 3491 participants), or that provider smoking cessation training (RR 1.10, 95% CI 0.85 to 1.41; I2 = 66%; 7 studies, 13,685 participants) or provider incentives (RR 1.14, 95% CI 0.97 to 1.34; I2 = 0%; 2 studies, 2454 participants) increased smoking abstinence rates. However, in assessing the former two strategies we judged the evidence to be of low certainty and in assessing the latter strategies it was of very low certainty. We downgraded the evidence due to imprecision, inconsistency and risk of bias across these comparisons. There was some indication that provider training increased the delivery of smoking cessation support, along with the provision of adjunctive counseling and cost-free medications. However, our secondary outcomes were not measured consistently, and in many cases analyses were subject to substantial statistical heterogeneity, imprecision, or both, making it difficult to draw conclusions. Thirty-four studies investigated multicomponent interventions to improve smoking cessation rates. There was substantial variation in the combinations of strategies tested, and the resulting individual study effect estimates, precluding meta-analyses in most cases. Meta-analyses provided some evidence that adjunctive counseling combined with either cost-free medications or provider training enhanced quit rates when compared with standard care alone. However, analyses were limited by small numbers of events, high statistical heterogeneity, and studies at high risk of bias. Analyses looking at the effects of combining provider training with flow sheets to aid physician decision-making, and with outreach facilitation, found no clear evidence that these combinations increased quit rates; however, analyses were limited by imprecision, and there was some indication that these approaches did improve some forms of provider implementation.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that providing adjunctive counseling by an allied health professional, cost-free smoking cessation medications, and tailored printed materials as part of smoking cessation support in primary care can increase the number of people who achieve smoking cessation. There is no clear evidence that providing participants with biomedical risk feedback, or primary care providers with training or incentives to provide smoking cessation support enhance quit rates. However, we rated this evidence as of low or very low certainty, and so conclusions are likely to change as further evidence becomes available. Most of the studies in this review evaluated smoking cessation interventions that had already been extensively tested in the general population. Further studies should assess strategies designed to optimize the delivery of those interventions already known to be effective within the primary care setting. Such studies should be cluster-randomized to account for the implications of implementation in this particular setting. Due to substantial variation between studies in this review, identifying optimal characteristics of multicomponent interventions to improve the delivery of smoking cessation treatment was challenging. Future research could use component network meta-analysis to investigate this further.

The Purdue Stepped Approach Model: Sequencing Community and Clinical Interventions to Reduce Cardiovascular Risk Factors

The Purdue Stepped Approach Model (PM) is applied to the reduction of cardiovascular risk factors. The PM is schema for service delivery that increases the intensity of interventions presented in a series. Community interventions are sequentially introduced followed by clinical programs. Benefits of community interventions and clinical programs are discussed which include target of a large number of people, optimal utilization of technology and human capital, responsiveness to individual differences, and increased likelihood of permanence of behavior change. Empirical support from community and clinical research are provided. The five steps of the model are described and an heuristic example is illustrated. The PM may expand the role of community health educators and may lead to the evolution of more inclusive means of delivering community and clinical health programs.

The Purdue Stepped Approach Model

This article presents an implementation strategy for health counseling based on the Purdue Stepped Approach Model (PM). The PM increases the intensity of interventions presented in a series. Selected issues in behavioral and health counseling that led to the development of the model, including cost-effectiveness, response of clients to treatment, and client commitment to and involvement in the therapeutic process, are discussed. A description of and empirical support for the PM are provided. Procedures and an example of the model's application to health counseling are included. Several potential benefits of the stepped approach are also discussed.

Predictors of Utilization of a Novel Smoking Cessation Smartphone App

BACKGROUND

Understanding the characteristics of high and low utilizers of smartphone applications (apps) for smoking cessation would inform development of more engaging and effective apps, yet no studies to date have addressed this critical question. Informed by prior research on predictors of cessation Web site utilization, this study examines the degree to which baseline demographic factors (gender, age, and education), smoking-related factors (smoking level and friends' smoking), and psychological factors (depression and anxiety) are predictive of utilization of a smartphone app for smoking cessation called SmartQuit.

MATERIALS AND METHODS

Data came from 98 participants randomized to SmartQuit as part of a pilot trial from March to May 2013. We used negative binomial count regressions to examine the relationship between user characteristics and utilization of the app over an 8-week treatment period.

RESULTS

Lower education (risk ratio [RR]=0.492; p=0.021), heavier smoking (RR=0.613; p=0.033), and depression (RR=0.958; p=0.017) prospectively predicted lower app utilization. Women (RR=0.320; p=0.022), those with lower education (RR=0.491; p=0.013), and heavier smokers (RR=0.418; p=0.039) had lower utilization of app features known to predict smoking cessation.

CONCLUSIONS

Many of the predictors of utilization of smoking cessation apps are the same as those of cessation Web sites. App-delivered smoking cessation treatment effectiveness could be enhanced by focusing on increasing engagement of women, those with lower education, heavy smokers, and those with current depressive symptoms.

Natural history of attempts to stop smoking

INTRODUCTION

This study provides a prospective fine-grain description of the incidence and pattern of intentions to quit, quit attempts, abstinence, and reduction in order to address several clinical questions about self-quitting.

METHODS

A total of 152 smokers who planned to quit in the next 3 months called nightly for 12 weeks to an Interactive Voice Response system to report cigarettes/day, quit attempts, intentions to smoke or not in the next day, and so forth. No treatment was provided.

RESULTS

Most smokers (60%) made multiple transitions among smoking, reduction, and abstinence. Intention to not smoke or quit often did not result in a quit attempt but were still strong predictors of a quit attempt and eventual abstinence. Most quit attempts (79%) lasted less than 1 day; about one fifth (18%) of the participants were abstinent at 12 weeks. The majority of quit attempts (72%) were not preceded by an intention to quit. Such quit attempts were shorter than quit attempts preceded by an intention to quit (<1 day vs. 25 days). Most smokers (67%) used a treatment, and use of a treatment was nonsignificantly associated with greater abstinence (14 days vs. 3 days). Making a quit attempt and failing early predicted an increased probability of a later quit attempt compared to not making a quit attempt early (86% vs. 67%). Smokers often (17%) failed to report brief quit attempts on an end-of-study survey.

CONCLUSIONS

Cessation is a more chronic, complex, and dynamic process than many theories or treatments assume.

Protecting children from taking up smoking: parents' views on what would help

ISSUE ADDRESSED

The present study investigated what factors the parents of children in low-income areas of Auckland, New Zealand, thought could help protect their children from smoking initiation.

METHODS

Participants in a large quasi-experimental trial that tested a community-, school- and family-based smoking-initiation intervention were asked in a questionnaire 'What could we do to help you protect your children from smoke and taking up smoking?' Free-text responses were divided into distinct meaning units and categorised independently by two of the researchers.

RESULTS

1806 participants (70% of parents who returned the questionnaire) completed the question. The majority of respondents (80%) were either Pacific Island or Māori mothers and 25% were current smokers. Five main categories of suggested strategies for preventing smoking initiation were identified: building children's knowledge of the ill-effects of smoking; denormalising smoking; reducing access to tobacco; building children's resilience; and health promotion activities. The most common suggestion was to educate children about smoking.

CONCLUSION

Building children's knowledge of smoking risks was the main strategy parents proposed. There was some support for banning smoking in most public areas and for tougher moves to stop tobacco sales to minors. Few parents suggested innovative or radical strategies, such as banning the sale of tobacco, fining children for smoking or use of competitions. So what? To ensure reductions in smoking initiation for lower socioeconomic and Māori and Pacific Island people, further research should engage Māori, Pacific Island and lower socioeconomic parents in a process that elicits innovative thinking about culturally acceptable strategies.

Multiple risk factor intervention trial revisited: a new perspective based on nonfatal and fatal composite endpoints, coronary and cardiovascular, during the trial

Background

The Multiple Risk Factor Intervention Trial evaluated a multifactor intervention on coronary heart disease (CHD) in 12 866 men. A priori defined endpoints (CHD death, CHD death or nonfatal myocardial infarction, cardiovascular disease [CVD] death, and all-cause death) did not differ significantly between the special intervention (SI) and usual care (UC) groups over an average follow-up period of 7 years. Event rates were lower than anticipated, reducing power. Other nonfatal CVD outcomes were prespecified but not considered in composite outcomes comparing SI with UC.

Methods and Results

Post-trial CVD mortality risks associated with nonfatal CVD events occurring during the trial were determined with Cox regression. Nonfatal outcomes associated with >2-fold risk of CVD death over the subsequent 20 years were combined with during-trial deaths to create 2 new composite outcomes. SI/UC hazard ratios and 95% confidence intervals were estimated for each composite outcome. Of 10 during-trial nonfatal events, 6 were associated (P<0.001) with >2-fold risk of CVD death. A CHD composite outcome (CHD death, myocardial infarction [clinical or serial ECG change], CHF, or coronary artery surgery) was experienced by 520 SI and 602 UC men (SI/UC hazard ratio = 0.86; 95% confidence interval, 0.76–0.97; P=0.01). A CVD composite outcome (CHD [as above], other CVD deaths, stroke, or renal impairment) was experienced by 581 SI and 652 UC men (hazard ratio = 0.89; 95% confidence interval, 0.79–0.99; P=0.04).

Conclusions

In post hoc analyses, composite fatal/nonfatal CHD and CVD rates over 7 years were significantly lower for SI than for UC. These findings reinforce recommendations for improved dietary/lifestyle practices, with pharmacological therapy as needed, to prevent and control major CVD risk factors.

The day-to-day process of stopping or reducing smoking: a prospective study of self-changers

INTRODUCTION

Almost all descriptions of attempts to quit smoking have focused on what happens after an abrupt quit attempt and end once a smoker relapses. The current study examined the day-to-day process preceding a quit or reduction attempt in addition to the daily process after a failure to quit or reduce.

METHODS

We recruited 220 adult daily cigarette smokers who planned to quit abruptly, to quit gradually, to reduce only, or to not change on their own. Participants called a voice mail system each night for 28 days to report cigarette use for that day and their intentions for smoking for the next day. No treatment was provided.

RESULTS

Three main findings emerged: (a) The large majority of participants did not show a simple pattern of change but rather showed a pattern of multiple transitions among smoking, abstinence, and reduction over a short period of time; (b) most of those who reported an initial goal to quit abruptly actually reduced; and (c) daily intentions to quit strongly predicted abstinence, while daily intentions to reduce weakly predicted reduction.

DISCUSSION

We conclude that the day-to-day process of attempts to change smoking among nontreatment seekers is much more dynamic than previously thought. This suggests that extended treatment beyond initial lapses and relapses and during postcessation reduction may be helpful.

Relapse to smoking after 1 year of abstinence: a meta-analysis

Most clinical trials use 6 months or 1 year follow-ups as proxies for life-time smoking cessation. Retrospective studies have estimated 2-15% of smokers relapse each year after the first year of abstinence, but these have methodological problems such as memory bias. We searched for prospective studies of adult quitters that reported the number of participants abstinent at 1 yr follow-up and who remained abstinent at >or=2 year follow-ups. We included studies that reported the percent which remained lapse-free, did not continue treatment after 1 year, and had <or=10% lost-to-follow-up. We did not locate any population-based studies but did locate eight randomized, controlled trials, all testing nicotine medications. After deleting one trial with outlier results, a meta-analysis estimated the annual incidence of relapse after 1 year to be 10%; however, the small sample sizes resulted in a wide 95% confidence interval (5-17%) suggesting this estimate is not very accurate. We conclude a non-significant amount of relapse occurs after 1 year. Better quantification of this relapse rate is important to improve estimates of life-long abstinence and reductions in morbidity and mortality from smoking cessation.

An algorithm for choosing among smoking cessation treatments

Currently, there are nine validated medications, four validated psychosocial strategies, and three validated ways to deliver psychosocial treatments for smoking cessation. This article presents an algorithm based on a literature review and the author's clinical experience. The algorithm integrates the recommendations of the major guidelines and meta-analyses and provides rationales for its treatment decisions. The algorithm suggests a brief assessment followed by use of one to two medications and counseling in most smokers. Because all treatments appear equally effective and have few adverse events, the algorithm suggests clinicians inform smokers of the pros and cons of the different treatments, and recommend use of one or more of each. If a smoker fails to quit, the algorithm suggests an assessment of why relapse occurred and then a more intense treatment, a new treatment, or both.

Prognostic factors for tobacco consumption reduction after relapse

INTRODUCTION

It is not properly estimated the cigarette consumption after a relapse compared with the consumption before a smoking cessation therapy. The aim of this study was to know if tobacco consumption among relapsed smokers that visited a smoking cessation unit is higher or lower than consumption preceding dishabituation therapy and the related factors to this consumption change.

SUBJECTS AND METHODS

1,516 smokers who received a multicomponent program for smoking cessation have been studied. The percentage of reduction after the relapse in relation to previous consumption and the consumption difference with regard to basal variables among 994 relapsed smokers has been calculated. A logistic regression model was used in order to analyze the predictors to reduce more than 50% of previous cigarette consumption.

RESULTS

Relapsed patients smoked 20.4% less than before the smoking cessation therapy. Smokers with chronic obstructive pulmonary disease, and with the age of 50 years or more, had the highest rate of reduction consumption. The best predictors for cigarette reduction were those of low nicotine dependence and being heavy smokers.

CONCLUSIONS

Heavy smokers or low nicotine dependence smokers have a higher probability to reduce their cigarette consumption. Other predictor variables are age of more than 50 years, high previous consumption or previous abstinence period of more than 6 months.

Social support interventions: do they work?

Presence of support has repeatedly been linked to good long-term health outcomes based on demonstrations of better immune function, lower blood pressures, and reduced mortality (among others). Despite a massive literature on the benefits of support, there is surprisingly little hard evidence about how, and how well, social support interventions work. Using a computerized search strategy, 100 studies that evaluated the efficacy of such interventions were located. The presenting problems ranged from cancer, loneliness, weight loss, and substance abuse to lack in parenting skills, surgery, and birth preparation. For the purpose of review and evaluation, studies were subdivided into (1) group vs. individual interventions, (2) professionally led vs. peer-provided treatment, and (3) interventions where an increase of network size or perceived support was the primary target vs. those where building social skills (to facilitate support creation) was the focus. On the whole, this review provided some support for the overall usefulness of social support interventions. However, because of the large variety of existing different treatment protocols and areas of application, there is still not enough evidence to conclude which interventions work best for what problems. Specific methodological and conceptual difficulties that plague this area of research and directions for future research are discussed.

Repeated tobacco-use screening and intervention in clinical practice: health impact and cost effectiveness

BACKGROUND

This report updates 2001 estimates of disease burden prevented and cost effectiveness of tobacco-use screening and brief intervention relative to that of other clinical preventive services. It also addresses repeated counseling because the literature has focused on single episodes of treatment, while in reality that is neither desirable nor likely.

METHODS

Literature searches led to four models for calculating the clinically preventable burden of deaths and morbidity from smoking as well as the cost effectiveness of providing the service annually over time. The same methods were used in similar calculations for other preventive services to facilitate comparison.

RESULTS

Using methods consistent with existing literature for this service, an estimated 190,000 undiscounted quality-adjusted life years (QALYs) are saved at a cost of $1100 per QALY saved (discounted). These estimates exclude financial savings from smoking-attributable disease prevented and use the average 12-month quit rate in clinical practice for tobacco screening and brief cessation counseling with cessation medications (5.0%) and without (2.4%). Including the savings of prevented smoking-attributable disease and using the effectiveness of repeated interventions over the lifetime of smokers (23.1%), 2.47 million QALYs are saved at a cost savings of $500 per smoker who receives the service.

CONCLUSIONS

This analysis makes repeated clinical tobacco-cessation counseling one of the three most important and cost-effective preventive services that can be provided in medical practice. Greater efforts are needed to achieve more of this potential value by increasing current low levels of performance.

The feasibility of smoking reduction: an update

AIM

To update conclusions of a previous review of smoking reduction on the extent to which (1) smokers spontaneously reduce their smoking, (2) smokers who try to quit and fail return to smoking less, (3) smokers can substantially reduce and maintain reductions via pharmacological and behavioral treatments and (4) smokers compensate when they reduce.

METHOD

Qualitative systematic review.

DATA SOURCES

Systematic computer searches and other methods.

STUDY SELECTION

Published and unpublished studies of smokers not trying to stop smoking. We located 13-26 studies for each of the four aims.

DATA EXTRACTION

The first author entered data with confirmation by second author.

DATA SYNTHESIS

Due to the heterogeneity of methods and necessity of extensive recalculation, a meta-analysis was not feasible.

RESULTS

Few daily smokers spontaneously reduce. Among those who try to stop smoking and relapse, some return to reduced smoking but whether they maintain this reduction is unclear. Nicotine replacement (and perhaps behavior therapies) can induce smokers not interested in quitting to make significant reductions in their smoking and maintain these over time. Some compensatory smoking occurs with reduction but significant declines in smoke exposure still occur.

CONCLUSIONS

These results indicate that reduction is feasible when aided by treatment. Whether reduction should be promoted will depend on the effect of reduction on health outcomes and future cessation.

Smoking cessation intervention in a large randomised population-based study. The Inter99 study

BACKGROUND

Several large and well-conducted community interventions have failed to detect an effect on prevalence of smoking.

METHODS

Two thousand four hundred eight daily smokers in all motivational stages were actively recruited and included in a randomised population-based intervention study in Copenhagen, Denmark. All smokers completed a questionnaire and underwent a health examination and a lifestyle consultation. Daily smokers in the high intensity intervention group were offered assistance to quit in smoking cessation groups.

RESULTS

The validated abstinence rate at 1-year follow-up was 16.3% in the high intensity group and 12.7% in the low intensity group compared with a self-reported abstinence rate of 7.3% in the background population. The adjusted odds ratio of abstinence in the high intervention group was significantly higher, OR = 2.2 (1.6-3.0) than in the background population, also in the 'intention-to-treat' analyses, OR = 1.5 (1.1-2.0). Higher socioeconomic status, higher age at onset of daily smoking, and a higher wish to quit were predictors of success.

CONCLUSION

In a population-based setting, using active recruitment and offering assistance to quit, it was possible to include many smokers and to achieve a significantly higher validated abstinence in the high intensity intervention than in the background population, even when using 'intention-to-treat' analyses.

A comparison of four self-report smoking cessation outcome measures

Interventions for smoking cessation have been developed by researchers in a number of distinct disciplines. As a result, a variety of different outcome measures have been developed and employed. This paper will report an analysis that compares four smoking cessation outcome measures on data gathered from three population-based studies: (1) 24-hour point prevalence abstinence, (2) 7-day point prevalence abstinence, (3) 30-day prolonged abstinence, and (4) 6-month prolonged abstinence. The three studies provided a total of 41 mean estimates for the first three measures but only 28 mean estimates for the 6-month prolonged abstinence measure. The data demonstrate an extremely high relationship between all four measures. The first three measures (24-hour point prevalence, 7-day point prevalence, and 30-day prolonged abstinence) all correlated in excess of.98 with each other. The only measure that did not demonstrate the same degree of almost perfect equivalence was 6-month prolonged abstinence, but even here the lowest correlation with the other three measures was.82. For practical purposes, the first three measures will result in the same conclusions when used as outcome measures in smoking cessation studies.

Reduction of quantity smoked predicts future cessation among older smokers

AIM

To examine whether smokers who reduce their quantity of cigarettes smoked between two periods are more or less likely to quit subsequently.

STUDY DESIGN

Data come from the Health and Retirement Study, a nationally representative survey of older Americans aged 51-61 in 1991 followed every 2 years from 1992 to 1998. The 2064 participants smoking at baseline and the first follow-up comprise the main sample.

MEASUREMENTS

Smoking cessation by 1996 is examined as the primary outcome. A secondary outcome is relapse by 1998. Spontaneous changes in smoking quantity between the first two waves make up the key predictor variables. Control variables include gender, age, education, race, marital status, alcohol use, psychiatric problems, acute or chronic health problems and smoking quantity.

FINDINGS

Large (over 50%) and even moderate (25-50%) reductions in quantity smoked between 1992 and 1994 predict prospectively increased likelihood of cessation in 1996 compared to no change in quantity (OR 2.96, P<0.001 and OR 1.61, P<0.01, respectively). Additionally, those who reduced and then quit were somewhat less likely to relapse by 1998 than those who did not reduce in the 2 years prior to quitting.

CONCLUSIONS

Reducing successfully the quantity of cigarettes smoked appears to have a beneficial effect on future cessation likelihood, even after controlling for initial smoking level and other variables known to impact smoking cessation. These results indicate that the harm reduction strategy of reduced smoking warrants further study.

Special intervention reduces CVD mortality for adherent participants in the multiple risk factor intervention trial

BACKGROUND

Patient adherence affects treatment efficacy, and surprisingly, adherence is frequently associated with reductions in mortality for those receiving placebo.

METHODS

This study considers the role of trial adherence for men (N = 12,338) in the Multiple Risk Factor Intervention Trial (MRFIT), a prospective study of 9-year follow-up mortality following randomization to Special Intervention (SI) or Usual Care (UC). Annual visit attendance rates were used as a measure of adherence.

RESULTS

A significant Adherence x Group Assignment interaction (p =.002) revealed that SI significantly reduced cardiovascular disease (CVD) mortality for highly adherent participants, RR =.91 (95% confidence interval [CI] =.84-.99) but significantly increased CVD mortality for poorly adherent participants, RR = 1.28 (95% CI = 1.05-1.57) when compared to UC. These associations remained after controlling for baseline characteristics (e.g., income), reported illness, or occurrence of a nonfatal CVD event during the trial. The beneficial effect of SI among the adherent participants was partly due to reduced smoking and diastolic blood pressure levels during the trial.

CONCLUSIONS

SI significantly reduced the risk of CVD mortality for participants adherent with the MRFIT, and this effect was accounted for by positive changes in CVD risk factors. These findings suggest a method for evaluating treatment efficacy in subgroups determined by patient responses (e.g., adherence to annual assessment visits) to the treatment program after randomization.

Pulmonary function as a predictor of lung cancer mortality in continuing cigarette smokers and in quitters

BACKGROUND

Forced expiratory volume in 1 second (FEV(1)) may be useful for identifying smokers at higher risk of lung cancer. We examined the association of FEV(1) with lung cancer mortality (LCM) among cigarette smokers in the Multiple Risk Factor Intervention Trial (MRFIT).

METHODS

In all, 6613 MRFIT baseline smokers alive at trial end in 1982 had acceptable FEV(1) measures and complete smoking history; men were classified as during-trial long-term quitters (N = 1292), intermittent quitters (1961), and never quitters (3360). Proportional hazards models for LCM were fit with quintiles of average FEV(1), adjusted for age, height, race, smoking history, and other risk factors.

RESULTS

For long-term, intermittent, and never quitters respectively, mean baseline cigarettes/ day was 28, 32, and 35; trial-averaged FEV(1) was 3201, 3146, and 3082 ml; and average decline in FEV(1) was -46.0, -54.6, and -62.5 ml/year. With median post-trial mortality follow-up of 18 years, there were 363 lung cancer deaths. Age-adjusted LCM rates varied across FEV(1) quintiles from 50 (lowest quintile) to 11 (highest quintile), 58 to 11, and 76 to 20, per 10 000 person-years, for long-term quitters, intermittent quitters, and never quitters, respectively. Multivariate adjusted hazard ratios for 100 ml higher FEV(1) were 0.92 [P = 0.004], 0.95 [P = 0.003], and 0.95 [P < 0.0001] respectively.

CONCLUSIONS

These results demonstrate the strong predictive value of FEV(1) for lung cancer among cigarette smokers independent of smoking history; results did not differ by during-trial quit status. FEV(1) may be a biological marker for smoking dose or it may be that genetic susceptibilities to both decreased FEV(1) and lung cancer are associated.

Smoking cessation, smoking reduction, and delayed quitting among smokers given nicotine patches and a self-help pamphlet

Over-the-counter nicotine replacement raises questions regarding its "real world" efficacy. This was an open-label, prospective study of 223 smokers who received 42 free nicotine patches and a self-help booklet via shopping mall distribution. The overall quit rate 6 months following distribution of the nicotine patches was 22% (50/223), almost the same quit rate found 6 weeks following patch distribution (21%, 47/223). Twelve percent (27/223) were abstinent at both 6 weeks and 6 months. Among the 83 participants who did not quit, cigarettes smoked per day dropped from 28 to 18. A substantial subgroup of quitters (14%) who, although still smoking at 6 weeks, were smoke free at 6 months, and it appears they had purposefully delayed a serious quit attempt. These results support the usefulness of nicotine patches in helping smokers quit, even with only minimal intervention such as a self-help manual.

Impact of incident diabetes and incident nonfatal cardiovascular disease on 18-year mortality: the multiple risk factor intervention trial experience

OBJECTIVE

To report long-term risks for total, cardiovascular disease (CVD), and coronary heart disease (CHD) mortality associated with incident diabetes (using current diagnostic criteria) and with incident nonfatal CVD (NF-CVD).

RESEARCH DESIGN AND METHODS

A total of 11645 participants without diabetes or CVD at baseline from the Multiple Risk Factor Intervention Trial who survived to the end of the trial were grouped by during-trial incident diabetes and/or NF-CVD events: neither diabetes nor NF-CVD, diabetes only, NF-CVD only, or both diabetes and NF-CVD. Incident diabetes was defined by use of hypoglycemic agents or fasting glucose >or=126 mg/dl at any time over the 6 trial years. Proportional hazards models tested group differences in mortality over 18 post-trial years.

RESULTS

Among 3859 total deaths were 1846 from CVD and 1277 from CHD, with death rates per 10000 person-years of 203, 97, and 67, respectively. Multivariate-adjusted hazard ratios (HRs) for total mortality were 2.75 (P < 0.0001) for those with NF-CVD and diabetes both, 1.92 (P < 0.0001) for those with NF-CVD only, and 1.49 (P < 0.0001) for those with diabetes only, relative to neither diabetes nor NF-CVD. NF-CVD was associated with a higher hazard of death than diabetes for total (HR 1.29, P = 0.0004), CVD (HR 1.76, P < 0.0001), and CHD (HR 1.88, P < 0.0001) mortality. Only the subgroup of participants on hypoglycemic agents showed an equivalent risk of total mortality relative to participants with NF-CVD (HR 0.93, P = 0.54).

CONCLUSIONS

Current diabetes diagnostic criteria conferred significantly increased total, CVD, and CHD mortality risks independent of the impact of NF-CVD. NF-CVD was more strongly predictive of mortality.

Independent risk for cardiovascular disease predicted by modified continuous score electrocardiographic criteria for 6-year incidence and regression of left ventricular hypertrophy among clinically disease free men: 16-year follow-up for the multiple risk factor intervention trial

Risk prediction for electrocardiographic (ECG) left ventricular hypertrophy related criteria, used in clinical trials, and epidemiologic studies of clinically healthy people, has depended in the past on dichotomous classification of ECG LVH criteria. Recent analyses have shown that more sensitive methods of LVH ECG classification without loss of specificity are needed to improve on dichotomous classification. This was done by relating six year incident significant change in continuous score criteria of ECG LVH to the 16 year (10 year post trial) coronary heart disease (CHD) and cardiovascular disease (CVD) mortality among 12,866 men, free of clinical disease, aged 35 to 57 years at baseline in the Multiple Risk Factor Intervention Trial. It was found that significant change in continuous ECG LVH criteria was a stronger independent predictor of future CHD and CVD mortality than was use of dichotomous classification of the same criteria. It was also demonstrated that increase in continuous ECG LVH indexes, below previous dichotomous thresholds independently (of standard CVD risk factors, including increase in obesity-indicated by an increase in adult BMI) predicted excess CHD and CVD mortality and that combinations of continuous indices increases the specificity and relative risk in clinically disease-free middle-aged men.

Compliance with cardiovascular disease prevention strategies: a review of the research

The efficacy of cardiovascular risk-reduction programs has been established. However, the extent to which risk-reduction interventions are effective may depend on adherence. Non-compliance, or non-adherence, may occur with any of the recommended or prescribed regimens and may vary across the treatment course. Compliance problems, whether occurring early or late in the treatment course, are clinically significant, as adherence is one mediator of the clinical outcome. This article, which is based on a review of the empirical literature of the past 20 years, addresses compliance across four regimens of cardiovascular risk reduction: pharmacological therapy, exercise, nutrition, and smoking cessation. The criteria for inclusion of a study in this review were: (a) focus on cardiovascular disease risk reduction; (b) report of a quantitative measure of compliance behavior; and (c) use of a randomized controlled design. Forty-six studies meeting these criteria were identified. A variety of self-report, objective, and electronic measurement methods were used across these studies. The interventions employed diverse combinations of cognitive, educational, and behavioral strategies to improve compliance in an array of settings. The strategies demonstrated to be successful in improving compliance included behavioral skill training, self-monitoring, telephone/mail contact, self-efficacy enhancement, and external cognitive aids. A series of tables summarize the intervention strategies, compliance measures, and findings, as well as the interventions demonstrated to be successful. This review reflects the progress made over two decades in compliance measurement and research and, further, advances made in the application of behavioral strategies to the promotion of cardiovascular risk reduction.

Smoking cessation and lung cancer resection

STUDY OBJECTIVE

This study was designed to examine the extent of smoking cessation prior to thoracotomy for resection of a pulmonary malignancy and the recidivism rate.

DESIGN

Prospective, longitudinal study.

PATIENTS

All patients presenting to the General Thoracic Clinic.

RESULTS

The study included 362 patients, with an average age of 64.7 years; 95% with a smoking history were followed up for an average of 17.5 months. Five surgeons in the same practice group performed the procedures: pneumonectomy, 45; lobectomy, 288; and lesser resections, 29. Forty-two percent of patients had quit prior to 1 year; 6% quit 3 months to 1 year; 15% quit between 2 weeks to 3 months; 12% quit at 2 weeks; and 19% continued to smoke up to surgery. Postoperatively, 86% of previously smoking patients were nonsmoking; 13% of patients started smoking again. Of the restarted smoking patients, 61% had never quit preoperatively. Only 59% of smoking patients admitted that a physician had ever told them to stop smoking; however, 89% of patients who were smoking postoperatively acknowledged physician advice to stop smoking.

CONCLUSIONS

Long-term smoking cessation occurs in a large proportion of patients after resection of lung cancer. The longer the patient is nonsmoking preoperatively, the more likely he or she is to remain nonsmoking postoperatively. Conversely, patients who do not quit preoperatively are at significant risk of continuing to smoke postoperatively.

Mortality after 16 years for participants randomized to the Multiple Risk Factor Intervention Trial

BACKGROUND

A mortality follow-up of 12,866 men was conducted 16 years after randomization to special intervention (SI) or usual care (UC) groups of the Multiple Risk Factor Intervention Trial to assess the long-term effect of cardiovascular risk factor intervention on coronary heart disease (CHD), cardiovascular death (CVD), and total mortality.

METHODS AND RESULTS

During the 7-year active-intervention phase of the trial, 6428 of the men were given dietary recommendations to lower blood cholesterol, antihypertensive drugs to lower blood pressure, and counseling for cigarette smoking cessation. The remaining 6438 men were referred to their usual source of medical care. After 16 years, 370 SI and 417 UC men had died from CHD, which represents an 11.4% lower mortality rate for SI versus UC men (95% CI, -23% to 1.9%). Results for total mortality followed a similar pattern; 991 SI and 1050 UC men had died by the end of follow-up (relative difference, -5.7%; 95% CI, -13% to 2.8%). For acute myocardial infarction, a subcategory of CHD, the relative difference was -20.4% (95% CI, -34.4% to -3.4%). Differences between SI and UC men in mortality rates from acute myocardial infarction, CHD, and all causes were greater during the posttrial follow-up period than during the trial.

CONCLUSIONS

Results of a 7-year multifactor intervention program aimed at lowering blood pressure and serum cholesterol and at cigarette smoking cessation among high-risk men give additional evidence of a long-term, continuing mortality benefit from the program.

Optimization of simulation models with GADELO: a multi-population genetic algorithm

In this paper, a new Genetic Algorithm based on the Dynamic Exploration of Local Optima (GADELO) was used to estimate the parameters of the MRD (Micro-population model of Risk-group Dynamics) micro-population model for smoking cessation by minimizing a deviation function between the model's predictions and the smoking cessation data of the Multiple Risk Factor Intervention Trial (MRFIT). The efficiency and accuracy of the GADELO estimations were consistently superior to those obtained using the standard genetic algorithm or the simplex algorithm of Nelder-Mead.

Estimating the causal effect of smoking cessation in the presence of confounding factors using a rank preserving structural failure time model

Estimating the causal effect of quitting smoking on time to death or first myocardial infarction requires that one control for the differences in risk factors between individuals who elect to quite at each time t versus those who elect to continue smoking at time t. In this paper we examine the limitations of standard time varying Cox proportional hazards models to yield tests and estimates of this effect. Implementing the method of G-estimation proposed by Robins, we perform an observational analysis of data from the Multiple Risk Factor Intervention Trial (MRFIT) and estimate the causal effect of cigarette cessation while controlling for such time varying confounders as angina. We reject the null hypothesis of no effect of quitting on time to failure, and estimate that by quitting smoking, an individual increases by 50 per cent his time to death or first myocardial infarction (MI).

Design of the Lung Health Study: a randomized clinical trial of early intervention for chronic obstructive pulmonary disease

The Lung Health Study is a multicenter randomized clinical trial. Participants are smokers aged 35-60 with spirometric evidence of moderate lung function impairment. The objective of the trial is to determine whether a program of smoking intervention and use of an inhaled bronchodilator can slow the rate of decline in pulmonary function over a 5-year follow-up period. This paper describes the background, design, sample size (approximately 6000 participants), and power estimates for the trial, as well as the treatment program and the rationale for the choice of inhaled bronchodilator. Plans for analysis of changes in pulmonary function parameters and for analysis of participants' survival and smoking-related morbidity are also discussed.

Recycling with nicotine patches in smoking cessation

The aim was to evaluate if recycling of failures from a smoking cessation study may be of value. The study comprised 126 smokers (50%) of 252 failures, from a double-blind smoking cessation trial with nicotine patch, who accepted recycling after 1 year. Subjects were allocated nicotine patches delivering 15, 20 or 25 mg of nicotine (over 16 hours) according to their base-line saliva cotinine concentrations in an open trial. The treatment period was 12 weeks followed by tapering over 6 weeks. The percentage of quitters after 3, 12, 26, and 52 weeks was 44, 20, 7 and 6%, respectively. After 26 weeks, all subjects had relapsed in the group previously treated with active nicotine patch compared with 12% abstainers in the previous placebo subjects. The sustained abstinence rate without slips after one year was 2%. Recycling does not seem to be of long-term clinical relevance in our set-up for subjects initially treated with nicotine, but of some value in subjects quitting without nicotine therapy initially.

A method for the analysis of randomized trials with compliance information: an application to the Multiple Risk Factor Intervention Trial

The standard approach to analyzing randomized trials ignores information on postrandomization compliance. Application of these methods results in estimates that may lack the desired causal interpretation. We employ a new method of estimation and analyze data from the Multiple Risk Factor Intervention Trial (MRFIT) to estimate the causal effect of quitting cigarette smoking. Our procedure utilizes a method proposed by Robins and Tsiatis and allows us to take advantage of postrandomization smoking history without requiring untenable assumptions about the comparability of compliers and noncompliers. We contrast the performance of our method and the standard intent-to-treat analysis in the MRFIT data and in simulated data in which compliance rates are varied.

Time trends of smoking cessation: a micro-population computer simulation model

The Micro-population model of Risk-group Dynamics (MRD) approaches smoking behavior at the level of the individual and integrates physiological and social factors to describe the evolution of behavior change in the population. MRD is innovative in several ways: (1) the model describes mathematically the interactions among these behavioral factors; (2) the model accounts for both the variability of these factors among different persons and the universality of basic rules describing these factors in all individuals; and (3) the model can be applied to various types of populations and a wide range of intervention strategies. MRD combines the physiological, psychological and social determinants into a hazard function for relapse to smoking. This hazard function is then organized into a three term expression incorporating: a baseline hazard characteristic to each individual, a decreasing term for the diminishing aspect of the initial hazard and an effect of external interventions. The model gives promising results when applied to the Multiple Risk Factors Intervention Trial (MRFIT) data using the assumptions of a Weibull distribution for the baseline hazard, a negative exponential for the decrease in the initial hazard and a constant intensity for the external intervention.

Smoking habits in relapsed subjects from a smoking cessation trial after one year

Reports of smoking cessation studies often claim that many relapsed subjects reduce their smoking. We investigated the smoking habits of relapsers 1 year after quitting in a smoking cessation trial using nicotine or placebo patches. All 289 participants in that study were summoned to a 1-year follow-up visit--148 (57%) of 259 relapsers attended, as did all 30 sustained abstainers. Fewer than 1% of the subjects had quit spontaneously after the primary relapse. Daily cigarette consumption, standard nicotine yield per cigarette, saliva cotinine concentration, expired carbon monoxide level and two nicotine dependency scales were assessed at entry and at the 1-year follow-up. In five of these six smoking-related characteristics, there was a small but significant mean reduction of 7%-27%. A significant weight gain of 0.5 +/- 2.9 kg (mean +/- SD) was recorded in the relapsers compared with 4.8 +/- 4.2 kg for abstainers (p less than 0.001). It is concluded that smoking habits in relapsers are relatively unchanged, and thus the most important outcome measure in smoking cessation trials is abstinent subjects.

Cigarette smoking and mortality. MRFIT Research Group

METHODS

The relationship of cigarette smoking and smoking cessation to mortality was investigated among men screened for and also among those randomized to the Multiple Risk Factor Intervention Trial (MRFIT).

RESULTS

Among the 361,662 men screened for the MRFIT, cigarette smoking was an important risk factor for all-cause, coronary heart disease (CHD), stroke, and cancer mortality. These risks, on the log relative scale, were strongest for cancers of the lung, mouth, and larynx. The excess risk associated with cigarette smoking was greatest for death from CHD. Overall, approximately one-half of all deaths were associated with cigarette smoking. Among the 12,866 randomized participants, weak positive associations with duration of cigarette smoking habit and tar and nicotine levels were found with all-cause mortality. For both SI and UC men, substantial differences in subsequent CHD (34-49%) and all-cause (35-47%) mortality were evident for men who reported cigarette smoking cessation by the end of the trial compared with those continuing to smoke. There was no evidence that lung cancer death rates were lower among cigarette smokers who quite compared with those who continued to smoke in this 10-year follow-up period.

CONCLUSION

The data are consistent with results of previous epidemiologic studies indicating that the benefits of smoking cessation on CHD are rapid, while for lung cancer, the benefit is not evident in a 10-year follow-up period.

Baseline factors associated with smoking cessation and relapse. MRFIT Research Group

BACKGROUND

Data on smoking cessation and relapse for 6 yers of the Multiple Risk Factor Intervention Trial were evaluated in univariate and multivariate analyses to determine the relationship between variables measured at the beginning of the trial and smoking cessation and relapse for special intervention and usual care participants.

RESULTS

The variables positively associated with smoking cessation in both the SI and the UC groups included age, education, and past success in quitting; there was a negative association with the number of cigarettes smoked per day. The expectation of quitting was positively associated with cessation in the special intervention group only, while life events, alcohol, and the presence of a wife who smokes were significant predictors of reduced cessation for the usual care group. The special intervention program may have overcome obstacles which interfered with cessation among the usual care participants. Associations with relapse were generally stronger in the usual care group than in the special intervention group. For usual care participants, multivariate analyses showed that education, past success in quitting smoking, alcohol, and life events were associated with relapse rates. For special intervention participants, only alcohol emerged as a significant predictor. Conclusion. The data are relevant in terms of factors that govern smoking cessation and relapse for adult smokers who take part in formal intervention programs and for those who are left to modify their behavior on their own.

Comparison of smoking behavior change for SI and UC study groups. MRFIT Research Group

BACKGROUND

The results of MRFIT smoking intervention program are presented for the 4,103 special intervention and 4,091 usual care men who reported smoking cigarettes at the first screening visit.

RESULTS

Among the special intervention men, the reported cessation rate increased from 43.1% at 12 months to 48.9% at 72 months. The reported cessation rate among the usual care men increased from 13.5% at 12 months to 28.8% at 72 months. Among smokers who reported cessation at 72 months, 51.3% of special intervention men and 22.7% of usual care men had quit smoking within the first year and remained abstinent thereafter. Average thiocyanate and expired-air carbon monoxide served as objective measures of smoking and were significantly lower among the special intervention men than among the usual care men over the entire follow-up period. The reported cessation rates at 72 months varied according to initial levels of smoking. Smokers reporting 1-19 cigarettes per day at entry were more likely to quit than heavier smokers. For each category of smoking at entry (1-19, 20-39, and 40 or more cigarettes per day) significantly more special intervention than usual care smokers reported cessation.

CONCLUSION

These results indicate that the MRFIT smoking intervention program was successful in promoting early cigarette smoking cessation and maintaining cessation over the entire trial for a large percentage of cigarette smokers.

Time trends of smoking cessation analyzed with six mathematical survival models

In this paper, six mathematical models were applied to model time trends of smoking cessation. Both statistical and non-statistical methods were used and included the exponential, ideodynamic, log-logistic, Pareto, sickle and Weibull models. All models included the possibilities of both permanent abstinence and relapse to smoking. Time trends from all models were compared with data from the Multiple Risk Factor Intervention Trial (MRFIT) program. The Pareto, log-logistic, Weibull and ideodynamic models yielded satisfactory fits to the data while the sickle and exponential models did not. Even though the data used in this paper were not sufficient to distinguish among these four models, the methodology will be useful for further narrowing the model choices as additional data for the testing become available.

Relationships between weight and caloric intake of men who stop smoking: the Multiple Risk Factor Intervention Trial

Data from 6,569 middle-aged men in the Multiple Risk Factor Intervention Trial were analyzed to determine whether the weight change associated with smoking cessation resulted primarily from appetite or metabolic alterations. The appetite hypothesis attributes weight gain to an enhanced appetite and subsequent increase in caloric intake. The metabolic change hypothesis attributes weight gain to a metabolic alteration and subsequent decrease in basic caloric needs. Caloric intake and weight changes were tabulated for men who quit smoking and were compared to similar changes in men who continued smoking over 12 months. The difference between caloric intake changes in men quitting smoking versus men continuing smoking, controlled for weight change, was attributed to the metabolic change hypothesis. Men who quit smoking consumed 103 calories per day less (95% confidence interval = 29 to 177) than men who continued smoking with similar body weight changes. The decrease in caloric intake attributed to smoking cessation was proportional to the number of cigarettes smoked prior to cessation [corrected].

The relationship of smoking cessation to coronary heart disease and lung cancer in the Multiple Risk Factor Intervention Trial (MRFIT)

The impact of smoking cessation on coronary heart disease (CHD) and lung cancer was assessed after 10.5 years of follow-up in the 12,866 men in the Multiple Risk Factor Intervention Trial (MRFIT). Those men who died of lung cancer (n = 119) were either cigarette smokers at entry or ex-smokers; no lung cancer deaths occurred among the 1,859 men who reported never smoking cigarettes. The risk of lung cancer for smokers, adjusted for selected baseline variables using a Cox proportional hazards model, increased as the number of cigarettes smoked increased (B = 0.0203, SE = 0.0076). There was not the same graded response for CHD among smokers at entry. The risk of CHD death was greater among smokers than nonsmokers (RR = 1.57) (B = -0.0034, S.E. = 0.0048). After one year of cessation, the relative risk of dying of CHD for the quitters as compared to non-quitters (RR = 0.63) was significantly lower even after adjusting for baseline differences and changes in other risk factors. The relative risk for smokers who quit for at least the first three years of the trial was even lower compared to non-quitters (RR = 0.38). However, the relative risk for lung cancer for quitters versus non-quitters was close to 1 both for quitters at 12 months and at three years. These data support the benefits of cessation in relation to CHD and are consistent with other epidemiologic studies which suggest that the lag time for a beneficial effect of smoking cessation on lung cancer may be as long as 20 years.

A description of cigarette smoking cessation and resumption in the Framingham Study

Cigarette smoking cessation and resumption patterns are presented from biennial examination data from the Framingham Study for the years 1956-1978. At 22 yr of follow-up, 68% of men and 53% of women stated they had stopped smoking for at least 1 year. Younger participants had lower cessation rates than older, and those who smoked more cigarettes per day had lower cessation rates than those who smoked fewer. Lower cessation rates were found in men who drank alcohol, and in women who drank coffee, were leaner, or were of lower education. Resumption of cigarette smoking after nonsmoking for at least 1 year occurred in 35% of women and 25% of men over 20 years of observation. Most resumption occurred in the first 4 years after quitting. Men who smoked a greater number of cigarettes prior to quitting were observed to have a smaller probability of resumption. This latter finding is paradoxical and needs confirmation from other studies.