Are financial incentives more effective than health campaigns to quit smoking? A community-randomised smoking cessation trial in Denmark

Incentives for smoking cessation

BACKGROUND

Financial incentives (money, vouchers, or self-deposits) can be used to positively reinforce smoking cessation. They may be used as one-off rewards, or in various schedules to reward steps towards sustained smoking abstinence (known as contingency management). They have been used in workplaces, clinics, hospitals, and community settings, and to target particular populations. This is a review update. The previous version was published in 2019.

OBJECTIVES

Primary To assess the long-term effects of incentives and contingency management programmes for smoking cessation in mixed and pregnant populations. Secondary To assess the long-term effects of incentives and contingency management programmes for smoking cessation in mixed populations, considering whether incentives were offered at the final follow-up point. To assess the difference in outcomes for pregnant populations, considering whether rewards were contingent on abstinence or guaranteed.

SEARCH METHODS

For this update, we searched CENTRAL, MEDLINE, Embase, PsycINFO, and two trials registers on 2 November 2023, and the Cochrane Tobacco Addiction Group Specialised Register on March 2023, together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We considered only randomised controlled trials (RCTs), allocating individuals, workplaces, groups within workplaces, or communities to smoking cessation incentive schemes or control conditions. We included studies in a mixed-population setting (e.g. community-, work-, clinic- or institution-based), studies with specific populations (e.g. those with diagnosed mental health conditions), and studies in pregnant people who smoke.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. The primary outcome measure in the mixed-population studies was abstinence from smoking at longest follow-up (at least six months from the start of the intervention). In the trials of pregnant people, we used abstinence from smoking measured at the longest follow-up, and at least to the end of the pregnancy. Where available, we pooled outcome data using a Mantel-Haenszel random-effects model, with results reported as risk ratios (RRs) and 95% confidence intervals (CIs), using adjusted estimates for cluster-randomised trials. We analysed studies carried out in mixed populations separately from those carried out in pregnant populations.

MAIN RESULTS

Forty-eight mixed-population studies met our inclusion criteria, recruiting more than 21,924 participants; 15 of these are new to this version of the review. Studies were set in varying locations, including community settings, clinics or health centres, workplaces, and outpatient drug clinics. We judged eight studies to be at low risk of bias, and 16 to be at high risk of bias, with the remaining 24 studies at unclear risk. Thirty-three of the trials were run in the USA, two in Thailand, one in the Philippines, one in Hong Kong, and one in South Africa. The rest were European. Incentives offered included cash payments, self-deposits, or vouchers for goods and groceries, offered directly or collected and redeemable online. The pooled RR for quitting with incentives at longest follow-up (six months or more) compared with controls was 1.52 (95% CI 1.33 to 1.74; I2 = 23%; 39 studies, 18,303 participants; high-certainty evidence). Results were not sensitive to the exclusion of seven studies that offered an incentive for cessation at long-term follow-up (result excluding those studies: RR 1.46, 95% CI 1.23 to 1.73; I2 = 26%; 32 studies, 15,082 participants), suggesting the impact of incentives continues for at least some time after incentives cease (at least six months). For this update, we included an adjusted analysis incorporating three cluster-RCTs. The pooled odds ratio was 1.57 (95% CI 1.37 to 1.79; I2 = 30%; 43 studies, 23,960 participants; high-certainty evidence). Although not always clearly reported, the total financial amount of incentives varied considerably between trials, from zero (self-deposits), to a range of between 45 US dollars (USD) and USD 1185. There was no clear difference in effect between trials offering low or high total value of incentives, nor those encouraging redeemable self-deposits. We ran an updated exploratory meta-regression and found no significant association between the outcome and the total value of the financial incentive (P = 0.963). Any such indirect comparison is particularly crude in this context, due to differences in the cultural significance of financial amounts (e.g. USD 50 might have different significance in different contexts). We included 14 studies of 4314 pregnant people (11 conducted in the USA, one in France, and two in the UK). We judged four studies to be at low risk of bias, three at high risk of bias, and eight at unclear risk. When pooled, the 13 trials with usable data delivered a risk ratio at longest follow-up (up to 48 weeks postpartum) of 2.13 (95% CI 1.58 to 2.86; I2 = 31%; 13 studies, 3942 participants; high-certainty evidence), in favour of incentives.

AUTHORS' CONCLUSIONS

Overall, our conclusion from this latest review update remains that there is high-certainty evidence that incentives improve smoking cessation rates at long-term follow-up in mixed population studies. The evidence demonstrates that the effectiveness of incentives is sustained even when the last follow-up occurs after the withdrawal of incentives. There is also now high-certainty evidence that incentive schemes conducted amongst pregnant people who smoke improve smoking cessation rates, both at the end of pregnancy and postpartum. This represents a change from the previous update in which we rated this evidence as moderate certainty. Current and future research might more precisely explore differences between trials offering low or high cash incentives and self-incentives (deposits), within a variety of smoking populations, focusing on low- and middle-income countries where the burden of tobacco use remains high.

How and why do financial incentives contribute to helping people stop smoking? A realist review

BACKGROUND

Tobacco smoking remains a key cause of preventable illness and death globally. In response, many countries provide extensive services to help people to stop smoking by offering a variety of effective behavioural and pharmacological therapies. However, many people who wish to stop smoking do not have access to or use stop smoking supports, and new modes of support, including the use of financial incentives, are needed to address this issue. A realist review of published international literature was undertaken to understand how, why, for whom, and in which circumstances financial incentives contribute to success in stopping smoking for general population groups and among pregnant women.

METHODS

Systematic searches were undertaken from inception to February 2022 of five academic databases: MEDLINE (ovid), Embase.com, CIHAHL, Scopus and PsycINFO. Study selection was inclusive of all study designs. Twenty-two studies were included. Using Pawson and Tilley's iterative realist review approach, data collected were screened, selected, coded, analysed, and synthesised into a set of explanatory theoretical findings.

RESULTS

Data were synthesised into six Context-Mechanism-Outcome Configurations and one overarching programme theory after iterative rounds of analysis, team discussion, and expert panel feedback. Our programme theory shows that financial incentives are particularly useful to help people stop smoking if they have a financial need, are pregnant or recently post-partum, have a high threshold for behaviour change, and/or respond well to external rewards. The incentives work through a number of mechanisms including the role their direct monetary value can play in a person's life and through a process of reinforcement where they can help build confidence and self-esteem.

CONCLUSION

This is the first realist review to synthesise how, why, and for whom financial incentives work among those attempting to stop smoking, adding to the existing evidence demonstrating their efficacy. The findings will support the implementation of current knowledge into effective programmes which can enhance the impact of stop smoking care.

PROSPERO REGISTRATION NUMBER

CRD42022298941.

The contribution of Dutch municipalities to stimulate smoke-free outdoor sports clubs: a qualitative study

Local governments may play a key role in making outdoor sports clubs smoke free. This study aims to assess the activities, motives, challenges and strategies of Dutch municipalities regarding stimulating outdoor sports clubs to become smoke free. Semi-structured interviews were conducted with 19 policy officers of different municipalities in the Netherlands. The included municipalities varied in terms of region, population size and degree of urbanization. Data were analyzed using content analysis. Municipalities stimulated sports clubs to become smoke free by providing information and support and, to a lesser extent, by using financial incentives. Motives of municipalities varied from facilitating a healthy living environment for youth, responding to denormalization of smoking and aligning with goals formulated in national prevention policy. Policy officers faced several challenges, including limited capacity and funds, a reluctance to interfere with sports clubs and little support within the municipal organization. These challenges were addressed by employing various strategies such as embedding smoke-free sports in a broader preventive policy, setting a good example by creating outdoor smoke-free areas around municipal buildings, and collaborating with stakeholders in the municipality to join forces in realizing smoke-free sports clubs. Municipalities demonstrated evident motivation to contribute to a smoke-free sports environment. Currently, most municipalities fulfil an informative and supportive role, while some municipalities still explore their role and position in relation to supporting sports clubs to become smoke free. Other municipalities have established, according to them, effective strategies.

Smoking Cessation Programs Are Less Effective in Smokers with Low Socioeconomic Status Even When Financial Incentives for Quitting Smoking Are Offered-A Community-Randomized Smoking Cessation Trial in Denmark

Financial incentives offered to those who quit smoking have been found effective, also in persons with low socioeconomic status (SES), but no previous study has investigated who benefits most: smokers with low or high SES. In this community-randomized trial ("Richer without smoking"), three Danish municipalities were randomized to reward persons who were abstinent when attending the municipal smoking cessation program (FIMs) and three municipalities were randomized to spend the same amount on smoking cessation campaigns recruiting smokers to the smoking cessation program (CAMs). The municipalities each received approximately USD 16,000. An intention-to-treat approach was used in analyses. In regression analyses adjusted for individual- and municipal-level differences, we found that smokers with high SES living in FIMs had significantly higher proportion of validated long-term successful quitters (OR (95% CI): 2.59 (1.6-4.2)) than high-SES smokers living in CAM. Smokers with low SES, however, did not experience the same benefit of financial incentives as smokers with high SES. Neither the FIMs nor the CAMs succeeded in attracting more smokers with low SES during the intervention year 2018 than the year before. Our study showed that smokers with low SES did not experience the same benefit of financial incentives as smokers with high SES.