Abstract: In the current update, we have added six new relevant studies, resulting in a total of 17 studies included in this review involving financial interventions directed at smokers or healthcare providers, or both. Full financial interventions directed at smokers had a favourable effect on abstinence at six months or longer when compared to no intervention (RR 1.77, 95% CI 1.37 to 2.28, I² = 33%, 9333 participants). There was no evidence that full coverage interventions increased smoking abstinence compared to partial coverage interventions (RR 1.02, 95% CI 0.71 to 1.48, I² = 64%, 5914 participants), but partial coverage interventions were more effective in increasing abstinence than no intervention (RR 1.27 95% CI 1.02 to 1.59, I² = 21%, 7108 participants). The economic evaluation showed costs per additional quitter ranging from USD 97 to USD 7646 for the comparison of full coverage with partial or no coverage. There was no clear evidence of an effect on smoking cessation when we pooled two trials of financial incentives directed at healthcare providers (RR 1.16, CI 0.98 to 1.37, I² = 0%, 2311 participants). Full financial interventions increased the number of participants making a quit attempt when compared to no interventions (RR 1.11, 95% CI 1.04 to 1.17, I² = 15%, 9065 participants). There was insufficient evidence to show whether partial financial interventions increased quit attempts compared to no interventions (RR 1.13, 95% CI 0.98 to 1.31, I² = 88%, 6944 participants). Full financial interventions increased the use of smoking cessation treatment compared to no interventions with regard to various pharmacological and behavioural treatments: nicotine replacement therapy (NRT): RR 1.79, 95% CI 1.54 to 2.09, I² = 35%, 9455 participants; bupropion: RR 3.22, 95% CI 1.41 to 7.34, I² = 71%, 6321 participants; behavioural therapy: RR 1.77, 95% CI 1.19 to 2.65, I² = 75%, 9215 participants. There was evidence that partial coverage compared to no coverage reported a small positive effect on the use of bupropion (RR 1.15, 95% CI 1.03 to 1.29, I² = 0%, 6765 participants). Interventions directed at healthcare providers increased the use of behavioural therapy (RR 1.69, 95% CI 1.01 to 2.86, I² = 85%, 25820 participants), but not the use of NRT and/or bupropion (RR 0.94, 95% CI 0.76 to 1.18, I² = 6%, 2311 participants). We assessed the quality of the evidence for the main outcome, abstinence from smoking, as moderate. In most studies participants were not blinded to the different study arms and researchers were not blinded to the allocated interventions. Furthermore, there was not always sufficient information on attrition rates. We detected some imprecision but we judged this to be of minor consequence on the outcomes of this study. Full financial interventions directed at smokers when compared to no financial interventions increase the proportion of smokers who attempt to quit, use smoking cessation treatments, and succeed in quitting. There was no clear and consistent evidence of an effect on smoking cessation from financial incentives directed at healthcare providers. We are only moderately confident in the effect estimate because there was some risk of bias due to a lack of blinding in participants and researchers, and insufficient information on attrition rates.

Plain-language summary: We searched all relevant studies that involved financial interventions directed at smokers and healthcare providers. For smokers, the aim of the healthcare financing interventions had to be to encourage the use of smoking cessation treatment or making successful quit attempts. For interventions directed at healthcare providers, the intervention had to stimulate the healthcare provider to assist people with quitting smoking, for example by prescribing smoking cessation treatment. For the update of this review, we searched studies on the effect of financial interventions on smoking cessation treatment and success in September 2016. We found six new relevant studies, resulting in a total of 17 studies. We found 15 studies directed at smokers. Covering all the costs of smoking cessation treatment for smokers (free treatment) when compared to providing no financial benefits increased the number of smokers who attempted to quit (4 studies, 9065 participants), used smoking cessation treatments (7 studies, 9455 participants), and succeeded in quitting (6 studies, 9333 participants). We found three studies directed at healthcare providers. The two studies that investigated the effect of a financial intervention on quit success (2311 participants) did not clearly show an increase in quit rates. Financial interventions directed at healthcare providers also did not have an effect on the use of smoking cessation medication (2 studies, 2311 participants). However, financial interventions did increase the number of smokers who used smoking cessation counselling (3 studies, 25,820 participants). Information on the costs of the intervention was available for eight studies (33,488 participants). The economic evaluation of the individual studies showed that although the absolute differences in quitting were small, the costs per person successfully quitting were low or moderate. We concluded that financial interventions directed at smokers increase the proportion of smokers who attempt to quit, use smoking cessation treatments, and succeed in quitting. We did not detect a clear effect on smoking cessation from financial incentives directed at healthcare providers. This review has some limitations that affect how confident we can be in the conclusions. The included studies varied substantially in quality and in methods and design, which makes it difficult to compare results.