Using incentives within the addictions field to support smoking cessation – A Cochrane review
Background: There is good evidence for contingency management approaches within addictions treatment. Previous reviews have found incentives to be effective for tobacco addiction, to support smoking cessation, but long-term effects have not been determined.
Methods: Systematic review of randomised controlled trials, allocating individuals, workplaces, groups or communities to smoking cessation incentives or control. Including mixed populations, those in substance misuse treatment, and pregnant women. The outcome was abstinence from smoking at longest follow-up (at least six months from intervention start).
Results: 33 mixed-population studies met inclusion criteria, including 21,600 participants in community settings, clinics, workplaces, and drug clinics. Eight studies recruited participants from substance misuse clinics. In mixed population studies, the relative risk (RR) for quitting with incentives at longest follow-up compared with controls was 1.49 (95% confidence interval (CI) 1.28 to 1.73; 31 RCTs, adjusted N = 20,097; I2 = 33%). We conducted a sensitivity analysis exploring the effect of incentives offered continuously, up until long term follow up, compared with studies where longest follow-up was beyond the end of the incentive period. Results were not sensitive to the exclusion of six studies where incentives were offered at long term follow up (RR 1.40 95% CI 1.16 to 1.69; 25 RCTs; adjusted N = 17,058; I2 = 36%). In a sub-group analysis of trials recruiting participants in substance misuse treatment, results also suggested a favourable benefit of incentives for smoking cessation at longest follow-up (no significant subgroup difference (P = 0.38; I2 = 0%; RR in substance misuse subgroup 1.24, 95% CI 0.81 to 1.89; 8 studies; N = 1055). Findings were consistent with the overall meta-analysis which found a beneficial effect of the intervention.
Conclusions: Overall there is high quality evidence that incentives improve smoking cessation rates at long term follow-up in mixed population studies, including populations in treatment for substance misuse. The effect of incentives appears to be sustained over time (both while in place and following discontinuation).