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

The aim of this community-randomised smoking cessation (SC) trial was to investigate both recruitment and SC-rates in three municipalities offering financial incentives (FIM) to smokers who stop smoking when attending a municipal SC-program and compare these with three municipalities investing in a campaign (CAM) that should encourage smokers to use the SC-program. Furthermore, in a non-randomised matched control design we investigated whether there was a difference in recruitment and SC-rates in the three FIM and the three CAM, comparing each with three matched control municipalities (MCM). Each municipality received approx. $16,000. The FIM rewarded persons who were abstinent when attending the municipal SC-program. The CAM spent the money on a campaign recruiting smokers to the SC-program. Two of three FIM were only partly active in recruiting smokers in the intervention year 2018. An intention-to-treat (ITT) approach was used in analyses. Complete case analyses and multiple imputation were used to address loss to follow-up. No difference in recruitment was found between the CAM and the FIM (p = 0.954), in adjusted analyses. In ITT analyses, FIM achieved significantly higher odds of validated abstinence from smoking at one-year follow-up (OR (95%CI): 1.63(1.1-2.4)), but not of self-reported continuous abstinence after six months than CAM. Compared with no intervention, campaigns increased the recruitment of smokers to the SC-program while financial incentives increased six months abstinence rates. In a randomised trial, no difference was demonstrated in the effect of financial incentives and campaigns to recruit smokers to a SC-program and financial incentives seemed superior to help smokers staying smoke-free for a year. TRIAL REGISTRATION: ClinicalTrials.Gov ID: NCT03849092.