Commitment contracts and team incentives: A randomized controlled trial for smoking cessation in Thailand

Abstract

Background Treatment for tobacco dependence is not available in many low-resource settings, especially in developing countries. Purpose To test the impact of a novel mix of monetary and social incentives on smoking abstinence in rural communities of Thailand. Design An RCT of commitment contracts and team incentives for rural smokers to quit smoking. Smokers were not blinded to treatment status, although the assessor of the biochemical urine test was. Setting/participants All adult smokers living in the study area were eligible to participate; 215 adult smokers from 42 villages in Nakhon Nayok province, Thailand, participated. Fourteen smokers who lacked teammates were dropped. Intervention A total of 201 smokers were assigned to a two-person team, and then randomly assigned by team (in a 2:1 ratio) with computer-generated random numbers to receive smoking-cessation counseling (control group) or counseling plus offer of a commitment contract, team incentives, and text message reminders for smoking cessation at 3 months (intervention group). Main outcome measures The primary outcome was biochemically verified 7-day abstinence at 6 months, assessed on an intention-to-treat basis. Secondary outcomes include study participation, biochemically verified abstinence at 3 months, self-reported abstinence at 14 months, and the incremental cost per quitter of the intervention, nicotine gum, and varenicline in Thailand. Data were collected in 2010-2011 and analyzed in 2012. Results The trial enrolled 215 (10.5%) of 2055 smokers. The abstinence rate was 46.2% (61/132) in the intervention group and 14.5% (10/69) in the control group (adjusted OR 7.5 [3.0-18.6]) at 3 months; 44.3% (58/131) and 18.8% (13/69) at the primary end point of 6 months (adjusted OR 4.2 [1.8-9.7]); and 42.0% (55/131) and 24.6% (17/69) at 14 months (adjusted OR 2.2 [1.0-4.8]). The purchasing power parity-adjusted incremental cost per quitter from the intervention is $281 (95% CI=$187, $562), less than for nicotine gum ($1780, 95% CI=$1414, $2401) or varenicline ($2073, 95% CI=$1357, $4388) in Thailand. Conclusions The intervention enhanced abstinence by 91%-136% at 6 months, relative to the control group, although self-reports at 14 months suggest tapering of the treatment effect. The intervention may offer a viable, cost-effective alternative to current smoking-cessation approaches in low-resource settings. Trial registration This study is registered at ClinicalTrials.gov NCT01311115. © 2013 American Journal of Preventive Medicine.