Financial Incentives for Smoking Abstinence in Homeless Smokers: A Pilot Randomized Controlled Trial

Abstract

Introduction: Three-quarters of homeless people smoke cigarettes. Financial incentives for smoking abstinence have appeared promising in nonexperimental studies of homeless smokers, but randomized controlled trial (RCT) data are lacking.

Methods: We conducted a pilot RCT of financial incentives for homeless smokers. Incentive arm participants (N = 25) could earn escalating $15-$35 rewards for brief smoking abstinence (exhaled carbon monoxide <8 parts per million) assessed 14 times over 8 weeks. Control arm participants (N = 25) were given $10 at each assessment regardless of abstinence. All participants were offered nicotine patches and counseling. The primary outcome was a repeated measure of brief smoking abstinence across 14 assessments. The secondary outcome was brief abstinence at 8 weeks. Exploratory outcomes were self-reported 1-day and 7-day abstinence from (1) any cigarette and (2) any puff of a cigarette. Other outcomes included 24-hour quit attempts, nicotine patch use, counseling attendance, and changes in alcohol and drug use.

Results: Compared to control, incentive arm participants were more likely to achieve brief abstinence overall (odds ratio 7.28, 95% confidence interval 2.89 to 18.3) and at 8 weeks (48% vs. 8%, p = .004). Similar effects were seen for 1-day abstinence, but 7-day puff abstinence was negligible in both arms. Incentive arm participants made more quit attempts (p = .03). Nicotine patch use and counseling attendance were not significantly different between the groups. Alcohol and drug use did not change significantly in either group.

Conclusions: Among homeless smokers, financial incentives increased brief smoking abstinence and quit attempts without worsening substance use. This approach merits further development focused on promoting sustained abstinence.

Registration: ClinicalTrials.gov (NCT02565381).

Implications: Smoking is common among homeless people, and conventional tobacco treatment strategies have yielded modest results in this population. This pilot RCT suggests that financial incentives may be a safe way to promote brief smoking abstinence and quit attempts in this vulnerable group of smokers. However, further development is necessary to translate this approach into real-world settings and to promote sustained periods of smoking abstinence.

Figures

Figure 1.

CONSORT diagram. aSum of exclusion reasons totals greater than 117 because individuals could be ineligible for more than one reason. bSmoking inclusion criteria were: 1) lifetime smoking of ≥100 cigarettes, 2) current daily smoking of ≥5 cigarettes per day, and 3) exhaled carbon monoxide level of ≥8 parts per million on 2 separate occasions.

Figure 2.

Point-in-time smoking abstinence at the 14 assessment visits, by study group. Note: We defined point-in-time smoking abstinence as an exhaled carbon monoxide (CO) level <8 parts per million. Abstinence percentages shown in this figure are based on the assumption that individuals with missing CO data were nonabstinent. We assessed the overall, time-averaged difference in abstinence between the study groups using repeated-measures logistic regression with generalized estimating equations.