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.

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.