Heterogeneity in the Effects of Reward- and Deposit-based Financial Incentives on Smoking Cessation

Abstract

Rationale: Targeting different smoking cessation programs to smokers most likely to quit when using them could reduce the burden of lung disease.

Objectives: To identify smokers most likely to quit using pure reward-based financial incentives or incentive programs requiring refundable deposits to become eligible for rewards.

Methods: We conducted prespecified secondary analyses of a randomized trial in which 2,538 smokers were assigned to an $800 reward contingent on sustained abstinence from smoking, a refundable $150 deposit plus a $650 reward, or usual care.

Measurements and main results: Using logistic regression, we identified characteristics of smokers that were most strongly associated with accepting their assigned intervention and ceasing smoking for 6 months. We assessed modification of the acceptance, efficacy, and effectiveness of reward and deposit programs by 11 prospectively selected demographic, smoking-related, and psychological factors. Predictors of sustained smoking abstinence differed among participants assigned to reward- versus deposit-based incentives. However, greater readiness to quit and less steep discounting of future rewards were consistently among the most important predictors. Deposit-based programs were uniquely effective relative to usual care among men, higher-income participants, and participants who more commonly failed to pay their bills (all interaction P values < 0.10). Relative to rewards, deposits were more effective among black persons (P = 0.022) and those who more commonly failed to pay their bills (P = 0.082). Relative to rewards, deposits were more commonly accepted by higher-income participants, men, white persons, and those who less commonly failed to pay their bills (all P < 0.05).

Conclusions: Heterogeneity among smokers in their acceptance and response to different forms of incentives suggests potential benefits of targeting behavior-change interventions based on patient characteristics. Clinical trial registered with www.clinicaltrials.gov (NCT 01526265).

Trial registration: ClinicalTrials.gov NCT01526265.

Keywords: behavior change; financial incentives; heterogeneity of treatment effect; smoking cessation.

Figures

Figure 1.

Six-month sustained smoking abstinence (overall effectiveness) following assignment to reward- and deposit-based incentive programs. Estimates are derived from a model that included the four interaction terms displayed and all covariates included in Table 1. Bars and shaded regions represent 95% confidence intervals. All interactions between incentive type (reward vs. deposit) and the patient characteristic (sex, race, annual household income, or months failed to pay bills) are significant at the prespecified threshold of P < 0.10.

Figure 2.

Acceptance of reward- and deposit-based incentive programs. Estimates are derived from a model that included the four interaction terms displayed and all covariates included in Table 1. Bars and shaded regions represent 95% confidence intervals. All interactions between incentive type (reward vs. deposit) and the patient characteristic (sex, race, annual household income, or months failed to pay bills) are significant at the prespecified threshold of P < 0.10.