Randomized Controlled Trial of Dyadic Financial Incentive Treatment for Dual Smoker Couples: Evaluation of Efficacy, Mechanisms, and Cost Effectiveness

Project Summary/Abstract Smokers partnered with other smokers (i.e., dual-smoker couples) represent ~2/3 of all smokers. Dual- smoker couples (DSCs) are less likely to try to quit smoking and more likely to relapse during a quit attempt, reducing overall smoking cessation rates and representing a high-risk clinical population. Despite their high

prevalence and risk for persistent smoking, however, there are limited data on smoking cessation interventions among DSCs. Building on previous research that suggests a) financial incentive treatments (FITs) are effective at increasing quit rates; and b) dyadic adaptations of FITs are feasible for implementation in DSCs, the proposed

randomized controlled trial (RCT) will systematically examine two adaptations of FITs to enhance smoking cessation among DSCs. In addition to determining the efficacy of these FITs for smoking abstinence in DSCs, we will examine mechanisms of change, secondary endpoints and outcomes, and the cost effectiveness of each

adaptation. We will address these questions in a three-group RCT that is informed by a highly supportive pilot trial we have completed on FITs for DSCs (R21CA241570). In all conditions, treatment-seeking smokers who are part of a DSC (i.e., targets) will receive usual care (combination fast and slow acting Nicotine Replacement

Therapy + quitting resources). In two experimental conditions (single FIT and dyadic FIT, SFT and DFIT), participants will receive incentives for abstinence at three time points (1-, 3-, and 6-months post-baseline). In the SFIT condition, only the target in a couple will be offered incentives; in the DFIT condition, both target and partner

in a couple will be offered incentives. Primary efficacy outcome is biochemically-verified abstinence at 6-months post-baseline among targets. We will concurrently evaluate candidate mechanisms of change (e.g., partner support, individual and partner motivation) to understand how FITs confer benefits and inform optimization.

Secondary outcomes are point-prevalence abstinence at 1- and 3-months during the treatment and 6-months post-treatment (12-months post-baseline), as well as partner smoking outcomes. As FITs inherently rely on financial resources, cost-effectiveness analysis will quantify the cost and relative cost of positive outcomes within

and across conditions. These data on the efficacy, mechanisms, and costs of FITs for DSCs will inform population level implementation and promote successful quitting in this treatment refractory population.