Abstract
INTRODUCTION: Evidence of digital interventions that are efficacious among low-income populations is scarce. In a secondary analysis, we determined the efficacy and utilization of an Acceptance and Commitment Therapy (ACT)-based smartphone application (iCanQuit) versus a U.S. Clinical Practice Guidelines (USCPG)-based smartphone application (QuitGuide) for smoking cessation in low-income adults enrolled in the iCanQuit randomized trial. METHODS: Participants were randomized to receive iCanQuit (n = 437) or QuitGuide (n = 460) for 12-months. Consistent with the main trial, the primary outcome was self-reported complete-case 30-day point prevalence abstinence (PPA) at 12-months. Secondary outcomes were 7-day PPA, missing-as-smoking and multiple imputation, prolonged abstinence, and cessation of all tobacco products at 12-months. Outcome data retention, utilization, and change in ACT-based processes were compared across arms. RESULTS: Participants were recruited from 48 U.S. states. Retention rate was 88% at 12-months and did not differ by arm. At 12-months, iCanQuit was 1.46 times more efficacious than QuitGuide for smoking cessation (27% vs. 20%; OR=1.46 95% CI: 1.04, 2.06). Findings were similar for missing-as-smoking imputation (23% vs. 18%; OR=1.41 95% CI: 1.01, 1.97) and multiple imputation at 12-months (27% vs. 20%; OR=1.51 95% CI: 1.07, 2.14). Treatment utilization was significantly higher among iCanQuit than QuitGuide participants. Increased acceptance of cues to smoke mediated the effect of treatment on cessation. CONCLUSIONS: The iCanQuit smartphone application was more efficacious and engaging for smoking cessation among low-income adults than a USCPG-based smartphone application. A nationwide dissemination trial of iCanQuit is warranted to determine whether iCanQuit may alleviate cessation-related disparities among low-income adults.