Efficacy of smartphone applications for smoking cessation in heavy-drinking adults: Secondary analysis of the iCanQuit randomized trial

Abstract

IntroductionEfficacious smoking cessation treatments are needed for heavy-drinking adults who often have difficulty quitting smoking. In a secondary analysis of a parent randomized controlled trial, we explored the efficacy of an Acceptance and Commitment Therapy (ACT)-based smartphone application (iCanQuit) versus a US Clinical Practice Guidelines (USCPG)-based smartphone application (QuitGuide) for smoking cessation among heavy-drinking participants (4 + drinks/day for women; 5 + drinks/day for men). MethodsParticipants were randomized to receive iCanQuit (n = 188) or QuitGuide (n = 160) for 12-months. Smoking cessation outcomes were measured at 3, 6 and 12-months. The primary outcome was self-reported complete-case 30-day point prevalence abstinence (PPA) at 12-months. Secondary outcomes were 7-day PPA at all timepoints; prolonged abstinence; and cessation of all nicotine-containing products at 12-months. Multiple imputation and missing-as-smoking analyses were also conducted. Exploratory outcomes were cessation of both smoking and heavy drinking and change in alcohol use (drinks/day) at 12-months. Treatment engagement and satisfaction and change in ACT-based processes were compared between arms. ResultsRetention rate was 85% at 12-months and did not differ by arm. At 12-months, iCanQuit participants had nearly double the odds of smoking cessation compared to QuitGuide (complete-case 30-day PPA = 24% vs. 15%; OR = 1.87 95% CI: 1.03, 3.42). Findings were similar for the multiple imputation and missing-as-smoking outcomes at 12-months. Combined cessation of smoking and heavy drinking, and alcohol use at 12-months did not differ by arm. iCanQuit was significantly more engaging and satisfying than QuitGuide. Increased acceptance of thoughts about smoking mediated the effect of treatment on cessation of heavy drinking at 12-months. ConclusionsThe iCanQuit smartphone application was more efficacious and engaging for smoking cessation among heavy-drinking adults than a USCPG-based smartphone application.