Long-term effectiveness of a clinician-assisted digital cognitive behavioral therapy intervention for smoking cessation: secondary outcomes from a randomized controlled trial

INTRODUCTION: This study evaluated the secondary effectiveness outcomes for Quit Genius, a digital clinician-assisted cognitive behavioral therapy (CBT) intervention for smoking cessation. METHODS: Adult smokers (N=556) were randomly assigned to Quit Genius (n=277), a digital, clinician-assisted CBT intervention or Very Brief Advice (VBA) to stop smoking, an evidence-based, 30-second intervention designed to facilitate quit attempts, coupled with referral to a cessation service (n=279). Participants were offered combination nicotine replacement therapy (patches and gum) tailored to individual nicotine dependence. Analyses (N=530), by intention-to-treat, compared Quit Genius and VBA at 4, 26, and 52 weeks post-quit date. The primary outcome was self-reported seven-day point prevalence abstinence at 4 weeks post-quit date. Consecutive seven-day point-prevalence abstinence, defined as abstinent at two or more consecutive timepoints, was examined at weeks 26 and 52 to indicate long-term effectiveness. Abstinence was verified using a random sample of participants with carbon monoxide breath testing of