Improving quit rates of web-delivered interventions for smoking cessation: full-scale randomized trial of WebQuit.org versus Smokefree.gov

Background and aims Millions of people world-wide use websites to help them quit smoking, but effectiveness trials have an average 34% follow-up data retention rate and an average 9% quit rate. We compared the quit rates of a website using a new behavioral approach called Acceptance and Commitment Therapy (ACT; WebQuit.org) with the current standard of the National Cancer Institute's (NCI) Smokefree.gov website. Design A two-arm stratified double-blind individually randomized trial (n=1319 for WebQuit; n=1318 for Smokefree.gov) with 12-month follow-up. Setting United States. Participants Adults (n=2637) who currently smoked at least five cigarettes per day were recruited from March 2014 to August 2015. At baseline, participants were mean [standard deviation (SD)] age 46.2years (13.4), 79% women and 73% white. Interventions WebQuit.org website (experimental) provided ACT for smoking cessation; Smokefree.gov website (comparison) followed US Clinical Practice Guidelines for smoking cessation. Measurements The primary outcome was self-reported 30-day point prevalence abstinence at 12 months. Findings The 12-month follow-up data retention rate was 88% (2309 of 2637). The 30-day point prevalence abstinence rates at the 12-month follow-up were 24% (278 of 1141) for WebQuit.org and 26% (305 of 1168) for Smokefree.gov [odds ratio (OR)=0.91; 95% confidence interval (CI)=0.76, 1.10; P=0.334] in the a priori complete case analysis. Abstinence rates were 21% (278 of 1319) for WebQuit.org and 23% (305 of 1318) for Smokefree.gov (OR=0.89 (0.74, 1.07; P=0.200) when missing cases were imputed as smokers. The Bayes factor comparing the primary abstinence outcome was 0.17, indicating 'substantial' evidence of no difference between groups. Conclusions WebQuit.org and Smokefree.gov had similar 30-day point prevalence abstinence rates at 12 months that were descriptively higher than those of prior published website-delivered interventions and telephone counselor-delivered interventions.