We used maximum likelihood estimation of mixed-effects Cox proportional hazards regression and mixed effects logistic regression models of the two trials combined with a random effect representing variability across sites (n=4) when testing whether AGES quotient moderated survival to day of first lapse after quit day and biochemically verified seven-day point prevalence abstinence at the end of treatment (PPA-EOT). Self-reports of no smoking in the past seven days was confirmed with saliva cotinine values >15ng/ml and expired CO <10ppm. Missed self-reports of smoking status were presumed to be smoking in this intention-to-treat analysis. Age, gender and level of nicotine dependence were included as covariates in all analyses.
