Both trials include a placebo arm and the genotypic associations in the placebo arms significantly differed between these two trials (interaction wald=3.94, df=1, p=0.047). In the UW-TTURC trial, CHRNA5 rs16969968 genotypes were associated with abstinence at EOT in the placebo group (X2=6.54, df=2, p=0.038). Unlike the UW-TTURC trial results, rs16969968 genotype was not associated with abstinence at EOT in the placebo group (X2=0.21, df=2, p=0.90) in the varenicline trial.
