The effect of NRT differed by CYP2A6-defined metabolism (interaction effect size=1.82, 95%CI=1.07-3.10, p=0.028) while the effect of bupropion did not (interaction effect size=0.95, 95%CI=0.58-1.58, p=0.85, Table 1B). NRT was effective in fast (HR=0.50, 95%CI=0.38-0.68, p=4.41x10-6), but not slow, metabolizers (HR=0.93, 95%CI=0.59-1.46,p=0.75, Fig 2). Buproprion was effective in both slow and fast metabolizers (HR=0.76, 95%CI=0.60-0.96, p=0.022, Table 1B, Model 2), its effect not varying with metabolism (Fig S1).
