Comparative effectiveness of intervention components for producing long-term abstinence from smoking: a factorial screening experiment.

AIMS To identify promising intervention components that help smokers attain and maintain abstinence during a quit attempt. DESIGN A 2 × 2 × 2 × 2 × 2 randomized factorial experiment. SETTING Eleven primary care clinics in Wisconsin, USA. PARTICIPANTS A total of 544 smokers (59% women, 86% white) recruited during primary care visits and motivated to quit. INTERVENTIONS Five intervention components designed to help smokers attain and maintain abstinence: (1) extended medication (26 versus 8 weeks of nicotine patch + nicotine gum); (2) maintenance (phone) counseling versus none; (3) medication adherence counseling versus none; (4) automated (medication) adherence calls versus none; and (5) electronic medication monitoring with feedback and counseling versus electronic medication monitoring alone. MEASUREMENTS The primary outcome was 7-day self-reported point-prevalence abstinence 1 year after the target quit day. FINDINGS Only extended medication produced a main effect. Twenty-six versus 8 weeks of medication improved point-prevalence abstinence rates (43 versus 34% at 6 months; 34 versus 27% at 1 year; P = 0.01 for both). There were four interaction effects at 1 year, showing that an intervention component's effectiveness depended upon the components with which it was combined. CONCLUSIONS Twenty-six weeks of nicotine patch + nicotine gum (versus 8 weeks) and maintenance counseling provided by phone are promising intervention components for the cessation and maintenance phases of smoking treatment.