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.