Proactive interventions for smoking cessation in general medical practice: a quasi-randomized controlled trial to examine the efficacy of computer-tailored letters and physician-delivered brief advice*

AIMS: To test the efficacy of (i) computer-generated tailored letters and (ii) practitioner-delivered brief advice for smoking cessation against an assessment-only condition; and to compare both interventions directly. DESIGN: Quasi-randomized controlled trial. SETTING: A total of 34 randomly selected general practices from a German region (participation rate 87%). PARTICIPANTS: A total of 1499 consecutive patients aged 18–70 years with daily cigarette smoking (participation rate 80%). INTERVENTIONS: The tailored letters intervention group received up to three individualized personal letters. Brief advice was delivered during routine consultation by the practitioner after an onsite training session. Both interventions were based on the Transtheoretical Model of behaviour change. MEASUREMENTS: Self-reported point prevalence and prolonged abstinence at 6-, 12-, 18- and 24-month follow-ups. FINDINGS: Among participants completing the last follow-up, 6-month prolonged abstinence was 18.3% in the tailored letters intervention group, 14.8% in the brief advice intervention group and 10.5% in the assessment-only control group. Assuming those lost to follow-up to be smokers, the rates were 10.2%, 9.7% and 6.7%, respectively. Analyses including all follow-ups confirmed statistically significant effects of both interventions compared to assessment only. Using complete case analysis, the tailored letters intervention was significantly more effective than brief advice for 24-hour [odds ratio (OR) = 1.4; P = 0.047] but not for 7-day point prevalence abstinence (OR = 1.4; P = 0.068) for prolonged abstinence, or for alternative assumptions about participants lost to follow-up. CONCLUSIONS: The study demonstrated long-term efficacy of low-cost interventions for smoking cessation in general practice. The interventions are suitable to reach entire populations of general practices and smoking patients. Computer-generated letters are a promising option to overcome barriers to provide smoking cessation counselling routinely.