Predictors and moderators of outcome in different brief interventions for smoking cessation in general medical practice.

Abstract Objective To explore demographic-, health-, and smoking-related predictors and moderators of outcome in smokers who participated in two different brief smoking cessation interventions. Methods Data were acquired using a quasi-randomized controlled trial that tested the efficacy of computer-generated tailored letters and physician-delivered brief advice against assessment only. Daily smokers ( n  = 1499) were recruited from 34 general medical practices. We used Generalized Estimating Equation analyses to investigate the relationship between 6-month prolonged smoking abstinence assessed at 12-, 18-, and 24-month follow-ups and potential predictors and moderators. Results Female gender (OR = 1.49, 95% CI = 1.01–2.19), higher level of education (OR = 1.82, 95% CI = 1.18–2.82), intention to quit smoking (OR = 1.66, 95% CI = 1.16–2.38), and smoking cessation self-efficacy (OR = 1.30, 95% CI = 1.03–1.64) were positively, nicotine dependence (OR = 0.84, 95% CI = 0.76–0.94) and the presence of a smoking partner (OR = 0.60, 95% CI = 0.42–0.85) were negatively associated with smoking abstinence. Compared to assessment only, physician advice was less effective for people without an intention to quit smoking and for unemployed. Conclusion Smoking cessation interventions might be improved by tailoring them to demographic- and smoking-related variables which were identified as predictors in this study. Practice implications The results suggest that tailored letters are a more universally applicable brief intervention in general medical practice than physician advice.