Counselor and stimulus control enhancements of a stage-matched expert system intervention for smokers in a managed care setting.

BACKGROUND Previous research has demonstrated the efficacy of an interactive expert system intervention for smoking cessation for a general population. The intervention provides individualized feedback that guides participants through the stages of change for cessation. Enhancing the expert system by adding proactive telephone counseling or a stimulus control computer designed to produce nicotine fading could produce preventive programs with greater population impacts. METHODS Four interventions were compared: (a) the interactive expert system intervention; (b) the expert system intervention plus counselor calls; (c) the expert system intervention plus the stimulus control computer; and (d) an assessment only condition. A 4 (intervention) x 4 (occasions) (0,6,12, and 18 months) design was used. Smokers were contacted at home via telephone or mail. The initial subject pool was the 24,178 members of a managed care company. Screening was completed for 19,236 members (79.6%), of whom 4,653 were smokers; 85.3% of the smokers were enrolled. RESULTS Thirty-eight percent were in the precontemplation stage, 45% in the contemplation stage, and only 17% in the preparation stage. At 18 months, the expert system resulted in 23.2% point prevalence abstinence, which was 33% greater than that of assessment only. The counselor enhancement produced increased cessation at 12 months but not at 18 months. The stimulus control computer produced no improvement, resulting in 20% worse cessation rates than the assessment only condition. CONCLUSIONS The enhanced conditions failed to outperform the expert system alone. The study also demonstrated the ability of the interactive expert system to produce significantly greater cessation in a population of smokers than assessment alone.