Adherence to the principles of Motivational Interviewing, clients' characteristics and behavior outcome in a smoking cessation and relapse prevention trial in women postpartum.

Objectives: 1. Quantitative description of the adherence to the principles of Motivational Interviewing (MI) in smoking counseling sessions, 2. Examination of the relation between clients' characteristics and the adherence to the principles of MI, and between adherence to the principles of MI and future smoking status.
Methods: A sample of n=163 sessions conducted during a randomized controlled trial in testing the effectiveness of a population-based smoking intervention in women postpartum was investigated. Demographic and behavior-related variables were included in a logistic regression to predict adherence to MI. Adherence was measured using the Motivational Interviewing Treatment Integrity (MITI) scale.
Results: Of the sessions, 49.4% showed good adherence to MI. The OR of receiving a good MI session was 3.1 for non-smokers in comparison to daily smokers. No other demographic or behavioral variable gained statistical significance. The relation between adherence and intervention outcome after 6 months was statistically significant (chi(2)=6.459, p<0.05).
Conclusions: This intervention study shows a satisfactory degree of adherence to and the effectiveness of MI. MI-adherence seems more likely in sessions concerned with smoking relapse prevention compared to smoking cessation sessions.