Major Finding: Motivational interviewing has the greatest impact on smoking cessation when it is delivered by a primary care physician, compared with delivery by counselors or nurses (relative risk 3.49 vs.1.23 and 1.27, respectively).
Data Source: Meta-analysis of 14 smoking cessation studies involving over 10,000 individuals in which motivational interviewing was used.
Disclosures: The authors reported no conflicts of interest.
Motivational interviewing can be an effective counseling technique for smoking cessation, particularly when it is delivered by a primary care physician, a review of intervention studies shows. However, the review results should be interpreted with caution, the authors wrote.
Dr. Douglas T.C. Lai, a family medicine physician affiliated with the Chinese University of Hong Kong, and his colleagues from that university and the University of Oxford (England), conducted a Cochrane Collaboration review of data from 14 studies involving more than 10,000 individuals and published between 1997 and 2008.
The review included randomized controlled trials, identified through the Cochrane Tobacco Addiction Group Specialized Register, in which motivational interviewing or its variants were used to assist in smoking cessation (Cochrane Database Syst. Rev. 2010 Jan. [doi: 10.1002/14651858.CD006936.pub2]).
Motivational interviewing (MI) is a nonconfrontational counseling technique designed to help people explore and resolve their uncertainties about behavior changes, the authors wrote. The brief psychotherpapeutic technique has been widely implemented as a smoking cessation technique and is recommended in smoking cessation guidelines.
However, little attempt has been made “to systematically review the evidence” about the intervention, Dr. Lai and his colleagues wrote.
In the current review, the investigators sought to include studies of interventions that made explicit reference to core MI principles as described by W. R. Miller and S. Rollnick in their book, “Motivational Interviewing: Preparing People to Change” (New York: Guilford Press, 2002).
The studies that were included had a monitoring element, such as the details of counselor training or measures to ensure the quality of MI sessions (videotaping sessions or use of an assessment scale and supervision, for example). The main outcome measure used in the review was abstinence from smoking after at least 6 months' follow-up, based on the most rigorous definition of abstinence in each trial and biochemically validated rates, where available.
All except two of the intervention studies reviewed took place in the United States, and the most commonly used MI approach was one in which the smoker received nonthreatening feedback designed to develop discrepancy between smoking and personal goals, the authors explained.
Dr. Lai and his colleagues noted that the interventions involved face-to-face sessions, except for three in which the counseling was telephone based.
Ten of the studies looked at single-session interventions, and the rest looked at three- and four-session interventions. Most of the studies compared the MI intervention with usual care or brief advice, often accompanied by self-help materials, the investigators reported.
The investigators conducted a conventional meta-analysis to estimate pooled treatment effects. They observed a modest but significant increase in smoking cessation among patients who underwent motivational interviewing, compared with those who received usual care.
With the strictest definition of abstinence and the longest follow-up, the overall effect across all 14 trials was a relative risk for smoking cessation in the treatment vs. usual care group of 1.27, the authors reported.
A slightly higher but similar effect (relative risk 1.37) was observed in a sensitivity analysis that excluded trials of participants who were already motivated to make a quit attempt, and a comparable relative risk (1.31) was noted in an analysis of findings from the nine trials in which the outcomes were validated biochemically, they said.
In a subgroup analysis by therapist type, the largest effect was observed in the interventions delivered by primary care physicians, followed by those with counselors and nurses, with respective relative risks of 3.49, 1.23, and 1.27, the authors reported.
Primary care doctors might be best suited to deliver this type of intervention because they are already familiar with the patients and, presumably, have an established rapport.
The authors point out that “this finding is based on two relatively small studies and should not be overstated.”
Despite the positive findings of the meta-analysis, “absolute quit rates were relatively low,” probably because most of the trials included smokers who were not motivated to quit, Dr. Lai and his colleagues reported.
The authors urged caution in interpreting results because of “variations in study quality, treatment fidelity, and the possibility of publication or selective reporting bias.” Future studies “should attempt to identify which core components of the motivational interviewing approach are effective,” they wrote.