Conference Coverage
VANCOUVER, B.C. – Motivational interviewing in the primary care setting promotes weight loss among overweight and obese children, according to results from a randomized trial reported at the annual meeting of the Pediatric Academic Societies.
Investigators conducted the trial, Brief Motivational Interviewing to Reduce Child Body Mass Index (BMi2), in 42 practices across the United States belonging to the Pediatric Research in Office Settings (PROS) research network.
Participants were 645 racially/ethnically and socioeconomically diverse children aged 2-8 years with a body mass index (BMI) in the 85th-97th percentile, and their parents.
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Motivational interviewing delivered by primary care providers significantly reduced BMI percentile and raw BMI in obese children, researchers said.
The practices were randomized into three even groups assigned to deliver usual care (assessment and health education materials), four sessions of motivational interviewing by pediatricians only, or four sessions by pediatricians plus six sessions by registered dietitians, generally by telephone.
Motivational interviewing entails rolling with patient/parent resistance to change, building a discrepancy between their current health status/behaviors and their values and goals, supporting their autonomy, and energizing them to change, explained lead author Ken Resnicow, Ph.D., professor of health behavior and health education, University of Michigan School of Public Health in Ann Arbor.
"When we train clinicians to do motivational interviewing, we want to move them from asking to reflecting, from counterpunching to rolling with resistance, and from informing and advising to eliciting autonomous change talk," he elaborated. If the technique is used properly, patients/parents should be talking more than half the time.
Main trial results showed that at the 2-year mark, all groups had a lower adjusted BMI percentile than the baseline average of about 92. However, the children who received motivational interviewing from both a pediatrician and dietitian had a significantly lower value than the children who received usual care (87.1 vs. 90.3) and a significantly greater reduction in that value from baseline (4.9 vs. 1.8). The findings were similar for raw BMI.
In addition, children in that intervention group consumed more servings of fruits and vegetables daily than their usual-care peers (4.3 vs. 3.8), and had fewer hours of screen time per day (2.2 vs. 2.5). Daily servings of sweet beverages and daily hours of physical activity did not differ significantly.
There were intermediate but generally nonsignificant benefits among the children who received motivational interviewing only from pediatricians.
Pediatricians were highly satisfied with their training, and parents were highly satisfied with pediatrician-delivered motivational interviewing.
"This is actually the first large-scale randomized controlled trial to show that motivational interviewing delivered by primary care providers significantly reduced BMI percentile and raw BMI, and with the effect size, I think most of our colleagues agree that these are clinically significant," Dr. Resnicow commented.
Pediatricians completed an average of 3.4 of their four planned motivational interviewing sessions, and dietitians completed 2.7 of their six planned sessions. Findings showed a dose-response whereby improvements in BMI were greater the more sessions a family completed.
"Of course, there are confounders here, and maybe families that are doing better are more likely to continue therapy, so we have to be careful not to infer causality. But it certainly suggests that our next couple of studies might want to focus on improving the dose of the motivational interviewing delivery," Dr. Resnicow commented. "We do feel that the dose of 4 and 10 sessions that we shot for is something that can be replicated in practice."
Attendee Dr. James M. Perrin, professor of pediatrics at Harvard Medical School, Boston, and president of the American Academy of Pediatrics, asked why results were better with motivational interviewing from both pediatricians and dietitians when the number of sessions delivered by dietitians was so low.
"I would just have to conclude that those additional three contacts, although only around 50% of what was prescribed, were still important. The dietitians did address different content, so it may be that the docs were very good at approaching the topics and setting goals, but the dietitians were able to get into more of the nutrition therapy, so even at that low dose, it seemed to add to what the docs were doing as sort of the background intervention," Dr. Resnicow speculated.
The pediatricians in the trial showed high competence and fidelity in their ability to deliver the motivational interviewing intervention, he noted. "They were handpicked in some ways; we had just an amazing group of pediatricians participating in the study. The next question is, can the average clinician do it – that’s a very important next step."