Motivational interviewing targeting diet and physical activity improves adherence to paediatric obesity treatment: results from the MI†Values randomized controlled trial.

BACKGROUND: Adherence is a challenge in obesity treatment. Motivational interviewing (MI) may promote patient adherence. MI Values is a randomized controlled trial of MI implemented as an adjunct to an adolescent obesity treatment [Teaching Encouragement Exercise Nutrition Support (T.E.E.N.S.)]. OBJECTIVE: Assess effects of MI Values on T.E.E.N.S. attrition and adherence. METHODS: Participants were randomized to MI (n = 58) or control (n = 41). At weeks 1 and 10, MI participants had brief MI sessions; controls viewed health education videos. All participants continued with T.E.E.N.S. (biweekly dietitian and behavioural support visits; 3 times per week supervised physical activity). Assessments were repeated at baseline, 3 and 6 months. T-tests and chi-square analyses examined T.E.E.N.S. attrition and adherence by group. RESULTS: Adolescents (N = 99) were primarily African-American (73%) females (74%); age = 13.8 ± 1.8 years, body mass index percentile = 98.0 ± 1.2. Compared with controls, MI participants had greater 3-month adherence overall (89.2% vs. 81.0%, P = 0.040), and to dietitian (91.3% vs. 84.0%; P = 0.046) and behavioural support (92.9% vs. 85.2%; P = 0.041) visits, and greater 6-month adherence overall (84.4% vs. 76.2%, P = 0.026) and to behavioural support visits (87.5% vs. 78.8%, P = 0.011). CONCLUSIONS: MI enhanced adherence to this obesity intervention. MI Values is the first study to examine the impact of MI on treatment adherence among obese, primarily African-American adolescents.