Motivational interviewing improves weight loss in women with type 2 diabetes.

OBJECTIVE We sought to determine whether adding motivational interviewing to a behavioral weight control program improves weight loss outcomes and glycemic control for overweight women with type 2 diabetes. RESEARCH DESIGN AND METHODS We conducted a randomized, controlled, clinical trial in which participants all received an 18-month, group-based behavioral obesity treatment and were randomized to individual sessions of motivational interviewing or attention control (total of five sessions) as an adjunct to the weight control program. Overweight women with type 2 diabetes treated by oral medications who could walk for exercise were eligible. Primary outcomes were weight and A1C, assessed at 0, 6, 12, and 18 months. RESULTS A total of 217 overweight women (38% African American) were randomized (93% retention rate). Women in motivational interviewing lost significantly more weight at 6 months (P = 0.01) and 18 months (P = 0.04). Increased weight losses with motivational interviewing were mediated by enhanced adherence to the behavioral weight control program. African-American women lost less weight than white women overall and appeared to have a diminished benefit from the addition of motivational interviewing. Significantly greater A1C reductions were observed in those undergoing motivational interviewing at 6 months (P = 0.02) but not at 18 months. CONCLUSIONS Motivational interviewing can be a beneficial adjunct to behavioral obesity treatment for women with type 2 diabetes, although the benefits may not be sustained among African-American women.