Association of Weight Loss and Medication Adherence Among Adults With Type 2 Diabetes Mellitus: SHIELD (Study to Help Improve Early evaluation and management of risk factors Leading to Diabetes)()

BACKGROUND: Adherence to prescribed diabetes medications is suboptimal, which can lead to poor glycemic control and diabetic complications. Treatment-related weight gain is a side effect of some oral antidiabetic agents and insulin, which may negatively affect adherence to therapy. OBJECTIVE: This study investigated whether adults with type 2 diabetes mellitus (T2DM) who lost weight had better medication adherence than those who gained weight. METHODS: Weight change over 1 year (2007 to 2008) was assessed among respondents in the US Study to Help Improve Early evaluation and management of risk factors Leading to Diabetes (SHIELD). Weight loss of >1.0%, ≥3%, and ≥5% of weight was compared with weight gain of ≥1.0%. Medication adherence was assessed using the Morisky 4-item questionnaire for medication-taking behavior, with lower scores representing better adherence. RESULTS: There were 746 T2DM respondents who lost >1.0%, 483 who lost ≥3%, 310 who lost ≥5%, and 670 who gained ≥1.0% of weight. Each weight-loss group had significantly lower Morisky scores than the weight-gain group; mean scores of 0.389 versus 0.473 (P = 0.050) for the >1.0% weight-loss group, 0.365 versus 0.473 (P = 0.026) for the ≥3% weight-loss group, and 0.334 versus 0.473 (P = 0.014) for the ≥5% weight-loss group. Significantly fewer respondents who lost weight had received insulin, sulfonylurea, or thiazolidinedione therapy (57%) compared with respondents who gained weight (64%) (P = 0.002). Demographics, exercise habits, and dieting were similar between weight-loss and weight-gain groups. CONCLUSIONS: T2DM respondents with weight loss had significantly better medication adherence and were less likely to be on treatment regimens that increase weight than T2DM respondents with weight gain. These findings suggest that strategies that lead to weight loss, including use of diabetes medications associated with weight loss, may improve medication adherence.