Body Weight Changes with β-Blocker Use: Results from GEMINI

Purpose: Patients with type 2 diabetes are commonly overweight, which can contribute to poor cardiovascular outcomes. β-blockers may promote weight gain, or hamper weight loss, and are a concern in high-risk patients. The current analysis of the Glycemic Effect in Diabetes Mellitus: Carvedilol-Metoprolol Comparison in Hypertensives (GEMINI) trial evaluates the effects of carvedilol and metoprolol tartrate on weight gain in patients with type 2 diabetes and hypertension. Methods: This prespecified secondary analysis of the GEMINI study (n=1106) evaluated change in body weight after 5 months. Results: Mean (±SE) baseline weights were 97.5 (±20.1) kg for carvedilol and 96.6 (±20.1) kg for metoprolol tartrate. Treatment difference (c vs m) in mean (±SE) weight change from baseline was -1.02 (±0.21) kg (95% confidence interval [CI], -1.43 to -0.60; P <.001). Patients taking metoprolol had a significant mean (±SE) weight gain of 1.19 (±0.16) kg (P <.001); patients taking carvedilol did not (0.17 [±0.19] kg; P =.36). Metoprolol tartrate-treated patients with body mass index (BMI) >30 kg/m² had a statistically significant greater weight gain than comparable carvedilol-treated patients. Treatment differences (c vs m) in the obese (BMI >30 kg/m²) and morbidly obese groups (BMI >40 kg/m²) were -0.90 kg (95% CI, -1.5 to -0.3; P =.002) and -1.84 kg (95% CI, -2.9 to -0.8; P =.001), respectively. Pairwise correlation analyses revealed no significant associations between weight change and change in HbA_1c, HOMA-IR, or blood pressure. Conclusions: Metoprolol tartrate was associated with increased weight gain compared to carvedilol; weight gain was most pronounced in subjects with hypertension and diabetes who were not taking insulin therapy.