Inadequately Controlled Type 2 Diabetes and Hypercortisolism: Improved Glycemia With Mifepristone Treatment

Abstract

Objective: In many individuals, type 2 diabetes (T2D) remains poorly controlled despite taking multiple glucose-lowering therapies. Several studies have demonstrated that endogenous hypercortisolism is prevalent among these individuals. We tested whether cortisol-directed therapy improves their glycemic control.

Research design and methods: In this prospective, multicenter, double-blind study, 136 individuals with T2D (hemoglobin A1c [HbA1c] 7.5%-11.5% [58-102 mmol/mol] on multiple medications) and hypercortisolism (by dexamethasone suppression test) were randomized 2:1 to the glucocorticoid receptor antagonist mifepristone (300-900 mg once daily; n = 91) or placebo (n = 45) for 24 weeks, with stratification by presence/absence of an adrenal imaging abnormality. The primary end point was the change in HbA1c. Secondary end points included changes in glucose-lowering medications, weight, and waist circumference and safety.

Results: Mean baseline HbA1c in the study cohort was 8.55% (69.9 mmol/mol). At 24 weeks, the least squares mean (LSM) difference from placebo in HbA1c was -1.32% (95% CI -1.81 to -0.83; P < 0.001). Participants receiving mifepristone experienced reductions in body weight and waist circumference (placebo-adjusted LSM differences of -5.12 kg [95% CI -8.20 to -2.03] and -5.1 cm [-8.23 to -1.99], respectively). Of participants on mifepristone, 46% discontinued therapy, compared with 18% on placebo. Adverse events with mifepristone (>10% of participants) included hypokalemia, fatigue, nausea, vomiting, headache, peripheral edema, diarrhea, and dizziness, consistent with mifepristone's known tolerability profile. Increases in blood pressure also occurred.

Conclusions: In individuals with inadequately controlled T2D and hypercortisolism, cortisol-directed medical therapy with mifepristone reduced HbA1c, with a manageable tolerability profile.