Effect of mineralocorticoid receptor antagonist on insulin resistance and endothelial function in obese subjects

Aim Obese individuals have high aldosterone levels that may contribute to insulin resistance (IR) and endothelial dysfunction leading to obesity‐induced cardiovascular disease. We conducted a study to evaluate the effect of mineralocorticoid receptor antagonism on IR and endothelial function in obese individuals. This was a placebo‐controlled, double‐blind, randomized, parallel‐group study (NCT01406015). Methods Thirty‐two non‐diabetic, obese subjects [body mass index (BMI) 30 to 45 kg/m2] with no other medical problems were randomized to 6 weeks of treatment with spironolactone 50 mg daily or placebo. Insulin sensitivity index (ISI) was assessed by Matsuda method, endothelial function by flow mediated vasodilatation (FMD) of brachial artery and renal plasma perfusion by clearance of para‐aminohippurate (PAH). Results There was no change in weight, BMI or plasma potassium during the study period. Treatment with spironolactone led to increases in serum aldosterone (7.6 ± 6.6 vs. 3.2 ± 1.3 ng/dl; p