Different pathogenesis of glucose intolerance in two subtypes of primary aldosteronism: Aldosterone‐producing adenoma and idiopathic hyperaldosteronism

AIMS/INTRODUCTION: An increased risk of diabetes mellitus has been reported in primary aldosteronism, but the pathogenesis of glucose intolerance between the primary aldosteronism subtypes remains unclear. This study aimed to evaluate glucose metabolism in oral glucose tolerance test between aldosterone‐producing adenoma and idiopathic hyperaldosteronism, and characterize patients with improved glucose intolerance after primary aldosteronism treatment. MATERIALS AND METHODS: Oral glucose tolerance test was carried out in 116 patients who were diagnosed with primary aldosteronism and received adrenal venous sampling for subtyping. Oral glucose tolerance test was re‐evaluated after starting the treatment of primary aldosteronism for those who had glucose intolerance before the treatment. RESULTS: A total of 46.4% and 52.3% of patients with aldosterone‐producing adenoma and idiopathic hyperaldosteronism, respectively, were diagnosed with impaired glucose tolerance or diabetes. The insulinogenic index was significantly lower in aldosterone‐producing adenoma than in idiopathic hyperaldosteronism (P = 0.045), whereas the Matsuda insulin sensitivity index was significantly higher in aldosterone‐producing adenoma than in idiopathic hyperaldosteronism (P = 0.022). After the treatment of primary aldosteronism, glucose intolerance was improved in 66.6% and 45.8% of aldosterone‐producing adenoma and idiopathic hyperaldosteronism, respectively. The presence of obesity and central obesity were significantly lower in patients who improved glucose intolerance after the treatment of primary aldosteronism as compared with those not improved (P = 0.013 and P = 0.033, respectively). CONCLUSIONS: Insulin secretion impairment and insulin resistance play pathogenic roles for glucose intolerance in aldosterone‐producing adenoma and idiopathic hyperaldosteronism, respectively. In addition, primary aldosteronism treatments can ameliorate glucose intolerance more effectively in patients without obesity and/or central obesity.