MILD CORTISOL HYPERPRODUCTION IS ASSOCIATED WITH IMPAIRED GLUCOSE HOMEOSTASIS AND INSULIN-RESISTANCE IN NON-DIABETIC ESSENTIAL HYPERTENSIVE PATIENTS

Abstract

Objective: Patients with Cushing syndrome (CS) and subclinical Cushing syndrome (SCS) have higher risk of cardiovascular events than the general population. Excess cortisol secretion might reduce insulin secretion, insulin sensitivity, glucose uptake, and increase gluconeogenesis. Data on cortisol secretion in patients with essential hypertension and on its relationships with glucose homeostasis are scanty. The aim of the study was to evaluate cortisol secretion and its relationship with glucose homeostasis and insulin-sensitivity in essential hypertensive (EH) patients. Design and method: In 155 EH patients (age 43 ± 13 years, 81 men) we measured fasting glucose and insulin, HOMA index, plasma cortisol levels at 8 AM, 5 PM and 11 PM, and after an overnight suppression test (DST) with 1 mg of dexamethasone, 24-h free urinary cortisol, and ACTH, and performed a standard oral glucose tolerance test (OGTT), calculating the area under the curve for glucose (G-AUC) and insulin (I-AUC). Results: Fasting glucose was positively related to 11 PM cortisol level (r = 0.221, P = 0.019) and post-DST cortisol levels (r = 0.244, P = 0.002). Post-DST cortisol level was positively related with fasting insulin (r = 0.264, P = 0.001), HOMA (r = 0.273, P = 0.001) and I-AUC (r = 0.185, P = 0.023). G-AUC was positively related to 11 PM cortisol (r = 0.246, P = 0.008) and post-DST cortisol levels (r = 0.216, P = 0.007). These associations were independent of age, body mass index, alcohol intake, physical activity, plasma potassium and ACTH levels. Conclusions: In non-diabetic patients with EH, relative cortisol hypersecretion is independently associated with impaired glucose homeostasis and insulin resistance.