The Quantitative Relationship Between Autonomous Cortisol Secretion, Dysglycemia and the Metabolic Syndrome

Objective: Autonomous cortisol secretion (ACS) is the most common endocrine abnormality in the evaluation of adrenal incidentalomas. The categorization of ACS is derived from a 1 mg dexamethasone suppression test (DST). Impaired DST is associated with several metabolic derangements. In this study we analyzed the association between post-DST cortisol level, analyzed as a continuous parameter, and indices of glycemic metabolism. Methods: We prospectively collected data of 1,976 patients evaluated for adrenal incidentalomas in a large tertiary medical center between December 1, 2017, and August 31, 2019. Seventy-three patients completed the evaluation process. Post-DST cortisol levels were analyzed for correlation with various metabolic parameters, including fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) among the general cohort and for subgroups stratified by the number of metabolic syndrome (MS) criteria. Results: Post-DST cortisol demonstrated a linear association with FPG and HbA1c across its entire cortisol range (R = 0.51 and 0.41, respectively; P≤.01). The association between post-DST cortisol and FPG was strengthened with an increased number of metabolic syndrome criteria. Patients with 4 MS criteria show a stronger association (R = 0.92) compared to patients with only a single criterion (R = 0.509). Furthermore, mean post-DST cortisol levels increased as the number of MS criteria accumulated. Conclusion: Post-DST cortisol should be viewed as a continuous parameter in risk stratification algorithms for the development of MS and particularly dysglycemia.