Prevalence of Hypercortisolism in Patients with Adrenal Adenomas and Type 2 Diabetes Mellitus: A Mixed Retrospective-Prospective Study

Objective: Adrenal adenomas are often discovered incidentally, and some demonstrate autonomous cortisol secretion that can worsen metabolic and cardiovascular outcomes. Patients with type 2 diabetes mellitus (T2DM) may be at higher risk, yet the prevalence and clinical significance of mild hypercortisolism in this group are not well defined. Design: Mixed retrospective-prospective review of patient records. Methods: Electronic medical records from NYC Health + Hospitals/Queens Diabetes Center (2014-2020) were reviewed. Adults (≥18 years) with radiologically confirmed adrenal adenomas and T2DM were included. Patients on corticosteroids, psychiatric medications, or with life-threatening illness were excluded. Hypercortisolism was defined by a 1-mg dexamethasone suppression test (DST) with a cortisol cutoff ≥ 1.8 μg/dL. Clinical and biochemical parameters, medication use, and imaging follow-up were assessed over one year. Results: Among 500 screened patients, 30 had adrenal adenomas. Thirteen (43.3%) demonstrated abnormal DST cortisol levels (≥1.8 μg/dL). Compared with patients with normal DST results, those with abnormal values were more likely to require escalation of diabetes (77%) and antihypertensive (77%) therapy during follow-up. Five patients also had an increase in adenoma size, while most with normal DST values showed stable adenoma size and fewer medication changes. Conclusions: Nearly half of patients with T2DM and adrenal incidentalomas showed biochemical evidence of hypercortisolism, which was associated with worsening glycemic and blood pressure control. These findings highlight the need for careful endocrine and metabolic monitoring in this population.