Abstract
Cross-sectional studies in small and selected populations report a high prevalence
of hypercortisolism in patients with type 2 diabetes (T2D), which could have therapeutic
implications, if confirmed. We therefore estimated the prevalence of hypercortisolism
in a large and unselected cohort of recently diagnosed T2D patients. Consecutive patients
with recently diagnosed T2D first underwent an overnight dexamethasone (1 mg) suppression
test (OD). Patients not suppressing serum cortisol ≤50 nmol/l proceeded with a 48-h
low dose dexamethasone suppression test (LDDST) and 24-h urinary free cortisol collection
(UFC). Patients with elevated cortisol levels according to LDDST and/or UFC underwent
imaging guided by plasma ACTH levels, and assessment of bone mineral density. A total
of 384 T2D patients (232male/152 females) with a mean age of 60±10 years were included.
Eighty-five (22%) patients suppressed incompletely to OD of whom 20 (5%) failed to
suppress after LDDST and/or had elevated UFC (=hypercortisolism). Patients with hypercortisolism
did not differ as regards age, BMI, HbA1c, T-score or blood pressure, but a higher
proportion of them received antihypertensive treatment (100% vs. 64%, p=0.001). Imaging
revealed adrenal adenoma(s) in 9 cases and a pituitary macroadenoma in 1 case. We
found a 5% prevalence of hypercortisolism in unselected, recently diagnosed T2D, which
was not associated with a persuasive cushingoid phenotype. The clinical implications
are therefore uncertain.
Key words
cortisol - Cushing’s syndrome - subclinical Cushing’s syndrome - Type 2 diabetes
