Endocrine Abstracts

Introduction: Prevalence of CS without specific signs is thought to be high, which might be an indication for its general screening. However, conclusive data about its diagnostics is absent.

Design: 189 overweight patients were studied. Nobody had clinical evidence of hypercortisolism. Diagnostic of CS was 1-mg overnight dexamethasone suppression test (1-mg DST; cut off 50 nmol/l) as a screening; midnight plasma cortisol (MPC) (<207 nmol/l) and 24-h urinary free cortisol (UFC) (<180 μg/24 h) as a confirmatory tests; morning plasma ACTH (5–46 pg/ml), 8-mg DST and imaging studies as topical diagnostics.

Results: Among 189 patients 166 were excluded to have CS according to results of DST 1 mg (<50 nmol/l). 23 had impaired result of 1-mg DST. Among these 23 patients there were diagnosed four cases of corticotropinomas, two corticosteromas. Other 17 patients were excluded to have CS by long-term follow-up and, therefore, they had falsely positive results of confirmatory tests. The diagnostic characteristic of MPC and UFC with established cut off were calculated: MPC – Sen 83.33% (95% CI 35.88–99.58), Sp 63.64% (95% CI 30.79–89.07), LR+ 2.29, LR− 0.26, DOR 8.75 (95% CI 0.73–103.82), UFC – 83.33% (95% CI 35.88–99.58), Sp 18.18% (95% CI 2.28–51.78), LR+ 1.02, LR− 0.92, DOR 1.11 (95% CI 0.07–15.53). In order to adjust diagnostic efficiency without a certain threshold value, the logit regression equation was calculated. The percent of concordance for UFC made 53%, MPC – 81.8%. Also there were performed comparison results of patients with and without CS: results of MPC (significant difference) and UFC (insignificant difference).

Conclusions: High prevalence of CS without specific signs was confirmed on our study (about 3%). Among tests used to screen and confirm CS without specific signs, UFC has the worst diagnostic characteristics and, therefore, should not be used. MPC has better characteristics, however, the question of threshold value has to be discussed.