SAT-370 Clinical Characteristics and Metabolic Features of Patients with Subclinical Cushing's Syndrome and Its Correlation with Cortisol Level

Objective The aim of this study was to examine the clinical characteristics and metabolic features of subclinical Cushing’s syndrome (SCS), and to investigate the association of the cortisol level with the metabolic features in patients with SCS. Methods 52 patients with non-functioning adenoma (NFA), 45 patients diagnosed with SCS and 61 patients with overt adrenal Cushing’s syndrome (CS) participated in this study. Clinical data and endocrine function of the patients as well as histological findings were all reviewed. Results 1) The average age of patients with SCS was 52.56±13.25 years, 68.9% patients were female. No difference was detected in age, gender and BMI between patients with SCS and NFA (P > 0.05). Compared to patients with SCS, CS was more common in younger and female patients (43.90±13.83, 83.6%). The prevalence of diabetes mellitus, hypertension, and osteopenia/osteoporosis were significantly higher in patients with SCS compared to those with nonfunctioning tumors (57.8% vs 32.7%, 73.3% vs 53.8%, 41.2% vs 19.2%; P < 0.05). No difference was detected between SCS and CS patients in the prevalence of metabolic disease. 2) Compared to patients with NFA, plasma ACTH level is lower in patients with SCS (P < 0.05). Whereas, the midnight cortisol level and cortisol level after 1mg overnight dexamethasone suppression is higher in SCS than NFA (P < 0.05). No difference was detected between SCS and NFA in 24h urinary free cortisol and early-morning cortisol level (P > 0.05). Compared to SCS, the derangement of ACTH-cortisol axis is more prominent in CS patients demonstrated as suppressed plasma ACTH level and elevated plasma and 24h urine cortisol level. 3) In SCS cohort, SBP, FBG and HbA1c correlated positively with 24h urinary free cortisol (r =0.394, P =0.021; r =0.426, P =0.011, r =0.398, P =0.015; respectively). When controlling for age and gender, the correlation was also significant (P < 0.05). No correlations were found between BMI, TG, HDL and 24h urinary free cortisol. Conclusion Patients with SCS showed slight derangement of the circadian rhythm of cortisol and cortisol excess, and increased prevalence of metabolic disease. Furthermore, the cortisol level was related closely to blood glucose and blood pressure. Our findings might suggestive in therapeutic decision making (conservative vs surgery approach) in patients with SCS.