Analyses of clinical and biochemical features in subclinical Cushing's syndrome

Abstract

Objective To evaluate the clinical and biochemical features of subclinical Cushing's syndrome (SCS) and the sensitivity and specificity of various diagnostic methods in SCS.Methods Forty-five cases of SCS underwent abdominal computed tomography scan,plasma cortisol,urinary free eortisol and dexamethasone suppression tests (DST).Then,results were compared with those of the 51 patients with nonfunctiou adrenal adenoma (NAA).Results ( 1 ) As defined by Adult Treatment Panel Ⅲ criteria,the prevalence of metabolic syndrome (MS) was 31.1% in patients with SCS and 11.8% in patients with NAA.The prevalence of abdominal obesity,hypertension,hyperglycemia and disturbance of lipid in SCS patients was higher than that of the patients with NAA.Waist circumference,systolic blood pressure and plasma triglyceride for patients with SCS were larger than those of the patients with NAA.(2) Sensitivity of various laboratory tests for patients with SCS was listed below in the numerical order (from high to low): 2 mg dexamethasone suppression test (DST) (100.00%),24 h plasma cortisol (77.8%),24 h urinary free cortisol (46.7%) and 8 h plasma eortisol (40.0%).The specificity for 2 mg DST and elevation of 8 h plasma eortisol were most ideal (94.1%),next were the elevation of urinary cortisol and 24 h plasma cortisol (84.3% and 74.5% ).Conclusions Some patients with SCS have such metabolic syndromes,as abdominal obesity,hypertension,hyperglycemia and disturbance of lipid.The 2 mg dexamethasone non-suppression test and the elevation of 24 h plasma eortisol were of better clinical value in the diagnosis of SCS. Key words: Subclinical Cushing' s syndrome; Adrenal incidentaloma; Nonfunctional adrenal adenoma