Nonfunctioning adrenal incidentaloma: A novel predictive factor for metabolic syndrome.

CONTEXT: Although metabolic syndrome has been studied in patients with autonomous cortisol secretion, there are limited data for those with nonfunctioning adrenal incidentaloma (NFAI). OBJECTIVE: To assess metabolic syndrome frequency in NFAI patients and controls without adrenal adenoma according to World Health Organization (WHO), National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III), American Association of Clinical Endocrinologists/American College of Endocrinology (AACE/ACE) and International Diabetes Federation (IDF) criteria. DESIGN: Retrospective and transversal study. PATIENTS: Seventy-four NFAI and 90 controls were evaluated. NFAI diagnosis was established according to current guidelines. The control group was selected based on normal adrenal imaging examinations. MEASUREMENTS: Subjects were categorized by metabolic syndrome presence according to WHO, NCEP-ATP III, AACE/ACE and IDF. RESULTS: Age, gender, ethnicity, body mass index, smoking, menopause, statin and fibrate use were comparable between patients and controls. The frequency of prediabetes, dyslipidaemia and hypertension as well as waist circumference were significantly higher in the NFAI patients compared to the controls. The metabolic syndrome frequency in the NFAI group was significantly higher compared to the normal adrenal group: WHO: 69.2% × 31.0% (P < 0.001); NCEP-ATP III: 81.7% × 44.9% (P < 0.001); AACE/ACE: 77.1% × 31.9% (P < 0.001); IDF: 78.6% × 45.5% (P < 0.001). Logistic regression analysis showed that NFAI was a predictor of metabolic syndrome according to WHO (P = 0.001), NCEP-ATP III (P = 0.005) and AACE/ACE (P = 0.007). CONCLUSIONS: Metabolic syndrome is frequently found in patients with NFAI, and this frequency is higher in NFAI patients than in those with normal adrenal imaging.