Abstract
BACKGROUND: Adrenal incidentalomas (AI) are clinically silent adrenal masses that are detected incidentally during imaging procedures performed for unrelated diseases. The aim of this study was to investigate the prevalence of sub-clinical hypercortisolism (SH) and associated co-morbidities in patients with unilateral AI (UAI) and bilateral AI (BAI). METHODS: We evaluated 152 patients, 105 (69.1%) with UAI and 47 (30.9%) with BAI. SH was diagnosed in the presence of serum cortisol levels after 1 mg dexamethasone suppression test (DST) or after 2-day low-dose DST (LDDST) > 50 nmol/L with at least one of the following parameters: midnight serum cortisol > 208 nmol/L, 24-h urinary free cortisol > 245 nmol/24 h, or ACTH < 10 ng/L. Bone mineral density (BMD) was measured at lumbar spine (LS) and femoral neck (FN). RESULTS: Age, BMI, and waist circumference were comparable, and diabetes, hypertension and dyslipidemia occurred with similar frequency in both groups. The overall prevalence of SH was 20.5% based on post-1 mg DST, and 20.0% based on post-LDDST cortisol levels, and it was more prevalent in BAI than UAI patients (31.1% vs 15.2%, respectively, p=0.026). LS BMD was lower in BAI than in UAI patients (0.96±0.14 vs 0.87±0.15, p=0.002). There were no differences in FN BMD. The prevalence of osteoporosis was higher in BAI compared to UAI patients (37.1% vs 15.9%, respectively, p=0.011). CONCLUSIONS: Patients with BAI had higher prevalence of SH and osteoporosis than those with UAI. Frequency of other co-morbidities was similar. This may be due to the higher degree of autonomous cortisol secretion or different tissue-specific sensitivity to glucocorticoids.