Bilateral and unilateral adrenal incidentalomas: biochemical and clinical characteristics

Abstract

The possible different prevalence of arterial hypertension (AH), type 2 diabetes mellitus (T2DM), dyslipidaemia (DL) and vertebral fractures (FX) between patients with bilateral and unilateral adrenal incidentalomas (BAI and UAI, respectively) with and without subclinical hypercortisolism (SH) is unknown. In this study we compared the prevalence of AH, T2DM, DL and FX in BAI and UAI patients in relation to SH. Prospective study. In 175 UAI and 38 BAI patients, we evaluated BMI, spinal and femoral bone mineral density (LS and FN BMD, respectively) and the presence of AH, T2DM, DL and FX. SH was diagnosed in the presence of 2 of the following: urinary free cortisol levels >193 nmol/24 h, serum cortisol levels after 1 mg dexamethasone suppression test >83 nmol/l or ACTH levels <2.2 pmol/l. Age, BMI and cortisol secretion were comparable, while FN BMD was lower in BAI than in UAI patients (-0.45±0.86 vs 0.09±1.07, P=0.004). The prevalence of SH, AH, T2DM, and DL was comparable, while the prevalence of FX was higher in BAI than in UAI (52.6 vs 28%, P=0.007). The presence of FX was associated with BAI (odds ratio (OR) 2.6, 95% confidence interval (95% CI) 1.2-5.6, P=0.016), after adjusting for SH (OR 1.77, 95% CI 0.85-3.7, P=0.12), BMI (OR 1.06, 95% CI 0.98-1.13, P=0.1), age (OR 1.07, 95% CI 1.04-1.11, P=0.0001) and LS BMD (OR 1.31, 95% CI 1.03-1.67, P=0.03). BAI patients have an increased FX risk than UAI ones. Further studies should investigate the causes of bone involvement in BAI patients.