Endocrine Abstracts

Introduction: In patients with unilateral adrenal incidentaloma (AI) and mild autonomous cortisol secretion (MACS) the best therapeutic approach is still a matter of debate. The only available randomized study showed a short-term beneficial effect of surgery on diabetes and hypertension. Importantly, recent data demonstrated that MACS is associated to an increased risk of mortality, especially due to cardiovascular causes.

Study aim: to evaluate, in the medium term, the effect of adrenalectomy on blood pressure and glycometabolic control, in patients with AI and MACS.

Patients and methods: We performed a prospective randomized study on 62 patients with AI >1 cm and cortisol after 1 mg dexamethasone suppression test (1 mgDST) between 1.8 and 5 μg/dl. Patients were randomized to adrenalectomy (operated) or conservative approach (non-operated). A total of 46 subjects (20 operated and 26 not operated) completed a 12 months follow-up. Blood pressure (BP), body weight, glycometabolic control, insulin secretion by homeostasis model assessment (HOMA-β) index and the medical therapy changes were assessed.

Results: At 12 months, the frequency of BP improvement was higher in operated (45%) than in non-operated patients (11.5%, P=0.01), while the BP worsening was more frequent in the latter group (30.8%) than in the former one (10.0%, P=0.008). Glycometabolic control ameliorated in the 25% and worsened in the 15% of surgically treated patients and in 11.5% and 30.8% of non-operated ones, respectively (P-for-trend=0.300). The operated patients showed a significant increase in insulin secretion levels at 12 months compared to non-operated ones (HOMA-β 167.6±79.4 vs 111.4±47.7%, P=0.009; fasting insulin 12.3±4.6 vs 8.8±3.9 μU/ml, P=0.018; insulin AUC after OGTT 12817.1±8006.1 vs 7912.5±2397.0 μU/ml per 120 minutes, P=0.050). BP and/or glycometabolic control improved more frequently in surgically treated patients (55.0%) than in non-operated ones (19.2%, P=0.015), while BP and/or glycometabolic control worsened more commonly among non-operated patients (52.0%) than among surgically treated ones (20.0%, P=0.028). The improvement of BP and/or glycometabolic control was 10.2-fold more frequent in operated patients (confidence interval, 2.82–37.1, P<0.001), regardless for age, gender, and presence of glycometabolic alterations and hypertension at baseline.

Discussion: In patients with AI and MACS surgery leads to a persistent improvement of blood pressure control and insulin secretion and, in more than half of cases, it is beneficial in terms of BP and/or glycometabolic control. At variance, in more than half of patients a conservative approach seems to be deleterious in terms of BP and/or glycometabolic control.