Systematic review of surgical treatment of subclinical Cushing's syndrome

Background: Subclinical Cushing's syndrome (SCS) is a condition of biochemical cortisol excess without the classical clinical features of overt hypercortisolism; it may be associated with some consequences of metabolic syndrome. The most appropriate treatment remains controversial. This study aimed to assess the outcomes of adrenalectomy for SCS. Methods: A systematic review was performed. MEDLINE, Embase and Cochrane Databases (1980-2013) were searched for studies reporting the outcomes of unilateral adrenalectomy with respect to hypertension, diabetes, dyslipidaemia, obesity and osteoporosis in patients with SCS. Studies with a questionable diagnosis of SCS, bilateral adrenal involvement and insufficient data were excluded. Results: Of the 105 papers screened, seven were selected; there were six retrospective studies and one randomized clinical trial, including 230 patients. Data analysis was limited by heterogeneity in definition of SCS and endpoints. Hypercortisolism was cured in all operated patients. Laparoscopy was the preferred approach, with a morbidity rate of 0.8 per cent. A beneficial effect of surgery on blood pressure, glucometabolic control and obesity was evident in all studies, with cure or improvement in 72, 46 and 39 per cent of patients respectively, compared with conservative management. The results for lipid metabolism were equivocal, because of a decrease in triglyceridaemia but discordant effects on cholesterol metabolism among the different studies. No beneficial effects on osteoporosis were found. Conclusion: Laparoscopic adrenalectomy seems to be beneficial in reversing several metabolic effects of hypercortisolism, with a low morbidity rate. However, the heterogeneity and low quality of the available studies preclude definitive recommendations.