Improvement of cardiovascular risk factors after adrenalectomy in patients with adrenal tumors and subclinical Cushing's syndrome: a systematic review and meta-analysis

Objective: Beneficial effects of adrenalectomy on cardiovascular risk factors in patients with subclinical Cushing's syndrome (SCS) are uncertain. We sought to conduct a systematic review and meta-analysis with the following objectives: (i) determine the effect of adrenalectomy compared with conservative management on cardiovascular risk factors in patients with SCS and (ii) compare the effect of adrenalectomy on cardiovascular risk factors in patients with SCS vs those with a nonfunctioning (NF) adrenal tumor. Methods: MEDLINE In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE and Cochrane Central Register of Controlled Trial were searched on 17 November 2015. Reviewers extracted data and assessed methodological quality in duplicate. Results: We included 26 studies reporting on 584 patients with SCS and 457 patients with NF adrenal tumors. Studies used different definitions of SCS. Patients with SCS undergoing adrenalectomy demonstrated an overall improvement in cardiovascular risk factors (61% for hypertension, 52% for diabetes mellitus, 45% for obesity and 24% for dyslipidemia). When compared with conservative management, patients with SCS undergoing adrenalectomy experienced improvement in hypertension (RR 11, 95% CI: 4.3-27.8) and diabetes mellitus (RR 3.9, 95% CI: 1.5-9.9), but not dyslipidemia (RR 2.6, 95% CI: 0.97-7.2) or obesity (RR 3.4, 95% CI: 0.95-12). Patients with NF adrenal tumors experienced improvement in hypertension (21/54 patients); however, insufficient data exist for comparison to patients with SCS. Conclusions: Available low-to-moderate-quality evidence from heterogeneous studies suggests a beneficial effect of adrenalectomy on cardiovascular risk factors in patients with SCS overall and compared with conservative management.