Introduction: Patients with subclinical Cushings syndrome (SCS) present with increased cardiovascular morbidity and mortality, however, the beneficial effect of adrenalectomy on cardiovascular risk factors is uncertain.
Objective: Systematic meta-analysis to determine the effect of adrenalectomy vs conservative follow-up on cardiovascular risk factors in patients with adrenal tumors and SCS.
Methods: We searched 6 databases through July 2014. Pairs of independent reviewers selected studies and appraised the risk of bias. We included and extracted studies with at least five SCS patients with adrenal tumors undergoing adrenalectomy where outcomes of interest were measured before and after surgery. Outcomes of interest included hypertension, diabetes, dyslipidemia, and obesity. In majority of studies, improvement of an outcome was defined as postsurgical decrease in dose, number or discontinuation of medications used to treat the comorbidity.
Results: Definition of SCS was heterogeneous among the 23 included studies (526 SCS patients). In eight studies, SCS patients undergoing adrenalectomy (n=116) were compared with SCS patients followed conservatively (n=128). In comparison with follow up, adrenalectomy had a positive effect on improvement in hypertension (RR 11.3 (4.230.2)), diabetes mellitus (RR 5.0 (1.7414.4)), dyslipidemia (RR 3.0 (1.08.9)), and obesity (RR 3.4 (0.9512.1)). When compared with follow up, patients with adrenalectomy had a systolic blood pressure decrease of 12.5 (6.518.6) mmHg, diastolic blood pressure decrease of 9.3 (3.515) mmHg and fasting glucose decrease of 23.4 (8.338.5) mg/dl. The quality of evidence was low due to increased risk of bias, heterogeneity in both SCS and outcome definitions, as well as variable time of postsurgical assessment.
Conclusion: Low quality evidence from the included studies suggests improvement of cardiovascular factors in patients with SCS undergoing adrenalectomy. This is derived from short-term imprecise evidence warranting low confidence. However, our conclusions represent a summary of the best available evidence. Prospective studies are required to confirm these findings.