Mortality in Cushing's Syndrome: a Systematic Review and Meta-analysis

Context: Data on mortality associated with Cushing's disease (CD) and Cushing's syndrome (CS) are scarce.

Objective: To perform a systematic review and meta-analysis of mortality studies in patients with CD and CS secondary to a benign adrenal adenoma.

Data Sources: A search was performed in seven electronic databases. Sixty-six articles were retrieved for analysis and 7 included in the final study. The main outcome measure was standardized mortality ratio (SMR).

Study Eligibility Criteria, Participants, And Interventions: Studies reporting SMR for patients diagnosed with CD and/or CS. Outcomes were stratified by subtype of Cushing's syndrome.

Study Appraisal And Synthesis Methods: Studies were appraised by two authors and were synthesized using a weighted estimate based on the standard error of the SMR.

Results: The weighted mean of SMR for patients with CD was 1.84 (95% confidence interval (CI): 1.28-2.65). CD patients with persistent disease after initial surgery had a SMR of 3.73 (95% CI: 2.31-6.01), whereas mortality of CD patients with initial remission did not differ significantly from the general population (SMR: 1.23 (95% CI: 0.51-2.97)). SMR for patients with a benign adrenal adenoma was 1.90 (95% CI: 0.93-3.91). Age, sex and observation time did not significantly impact mortality.

Conclusions: CD as opposed to CS due to a benign adrenal adenoma is associated with an excess mortality, which is attributed to patients in whom initial surgical cure is not obtained. This underlines the importance of a rigorous and early follow-up of newly operated patients with CD.