Increased Mortality Persists after Treatment of Cushing's Disease: A Matched Nationwide Cohort Study

Context: Whether biochemical remission normalizes life expectancy in Cushing's disease (CD) patients remains unclear. Previous studies evaluating mortality in CD are limited by using the expected number of deaths in the background population instead of the actual number in matched controls. Objective and setting: To study mortality by time-to-event analysis in an unselected nationwide CD patient cohort. Design and participants: Longitudinal data from the Swedish Pituitary Register of 371 patients diagnosed with CD from 1991 to 2018 and information from the Swedish Cause of Death Register were evaluated. Four controls per patient (n = 1484) matched at the diagnosis date by age, sex, and residential area were included. Main outcome measures: Mortality and causes of death. Results: The median diagnosis age was 44 years (interquartile range 32-56), and the median follow-up was 10.6 years (5.7-18.0). At the 1-, 5-, 10-, 15-, and 20-year follow-ups, the remission rates were 80%, 92%, 96%, 91%, and 97%, respectively. Overall mortality was increased in CD patients compared with matched controls [hazard ratio (HR) 2.1 (95% CI 1.5-2.8)]. The HRs were 1.5 (1.02-2.2) for patients in remission at the last follow-up (n = 303), 1.7 (1.03-2.8) for those in remission after a single pituitary surgery (n = 177), and 5.6 (2.7-11.6) for those not in remission (n = 31). Cardiovascular diseases (32/66) and infections (12/66) were overrepresented causes of death. Conclusions: Mortality was increased in CD patients despite biochemical remission compared to matched controls. The study highlights the importance of careful comorbidity monitoring, regardless of remission status.