Cushing's syndrome is associated with an increased risk of atrial fibrillation/flutter (HR 1.55, 95% CI 1.19-2.03) that persists despite disease remission and appears primarily driven by coexisting cardiovascular comorbidities rather than cortisol excess.
Pre-existing atrial fibrillation/flutter was significantly more common in patients with Cushing's syndrome than in matched controls.
Patients with Cushing's syndrome had a significantly higher risk of developing new-onset atrial fibrillation/flutter compared with matched controls.
The increased risk of new-onset atrial fibrillation/flutter was observed in both Cushing's disease and adrenal Cushing's syndrome subtypes.
AF/AFL risk did not significantly differ according to remission status, though a trend toward lower risk was observed in patients achieving remission.
Multivariate analysis identified older age at diagnosis, male sex, hypertension, vascular disease, and higher BMI as independent predictors for new-onset AF/AFL in this cohort.
The study population comprised 609 patients with Cushing's syndrome matched 1:5 to 3018 controls using the Clalit Health Services database.
This research suggests that people diagnosed with Cushing's syndrome — a condition caused by prolonged exposure to high levels of the stress hormone cortisol — have a meaningfully higher chance of developing an irregular heart rhythm called atrial fibrillation or flutter (AF/AFL) compared to people without the condition. Analyzing data from over 600 Cushing's syndrome patients and more than 3,000 matched comparison patients over an average of 15 years, the study found that Cushing's syndrome patients were about 55% more likely to develop AF/AFL. This elevated risk was seen regardless of whether the excess cortisol originated from a pituitary gland tumor (Cushing's disease) or from the adrenal glands. Importantly, the research also found that this higher AF/AFL risk did not go away even after patients achieved remission from Cushing's syndrome. When researchers looked more closely at what factors were driving the risk, they found that common cardiovascular risk factors — including older age, being male, having high blood pressure, having vascular disease, and having a higher BMI — were the main predictors, rather than the cortisol excess itself. This suggests that the heart rhythm problems are largely a consequence of the broader cardiovascular damage that Cushing's syndrome causes, rather than a direct effect of high cortisol. These findings highlight the importance of ongoing heart monitoring in people with Cushing's syndrome, even after their hormone levels return to normal following treatment. This research suggests that doctors caring for these patients should be vigilant for signs of atrial fibrillation and actively manage cardiovascular risk factors like blood pressure and weight, not just the underlying hormonal disorder.
Polansky A, Rudman Y, Kushnir S, Shochat T, Gurevitz C, Isand K, et al.. (2026). Increased risk of atrial fibrillation and flutter in patients with Cushing's syndrome: a population-based matched cohort study.. European journal of endocrinology. https://doi.org/10.1093/ejendo/lvag094