Changes in clinical features of adrenal Cushing syndrome: a national registry study.

Graphical abstract: Abstract: Adrenal Cushing syndrome (CS) has been rarely studied in recent years in Japan. This study aimed to investigate clinical characteristics and their changes over time in patients with adrenal CS. We analyzed 101 patients with adrenal CS caused by adenoma, dividing them into two groups based on diagnosis period: December 2011-November 2016 (later group, n = 50) and August 2005-November 2011 (earlier group, n = 51). Differences between the groups and comparisons with previous reports were assessed. Patients with subclinical CS were excluded. Adrenal incidentalomas were the most frequent reason for CS diagnosis (34%). Most patients exhibited few specific cushingoid features (2.5 ± 1.3), with moon faces and central obesity being the most common. Compared to earlier reports, specific cushingoid features were less frequent; nonetheless, no significant differences were observed between the earlier and later groups. All patients had midnight and post-dexamethasone suppression test serum cortisol levels exceeding 5 μg/dL. No significant differences were found between the groups regarding non-specific symptoms, endocrinological findings related to cortisol secretion, cardiometabolic commodities or infections, except for glucose intolerance and bone complications. The prevalence of metabolic disorders other than glucose intolerance and osteoporosis fluctuated over time. Sixteen patients developed cardiovascular diseases or severe infections. In conclusion, adrenal CS became less florid in the 2000s, showed no improvement in the following years, and remained associated with a high complication rate. Further research is needed to establish an early detection model for CS. Plain language summary: Our study found that one-sixth of patients with adrenal Cushing syndrome continued to develop severe complications in this century despite their specific cushingoid features being less pronounced than in the past. Notably, the findings provide clinical insights that may aid in earlier disease diagnosis.