Mortality and morbidity in Cushing's syndrome in New Zealand.

Objective: Untreated Cushing's syndrome (CS) is associated with significant morbidity and mortality. However, recent operative series suggest low morbidity and mortality for CS, whereas population-based surveys report elevated mortality rates. We investigated the mortality and morbidity of CS in New Zealand.

Design: A nationwide retrospective survey of patients with CS between 1960 and 2005 managed at the four main endocrinology services.

Patients: A total of 253 patients with CS were identified, excluding adrenal carcinoma and malignant ectopic CS. MEASUREMENTS; The primary outcome was the standardized mortality ratio (SMR), comparing the observed number of deaths with the expected number for the population matched for age, sex and duration of follow-up. Secondary outcomes were the change in prevalence of co-morbidities at presentation and at final follow-up.

Results: The approximate prevalence and incidence of CS was 79/million and 1·8/million/y. The mean age at presentation was 39 year, and median duration of follow-up was 6·4 year (range 0-46). Overall, 89% achieved biochemical cure at last follow-up, with >90% achieving biochemical cure for CS from adrenal adenoma and pituitary causes. Thirty-six patients died during follow-up compared with 8·8 expected deaths (SMR 4·1, 95%CI 2·9-5·6). While hypertension, sexual dysfunction, myopathy and mild psychiatric illness were significantly reduced after treatment, hypertension, diabetes mellitus, moderate or major psychiatric illness, and osteoporosis were common at final follow-up.

Conclusion: CS is associated with both high mortality and a high prevalence of co-morbidities, even when biochemical cure rates are between 80% and 90%.