Context: Primary adrenal insufficiency (Addison's disease) is a rare autoimmune disease. Until recently, life expectancy in Addison's disease patients was considered normal.
Objective: To determine the mortality rate in Addison's disease patients.
Design and methods: i) Patients registered with Addison's disease in Norway during 1943-2005 were identified through search in hospital diagnosis registries. Scrutiny of the medical records provided diagnostic accuracy and age at diagnosis. ii) The patients who had died were identified from the National Directory of Residents. iii) Background mortality data were obtained from Statistics Norway, and standard mortality rate (SMR) calculated. iv) Death diagnoses were obtained from the Norwegian Death Cause Registry.
Results: Totally 811 patients with Addison's disease were identified, of whom 147 were deceased. Overall SMR was 1.15 (95% confidence intervals (CI) 0.96-1.35), similar in females (1.18 (0.92-1.44)) and males (1.10 (0.80-1.39)). Patients diagnosed before the age of 40 had significantly elevated SMR at 1.50 (95% CI 1.09-2.01), most pronounced in males (2.03 (1.19-2.86)). Acute adrenal failure was a major cause of death; infection and sudden death were more common than in the general population. The mean ages at death for females (75.7 years) and males (64.8 years) were 3.2 and 11.2 years less than the estimated life expectancy.
Conclusion: Addison's disease is still a potentially lethal condition, with excess mortality in acute adrenal failure, infection, and sudden death in patients diagnosed at young age. Otherwise, the prognosis is excellent for patients with Addison's disease.