Natural History of Adrenal Steroidogenesis in Autoimmune Addison’s Disease Following Diagnosis and Treatment

CONTEXT: The natural history of adrenal function in autoimmune Addison disease once diagnosed and treated has not been systematically studied, but several case reports of recovery from established adrenal failure suggest it may not be uniform. OBJECTIVE: To ascertain steroidogenic function in autoimmune Addison disease immediately following diagnosis and during prolonged treatment. DESIGN: We studied peak serum cortisol in response to ACTH(1-24) in 20 newly diagnosed autoimmune Addison disease patients at first presentation and then again within a month. We also studied 37 patients with established Addison disease (for between 7 months and 44 years) in a medication-free state, measuring peak serum cortisol responses to ACTH(1-24) and the urine LC-MS steroid metabolome. RESULTS: Adrenal steroidogenesis declined rapidly after steroid replacement treatment for newly diagnosed Addison disease was started, with a peak serum cortisol falling from 138 ± 19 nmol/L (SEM) at presentation to 63 ± 13 nmol/L over 4 weeks (P < 0.003). Six of 37 participants (16%) with established Addison disease had detectable serum cortisol and urine glucocorticoid and mineralocorticoid metabolites during repeat testing, indicating variable degrees of residual adrenal function. CONCLUSION: Autoimmune Addison disease is a heterogeneous condition, showing a rapid decline in adrenal steroidogenesis during the first few weeks following diagnosis, but low-level residual function in a minority of patients, which appears to persist for many years.