[Frequency and risk factors of biological adrenal insufficiency screened by the 250 microg Synacthene stimulation test after a prolonged course of systemic glucocorticoid therapy. A study of 100 patients].

Purpose: The frequency of adrenal insufficiency after a prolonged, continuous course of oral high-dose corticosteroids is poorly documented. We evaluated it retrospectively in our internal medicine department.

Methods: The patients were included between February 2000 and June 2007 and were administered a Synacthene 250 microg test (ST250) before tapering prednisone dose below 5mg per day. A non-responsive test was defined by a cortisol increase below 18 microg/dL, 60 min after stimulation. We also studied the risk factors associated with biological adrenal insufficiency by a multivariate logistic regression analysis.

Results: Hundred patients were included (mean age: 61.5+/-16.3 years). Mean initial dose of corticosteroids was 65.5+/-112 mg/d. Forty-five patients failed to respond to the ST250. A normal ST250 was negatively associated with a duration of corticosteroids therapy longer than 19.5 months (OR=0.38 [0.15-0.94]; p=0.04) and positively with an age over 63.5 years (OR=2.5 [1.1-6.4]; p=0.05). Two patients experienced a clinical adrenal insufficiency crisis.

Conclusion: Biological adrenal insufficiency is very common after a prolonged course of oral high-dose corticosteroids. The risk does not seem to increase with age. The clinical benefit of a systematic ST250 at the time of corticosteroids withdrawal followed by hydrocortisone substitution if the test is non responsive remains unknown, and this practice is still a matter of debate.