Pituitary-adrenal function after prolonged glucocorticoid therapy for systemic inflammatory disorders: an observational study.

ABSTRACT

CONTEXT Glucocorticoid therapy is being used in a wide variety of systemic disorders. Reference papers, published more than 20 years ago, showed no correlation between adrenal insufficiency risk and dose or duration of glucocorticoid therapy. OBJECTIVE: Our objective was to evaluate the extent to which long-term glucocorticoid therapy damages the pituitary-adrenal axis in patients with systemic inflammatory disorders. DESIGN: We conducted a retrospective observational study from January 2011 to August 2012. SETTING: This was a monocentric study at the Department of Internal Medicine, Bichat Hospital, Paris-Diderot University, Paris, France. PARTICIPANTS: Sixty consecutive patients who were receiving long-term prednisone therapy for systemic inflammatory disorders and in whom discontinuation of glucocorticoid treatment was planned. INTERVENTION A short Synacthen test was performed. A bolus of 0.25 mg 1-24-ACTH was injected in the morning, 24 hours after the most recent dose of prednisone. Cortisol was measured at baseline and 60 minutes after Synacthen injection. MAIN OUTCOME MEASURES: We assessed frequency and risk estimate of pituitary-adrenal dysfunction. RESULTS: Twenty-nine patients (48.3%) had adrenal insufficiency defined by a plasmatic cortisol <100 nmol/L (n = 13) at baseline (time 0) or <550 nmol/L (n = 16) 60 minutes after Synacthen injection. Cumulative dose (area under the receiver operating characteristic curve = 0.77 [95% confidence interval = 0.62-0.91], P = .007) and exposure (area under the receiver operating characteristic curve 0.80 [95% confidence interval = 0.67-0.93], P = .002) to prednisone were predictive for adrenal insufficiency based on a T0 <100 nmol/L. Prednisone was stopped in 29 of 31 patients (93.5%) showing a normal response to short Synacthen test; none of these patients required hydrocortisone replacement with a mean follow-up of 10 (± 6) months. CONCLUSION: Adrenal insufficiency is frequent in patients treated with long-term glucocorticoids for systemic inflammatory disorders and is related to duration and cumulative dose of steroids.