Short-term treatment with high-dose glucocorticoids is commonly indicated for a wide range of inflammatory and immunologic conditions. Suppression of the normal adrenal response is a well-recognized but unpredictable complication of this therapy; however, little is known about its frequency or its risk factors for development. Henzen and colleagues used a low-dose corticotropin test to evaluate the frequency of adrenal suppression in patients following a short course of high-dose glucocorticoid therapy.

Patients were eligible for the study if they were receiving a first course of glucocorticoid therapy as treatment for any of a wide range of conditions, including chronic obstructive pulmonary disease, chemotherapy, inflammatory bowel disease, neurologic disorders and thyrotoxicosis. Patients who had adrenal disease or had previously taken glucocorticoids were excluded from the study. Patients who met the inclusion criteria received the equivalent of at least 25 mg of prednisone daily for five to 30 days. Between 24 and 72 hours after the glucocorticoid therapy was discontinued, the low-dose corticotropin test was performed. Patients with plasma cortisol concentrations lower than 550 nmol per L (19.9 μg per dL) in response to corticotropin stimulation were defined as having a deficient adrenal response. These patients were retested on days 2, 4, 6, 10, 12 and 14. Patients with suppressed adrenal function at day 14 were tested again after three and six months.

Of the 75 patients enrolled in the study, 34 (45 percent) had suppressed adrenal function for at least two days following cessation of treatment, and 41 (55 percent) had a normal adrenal response at this time. After six days, adrenal function remained suppressed in 20 patients (27 percent). No correlation could be made between suppressed adrenal response and the type or duration of glucocorticoid therapy. The median daily dosage of glucocorticoid also was similar in all patients.

The authors conclude that adrenal function is commonly suppressed immediately following conventional short-term therapy with glucocorticoids. Adrenal function typically returns to normal in almost all patients within two weeks, but suppression can persist in up to 25 percent of patients and for several weeks or months in a small proportion of patients. Patients are vulnerable to impaired stress response and other adverse effects when their adrenal response is suppressed. Unfortunately, it is impossible to identify ahead of time which patients will be affected, as adrenal suppression cannot be predicted based on dosage, or type or duration of therapy. Therefore, the authors urge vigilant follow-up of patients after glucocorticoid therapy.