Recovery of Adrenal Function in Patients with Glucocorticoids Induced Secondary Adrenal Insufficiency

BACKGROUND: The chronic use of glucocorticoids (GC) suppresses function of the hypothalamic-pituitary-adrenal axis and often results in secondary adrenal insufficiency (AI). The present study aimed to determine the recovery rate of adrenal function in patients with secondary AI within 1 to 2 years and to assess the factors predictive of adrenal function recovery. METHODS: This was a retrospective observational study that enrolled patients diagnosed with GC-induced secondary AI between 2007 and 2013. AI was defined by peak serum cortisol levels <18 µg/dL during a standard-dose short synacthen test (SST). A follow-up SST was performed after 1 to 2 years, and responders were defined as those with adrenocorticotropic hormone (ACTH)-stimulated peak serum cortisol levels ≥18 µg/dL. RESULTS: Of the total 34 patients diagnosed with GC-induced secondary AI at first, 20 patients (58.8%) recovered normal adrenal function by the time of the follow-up SST (median follow-up period, 16.5 months). Although the baseline serum ACTH and cortisol levels at the first SST did not differ between responders and non-responders, the incremental cortisol response during the first SST was higher in responders than that of non-responders (7.88 vs. 3.56, P<0.01). Additionally, higher cortisol increments during the first SST were an independent predictive factor of the adrenal function recovery (odds ratio, 1.58; 95% confidence interval, 1.02 to 2.46; P<0.05). CONCLUSION: In the present study, adrenal function recovery was achieved frequently in patients with GC-induced secondary AI within 1 to 2 years. Additionally, an incremental cortisol response at the first SST may be an important predictive factor of adrenal function recovery.