Endocrine Abstracts

Background: Prolonged, high dose glucocorticoid therapy is used in to treat a number of rheumatological diseases, including polymyalgia rheumatica (PMR), giant-cell arteritis (GCA) and large vessel vasculitis (LVV). However there can be significant consequences of long-term glucocorticoid use, including iatrogenic adrenal insufficiency, due to suppression of the hypothalamic-pituitary-adrenal axis. This study aims to evaluate the prevalence, investigation and recovery of iatrogenic adrenal insufficiency in patients with PMR, GCA and LVV at a large UK teaching hospital.

Methods: We retrospectively identified patients seen in rheumatology outpatient clinics with a diagnosis of PMR, GCA or LVV, who had cortisol levels or short synacthen tests (SST) performed, between January 2014 and November 2017. Data were collected using a standardised proforma which included demographics, co-morbidities, maximal glucocorticoid dose and duration, clinical symptoms and details of investigations for adrenal insufficiency (i.e. SST results or cortisol values).

Results: We evaluated a total of 95 patients. The mean duration of prednisolone use was 4 years, 3 months (range 11–204 months). Over 30% of patients used a peak dose of prednisolone greater than or equal to 40 mg. 72% of all patients had symptoms possibly consistent with adrenal insufficiency. In total, eighty patients had a SST, mostly via the rheumatology department. On retrospective review of the SST results by a consultant endocrinologist, 33% of all tests were found to have sub-optimal cortisol levels. However 17.5% of baseline SSTs were not conducted appropriately. Of the patients who were found to have abnormal results, only 35% went on to have a repeat SST. 54% of the repeat SSTs showed normal adrenal function. Of the asymptomatic patients, 51.9% (n=14) had baseline tests consistent with adrenal insufficiency. The mean time to adrenal recovery overall, from baseline test was 18 months. 18% of patients with evidence of adrenal insufficiency had their prednisolone switched to a shorter acting glucocorticoid. Despite having an abnormal SST result, 43% patients were not referred to an endocrinologist.

Conclusion: Our study suggests there is a high prevalence of adrenal insufficiency in both symptomatic and asymptomatic groups in this patient population. The vast majority of patients with abnormal SST results did not have suitable follow-up tests and a large proportion were not referred to endocrinology. These results suggest the need for a joint pathway of care for evaluation of adrenal insufficiency in this patient group. Further studies, evaluating the optimal intervention strategies to aid adrenal recovery are also needed.