Endocrine Abstracts

Introduction: Primary Adrenal Insufficiency (PAI or Addison’s disease) is a rare disease with an increasing prevalence that may be complicated by life-threatening acute adrenal crisis. Valid epidemiological data are difficult to obtain. In Belgium, a national PAI registry had not been established yet.

Objective: We collected epidemiological and clinical data in a large cohort of adult patients with a known Addison’s disease to have a better knowledge of epidemiology and management of PAI in Belgium.

Design: A nationwide multicentric study on PAI was designed to collect data on epidemiology, etiology, diagnostic circumstances, tests used for diagnosis, current substitution treatments, side effects of treatment and incidence of acute adrenal crises.

Results: One hundred eighty six patients with PAI were included in the registry between 2015 and 2018. The mean age at diagnosis was 37±18 years with a higher prevalence in women (sexe ratio F/M=1.45). The mean duration of the disease was 17±14 years (1–67 years). Auto-immune disease was the most common cause of PAI (61%), followed by bilateral adrenalectomy (26%), genetic causes (8%), adrenal hemorrhage (2%), tuberculosis (2%) and mitotane chemotherapy (1%). Bilateral adrenalectomy was performed for Cushing’s syndrome, bilateral pheochromocytoma and bilateral adrenal metastases. Type 2 polyglandular autoimmune syndrome was more prevalent in women (sexe ratio F/M=3.14). After exclusion of non-autoimmune causes, clinical presentation was mostly progressive with non-specific symptoms at diagnosis: asthenia in 85%, weight loss in 83%, anorexia in 72% and digestive symptoms in 56% of patients. Melanodermia was found in 79% of patients. On average, baseline morning plasma cortisol was decreased to 50% of the lower limit of the normal range whereas baseline ACTH was increased to 22-fold the upper limit of the normal range. All patients were substituted with glucocorticoids, mostly with hydrocortisone (97% of patients) at a mean daily dose of 25±7 mg or 13 mg/m². 88% of patients received mineralocorticoid substitution (fludrocortisone) at a mean daily dose of 100±50 μg. Thirty percent of patients experienced at least 1 acute adrenal crisis. There was no difference in age, hydrocortisone daily dose or etiology between patients having single or multiple crisis. Acute adrenal crisis were more prevalent in women than in men (sexe ratio F/M=1.9).

Conclusion: These data provide the first epidemiological data on primary adrenal insufficiency in Belgium that may help physicians to implement strategies to decrease the risk of overtreatment and to prevent acute adrenal crisis.