Altered insulin requirement in patients with type 1 diabetes and primary adrenal insufficiency receiving standard glucocorticoid replacement therapy

Abstract

Current glucocorticoid replacement regimens fail to fully mimic physiologic cortisol secretion in patients with primary adrenal insufficiency. This may lead to changes in insulin requirement in patients with primary adrenal insufficiency and type 1 diabetes. Therefore, we assessed insulin requirement in patients with autoimmune polyendocrine syndrome type 2 (APS-2). Ten females with primary adrenal insufficiency and type 1 diabetes (mean duration of type 1 diabetes 13+/-11 years and of primary adrenal insufficiency 11+/-9 years) were retrospectively assessed regarding insulin regimen and insulin dose adjustment. Data were compared with control patients matched for age, sex and duration of diabetes drawn from all patients with type 1 diabetes attending the diabetes outpatient clinics at the University Hospital Wuerzburg for a scheduled consultation. Glycaemia was well controlled in both groups (mean HbA1c 6.99+/-0.81% in APS-2 patients versus 6.69+/-1.03% in control patients). The mean weight-adjusted daily dose of insulin was non-significantly higher in patients with APS-2 compared with control patients (0.69+/-0.35 IU/kg body weight versus 0.51+/-0.17 respectively). The mean insulin (IU)/carbohydrate-ratio for 10 g of carbohydrate in the morning was 1.9+/-1.0 and 1.4+/-0.5 respectively. However, the insulin/carbohydrate-ratios were significantly higher in the APS-2 patients both at noon (mean ratio 2.0+/-0.9 vs 1.1+/-0.5 in control patients) and in the evening (mean ratio 2.1+/-1.1 vs 1.3+/-0.5 respectively; P<0.05). Glucocorticoid replacement therapy in patients with primary adrenal insufficiency and type 1 diabetes leads to significant changes in insulin requirement compared with patients with type 1 diabetes only.