Endocrine Abstracts

Objective: Determinants of why only a subset of patients with adrenal insufficiency (AI) experience recurrent adrenal crises (AC) and intercurrent illnesses are not well understood. This study aimed to identify whether residual adrenal function (RAF), defined by the peak response to a provocative test undertaken before commencing glucocorticoids, may help explain differences in prevalence.

Design and Methods: Patients with AI who previously were enrolled in the European Adrenal Insufficiency Registry (EU-AIR) were invited to participate in this parallel study (RAF study). The EU-AIR was a prospective observational study, collecting data on glucocorticoid dosage, episodes of intercurrent illness and AC in patients with AI irrespective of aetiology. Peak cortisol level to stimulation was collected from the hospitals electronic records.

Results: The cohort comprised 203 patients, of whom 114 had documented peak cortisol measurement on stimulation. This sub-cohort were of mean age 53.8+/-15.6, 71M/43F, 9 PAI and 105 SAI. Mean follow-up was 5.5+/-2.4 years. Over this period there were 457 intercurrent illnesses and 131 SAEs. Only four episodes of AC in two patients were recorded during the study period. Comparison of patients with peak cortisol of ≤200 nmol/l (n=52) or >200 nmol/l (n=62) showed no statistical difference for mean number of intercurrent illnesses (P=0.16) or SAE per year (P=0.79). Using the lower cut-off value of 125 nmol/l, patients with peak cortisol of ≤125 (32 patients) or >125 (82 patients) on stimulation showed no statistical difference for mean number of intercurrent illnesses (P=0.90) or mean number of SAE per year (P=0.43).

Conclusion: In this prospective study we found no evidence to support the degree of RAF in patients with AI to be a determinant of the rate of occurrence of intercurrent illnesses or SAEs. Why a subset of patients experience repeated intercurrent infections and adrenal crises, but others do not remains elusive.