A descriptive study of adrenal crises in adults with adrenal insufficiency: increased risk with age and in those with bacterial infections

BACKGROUND: An adrenal crisis (AC) is a major cause of morbidity in hypoadrenal patients. However, there is little information available on the incidence and underlying causes of AC. METHODS: The aim of the present study was to describe the incidence of AC in New South Wales (NSW), Australia. Using a health department database, we selected de-identified data on all adults aged 20 years and over who were treated in any hospital in NSW between July1, 2000-June 30, 2011, with either a principal or secondary diagnosis of an AC. AC admission rates were calculated overall and within age categories. Frequencies of co-morbid diagnoses were analysed by age and sex groups. Poisson regression was used to assess the significance of the observed change in AC related admissions with age, while controlling for any secular trends by including year in the model. Chi sq tests were used to assess the differences in frequencies of categorical variables between groups. RESULTS: 824 patients received treatment for an AC in hospital, corresponding to 74.9 admissions/year. The majority (62.5%) of the patients were women and 52.8% were aged 60 years and over. Admission rates were significantly associated with increasing age (p < 0.0001). Patients in the 60–69, 70–79 and 80+ age groups had the highest average admission rates (24.3, 35.2 and 45.8 per million/year). A principal or secondary diagnosis of an infection was reported in 317 (38.5%) patients and infection was significantly associated with age (p < 0.0001) with older patients having the highest proportion of cases. The most frequent infections were pneumonia/lower respiratory tract infection in 85 (10.3%) cases and urinary tract infection (UTI) in 82 (10.0%) patients. Women experienced 78.0% of the reported UTIs. There were 125 patients (15.2%) with an AC and a record of gastroenteritis. Twenty-six (3.2%) patients died in hospital but, of these, only 4 deaths (0.9%) were recorded among the 467 patients with a principal diagnosis of an AC. CONCLUSIONS: The incidence of AC increases with age. Infections, especially bacterial infections, are associated with the incidence of ACs and this increases with age.