The epidemiology of primary and secondary adrenal malignancies and associated adrenal insufficiency in hospitalised patients: an analysis of hospital admission data, NSW, Australia.

Background: Adrenal insufficiency (AI) causes considerable morbidity but may remain undiagnosed in patients with adrenal malignancy (AM). The epidemiology of AI and adrenal crises (AC) in AM is uncertain.

Methods: This was a retrospective study examining hospital admission data from 2006 to 2017. All admissions to all hospitals in NSW, Australia over this period with a principal or comorbid diagnosis of an adrenal malignancy were selected. Data were examined for trends in admissions for AM and associated AI/AC using population data from the corresponding years.

Results: There were 15,376 hospital admissions with a diagnosis of AM in NSW over the study period, corresponding to 1281 admissions/year. The AM admission rate increased significantly over the study period from 129.9/million to 215.7/million (p < 0.01). An AI diagnosis was recorded in 182 (1.2%) admissions, corresponding to an average of 2.1/million/year. This rate increased significantly over the years of the study from 1.2/million in 2006 to 3.4/million in 2017 (p < 0.01). An AC was identified in 24 (13.2%) admissions with an AI diagnosis. Four patients (16.7%) with an AC died during the hospitalisation.

Conclusion: Admission with a diagnosis of AM has increased over recent years and has been accompanied by an increase in AI diagnoses. While AI is diagnosed in a small proportion of patients with AM, ACs do occur in affected patients.