Risk factors that are associated with adrenal insufficiency among patients with fever of unknown origin

Adrenal insufficiency is one of the causes of fever of unknown origin (FUO). The purpose of this study is to find out risk factors that are associated with adrenal insufficiency in FUO patients.This study was conducted retrospectively in a tertiary hospital with 846 beds in South Korea. All adult inpatients (age ≥19 years) who have requested a consult with the department of infectious disease for FUO between 1 July 20191 July 2019 and 30 June 202030 June 2020 were included in the study. Among them, those who underwent an adrenocorticotropic hormone (ACTH) stimulation test and had a fever of 37.8°C or higher within 48 hours of the ACTH stimulation test were finally included in the study subjects.A total of 202 FUO patients were enrolled and 61 (30.1%) were finally diagnosed with adrenal insufficiency. In a multivariate analysis, use of immunosuppressant within 3 months (OR 6.06, 95% CI 1.82-20.13, P = 0.003), use of corticosteroid within 3 months (OR 8.23, 95% CI 1.35-50.17, P = 0.022), sodium ≥ 136.7 (OR 3.43, 95% CI 1.49-7.88, P = 0.004), and calcium ≥ 8.4 (OR 0.31, 95% CI 0.14-0.71, P = 0.005) were proven to be factors associated with adrenal insufficiency in FUO patients.In conclusion, 30.1% of FUO patients were diagnosed with adrenal insufficiency. The risk factors that are associated with adrenal insufficiency in FUO patients were immunosuppressive prescription or systemic steroid prescription within 3 months, or with sodium ≥ 136.7 or calcium < 8.4.