A retrospective registry-based study into the proportion of patients admitted to intensive care who have anaphylaxis as a principal diagnosis and their outcomes in Australia and New Zealand.

To describe the proportion of patients admitted to intensive care who have anaphylaxis as a principal diagnosis and their subsequent outcomes in Australia and New Zealand. Retrospective observational study of ICU admissions for severe anaphylaxis. ICU admissions recorded in the Australian and New Zealand Intensive Care Society Adult Patient Database between 2012 and 2022. Adults 16 years or older with severe anaphylaxis admitted to the ICU. None. Proportion of patients admitted to ICU who have anaphylaxis as a principal diagnosis, mortality rate, ICU and hospital length of stay. 7189 of the 7270 ICU admissions for severe anaphylaxis recorded between 2012 and 2022, were included in the analysis. This represented a proportion from 0.25% in 2012 to 0.43% in 2022. ICU and hospital mortality were 0.4% and 0.8%, respectively. The proportion of ICUs reporting at least one severe anaphylaxis each year increased from 61.7% in 2012 to 83.0% in 2022. Most of the patients were discharged home (92.6%, n = 6660). Increasing age (OR = 1.055; 95%CI: 1.008-1.105) and SOFA scores (OR = 1.616; 95%CI: 1.265-2.065), an immunosuppressive chronic condition (OR = 16.572; 95%CI: 3.006-91.349) and an increasing respiratory rate above 16 breaths/min (OR = 1.116; 95%CI: 1.057-1.178) predicted in-hospital mortality in patients with anaphylaxis, while higher GCS decreased in-hospital mortality (OR = 0.827; 95%CI: 0.705-0.969). The overall proportion of patients admitted to ICU who have anaphylaxis as a principal diagnosis has increased. In-hospital mortality remains low despite the need for vital organ support. Further studies should investigate these identified factors that may predict in-hospital mortality among these patients. Not applicable.