Relation between emergency department patient volume at time of patient arrival and likelihood of patient to 'wait' for clinical care. A state-wide data linkage analysis from New South Wales, Australia.

Objective This study aimed to investigate the relationship between emergency department (ED) patient volume at time of presentation and risk of departing before commencing treatment in the ED (did not wait; DNW). Methods A retrospective analysis of linked data was conducted using the New South Wales Emergency Department Data Collection for level 5 and level 6 hospitals, between April 2022 and March 2023. ED patient volume was measured at the time of each patient's presentation and categorised into quintiles by hospital level. Patients who DNW were compared to those who waited, using multivariable logistic regression to identify independent predictors of DNW, such as rising ED patient volumes, age, triage category, and time of presentation. Results Out of 1,673,247 ED presentations, 155,425 (9.29%) patients were recorded as DNW. ED patient volume was a significant predictor of increased likelihood of DNW, with those presenting when the ED was at the highest patient volume quintile being 3.5 times more likely not to wait compared to the lowest quintile of patient volume after adjusting for relevant characteristics such as age, triage category, and time of presentation. Conclusion ED patient volume was a significant predictor of DNW with a direct dose-response relationship observed further emphasising the effect of ED overcrowding on the quality of care in EDs.