Are service and patient indicators different in the presence or absence of nurse practitioners? The EDPRAC cohort study of Australian emergency departments.

OBJECTIVES: To evaluate the impact of nurse practitioner (NP) service in Australian public hospital emergency departments (EDs) on service and patient safety and quality indicators. DESIGN AND SETTING: Cohort study comprising ED presentations (July 2013-June 2014) for a random sample of hospitals, stratified by state/territory and metropolitan versus non-metropolitan location; and a retrospective medical record audit of ED re-presentations. METHODS: Service indicator data (patient waiting times for Australasian Triage Scale categories 2, 3, 4 and 5; number of patients who did not-wait; length of ED stay for non-admitted patients) were compared between EDs with and without NPs using logistic regression and Cox proportional hazards regression, adjusting for hospital and patient characteristics and correlation of outcomes within hospitals. Safety and quality indicator data (rates of ED unplanned re-presentations) for a random subset of re-presentations were compared using Poisson regression. RESULTS: Of 66 EDs, 55 (83%) provided service indicator data on 2 463 543 ED patient episodes while 58 (88%) provided safety and quality indicator data on 2853 ED re-presentations. EDs with NPs had significantly (p