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<0.001) higher rates of waiting times compared with EDs without NPs. Patients presenting to EDs with NPs spent 13 min (8%) longer in ED compared with EDs without NPs (median, (first quartile–third quartile): 156 (93–233) and 143 (84–217) for EDs with and without NPs, respectively). EDs with NPs had 1.8% more patients who did not wait, but similar re-presentations rates as EDs with NPs. CONCLUSIONS: EDs with NPs had statistically significantly lower performance for service indicators. However, these findings should be treated with caution. NPs are relatively new in the ED workforce and low NP numbers, staffing patterns and still-evolving roles may limit their impact on service indicators. Further research is needed to explain the dichotomy between the benefits of NPs demonstrated in individual clinical outcomes research and these macro system-wide observations.