Emergency Department Weekend Presentation and Mortality in Patients With Acute Myocardial Infarction

Background: Patients admitted to acute care hospitals on weekends have poorer outcomes than those admitted on weekdays, and patients admitted to hospitals for acute myocardial infarction (AMI) on weekends have a higher mortality rate than those admitted during the week. Very few studies have examined weekend presentation for patients with AMI with respect to mortality in the emergency department (ED). Objective: The purpose of this research was to determine if weekend and holiday presentation is associated with increased mortality in EDs among patients with AMI in New Jersey. Methods: A retrospective cohort and three data sources representing all hospitals in New Jersey, including patients 18-90 years of age who presented to the ED with symptoms of AMI from January 1, 2008 to January 31, 2010, were used. "Weekend" was defined as Saturday and Sunday, and "holiday" was defined as one of the six major U.S. holidays. Propensity score matching with probit regression was used to estimate the unbiased treatment effect of weekend/holiday presentation on mortality in the ED. Results: A total of 1,343 patients with a diagnosis of AMI presented to 73 EDs in New Jersey. Of these, 382 (28%) presented on a weekend/holiday and 961 (72%) during weekday hours. After propensity score matching and using probit regression, weekend/holiday presentation was significantly associated with mortality (b = 0.30, 95% CI [0.03, 0.57]). Other statistically significant covariates include patient age (b = 0.03, 95% CI [0.02, 0.04], hospital technology status (b = 0.75, 95% CI [0.20, 1.30]), and nurse staffing (b = -0.08, 95% CI [-0.13, -0.04]). Discussion: Weekend/holiday presentation to the ED for AMI was associated with increased mortality. The effect may be related to the limited availability of resources on weekend/holidays compared to weekdays. Future studies should examine potential variations of resources, nursing workload, and education and expertise of healthcare providers in the ED during the weekend.