Don't get sick on the weekend: an evaluation of the weekend effect on mortality for patients visiting US EDs

The primary objective of the study is to determine if the mortality for adult patients visiting US emergency departments (EDs) is greater on weekends than weekdays.

The secondary objective of the study is to examine whether patient factors (diagnosis, income, insurance status) or hospital characteristics (ownership, ED volume, teaching status) are associated with increased weekend mortality.

We used a retrospective cohort analysis of the 2008 Nationwide Emergency Department Sample. Evaluating 4225973 adults admitted through the ED to the hospital, signifying a 20% representative sample of US ED admissions. Logistic regression was used to examine associations of weekend mortality with patient and hospital characteristics, accounting for clustering by hospital.

Emergency department patients admitted to the hospital on the weekend are significantly more likely to die than those admitted on weekdays (odds ratio, 1.073; 95% confidence interval, 1.061-1.084). A significant weekend effect persisted after controlling for patient characteristics (odds ratio, 1.026; 95% confidence interval, 1.005-1.048). The top 10 primary diagnoses for patients dying did not identify any specific medical condition that explained the higher weekend admission mortality. The weekend effect was also relatively consistent across patient income, insurance status, hospital ownership, ED volume, and hospital teaching status.

Patients are more likely to die when admitted through the ED on the weekend. We were unable to identify specific circumstances or hospital attributes that help explain this phenomenon. Although the relative increased risk per case is small, our study demonstrates a significant number of potentially preventable weekend deaths occurring annually in the United States.