Mortality after nonemergent major surgery performed on Friday versus Monday through Wednesday

Ann Surg. 2007 Nov;246(5):866-74. doi: 10.1097/SLA.0b013e3180cc2e60.


Objective: To determine whether nonemergent major surgery leads to higher mortality when performed on Friday versus early weekdays.

Summary background data: Adults admitted emergently to acute-care hospitals on weekends experience higher mortality than those admitted on weekdays.

Methods: Cohort study of 188,212 patients undergoing nonemergent major surgery at 124 Veterans Affairs hospitals from 2000 to 2004. Risk-adjusted 30-day mortality was compared for operations performed on Fridays versus Mondays through Wednesdays. Data were derived from the Veterans Affairs' National Surgical Quality Improvement Program database. Patients were divided into 3 groups: floor (admitted postoperatively to regular floor), ICU (admitted postoperatively to intensive care unit), and outpatient (not admitted postoperatively). A stepwise logistic regression analysis was used to test the effect of day of surgery (Friday vs. Monday-through-Wednesday) on 30-day mortality in the presence of characteristics that were significant in bivariate analysis.

Results: In the floor group (n = 89,786), operations performed on Fridays were associated with a higher 30-day mortality rate than those performed on Mondays through Wednesdays (2.94% vs. 2.18%; odds ratio, 1.36; 95% confidence interval, 1.24-1.49; P < 0.001). After adjusting for patient characteristics, odds ratio of 30-day mortality for operations on Fridays, when compared with Mondays through Wednesdays, was 1.17 (95% confidence interval, 1.05-1.26; P = 0.003). Within the ICU (n = 14,271) and outpatient (n = 84,155) groups, nonsignificant differences in 30-day mortality were observed for operations on Fridays versus Mondays through Wednesdays.

Conclusions: For patients admitted to regular hospital floors after nonemergent major surgery, mortality is increased if surgery is performed on Friday versus Monday through Wednesday.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cohort Studies
  • Female
  • Hospital Mortality
  • Hospitalization / statistics & numerical data*
  • Hospitals, Veterans / statistics & numerical data*
  • Humans
  • Intensive Care Units
  • Male
  • Middle Aged
  • Patients' Rooms
  • Risk Factors
  • Surgical Procedures, Operative / mortality*
  • United States