Elective, major noncardiac surgery on the weekend: a population-based cohort study of 30-day mortality.
OBJECTIVE
Previous research has demonstrated that patients undergoing elective surgery on the weekend had an adjusted risk of 30-day mortality that was significantly higher than that of patients operated upon during the week. The generalizability of this association and effect size is unknown.


OBJECTIVE
The aim of this study was to investigate the generalizability of the association between elective weekend surgery and increased 30-day postoperative mortality.


METHODS
A retrospective, propensity score-matched cohort analysis of linked population-based health administrative data was carried out.


METHODS
Individuals undergoing elective, intermediate, intermediate-risk to high-risk all describe the noncardiac surgery exposure at all acute care hospitals in Ontario, Canada, between 2002 and 2012 were included.


METHODS
Elective surgery was performed on the weekends.


METHODS
All-cause mortality was measured within 30 days of the operation.


RESULTS
A total of 333,344 patients were studied, of whom 2826 died within 30 days of surgery (overall crude mortality rate 8.5 deaths per 1000). Weekend elective surgery was performed on 2520 patients, of whom 2518 were successfully propensity score matched to weekday surgical patients. Undergoing elective surgery on the weekend was associated with a 1.96 times higher odds of 30-day mortality than weekday surgery (95% confidence interval, 1.36-2.84) in a propensity-matched analysis. This significant increase in the odds of postoperative mortality was confirmed using a multivariable logistic regression analysis (odds ratio 1.51; 95% confidence interval, 1.19-1.92).


CONCLUSIONS
Similar to previous studies in distinct health care systems, patients in Ontario undergoing elective surgery on the weekend experienced an increased risk of 30-day postoperative mortality. Mechanisms underlying this effect require further study.
*Department of Anesthesiology, University of Ottawa †Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, ON.
Daniel I
DI
McIsaac
Gregory L
GL
Bryson
Carl
C
van Walraven
D000328:Adult; D039602:After-Hours Care / Q000706:statistics & numerical data*; D000368:Aged; D002423:Cause of Death; D015331:Cohort Studies; D017558:Elective Surgical Procedures / Q000401:mortality*; D005260:Female; D006302:Health Services Research; D017052:Hospital Mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D009864:Ontario; D011183:Postoperative Complications / Q000401:mortality; D016019:Survival Analysis; D013997:Time Factors