Weekend Surgical Care and Postoperative Mortality: A Systematic Review and Meta-Analysis of Cohort Studies

An association between weekend health care delivery and poor outcomes has become known as the "weekend effect." Evidence for such an association among surgery patients has not previously been synthesized.

To systematically review associations between weekend surgical care and postoperative mortality.

We searched PubMed, EMBASE, and references of relevant articles for studies that compared postoperative mortality either; (1) according to the day of the week of surgery for elective operations, or (2) according to weekend versus weekday admission for urgent/emergent operations. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for postoperative mortality (≤90 d or inpatient mortality) were pooled using random-effects models.

Among 4027 citations identified, 10 elective surgery studies and 19 urgent/emergent surgery studies with a total of >6,685,970 and >1,424,316 patients, respectively, met the inclusion criteria. Pooled odds of mortality following elective surgery rose in a graded manner as the day of the week of surgery approached the weekend [Monday OR=1 (reference); Tuesday OR=1.04 (95% CI=0.97-1.11); Wednesday OR=1.08 (95% CI=0.98-1.19); Thursday OR=1.12 (95% CI=1.03-1.22); Friday OR=1.24 (95% CI=1.10-1.38)]. Mortality was also higher among patients who underwent urgent/emergent surgery after admission on the weekend relative to admission on weekdays (OR=1.27; 95% CI=1.08-1.49).

Postoperative mortality rises as the day of the week of elective surgery approaches the weekend, and is higher after admission for urgent/emergent surgery on the weekend compared with weekdays. Future research should focus on clarifying underlying causes of this association and potentially mitigating its impact.