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A large study analyzing nearly 430,000 surgical patients has found that people who have surgery on Fridays or the day before a holiday face higher risks of complications, readmissions, and even death compared to those who undergo surgery after the weekend.
The research, published in JAMA Network Open, provides evidence for the so-called “weekend effect”, a long-standing concern that hospital care may be less effective over weekends due to staffing and resource differences.
What the Study Found
Researchers from Houston Methodist Hospital, UCLA, the University of Toronto, and other institutions examined data from 429,691 adults who underwent one of 25 common surgeries in Ontario, Canada, between 2007 and 2019. Patients were divided into two groups:
Pre-weekend surgery group: Those who had surgery on Friday or the day before a holiday
Post-weekend surgery group: Those who had surgery on Monday or the day after a holiday
When comparing outcomes over different timeframes (30 days, 90 days, and one year after surgery), the results revealed clear increased risks for Friday surgeries:
5% higher chance of complications, readmissions, or death within 30 days
9% higher risk of death at 30 days
10% higher mortality risk at 90 days
12% higher mortality risk at one year
Additionally, patients who had surgery before the weekend stayed in the hospital longer compared to those who had surgery after the weekend.
Why Is This Happening?
The study suggests several possible reasons why surgical outcomes are worse before the weekend:
Reduced hospital staffing: Fewer specialists and senior staff may be available on weekends, affecting post-surgical care.
Limited access to specialists: If complications arise, patients may not receive immediate attention from experienced doctors.
Variations in perioperative care: Differences in how patients are monitored and treated after surgery could impact recovery.
Interestingly, while scheduled or elective surgeries performed before the weekend showed worse outcomes, urgent, unplanned surgeries had slightly better outcomes on Fridays. The study also noted small differences in the experience levels of surgeons: those operating on Fridays had a median of 14 years of experience, compared to 17 years for Monday surgeons.
The “Weekend Effect”: More Than Just a Fear?
The “weekend effect” has been debated for years in medicine, with some studies finding increased risks for Friday surgeries and others showing no clear pattern. Patients often fear that hospital staff may be mentally distracted before the weekend or that weekend shifts have fewer qualified personnel.
While this study does not prove negligence, it does suggest that hospital staffing and care processes may contribute to poorer outcomes for pre-weekend surgeries.
What Should Patients and Hospitals Do?
The study does not suggest avoiding Friday surgeries altogether, but it does raise important questions about how hospitals can improve care quality throughout the week. Future research could explore strategies such as:
Ensuring adequate weekend staffing in critical areas like post-surgical care and monitoring
Improving access to specialists over the weekend for faster response to complications
Better scheduling of elective surgeries to reduce unnecessary risks
For patients, choosing a surgery date may be worth discussing with a doctor, especially if the procedure is elective. While hospitals maintain high standards of care, this study suggests that timing could make a small but meaningful difference in surgical outcomes.
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The research findings can be found in JAMA Network Open.
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