The Hidden Risk of Friday Surgeries: Why Timing Could Be a Matter of Life and Death
New Study Suggests Pre-Weekend Surgeries Have Higher Risks of Complications and Mortality
A Silent Risk in Surgical Timing
It’s a detail that few people consider when facing surgery: the day of the week. Yet a new study suggests that the calendar, not just the scalpel, could influence a patient’s survival. Published in JAMA Network Open1, this large-scale study of nearly half a million surgical cases in Ontario, Canada, reveals a troubling pattern—patients who undergo surgery on a Friday have a statistically higher chance of complications, readmissions, and even death compared to those who have surgery on a Monday.
For decades, researchers have speculated about a so-called "weekend effect," where hospital patients fare worse due to reduced staffing and resource availability. But this new study extends the concern beyond the weekend itself. The findings suggest that patients recovering over the weekend—when hospitals may be running with a skeleton crew—could face increased risks.
“Patients who underwent surgery immediately preceding the weekend had a significantly increased risk of complications, readmissions, and mortality compared with those treated after the weekend.”
The numbers don’t lie. The study, conducted by Dr. Sanjana Ranganathan and colleagues, found a 9% increase in 30-day mortality rates for patients who had surgery before the weekend, a 10% increase at 90 days, and a 12% increase at one year. These are not small differences; they suggest a systemic issue in postoperative care.
Why Does Surgery Timing Matter?
Hospitals operate differently on weekends. Staffing is reduced, fewer specialists are on-call, and routine post-surgical procedures—like imaging, consultations, or adjustments to care plans—may be delayed. Surgeons who perform Friday procedures may not be available for follow-ups, leaving their patients in the hands of unfamiliar weekend teams.
"Weekend teams may be less familiar with the patients than the weekday team previously managing care," the researchers note. "Furthermore, weekend teams have less access to senior colleagues and specialists."
This discrepancy in care can mean delayed interventions when complications arise, leading to worse outcomes. Moreover, diagnostic tests and emergency procedures that might be readily available on a Tuesday could require significant delays on a Saturday.
The Role of Surgeon Experience and Resources
One unexpected finding of the study is that Friday surgeries are more often performed by less-experienced surgeons. The study notes that Friday surgeons had slightly fewer years in practice compared to their Monday counterparts. It’s unclear whether this is due to scheduling preferences, hospital policies, or simple chance, but it raises important questions about whether the complexity of Friday cases should be reconsidered.
The study also found that hospitals may operate with reduced resources over the weekend. Imaging tests, lab results, and specialized consultations can be slower to arrange, potentially delaying crucial interventions.
"Diminished access to more senior colleagues or consultants on Friday may further compound this issue and has been shown to impact complications and length of stay," the study states.
Elective vs. Emergency Surgeries: A Surprising Twist
Interestingly, while elective surgeries performed on Fridays had worse outcomes, emergency surgeries showed a different trend. Patients who underwent emergency procedures before the weekend actually had better outcomes compared to those who had emergency surgeries delayed until after the weekend.
This suggests that delaying urgent surgeries—even by just a day or two—could result in more severe complications and a higher risk of mortality.
A Wake-Up Call for Patients and Hospitals
The study’s findings should prompt hospitals and policymakers to rethink surgical scheduling. If pre-weekend surgeries carry a higher risk, should elective procedures be limited to earlier in the week? Should hospitals bolster weekend staffing in critical care and post-operative units to mitigate these risks?
For patients, the takeaway is clear: if given a choice, it may be wise to avoid scheduling major elective surgeries on a Friday. While not every complication is avoidable, ensuring access to the best possible post-operative care—including immediate response teams, imaging services, and specialists—could be the difference between an uneventful recovery and a medical crisis.
The Cost of Convenience
We often think of modern medicine as an exact science, where every surgery is a controlled, predictable event. But this study highlights a hidden variable—the hospital schedule. If outcomes can be influenced by something as arbitrary as the day of the week, then the way we structure our healthcare systems needs serious reconsideration.
“These findings suggest that patients treated before the weekend are at increased risk of complications, emphasizing the need for further investigation into processes of surgical care to ensure consistent high-quality care and patient outcomes.”
Until that happens, both patients and doctors may want to pay closer attention to the calendar. Because in the world of surgery, timing really is everything.
Ranganathan S, Riveros C, Tsugawa Y, et al. Postoperative Outcomes Following Preweekend Surgery. JAMA Netw Open. 2025;8(3):e2458794. doi:10.1001/jamanetworkopen.2024.58794