Don’t get surgery on a Friday

If you have any say, you might want to avoid scheduling your next surgery on a Friday. The most comprehensive analysis of what happens to patients who have surgery on Fridays versus Mondays, published this month in JAMA by more than a dozen US and Canadian researchers, is unequivocal: The people who underwent all kinds of procedures before the weekend suffered on average more short-term, medium-term, and long-term complications than people who went under the knife after the weekend was over. The study was based in Ontario and included more than 450,000 patients who received one of the 25 most common surgeries between 2007 and 2019. Canada’s universal health care program allowed the researchers to more easily track patients over time and it eliminated finances as a variable in how patients fared. Previous studies have generally found the same effects across different types of health systems: One UK-based study had reported better outcomes for Monday surgeries after 30 days. A paper looking at Dutch patients detected higher mortality rates after one month for patients who had Friday surgeries compared to Monday. This appears to be a phenomenon no matter the country, as prior US-based research also attests. The new study covered all surgery specialties — including orthopedic surgery, vascular surgery, and obstetrics — and followed patients’ outcomes at 30 days, 90 days and one year. The study tracked whether patients died, were readmitted to the hospital, or experienced any other complications, like an infection, for example, during their hospital stay. People who received pre-weekend surgeries — defined as a Friday or a Thursday before a long weekend — were overall about 5 percent more likely to experience one of those complications within a year of their surgery than people who got post-weekend procedures (on Monday or the Tuesday after a long weekend). The effect was stronger for heart and vascular surgeries; it was negligible for obstetric and plastic surgeries. [Image: https://platform.vox.com/wp-content/uploads/sites/2/2025/03/p8b8M-pre-weekend-surgeries-have-more-complications-than-post-weekend-surgeries.png?quality=90&strip=all] There could be a few things going on here, according to the researchers’ analysis. Researchers found Friday surgeries were more likely to be performed by junior surgeons when compared to Monday surgeries. “This difference in expertise may play a role in the observed differences in outcomes,” they wrote, based on a statistical analysis that controlled for other factors. There could also be fewer senior colleagues on the hospital campus for the junior physicians to consult with, the authors said. In addition, the weekend doctors and nurses may be less familiar with the patient’s case, raising the risk that complications will be caught later and therefore lead to worse outcomes. It is common for hospitals to have fewer doctors and nurses working the weekends and those who do work tend to be less experienced, which could likewise help explain the study’s findings, said Betty Rambur, a nursing professor at the University of Rhode Island. “The combination of fewer staff and less experienced staff certainly can contribute to poor patient outcomes,” she said. The findings should motivate hospital executives to rethink how they are staffing their wards on Fridays and over the weekend, to avoid complications that put surgery patients in danger. Of course, this is also useful information for any of us who need elective surgery at any point in the future. When we’re able to plan ahead for a procedure — whether a vasectomy carefully timed to coincide with March Madness or a knee replacement or whatever — it’s worth trying to find a time slot earlier in the week.