Thinking About Surgery? Here's Why the Choice of Day Could Be Important

03 April 2025 2987
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Does it matter when you schedule your surgery? According to a new study, the day of the week on which you have surgery could impact whether you have a more positive outcome.

Researchers found that, in comparison to those who received surgical care early in the week, people who received a surgery before the start of the weekend had an increased risk of adverse outcomes such as post-surgery complications, hospital readmission after 30 days, 90 days, and one year, and even risk of death.

The study was published on March 4 in JAMA Network Open.

“We’ve seen in the literature that there have been talks previously of something called ‘the weekend effect,’ which is if you get surgery close to the weekend, you are more likely to have poorer outcomes,” Vatsala Mundra, a study co-author and a urology clinical research fellow at Houston Methodist Hospital, told Health.

This “weekend effect” has been observed in short-term data, but Mundra said she and her colleagues wanted to see if the issue would show up over a longer period of time, too.

After examining data from nearly 430,000 patients over the course of 13 years, they did find a “significantly increased risk” of poor outcomes in people who got surgeries on Fridays versus those who got surgeries on Mondays.

Experts said findings like these give patients a look into how factors such as hospital staffing might be affecting their health, as well as encourage the medical community to improve and standardize surgical care.

This study included data from 429,691 patients who received one of 25 common surgical procedures in Ontario, Canada, between January 2007 and December 2019. Researchers tracked patients’ health for a year after they had their surgery.

Just over half of the surgeries were performed on Mondays, while 46.5% were done on Fridays. They spanned a wide range of specialties, including cardiothoracic surgery, general surgery, neurosurgery, obstetrics and gynecology, orthopedic surgery, otolaryngology, plastic surgery, thoracic surgery, urology, and vascular surgery.

After analyzing all the data, the researchers found that people who had surgery on a Friday had a 5% increased risk of poor health outcomes—including death, hospital readmission, and complications in both the short and long term—as compared to the Monday surgery group.

The results are interesting, but there are some potential limitations.

This was an observational study, meaning researchers can’t say definitively that the day of the week caused worse surgery outcomes.

And it’s not just the way the study was designed—it is “extremely challenging to isolate the impact of the weekend itself from other factors” that might actually be behind a poor surgery outcome, explained Salva Balbale, PhD, an assistant professor with the Center for Health Services and Outcomes Research and the Northwestern Quality Improvement, Research, and Education in Surgery at Northwestern University.

The time of day could’ve played a role, in addition to the characteristics of the doctor doing the surgery, how the surgery was conducted, and the hospital characteristics or resources, Balbale told Health.

The study also didn’t include preoperative data for patients, meaning researchers weren’t able to determine which participants were sicker going into their surgeries, putting them at a higher risk of complications to begin with.

However, these limitations shouldn’t necessarily skew our perception of the findings, said Anupam Jena, MD, PhD, Joseph P. Newhouse Professor of Health Care Policy at Harvard Medical School and associate physician at Massachusetts General Hospital.

The characteristics of the patients who received surgeries were fairly similar regardless of whether they got operations done on a Friday or Monday, Jena told Health, and this study “did about as good a job as any” when it comes to examining the negative effects of pre-weekend surgeries.

It can be difficult to pinpoint what’s actually behind the weekend effect, said Jena. The question is whether there’s something not up to par with the hospital or hospital staff later in the week, or if patients who get surgeries on Fridays are just higher risk, or “systematically different in some way,” he explained.

Another issue is that research on this subject has been “mixed,” Balbale said.

“Some studies showed no significant association between weekend surgical care and postoperative outcomes, and others found a ‘small but significant association’ between the two,” she explained.

Still, the results of this latest JAMA Network Open study, as well as others, are prompting experts to dig into why postoperative outcomes are different depending on when people get surgery.

Though patient characteristics could play some role, the weekend effect could be explained by issues with hospital staffing.

On Fridays or weekends, staff might be “spread a little bit thin,” Jena said. Not as many nurses and doctors are on these shifts, he explained, and you might face a situation where a surgeon might be treating not just their own patients, but also those of other surgeons who aren’t working that day.

Mundra said she and her colleagues found that younger and less experienced surgeons were more likely to have these pre-weekend Friday shifts. There can be “limited access to specialists, tests, and scans on the weekends,” Balbale added.

And the weekend effect isn’t limited to just surgical care. “Across clinical specialties, healthcare quality and patient safety literature suggested long ago that patients may potentially face an increased risk of adverse outcomes when admitted to the hospital on weekends,” said Balbale.

In general, the fact that patients see worse outcomes when they seek care later in the week “is a symptom of a more pressing underlying challenge”—namely, many healthcare systems aren’t “equipped to deliver the same quality of care on weekends compared to weekdays,” she said.

While the weekend effect might raise some alarm bells if you have an upcoming surgery on the calendar, Mundra stressed that you should consult your healthcare team before rescheduling or making any changes.

If your surgeon only offers appointments on Fridays and you’re happy with your care, then this shouldn’t be a problem.

The weekend effect is a “complex issue,” Balbale said, and though getting late-week surgeries has been linked to a slightly higher risk of complications, it’s not so risky that people should ever consider delaying the care they need.

But if you have other concerns about the timing of your upcoming surgery, a consultation with your medical team will help you figure out what makes the most sense for you and your health. Past research doesn’t pinpoint a single day as the best to go in for a surgery, but Tuesdays and Wednesdays are often mentioned as days “with greater surgical volumes and surgeon experience,” said Balbale.

“Make sure you’re advocating for yourself if you’re getting surgery on a Friday and over the weekend,” Mundra said. “If you notice something that doesn’t seem quite normal, make sure you are bringing attention and awareness to it, informing your nurses, physicians, and surgeons.”

These results should also spur the medical community to action.

“We have to ensure we have enough staff over the weekends, people have access to senior surgeons and senior physicians, make sure we have a robust healthcare system [throughout] the week,” Mundra stressed. “It’s really important for us to make sure we have the staffing and the ability to do so. That would be the big takeaway here.”


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