Do weekends really affect surgical outcomes?

Researchers from Houston Methodist Hospital, UCLA, the University of Toronto, and others have tried to answer a longstanding fear that undergoing surgery on a Friday leads to higher levels of complications or even death. Their analysis of data from 429,691 patients has revealed higher rates of complications, readmissions, and mortality in the days and months following surgery compared to those who had procedures performed after the weekend.

The “weekend effect” refers to the observed trend of worse patient outcomes associated with medical care provided over weekends. In surgical settings, this effect may be influenced by variations in hospital staffing, access to specialists, and care processes during weekends and is an ongoing concern in medical research.

The weekend effect can also refer to a fear on the part of patients that surgical staff may be daydreaming about their weekend plans or that hospitals have less qualified staffing over the weekend. In the past, this weekend effect fear has also been associated with the automotive industry, where vehicles built on a Friday were thought to have more problems, attributing loose or missing bolts to mentally checked-out mechanics.

Research has previously explored this effect in hospital settings, with some studies reporting increased mortality for Friday surgeries while others found no clear pattern. With conflicting data and dual persistent concerns and fears of a weekend effect, a comprehensive investigation was needed to systematically evaluate any impact on postoperative outcomes across a broad range of procedures and timeframes.

In the study “Postoperative Outcomes Following Preweekend Surgery,” published in JAMA Network Open, researchers conducted a retrospective, population-based cohort analysis to determine whether patients undergoing surgery immediately before the weekend faced increased risks.

Data from 429,691 adults undergoing one of 25 common surgical procedures in Ontario, Canada, between 2007 and 2019 were analyzed. Patients were divided into two groups: those who underwent surgery one day before the weekend (Friday or pre-holiday) and those who had procedures one day after (Monday or post-holiday).

Researchers assessed short-term (30 days), intermediate (90 days), and long-term (one year) postoperative outcomes, including mortality, readmissions, complications, hospital length of stay, and duration of surgery.

Analysis found that the pre-weekend patient group had longer hospital stays than those in the post-weekend group.

Patients undergoing surgery immediately before the weekend had a 5% higher likelihood of experiencing a combination of mortality, complications, and readmissions within 30 days.

The risk of death was 9% higher at 30 days, and trended higher over time with 10% higher mortality at 90 days and 12% higher at one year.

Intriguingly, scheduled or elective procedures performed before the weekend were associated with worse postoperative outcomes, while urgent unplanned surgeries showed slightly better outcomes when performed before the weekend. Surgeons operating on Fridays had a median age of 47 years, compared to 48 years for those operating on Mondays. The median years in practice were 14 years for Friday surgeries versus 17 years for Monday surgeries.

The study concludes that variations in hospital staffing, reduced access to specialists, and differences in perioperative care processes may contribute to these trends. Future research could assess strategies to ensure high-quality postoperative care, regardless of the day of the week.

While the underlying causes of these disparities in surgical outcomes are not made clear by the study, both the concerns and fears seem justified by the trends. Hospitals and medical researchers are careful not to suggest the possibility of negligence, such as surgeons daydreaming about three-day weekend plans, yet this very normal human activity also should not be ruled out.

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