Study details and key findings

For the study, researchers analyzed data from 429,691 adult patients in Ontario, Canada, who underwent one of 25 common surgical procedures between Jan. 1, 2007, and Dec. 31, 2019. Among the patients, the mean age was 58.6 years, and 62.8% were female.

In total, 199,744 patients underwent surgery before the weekend (usually Friday or the day immediately before a long weekend), and 229,947 underwent surgery after the weekend (usually Monday or the day immediately after a long weekend).

According to the researchers, patients in the pre-weekend group had a higher risk of death at 30 days (9% increase), 90 days (10% increase), and one year (12% increase) compared to the post-weekend group. Patients in the pre-weekend group also had an increased risk of complications and readmissions.

Commentary

The "weekend effect" in surgery was first observed in the 1970s, and since then several studies have found increases in mortality following surgeries that occur right before the weekend.

The new JAMA study significantly expands upon previous research since it analyzed "both elective and emergent procedures, … the specific contributions of physician factors (such as age, experience, etc.), and … short-term (30 day), intermediate-term (90 day), and long-term (1 year) outcomes on the weekend effect," said Vatsala Mundra, a clinical research fellow at Houston Methodist Urology and one of the study's authors.

According to Mundra, reduced staffing on the weekends may negatively impact patient care and outcomes from surgeries performed right before the weekend.

"Pre-weekend surgeries may be riskier because often patients that have a procedure done on Friday may have to stay over the weekend for post-operative care, and studies have shown that there is a significant decrease in physicians, nurses, and clinical staff over the weekend," Mundra said.

Patients may also receive worse care close to the weekend due to a greater number of less experienced surgeons operating on Friday compared to Monday. Doctors working on the weekend also have less access to more senior colleagues and specialists, as well as tests and scans that could help guide patients' treatment.

"Furthermore, weekend teams may be less familiar with the patients than the weekday team previously managing care," the researchers said.

Overall, the researchers said that "[f]urther study is needed to understand differences in care that may underpin these observations and ensure that patients receive high-quality care regardless of the day of the week."

"It is important for health care systems to assess how this phenomenon may impact their practices to ensure that patients receive excellent care irrespective of the day," they added.