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“Weekday effect” not a factor in elective surgery mortality in Ontario


The day of the week elective surgery is performed in Ontario does not impact a patient’s risk of mortality, according to a new study from the Institute for Clinical Evaluative Sciences (ICES) and Western University.

“While previous studies have shown a higher risk of mortality in patients having elective surgery Friday rather than earlier in the week, our data indicates that’s not the case in Ontario,” says Dr. Christopher Vinden, the study’s senior author who is an adjunct scientist at ICES and an associate professor of surgery at Western University’s Schulich School of Medicine & Dentistry.

The study examined all adult patients who underwent one of 12 elective daytime surgical procedures during a 10-year period from 2002 to 2012. The researchers included 402,899 procedures performed by 1,691 different surgeons and found no difference in 30-day mortality when Friday was compared with Monday.

“Our data suggests that despite differences in surgeon experience, the risk of 30-day mortality after elective surgery was similar regardless of which day of the week the procedure took place,” says Dr. Luc Dubois, the study’s lead author, assistant professor at Schulich Medicine & Dentistry and a vascular surgeon at London Health Sciences Centre.

The researchers found that surgeon experience varied significantly by day of week, with those operating on Fridays having the least experience. Nearly all patients who had their procedure on a Friday had postoperative care on the weekend, while only 49.1 per cent of patients who were operated on a Monday did.

The study was published today in CMAJ.

Procedures included were elective surgeries on the esophagus, kidney, pancreas, colon, liver, hip and knee replacements, aortic valve replacements and others. The 12 procedures were chosen because they are commonly only done electively and typically result in at least a two-day hospital stay.

“These results suggest that increased mortality after elective surgery occurring later in the week is not a universal phenomenon across all healthcare systems. Therefore, should be a correctable issue in those jurisdictions where it occurs,” adds Dubois.

“Association between day of the week of elective surgery and postoperative mortality,” was published today in the CMAJ.

Author block: Dubois L, Vogt K, Vinden C, Winick-Ng J, McClure JA, Roshanov P, Bell CM, Garg AX.

The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. For the latest ICES news, follow us on Twitter: @ICESOntario


Deborah Creatura
Media Advisor, ICES
[email protected]
(o) 416-480-4780 or (c) 647-406-5996


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