“Emergency surgeries performed on a weekend may have poorer results than the same operation performed on a weekday, a new study concludes,” says an article in the New York Times.
However, the statement is not true.
First of all, it implies that all operations done on weekends have poorer results by failing to mention the fact that the study that found this result only concerned patients with inflammatory bowel disease (IBD)—that is, ulcerative colitis and Crohn's disease.  And although the paper looked at both types of IBD, only patients with ulcerative colitis were found to have significantly different outcomes based on day of admission.
Second and most important, the paper's significant result was that patients who wereadmittedon weekend days had worse results. On page 6 of the paper (the full text of which is available online), the authors state, “Hospitalisation [sic,the journal is from the UK] day of surgery did not influence post-operative outcomes.”
To recap. What the paper really says it that for one type of IBD, ulcerative colitis, admission to the hospital on a weekend day, not necessarily the day the surgery took place, is associated with a significant increase in mechanical wound complications (I assume they mean wound dehiscence or “burst” wound) and need for repeat laparotomy.
Some limitations of the study are as follows:
  • It is a retrospective review of an administrative, not a clinical database.
  • There was no information about the surgeons or other physicians in the database.
  • It is quite possible that by chance more patients in the weekend admission group were on corticosteroids, which are known to have a negative effect on wound healing.
  • The authors admit that “Unmeasured confounders beyond what we were able to capture in our study could also influence the estimates.”
  • It is not surprising that rates of wound dehiscence and need for repeat laparotomy would both increased since the former begets the latter.
  • The authors could not explain why wound problems occurred in ulcerative colitis but not Crohn's disease patients, nor could they explain what mechanism could lead to the adverse outcomes they found.
There is a plethora of literature on whether or not a “weekend effect” really exists. The Times article would have been better if in addition to getting the facts straight, some balance had been offered. 
A brief PubMed search reveals that patients admitted with strokes on weekends fare worse or do not fare worse according to which study you read. Similarly, patients with upper gastrointestinal bleeding fare worse or do not fare worse if admitted on weekends. Take your pick.
The times article concludes with a quote from the lead author, “If you need surgery, you should get it.”
That is the one part of the article I can agree with.
Skeptical Scalpel is a recently retired surgeon and was a surgical department chairman and residency program director for many years. He is board-certified in general surgery and a surgical sub-specialty and has re-certified in both several times. For the last two years, he has been blogging at SkepticalScalpel.blogspot.com and tweeting as @SkepticScalpel. His blog averages over 900 page views per day, and he has over 5200 followers on Twitter.