Considering the Calendar: Does the day of the week a procedure is performed on influence surgical outcomes?

Every individual who needs an operation wants to be assured that it will be performed in the best and safest conditions possible. So for those electing to undergo a surgical procedure, there are a lot of factors to take into consideration. Many people are aware that different procedures present with various levels of risk and will diligently seek to find a qualified, experienced surgeon. However, far less are as selective regarding what day of the week their surgery is performed on.


The reduction in considering a particular day for surgery could be due to a lack of available information regarding this subject, because up until just recently there was not much research on this topic. Schedule conflicts with work and other plans may also have a role in determining the day that surgery is performed. It was not until recently when a few studies were published on this subject that shed some light on this subject of whether or not the day of the week elective surgery is performed on has an influence on surgical outcomes. The results of such studies may influence some who have an upcoming surgery to place more consideration on the day of the week they elect to have the operation.


Study Results            

        When separated by day of the week, there was a trend for higher surgical mortalityon Friday, Saturday and Sunday when compared withall other days in most of the studies.1,2,3This trend did not reach statistical significance in all of the studies though. One study showed no consistent association between the day of week of the surgery and 30-day mortality or secondary adverse outcomes on Friday versus Monday.1Conversely, another study found that patients were 44% more likely to die after having a surgery on a Friday than a Monday. That rate nearly doubled to 82% for patients who have surgery on the weekend rather than Monday. (care2) These inconsistencies demonstrate the need for further studies investigating the true underlying causes that may be influencing post-op outcomes.


Expert Speculations

Although more research needs to be done to determine what may be influencing higher complication rates on weekends compared to earlier weekdays, researchers have speculated some potential causes. First, experts believe that hospitals are more understaffed on weekends and may not be as experienced as those who work a more conventional work schedule during the week.2Previous studies have identified hospitals with lower levels of  weekend staffing have higher rates of death following weekend admissions. Additionally, Tuesdays and Wednesdays were the days surgeons with the most years experience were working, whereas surgeons working Mondays and Fridays had less experience.3

Another speculation is that surgeons could be more mentally and physically prepared for surgeries on Monday after having a weekend off to recover from the stress and happenings of the previous week. As the week wears on, increased rates of stress and tiredness could potentially have an impact on performance.3




        It is important to note that although some studies suggest a higher incidence of mortality and complications for surgeries performed later in the week and the weekend, this only indicates an association and should not be interpreted as causation. Also, despite some of the studies which found a significant difference in the death rates between Monday and late-week, that only 1% of total patients died in the month following an operation. 2,3One of the most important factors remains selecting a qualified health professional to perform the particular surgery you are electing to undergo. Nevertheless, if presented with a choice of day when scheduling a surgery, selecting an appointment earlier in the week may be something to keep in mind.




  1. Singla AA, Guy GS, Field JBF, Ma N, Babidge WJ, Maddern GJ. No weak days? Impact of day in the week on surgical mortality. ANZ Journal of Surgery. 86(1-2):15-20. doi:10.1111/ans.13315.


  1. Aylin P, Alexandrescu R, Jen M H, Mayer E K, Bottle A. Day of week of procedure and 30 day mortality for elective surgery: retrospective analysis of hospital episode statistics BMJ 2013; 346:2424


  1. Dubois L, Vogt K, Vinden C, et al. Association between day of the week of elective surgery and postoperative mortality. CMAJ. 2017;189(8):E303-E309. doi:10.1503/cmaj.160511