Postoperative outcomes in colorectal surgery by day of surgery: A national cohort study.

Aim: Poorer postoperative outcomes have been observed for patients admitted and operated on later in the week and over the weekend. This is thought to be related to temporal fluctuations in the quality of perioperative care. The aim of this work was to identify if the day of surgery influenced outcomes in a national cohort of colorectal cancer (CRC) resections.

Method: A retrospective population-based study of patients undergoing CRC resection during the period 2010-2020 in Aotearoa New Zealand (AoNZ) was conducted. Ninety-day postoperative mortality, morbidity, postoperative length of stay (PLOS), reoperation and failure to rescue (FTR) were calculated for elective and acute cohorts, stratified by the day of surgery. FTR-Surgical (mortality following reoperation within 90 days of the index operation) was also analysed by day of reoperation. Univariable and mixed-effects, multivariate, logistic regression models were analysed.

Results: The overall cohort included 17 174 patients who underwent surgery for CRC. The 90-day mortality in the elective and acute cohorts was 2.4% (336/13 744) and 11% (371/3430), respectively. Ninety-day mortality, inpatient complications, FTR and PLOS did not differ by day of surgery in acute and elective cohorts. Notably, patients having elective surgery on a Wednesday had a significantly higher rate of reoperation (OR 1.29, 95% CI 1.06-1.56, p = 0.012). Furthermore, reoperation following complication of the index surgery was associated with a significantly higher 90-day mortality (FTR-Surgical) for patients having reoperation on a Friday (OR 2.10, 95% CI 1.01-4.33, p = 0.045).

Conclusion: There is no variation in postoperative outcomes across the week for both elective and emergency cases. This study does, however, highlight a higher FTR-S later on Friday, suggesting that these high-risk patients may require closer postoperative monitoring over the weekend.