Indexed on: 19 Oct '16Published on: 19 Oct '16Published in: CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne
In prior studies, higher mortality was observed among patients who had elective surgery on a Friday rather than earlier in the week. We investigated whether mortality after elective surgery was associated with day of the week of surgery in a Canadian population and whether the association was influenced by surgeon experience and volume.We conducted a population-based retrospective cohort study in the province of Ontario, Canada. We included adults who underwent 1 of 12 elective daytime surgical procedures from Apr. 1, 2002, to Dec. 31, 2012. The primary outcome was 30-day mortality. We used generalized estimating equations to compare outcomes for surgeries performed on different days of the week, adjusting for patient and surgeon factors.A total of 402 899 procedures performed by 1691 surgeons met our inclusion criteria. The median length of hospital stay was 6 (interquartile range 5-8) days. Surgeon experience varied significantly by day of week (p < 0.001), with surgeons operating on Fridays having the least experience. Nearly all of the patients who had their procedure on a Friday had postoperative care on the weekend, as compared with 49.1% of those whose surgery was on a Monday (p < 0.001). We found no difference in the 30-day mortality between procedures performed on Fridays and those performed on Mondays (adjusted odds ratio 1.08, 95% confidence interval 0.97-1.21).Although surgeon experience differed across days of the week, the risk of 30-day mortality after elective surgery was similar regardless of which day of the week the procedure took place.