Effects of an increase in emergency cases with difficulties in transport to hospital during the COVID-19 pandemic on postoperative short-term outcomes of colorectal perforation: A study based on the National Clinical Database.

Aim: During the COVID-19 pandemic, there were delays in transport of emergency cases to hospital by ambulance due to increased difficulties in obtaining hospital acceptance. The aim of this study was to examine if this had a negative effect on postoperative short-term outcomes in patients with colorectal perforation. Methods: The National Clinical Database (NCD) includes >95% of surgical cases in Japan. Postoperative 30-day mortality, surgical mortality, and postoperative complications (Clavien-Dindo grade ≥3) were examined in 17 770 cases of colorectal perforation registered from 2019 to 2022 in the NCD. These outcomes were compared for cases with new COVID-19 infection and emergency cases with difficulties in transport to hospital. Months were considered to have significantly high or low mortality or complication rates, if the 95% confidence interval (CI) of the standardized mortality (morbidity) ratio (SMR) did not contain 1. Results: Postoperative 30-day mortality occurred in 1826 cases (10.3%), surgical mortality in 2382 cases (13.4%), and postoperative complications in 5276 cases (29.7%). Significantly higher SMRs were found for 30-day mortality in November 2020 (1.44 [95% CI: 1.07-1.89]) and February 2021 (1.54 [95% CI: 1.14-2.03]), and for postoperative complications in June 2020 (1.27 [95% CI: 1.07-1.50]). In 2022, there were marked increases in new COVID-19 cases and in emergency cases with difficulties in transport to hospital, but no month had a significantly high SMR. Conclusions: Emergency cases with difficulties in transport markedly increased during the COVID-19 pandemic but had little effect on short-term outcomes of colorectal perforation.