Surgical reorganization during the COVID-19 pandemic and impact on case-mix and surgical site infections: A multicenter cohort study in Italy

Background: The coronavirus 2019 (COVID-19) pandemic led to major disruptions in surgical activity, particularly in the first year (2020). The objective of this study was to assess the impact of surgical reorganization on surgical outcomes in Northern Italy in 2020 and 2021. Methods: A retrospective cohort study was conducted among 30 hospitals participating in the surveillance system for surgical site infections (SSIs). Abdominal surgery procedures performed between 2018 and 2021 were considered. Predicted SSI rates for 2020 and 2021 were estimated based on 2018-2019 data and compared with observed rates. Independent predictors for SSI were investigated using logistic regression, including procedure year. Results: 7605 procedures were included. Significant differences in case -mix were found comparing the three time periods. Observed SSI rates among all patients in 2020 were significantly lower than expected based on 2018-2019 SSI rates (p 0.0465). Patients undergoing procedures other than cancer surgery in 2020 had significantly lower odds for SSI (odds ratio, OR 0.52, 95 % confidence interval, CI 0.3-0.89, p 0.018) and patients undergoing surgery in 2021 had significantly higher odds for SSI (OR 1.49, 95 % CI 1.07-2.09, p 0.019) compared to 2018-2019. Conclusions: Enhanced infection prevention and control (IPC) measures could explain the reduced SSI risk during the first pandemic year. IPC practices should continue to be reinforced beyond the pandemic context.