The side effects of the pandemic on all-cause postoperative mortality in a COVID reference Hospital in Brazil: a before and after cohort study with 15156 patients

Background

Before the pandemic, healthcare systems in Low-Middle Income Countries (LMIC) experienced a limited capacity to treat postoperative complications. It is uncertain whether the interference of the Coronavirus (COVID-19) pandemic on surgical systems has increased postoperative mortality.

Methods

This before and after cohort study aimed to assess the pandemic's impact on in-hospital postoperative mortality in a university COVID-19 reference hospital in southern Brazil. Data from patients who underwent surgery before (January 2018 to December 2019) the pandemic were compared to data from patients who underwent surgery during the pandemic (February to December 2020). The primary outcome was in-hospital mortality. We developed Poisson regression models to examine the mortality risk of being operated on during the COVID-19 pandemic.

Results

We assessed 15156 surgical patients, 12207 of whom underwent surgery before the pandemic and 2949 during the first year of the pandemic. Mortality rates were 2.5% (309/12207) in the pre-pandemic versus 7.2% (212/2949) in the pandemic. Of these, 25.8% (32/124) of patients with COVID-19 and 6.4% (80/2816) of patients without COVID-19 died. The proportion of urgent surgeries and ASA-PS III was higher in the pandemic group. After adjusting for mortality-related variables, the Relative Risk (RR) associated with undergoing surgery during the pandemic was 1.51 (95% CI 1.27 to 1.79). We excluded COVID-19-positive to perform a sensitivity analysis that confirmed the increased risk of undergoing surgery during the pandemic RR = 1.50 (95% CI 1.27 to 1.78).

Conclusion

The substantial number of additional deaths, even amongst those without COVID-19 infection, suggests the pandemic disrupted the surgical service in an LMIC context. Fragile surgical systems may suffer more significant adverse impacts from external stressors such as a pandemic, and urging measures are needed to increase their performance and resilience.