Mortality due to COVID-19 infection: A comparison of first and second waves

Background: The USA suffered an initial wave of COVID-19 cases from March to July in 2020. Cases again surged in August 2020 as business restrictions were lifted. We aimed to describe demographic, treatment, and mortality differences between both waves. Methods: We identified all hospitalized patients with COVID-19 infection in one US six-hospital health system between 1 March 2020 and 31 January 2021. We compared data obtained on patient demographics, treatment received, and mortality between first and second waves of the pandemic. Results: A total of 4434 hospitalized COVID patients were identified, including 1313 patients in the first wave and 3121 patients in the second wave. Mortality was significantly higher in the first wave as compared to the second wave (23.2% vs. 12.3%, p < 0.001). Age and sex were similar in each wave. In the first wave, there were significantly more Non-Hispanic Black patients (28.8 vs. 18.1%, p < 0.001) and Hispanic patients (26.6% vs. 14.9%, p < 0.001) as compared to the second wave. There was a higher mortality rate in the first wave as compared to the second, which persisted after multivariable adjustment for sex, age, ethnicity, laboratory results at admission, treatment received, high flow use and mechanical ventilation (OR: 2.66, 95% CI: 1.83-3.87, p < 0.001). Conclusion: Mortality in the second wave was lower than the first wave with significantly higher utilization of steroids, remdesivir and convalescent plasma in second wave.