Trends in Risk-Adjusted 28-Day Mortality Rates for Patients Hospitalized with COVID-19 in England.

Early reports showed high mortality from coronavirus disease 2019 (COVID-19). Mortality rates have recently been lower; however, patients are also now younger, with fewer comorbidities. We explored 28-day mortality for patients hospitalized for COVID-19 in England over a 5-month period, adjusting for a range of potentially mitigating variables, including sociodemographics and comorbidities. Among 102,610 hospitalizations, crude mortality decreased from 33.4% (95% CI, 32.9-34.0) in March 2020 to 15.5% (95% CI, 14.1-17.0) in July. Adjusted mortality decreased from 33.4% (95% CI, 32.8-34.1) in March to 17.4% (95% CI, 11.3-26.9) in July. The relative risk of mortality decreased from a reference of 1 in March to 0.52 (95% CI, 0.34-0.80) in July. This demonstrates that the reduction in mortality is not solely due to changes in the demographics of those with COVID-19.