The association between vital signs at hospital admission and adverse outcomes in patients with COVID-19: a retrospective cohort study.

Background: Vital sign measurements at hospital admission are used to identify patients at risk for adverse events. However, how vital signs at admission are related to adverse outcomes among COVID-19 patients is not fully characterized. Objectives: To characterize vital signs at admission and their associations with intensive care unit/intermediate care unit (ICU/IMCU) admission and in-hospital mortality in adult patients with COVID-19. Methods: This retrospective cohort study included 2,826 adults admitted with COVID-19 to Karolinska University Hospitals, Stockholm, Sweden, between 2 March 2020 and 1 June 2021. The Cox proportional hazards model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between vital signs at admission and ICU/IMCU admission and in-hospital mortality. Results: The median age was 62.2 years, and 62.1% were men. Each unit increase in respiratory rate (HR 1.03, 95% CI 1.02-1.05), heart rate (HR 1.01, 95% CI 1.00-1.02), temperature (HR 1.21, 95% CI 1.11-1.32), and each unit decrease in saturation (HR 1.05, 95% CI 1.04-1.06) were associated with ICU/IMCU admission. Respiratory rate (HR 1.04, 95% CI 1.02-1.07) and saturation (HR 1.04, 95% CI 1.02-1.06) were also associated with in-hospital mortality. These associations persisted across pandemic waves. Conclusion: Respiratory rate and lower saturation at admission were associated with increased ICU/IMCU admission and in-hospital mortality. Our findings suggest that greater emphasis on respiratory rate and oxygen saturation in early warning scores-such as the revised Sequential Organ Failure Assessment (SOFA) score and other sepsis prediction models, to improve risk stratification of viral sepsis, especially in patients with COVID-19.