Clinical Characteristics and Factors Associated With Critical Illness and Mortality in Patients Hospitalized With COVID-19: A Retrospective Cohort Study in Taiwan.

Abstract

Background: The ongoing COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to significant morbidity and mortality worldwide. Identifying the clinical features and factors influencing severe disease and mortality in individuals hospitalized with COVID-19 is essential for informing clinical management strategies and optimizing healthcare resource distribution.

Methods: We conducted a retrospective cohort study of 684 patients hospitalized with COVID-19 at a single center in Taiwan between April and June 2022. Demographic characteristics, comorbidities, vaccination status, and clinical outcomes were compared among different age groups (< 50 years, 50-74 years, and ≥ 75 years). Logistic regression analyses were performed to identify factors associated with critical illness and mortality.

Results: The median age of the cohort was 72 years (interquartile range [IQR]: 58-82), and 59.6% were male. Older patients had a significantly higher prevalence of comorbidities. The overall rates of mortality and critical illness were 15.1% and 30.4%, respectively. There were no significant differences in the occurrence of critical illness among the age groups. However, mortality was significantly higher in patients aged ≥ 50 years. In the multivariate analysis, oral antiviral drug use (adjusted odds ratio [aOR]: 0.5, 95% CI [confidence interval]: 0.3-0.7) and being fully vaccinated (aOR: 0.6, 95% CI: 0.4-0.8) were associated with lower mortality, while having ≥ 3 risk factors (aOR: 1.9, 95% CI: 1.2-3.0) was associated with higher mortality. Additionally, age ≥ 50 years was associated with increased mortality; 50-74 years (aOR: 2.3, 95% CI: 1.1-4.8); ≥ 75 years (aOR: 2.3, 95% CI: 1.1-4.8) compared to age < 50 years. Similar factors were associated with critical illness.

Conclusions: Older age was associated with higher mortality but not with an increased risk of critical illness in patients hospitalized with COVID-19. Oral antiviral drug use and being fully vaccinated were associated with better outcomes, highlighting the importance of early treatment and vaccination in mitigating severe COVID-19.