Basic host response parameters to classify mortality risk in COVID-19 and community-acquired pneumonia

Area of Science:

• Pulmonology and Critical Care Medicine
• Infectious Diseases
• Biomarker Discovery and Validation

Background:

• Accurate risk stratification is crucial for managing pneumonia, including COVID-19 and community-acquired pneumonia (CAP).
• Current phenotyping methods may not fully capture the host's response to infection.
• There is a need for accessible and multidimensional approaches to assess disease severity.

Purpose of the Study:

• To evaluate the effect of host response at admission on severity stratification in COVID-19 and CAP.
• To assess the utility of three easily available biomarkers (absolute lymphocyte count, C-reactive protein, SpO2/FiO2) in predicting outcomes.

Main Methods:

• Retrospective analysis of three COVID-19 and one CAP multicenter cohorts.
• Selection of absolute lymphocyte count (ALC), C-reactive protein (CRP), and SpO2/FiO2 as key biomarkers.
• Multivariable logistic regression analysis to determine the association between biomarker levels and outcomes (in-hospital mortality, ICU admission).

Main Results:

• Increased odds ratios for in-hospital mortality and ICU admission were observed with an increasing number of abnormal biomarkers in COVID-19 patients.
• The predictive model for mortality in COVID-19 achieved an Area Under the Receiver Operating Characteristic Curve (AUROC) of 0.83.
• Comparable trends were noted in the CAP cohort, though not statistically significant.

Conclusions:

• Accessible biomarkers reflecting immune, inflammatory, and respiratory status can effectively stratify pneumonia severity.
• This host response assessment provides a simple, rapidly applicable approach for clinical decision-making in pneumonia management.
• The findings support the use of ALC, CRP, and SpO2/FiO2 for enhanced risk assessment in hospitalized pneumonia patients.