Assessing Humoral Immuno-Inflammatory Pathways Associated with Respiratory Failure in COVID-19 Patients.

Area of Science:

• Critical Care Medicine
• Infectious Diseases
• Clinical Pathology

Background:

• Severe COVID-19 cases risk progression to Acute Respiratory Distress Syndrome (ARDS).
• Respiratory symptoms in COVID-19 patients may not accurately reflect disease worsening.
• Understanding inflammatory markers is crucial for predicting severe COVID-19 outcomes.

Purpose of the Study:

• To investigate the asynchronous trends of neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) in severe COVID-19 patients.
• To evaluate the predictive value of NLR and CRP for mortality and intensive care unit (ICU) admission.
• To determine the relationship between NLR, CRP, and the PaO2/FiO2 (P/F) ratio.

Main Methods:

• Retrospective analysis of 764 severe COVID-19 patients from two Italian hospitals.
• Monitoring of NLR and CRP trends throughout hospitalization.
• Statistical analysis to assess the association of NLR and CRP with mortality, ICU admission, and P/F ratio.

Main Results:

• NLR showed an increasing trend in deceased patients, predicting mortality (HR: 1.77).
• CRP levels decreased initially but increased sharply at hospitalization's end in ICU-admitted patients, predicting ICU admission (HR: 1.70).
• Age, neutrophils, CRP, and lymphocytes were directly linked to the P/F ratio, with neutrophils mediating CRP's influence.

Conclusions:

• NLR and CRP exhibit distinct trends and predictive values for COVID-19 severity.
• NLR is a significant predictor of mortality, whereas CRP is associated with ICU admission.
• Inflammatory markers, particularly neutrophils and CRP, play a key role in the respiratory compromise (P/F ratio) of severe COVID-19.