Acute-phase reactants during tocilizumab therapy for severe COVID-19 pneumonia

Area of Science:

• Critical Care Medicine
• Infectious Diseases
• Immunology

Background:

• Severe COVID-19 pneumonia is associated with significant morbidity and mortality.
• Tocilizumab (TCZ), an interleukin-6 (IL-6) inhibitor, is used to treat severe COVID-19.
• Predictors of clinical response and adverse outcomes in TCZ-treated patients require identification.

Purpose of the Study:

• To identify predictors of clinical improvement and intubation/death in severe COVID-19 patients treated with tocilizumab.
• To evaluate the role of longitudinal monitoring of C-reactive protein (CRP) and IL-6 levels.

Main Methods:

• Prospective cohort study of 173 severe COVID-19 patients receiving tocilizumab.
• Clinical improvement and a composite outcome of intubation/death were assessed.
• CRP and IL-6 levels were measured at baseline (T0), day 3 (T3), and day 7 (T7).

Main Results:

• Elevated CRP levels at T0 and T3 were associated with poorer clinical improvement and increased risk of intubation/death.
• No significant association was found between IL-6 levels and clinical outcomes.
• Serial CRP measurements showed distinct trends differentiating patients based on outcome; a baseline CRP of 15.8 mg/dl best predicted intubation/death (AUC=0.711).

Conclusions:

• Longitudinal CRP measurements within the first week of tocilizumab therapy are valuable for predicting poor outcomes in severe COVID-19.
• CRP monitoring can aid in identifying patients at high risk for adverse events, potentially guiding treatment adjustments.