Serial interleukin-6 titer monitoring in COVID-19 pneumonia: Valuable inflammatory marker in the assessment of severity, predicting ventilatory support requirement, and final radiological outcome – Prospective observational study in tertiary care setting in India

Abstract

Introduction: Coronavirus disease 2019 (COVID-19) pneumonia is heterogeneous disease with variable effect on lung parenchyma, airways, and vasculature, leading to long-term effects on lung functions. Materials and Methods: Multicentric, prospective, observational, and interventional study included 1000 COVID-19 cases confirmed with reverse transcription-polymerase chain reaction. All cases were assessed with lung involvement documented and categorized on high-resolution computed tomography (CT) of the thorax, oxygen saturation, inflammatory marker as interleukin-6 (IL-6) at entry point and follow-up. Age, gender, comorbidity, and use bilevel positive airway pressure/noninvasive ventilation (BIPAP/NIV) and outcome as with or without lung fibrosis as per CT severity were key observations. Statistical analysis is performed using Chi-square test. Results: Age ( 50 years) and gender (male versus female) has significant association with IL-6 (P < 0.00001) and (P < 0.010], respectively. CT severity score at entry point has significant correlation with IL-6 level (P < 0.00001) IL-6 level has significant association with duration of illness (P < 0.00001). Comorbidity as diabetes mellitus, hypertension, chronic obstructive pulmonary disease, ischemic heart disease, and obesity has significant IL-6 level (P < 0.00001). IL-6 level has significant association with oxygen saturation (P < 0.00001). BIPAP/NIV requirement during course hospitalization has significant association with IL-6 level (P < 0.00001). Timing of BIPAP/NIV requirement during hospitalization has significant association with IL-6 level (P < 0.00001) Serial IL-6 titer during hospitalization as compared to entry point normal and abnormal IL-6 has significant association in post-COVID lung fibrosis (P < 0.00001). Conclusions: IL-6 is easily available, and universally acceptable inflammatory marker, documented crucial role in COVID-19 pneumonia in predicting the severity of illness, progression of illness including “cytokine storm” and assessing response to treatment during hospitalization.

Keywords

• coronavirus disease 2019 pneumonia
• interleukin-6 inflammatory marker
• oxygen saturation
• post-coronavirus disease lung fibrosis