The Role of initial and follow-up C-reactive protein titer in COVID-19 pneumonia: A single-center study of 1000 cases in a tertiary care setting in India

Introduction: Robust data of C-reactive protein (CRP) are available in bacterial infection, and it can be utilized in this coronavirus disease 2019 (COVID-2019) pneumonia pandemic for initial assessment before planning of treatment in indoor setting compared to other inflammatory markers and computerized tomography (CT) severity. Methods: A prospective, observational, 12-week-follow-up study, included 1000 COVID-19 cases confirmed with real-time reverse transcription-polymerase chain reaction; all cases were assessed with lung involvement documented and categorized on high-resolution computerized tomography (HRCT) thorax, oxygen saturation, and inflammatory marker as CRP at entry point and follow-up. Age, gender, comorbidity, use of 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: The HRCT severity score at entry point has significant correlation with CRP titer [P < 0.00001]. CRP titer has significant association with duration of illness (P < 0.00001). Comorbidities has significant association with CRP titer (P < 0.00001). CRP titer has significant association with oxygen saturation at entry point (P < 0.00001). BiPAP/NIV requirement during hospitalization has significant association with CRP titer (P < 0.00001). Timing of BiPAP/NIV requirement has significant association with CRP titer (P < 0.00001). Follow-up CRP titer during hospitalization compared to entry point normal and abnormal CRP has significant association in post-COVID lung fibrosis (P < 0.00001). Conclusions: CRP has documented a very crucial role in COVID-19 pneumonia in predicting severity of illness, progression of illness, and sequential CRP titers that will help assessing response to treatment during hospitalization and analyzing post-COVID lung fibrosis.