Predictive Value of Chest CT Score in Assessing Disease Severity and Short-term Mortality in COVID-19 Pneumonia at a Tertiary Care Centre in Northern India: A Prospective Observational Study

Abstract

Introduction: Severe Acute Respiratory Syndrome-Coronavirus (SARS-CoV-2) infection, also known as Coronavirus Disease2019 (COVID-19) is the global pandemic, first described in Wuhan city of China in December of 2019. Its diagnosis depends upon real-time Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). On chest Computerised Tomography (CT), it is almost similar to other viral pneumonia with extensive parenchymal involvement. Semiquantitative scores depicting this extensiveness of involvement could correlate with disease severity, laboratory parameters, mortality, like Intensive Care Unit (ICU) admission, requirements of ventilatory support and longer hospital stay. Aim: To define role of chest CT score in determining disease severity, predicting poor prognosis and mortality of COVID-19 pneumonia in short-term follow-up. Materials and Methods: This prospective study enrolled all admitted real-time RT-PCR positive patients for COVID19 at All India Institute of Medical Sciences, Rishikesh, India between 15th April and 31st May 2021. All patients were assigned semiquantitative CT scores based on the extent of lung parenchymal involvement of 20 lung regions in chest CT. Clinical severity was matched with chest CT scoring and laboratory findings. Survival curves along with univariate and multivariate analysis were applied to define the role of CT scoring in predicting short term prognosis. Results: Total 547 subjects were included in the study, of which the chest CT score showed a significant association with clinical severities (p-value <0.001). CT score were correlating significantly with increased serum C-Reactive Protein (CRP) (p-value=0.001) and D-dimer (p-value=0.01), and decreased lymphocyte count (p-value=0.003). A CT score ≥31 was found to be associated with an increased risk of mortality in both univariate and multivariate analysis {Odd Ratio (OR)=276.8; 95% Confidence Interval (CI)= 45.21-1695.43; p-value <0.001}. Conclusion: Chest CT score can be imaging measure of disease severity and predict a higher probability of mortality in score ≥31. It can also predict other defined variables of short-term prognosis. So, it has an advantage in speedy diagnostic workflow of symptomatic cases, timely referral of patients to higher centre, and better management of critical care resources.