Correlation of biomarkers and radiological findings among COVID-19 patients: a retrospective study

Introduction: The severity of COVID-19 is classified based on clinical, laboratory, and radiology characteristics. Although chest X-ray (CXR) is not sensitive in early stage disease, it can be useful in assessing the rapid progression of lung abnormalities in COVID-19. While CXR findings correlate with the severity of the disease, computed tomography (CT) scans of the chest are widely and repeatedly done. As it exposes the patient to a large dose of radiation and risks the spread of infection to other patients, it is worthwhile to explore the utility of CXR to overcome the above problem, especially in resource-poor settings. Materials and Methods: Inpatients with reverse transcriptase–polymerase chain reaction (RT-PCR)-positive COVID-19 irrespective of severity, admitted in the COVID wards from June to September 2020, were included in a retrospective study. CXR done at admission was scored for radiological severity of COVID-19 by an independent radiologist, unaware of the clinical/laboratory parameters of patients. It was then co-related with clinical severity and standard biomarkers at admission. Results: We studied 400 patients, the mean age (SD) was 53.69 (15.43) years, 268 (67%) were males, the majority of them were symptomatic (95%), 192 (48%) had severe disease, and 238 (59.5%) patients had co-morbidities. Receiver-operating curve (ROC) for CXR severity score showed a threshold of 3.5 to predict severe COVID, which had a positive predictive value of 71% and a negative predictive value of 73%. Using Pearson’s correlation coefficient, CXR severity scores significantly correlated with the clinical severity and standard biomarkers. Conclusion: With the overwhelming number of COVID-19 patients burdening the healthcare system, monitoring of the severity of the disease can be achieved with regular clinical assessment and laboratory parameters with limited radiation exposure, avoiding repeated CT scans, especially in resource-poor settings.