Study of Correlation between Plasma D-dimer and Chest CT Severity Score in Covid-19

Background and objectives: covid -19 is caused by SARS-CoV-2 which severely affects the alveolar vascular endothelium leading to covid pneumonia. The direct damaging effects of virus along with inflammation triggered by the virus leads to hypercoagulability in covid-19 patients. This predisposes the patient to DIC, ARDS, increased oxygen requirement, thus, poor prognosis. D-dimer is a biomarker of hypercoagulability and inflammation. Chest CT severity score visually scores the lung lesions in percentage of lung tissue affected. Aims and objectives: estimation of plasma D-dimer levels and its' correlation with Chest CT severity score in covid-19 patients. Material and Method: This is hospital based single centre retrospective study consisting of 91 covid-19 patients admitted in our hospital from19 July 2022 to 25 august 2022 after being diagnosed clinically and confirmed by RT-PCR. We divided the patient into three groups depending on Chest CT severity score and compared the mean plasma D-dimer levels. Results: We found the plasma D-dimer levels were significantly increased in covid-19 patients as compared to the normal proposed level of <500 ng/ml .The plasma D-dimer levels in patients ranged from 49 to 8815 ng/ml. The mean level of plasma D-dimer of all patients was 3629±1819 ng/ml.The three groupshad mean plasma D-dimer levels 453±508, 2705±1256, 5642±1824 respectively(p <0.0001). The plasma D-dimer levels showed significant positive correlation with Chest CT severity score in three groups (p<0.0001 and r<0.8455, r <0.6818, r <0.6753respectively).Conclusion: Plasma D-dimer levels are significantly increased in covid-19 patients suggestive of hypercoagulable state. The plasma D-dimer levels correlated well with Chest CT severity score in covid-19 patients which in turn reflects the disease severity. Hence, estimation of plasma D-dimer levels may predict the severity of infection and further risk estimation.