Cutoff levels of D-dimer to predict pulmonary thromboembolism in COVID-19 at first admission: A retrospective study

BACKGROUND AND AIM: In coronavirus disease 2019 (COVID-19), prothrombotic clotting abnormalities and thromboembolism are frequent complications that could be contributed to morbidity and mortality. We aimed to determine the incidence of pulmonary thromboembolism (PTE) at the time of diagnosis of COVID-19 and to evaluate the association of D-dimer levels in patients with COVID-19. METHODS: Patients who were diagnosed with COVID-19, had elevated D-dimer levels (>500 mg/L), and underwent pulmonary CT angiography (CTA) were included. The data were reviewed retrospectively. Patients were divided into two groups based on the presence or absence of a diagnosis of PTE, and univariate and multivariate analyses were performed.RESULTS: A total of 687 patients with COVID-19 were included. PTE was identified in 11.4% of the patients (n=78) using pulmonary CTA. There were significantly more male patients in the PTE group (60.3% vs 39.7%). PTE patients had significantly higher D-dimer levels (1535 mg/L; range: 960-3710). Age, gender, and D-dimer were found as independent predictors for a diagnosis of PTE in the multi-logistic regression analysis. Also, a receiver operating characteristic curve analysis performed to evaluate the diagnostic value of D-dimer in PTE showed an area under curve of 0.651 (0.585-0.718). A cutoff value of 1000 ng/mL provided diagnostic utility.CONCLUSIONS: COVID-19 has constituted a predisposition to thromboembolism. Age-adjusted D-dimer levels, which have recently become prominent for suspected PTE, do not appear to be beneficial in patients with COVID-19. The results of this study suggest that a cutoff of 1000 ng/mL can be utilized in these patients.