D-dimer levels and lymphocyte counts as prognostic and predictive factors in patients with COVID-19:

Objective: Coronavirus Disease 2019 (COVID-19) is characterized by high fever, sudden developing respiratory distress, and radiological findings failing to respond to conventional treatments. The purpose of this study is to identify the association of D-dimer levels and lymphocyte counts with poor prognosis and to predict the clinical course in patients with COVID-19.\r\nMethods: A total of 118 hospitalized adult patients diagnosed with COVID-19  were included in the study. According to the National Institutes of Health (NIH) COVID-19 treatment guidelines, patients were divided into two groups with severe disease (n= 26) and non-severe (n= 92) disease. Detected at the time of diagnosis, D-dimer levels and lymphocyte counts were compared between severe and non-severe COVID-19 patient groups. Distinctive performance analysis of  these values  was performed, and cut-off  values were determined.\r\nResults: The mean age of patients was 62 ± 7 years (range 42-80 years), and 63 (53.4 %) were female. The lymphocyte count was  lower (p \u003c0.001), and D-dimer was  higher in patients with severe COVID-19 compared to non-severe patients (p \u003c0.001). D-dimer\u0027s cut-off point when the sum of specificity and sensitivity is maximized was 2 mg/L (sensitivity, 0.731; specificity, 0.913), and 1500/mm3 was for lymphocyte count (sensitivity, 0.692; specificity, 0.609). Lymphocyte count and D-dimer had a significant discrimination power (AUC: 0.745 [95 CI: 0.644 - 0.846 ],  AUC: 0.928 [95% CI: 0.879 - 0.978] respectively, p \u003c0.0001).\r\nConclusion: The lymphocyte value of  ≤ 1500/mm3 and D-dimer value of  ≥ 2 mg/L  can be used in the early determination of patients with poor prognosis in COVID-19. Using these cut-off values for D-dimer and lymphocyte count will help predict prognosis and make rapid treatment decisions in patients with COVID-19.