Predicting Covid-19 Progression in Elderly Patients: The Role of Lactate Dehydrogenase and D-Dimer

Background and aim: Because lactate dehydrogenase (LDH) levels increase progressively in severe COVID-19 cases, D-dimer levels also increase due to microcirculation disturbances in severe pneumonia, which is related to age. Therefore, this study aimed to investigate the correlation between LDH and D-dimer levels and disease severity in COVID-19 patients.Methods: This retrospective study enrolled patients aged 60 years. Spearman's correlation analysis was used to evaluate the association between the biomarkers. The sensitivity and specificity of the LDH and D-dimer levels were evaluated using Receiver Operating Characteristic Curve(ROC) curves.Results: This study included 99 patients with confirmed COVID-19 pneumonia(60 asymptomatic patients in the non-severe group and 39 patients with pneumonia symptoms in the severe group). The average age of the patients was 82.73 ± 9.15 years. Patients in the severe group had significantly higher LDH and D-dimer levels, which were positively correlated with infection-related biomarkers. D-dimer levels had an AUROC of 0.9007 with a cut-off level of >1.31 mg/L and LDH levels had an AUROC of 0.974 with a cut-off level of >263.5U/L. The combination of LDH and D-dimer levels improved the prediction accuracy for severe COVID-19 cases.Conclusions: Clinicians can distinguish between mild and severe COVID-19 in elderly patients using LDH and D-dimer levels. This allows medical resources to be allocated to those who need them the most, thus improving the efficiency of diagnosi-ng critical illness and shortening the treatment period for patients.