Increased lactate dehydrogenase reflects the progression of COVID-19 pneumonia on chest computed tomography and predicts subsequent severe disease: A retrospective cohort study

Abstract Background: Chest computed tomography (CT) is very effective for assessing the severity and prognosis of coronavirus disease 2019 (COVID-19). However, the clinical factors that are associated with the disease progression of COVID-19 pneumonia on chest CT at admission and that can consistently predict a subsequent severe clinical course remain unclear.Methods: We conducted a single-center retrospective cohort study of 450 patients admitted with confirmed SARS-Cov-2 infection between October 2020 and September 2021. An automated image processing tool was used to quantify the COVID-19 pneumonia lesion extent within total lung on chest CT at admission. Factors associated with the progression of COVID-19 pneumonia on chest CT were estimated by a multiple regression analysis using the quantified value as the objective variable. After adjusting for background factors by propensity score matching, a multivariate Cox proportional hazards analysis with the factors estimated by a multiple regression analysis as explanatory variables was conducted to identify factors associated with severe disease after admission.Results: In the multiple regression analysis, sex, body-mass index (BMI), lactate dehydrogenase (LDH), C-reactive protein (CRP), and albumin were identified as independent factors associated with the COVID-19 pneumonia lesion extent on chest CT: female sex (partial regression coefficient [B], 1.11; 95% confidence interval [CI], 1.02–1.21), BMI (B, 4.19; 95% CI, 2.65–6.66), LDH (B, 3.38; 95% CI, 2.33–4.89), CRP (B, 1.18; 95% CI, 1.08–1.29), and albumin (B, 0.36; 95% CI, 0.21–0.63). The standardized partial regression coefficients (β) for continuous variables (BMI, LDH, CRP, and albumin) were 1.76, 2.42, 1.54, and 0.71, respectively. In a multivariate Cox proportional hazards analysis, LDH (hazard ratio [HR], 1.003; 95% CI, 1.001-1.005) was identified as a factor independently associated with severe COVID-19 pneumonia.Conclusion: LDH was found to be an independent factor reflecting the disease progression of COVID-19 pneumonia on chest CT at admission and was also associated with subsequent severe disease. Increased serum LDH level at admission may be useful in real-world clinical practice for appropriate and early non-invasive and simple screening of patients with COVID-19 who are at high risk of developing severe disease.