Prognostic value of lactate dehydrogenase for in-hospital mortality in severe and critically ill patients with COVID-19

Abstract

Background: Lactate dehydrogenase (LDH) has been proved to be a prognostic factor for the severity and poor outcomes of coronavirus disease 2019 (COVID-19). In most studies, patients with various levels of COVID-19 severity were pooled and analyzed which may prevent accurate evaluation of the relationship between LDH and disease progression and in-hospital death. In this study, we aimed to evaluate the association of LDH with in-hospital mortality in severe and critically ill patients with COVID-19. Methods: This single-center retrospective study enrolled 119 patients. Survival curves were plotted using Kaplan-Meier method and compared by log-rank test. Multivariate Cox regression models were used to determine the independent risk factors for in-hospital mortality. Receiver-operator curves (ROCs) were constructed to evaluate the predictive accuracy of LDH and other prognostic biomarkers. Results: Compared to the survival group, LDH levels in the dead group were significantly higher [559.5 (172, 7575) U/L vs 228 (117, 490) U/L, (P < 0.001)]. In Multivariate Cox regression, it remained an independent risk factor for in-hospital mortality (Hazard ratio 5.985, 95.0%CI: 1.498-23.905; P=0.011). A cutoff value of 353.5 U/L predicted the in-hospital mortality with a sensitivity of 94.4% and a specificity of 89.2% respectively. Conclusion: LDH is a favorable prognostic biomarker with high accuracy for predicting in-hospital mortality in severe and critically ill patients with COVID-19. This may direct physicians worldwide to effectively prioritize resources for patients at high risk of death and to implement more aggressive treatments at an earlier phase to save patients' lives.

Keywords: COVID-19; lactate dehydrogenase; multiple organ dysfunction; prognostic value.

Figure 1

Comparison of survival rates between groups with different levels of LDH. Fifty-seven patients were with LDH≥ 353.5 U/L while sixty-two patients were with LDH < 353.5 U/L. We chose 26 days as the observation time point according to the longest follow-up time within our study. Patients who died or discharged prior to the observation time were defined as censored. Patients with higher level of LDH were associated with higher in-hospital mortality.

Figure 2

ROC analysis of different biomarkers in predicting in-hospital mortality in patients with severe and critically ill COVID-19. The ROCs of different biomarkers showed that LDH had the biggest AUC and a credible prognostic value with a high sensitivity and specificity for predicting in-hospital mortality in patients with severe and critically ill COVID-19.