Lactic dehydrogenase-lymphocyte ratio for predicting prognosis of severe COVID-19

To develop a useful score for predicting the prognosis of severe corona virus disease 2019 (COVID-19) patients. We retrospectively analyzed patients with severe COVID-19 who were admitted from February 10, 2020 to April 5, 2020. First, all patients were randomly assigned to a training cohort or a validation cohort. By univariate analysis of the training cohort, we developed combination scores and screened the superior score for predicting the prognosis. Subsequently, we identified the independent factors influencing prognosis. Finally, we demonstrated the predictive efficiency of the score in validation cohort. A total of 145 patients were enrolled. In the training cohort, nonsurvivors had higher levels of lactic dehydrogenase than survivors. Among the 7 combination scores that were developed, lactic dehydrogenase-lymphocyte ratio (LLR) had the highest area under the curve (AUC) value for predicting prognosis, and it was associated with the incidence of liver injury, renal injury, and higher disseminated intravascular coagulation (DIC) score on admission. Univariate logistic regression analysis revealed that C-reactive protein, DIC score ≥2 and LLR >345 were the factors associated with prognosis. Multivariate analysis showed that only LLR >345 was an independent risk factor for prognosis (odds ratio [OR] = 9.176, 95% confidence interval [CI]: 2.674–31.487, P < .001). Lastly, we confirmed that LLR was also an independent risk factor for prognosis in severe COVID-19 patients in the validation cohort where the AUC was 0.857 (95% CI: 0.718–0.997). LLR is an accurate predictive score for poor prognosis of severe COVID-19 patients.