Objective: To investigate the clinical significance of neutrophil-to-lymphocyte ratio (NLR) in classification of patients with coronavirus disease 2019 (COVID-19).
Methods: A retrospective analysis was performed on 72 patients with COVID-19 admitted to the critical ward of Cancer Center of Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology in Wuhan from February to March in 2020. The patients were divided into two groups: moderate type (non-severe group) and severe/critical type (severe group). The results of white blood cell count (WBC), neutrophil count (NEU), lymphocyte count (LYM), interleukin-6 (IL-6) and D-dimer were collected at the 2nd day after admission from the two groups, and the NLR was calculated. The diagnostic value of WBC, NEU, LYM, IL-6, D-dimer and NLR on COVID-19 classification was evaluated by the receiver operating characteristic (ROC) curve.
Results: A total of 72 COVID-19 patients were enrolled, among whom 52 were moderate, 17 were severe, and 3 were critical. The most common clinical manifestations of patients were fever (70.8%), cough (36.1%), chest tightness and breathlessness (37.5%), diarrhea (15.3%), fatigue (15.3%), vomiting and nausea (11.1%), occasionally accompanied by acute dyspnea (2.8%), and only one patient had no clinical symptom (1.4%). The levels of WBC, NEU, IL-6, D-dimer and NLR in the severe group were significantly higher than those in the non-severe group [WBC (×109/L): 7.81±3.65 vs. 5.34±1.69, NEU (×109/L): 5.83±3.13 vs. 3.24±1.53, IL-6 (ng/L): 133.63 (71.09, 249.61) vs. 28.05 (6.41, 101.24), D-dimer (mg/L): 0.86 (0.31, 2.56) vs. 0.33 (0.20, 0.71), NLR: 6.14±4.75 vs. 2.66±1.93, all P < 0.05], and the level of LYM was significantly lower than that in the non-severe group (×109/L: 1.09±0.56 vs. 1.49±0.74, P < 0.05). The results of ROC curve analysis showed that the areas under ROC curve (AUC) of WBC, NEU, LYM, IL-6, D-dimer and NLR for COVID-19 classification were 0.790 [95% confidence interval (95%CI) was 0.684-0.897), 0.869 (95%CI was 0.789-0.949), 0.719 (95%CI was 0.592-0.847), 0.790 (95%CI was 0.682-0.898), 0.676 (95%CI was 0.526-0.827), and 0.888 (95%CI was 0.814-0.963) respectively. The AUC of NLR was the highest, which was of high diagnostic value; when the optimum cut-off value of NLR was 3.00, the sensitivity was 100%, and the specificity was 73.1%.
Conclusions: NLR can be used as a biomarker to predict classification of COVID-19 patients independently, which can provide a theoretical basis for the classification management of COVID-19 patients.