EMR Combined with CRB-65 Superior to CURB-65 in Predicting Mortality in Patients with Community-Acquired Pneumonia

Background: Data about eosinophil-to-lymphocyte ratio (ELR) and eosinophil-to-monocyte ratio (EMR) in patients with communityacquired pneumonia (CAP) are rare. We aimed to evaluate the role of EMR and ELR in predicting disease severity and mortality in patients with CAP. Methods: A total of 454 patients (76 with severe CAP (SCAP), 378 with non-SCAP) were enrolled from November 18, 2020, and November 21, 2021. Laboratory examination on day 1 after admission was measured. The ELR and EMR values were calculated for patients. Propensity score matching (PSM) was performed to balance potential confounding factors. Binary logistic regression model was fitted to identify the potential risk factors for disease severity and Cox proportional hazards regression model analysis for mortality in CAP. Receiver operating characteristic (ROC) analysis was performed to distinguish disease severity and mortality. Results: EMR and ELR at admission were significantly lower in SCAP patients than in non-SCAP patients (P<0.001). EMR < 0.018 ([OR] = 12.104, 95% CI: 4.970-29.479), neutrophil (NEU) ([OR]=1.098, 95% CI:1.005-1.199), and age ([OR]=1.091, 95% CI:1.054- 1.130) were independent risk factors for disease severity of CAP. EMR < 0.032 ([HR] = 5.816, 95% CI: 1.704-9.848) was an independent predictor of in-hospital mortality. Combining EMR or ELR with CRB-65 improved the overall accuracy of disease severity prediction (AUC from 0.894 to 0.937), the same as CURB-65. The area under the curve of EMR (AUC=0.704; 95% CI: 0.582-0.827) to predict in-hospital mortality was higher than that of CURB-65 (AUC=0.619; 95% CI: 0.484-0.754). Otherwise, EMR combined with CRB-65 (AUC=0.721; 95% CI: 0.592-0.851) had significantly higher diagnostic accuracy for in-hospital mortality than that of CURB-65 alone. Conclusion: EMR combined with CRB-65 was superior to CURB-65 in predicting mortality in patients with CAP. This new combination was simpler and easier to obtain for physicians in clinics or admission, and it was more convenient for early recognition of patients with poor prognoses.