Predicting value of neutrophil–lymphocyte ratio and CURB-65 score for early clinical stability of adult community-acquired pneumonia

Abstract

Early clinical stability has been proven to be vital for the treatment of community-acquired pneumonia (CAP). This research retrospectively analyzed the predictive implication of neutrophil–lymphocyte ratio (NLR) and confusion, urea >7 mmol/L, respiratory rate ⩾30 breaths/min, low blood pressure, and age ⩾65 years (CURB-65) score to predict early clinical stability of the adult CAP. Clinical data, CURB-65 scores, pneumonia severity index (PSI) scores, NLR on admission (within 24 h) of 230 patients between January 2012 and June 2015 were obtained from the Affiliated Hospital of Chengdu University. Instable patients had significantly higher CURB-65, PSI, white blood cell (WBC), neutrophil, and NLR than the stable patients (P < 0.05); NLR was positively correlated with CURB-65 (r = 0.270, P < 0.001) and PSI (r = 0.316, P < 0.001). NLR and CURB-65 were screened as risk factors through the discriminant analysis. The area under the curve (AUC) was 0.662 (95% confidence interval (CI): (0.569, 0.756), P = 0.002) for NLR, 0.670 (95% CI (0.569, 0.772) P = 0.001) for CURB-65. The enhanced predictive power was observed for combining NLR-CURB-65 with the AUC of 0.704 (95% CI (0.606, 0.802), P < 0.001). The risk of early clinical instability rose significantly in patients with NLR (odds ratio (OR) = 3.440, 95% CI (1.741, 6.798) with the cut-off value of NLR = 6.161) and higher CURB-65 (OR = 3.797, 95% CI (1.801, 8.005), with the CURB-65 cut-off value of 1.5). Both NLR and CURB-65 are qualitatively accurate for predicting early clinical stability of CAP, an accuracy-enhanced predicting power was observed in the NLR-CURB-65 combined test, further large-sample studies are required to validate the conclusion.