The Role Of Neutrophil-To-Lymphocyte Ratio In Predicting Mortality Of Chronic Obstructive Pulmonary Disease Exacerbations

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a prevalent condition and a leading cause of mortality worldwide. Acute exacerbations of COPD (AECOPD) are associated with heightened airway inflammation. The neutrophil-to-lymphocyte ratio (NLR) is recognized as a reliable marker of systemic inflammation and an independent predictor of outcomes in stable COPD. However, its predictive value for in-hospital mortality in AECOPD patients remains uncertain.

Objectives: This study aimed to determine the cut-off point, area under the curve (AUC), sensitivity, and specificity of the NLR for predicting in-hospital mortality in AECOPD patients, as well as to identify independent risk factors associated with mortality.

Methods: A hospital-based cohort study was conducted with follow-up during hospitalization. Patients aged ≥18 years with AECOPD admitted to Nguyen Tri Phuong Hospital between December 2023 and October 2024 were included, provided they met the inclusion criteria. Univariate and multivariate regression analyses were used to evaluate associations between in-hospital mortality and clinically significant risk factors. The receiver operating characteristic (ROC) curve was used to identify the NLR cut-off for predicting mortality.

Results: A total of 150 patients (mean age 67.60 ± 9.42 years) were included in the study. The median NLR was 7.80 (IQR 2.75–9.66), with significantly higher values in the mortality group (median NLR 16.01, IQR 6.33–21.28) compared to the non-mortality group (median NLR 7.12, IQR 2.46–9.12, p<0.05). The ROC curve analysis identified an NLR cut-off of 6.28 (AUC 0.793, p=0.001) for predicting in-hospital mortality, with a sensitivity of 81.80%, specificity of 62.70%, positive predictive value (PPV) of 15.26%, and negative predictive value (NPV) of 97.67%.

Univariate regression analysis revealed significant risk factors for in-hospital mortality, including ICU admission (OR=6.611, p=0.004), severe AECOPD (OR=3.825, p=0.036), mechanical ventilation (OR=14.743, p=0.001), increased pulse rate ≥95 beats/minute (OR=7.096, p=0.015), and NLR ≥6.28 (OR=7.56, p=0.012). Multivariate analysis identified a high NLR (≥6.28) as the only independent risk factor, increasing the risk of in-hospital mortality by 7.831 times (p=0.016).

Conclusions: Patients with AECOPD had a median NLR of 7.80 (IQR 2.75–9.66). An NLR cut-off of 6.28 demonstrated high sensitivity (81.80%) and specificity (62.70%) for predicting in-hospital mortality. Clinicians should closely monitor the NLR in AECOPD patients, particularly when it exceeds 6.28, to assess mortality risk and optimize treatment strategies.