Can we predict the prognosis of COPD with a routine blood test?

Abstract

Background: The major characteristic of COPD is systemic inflammation. The parameters such as neutrophil-to-lymphocyte ratio (NLR) and eosinophil-to-basophil ratio (EBR) in routine blood test (RBT) are considered to be the underlying biomarkers of inflammation. We hypothesized that the prognosis of patients with COPD can be predicted with RBT.

Methods: Patients with COPD in stable stage were enrolled. The RBT, pulmonary function testing (PFT), BODE index, C-reactive protein (CRP), procalcitonin, and erythrocyte sedimentation rate (ESR) were performed at enrollment and every follow-up once in every 3 months during the 24-month follow-up period. Meanwhile, exacerbation count and mortality incidence were recorded. The correlation between the prognostic biomarkers and the prognosis of patients was analyzed.

Results: The NLR and EBR in RBT have a significant correlation with the severity of patients with COPD. The NLR is an independent predictor for mortality and the EBR is an independent predictor for exacerbation.

Conclusion: As an inexpensive, accessible, and convenient assay, RBT may be used as a practical means in the prediction of prognosis of patients with COPD in future clinical settings.

Keywords: COPD; eosinophil-to-basophil ratio; inflammation; neutrophil-to-lymphocyte ratio; prognosis; routine blood test.

Figure 1

Enrollment, screening, and follow-up. Abbreviations: CRP, C-reactive protein; PFT, pulmonary function testing; RBT, routine blood test.

Figure 2

Receiver operating characteristic (ROC) curve of NLR for the prediction of mortality (left); ROC curve of EBR for the prediction of mortality (right). Abbreviations: AUC, area under the curve; CI, confidence interval; EBR, eosinophil-to-basophil ratio; NLR, neutrophil-to-lymphocyte ratio.

Figure 3

Comparison of survival rate between high NLR group and low NLR group (left); comparison of exacerbation rate between high NLR group and low NLR group (right). Notes: ○, high NLR group; ●, low NLR group. Abbreviation: NLR, neutrophil-to-lymphocyte ratio.

Figure 4

Comparison of survival rate between high EBR group and low EBR group (left); comparison of exacerbation rate between high EBR group and low EBR group (right). Notes: ○, low EBR group; ●, high EBR group. Abbreviation: EBR, eosinophil-to-basophil ratio.