Blood Biomarkers as Predictors of Long-Term Mortality in COPD

Abstract

Background

Blood biomarkers are easily accessible and might reflect chronic obstructive pulmonary disease (COPD) activity.

Aim

To determine whether a panel of blood biomarkers (C-reactive protein [CRP], neutrophils, eosinophils, albumin and vitamin D) could predict mortality in COPD.

Methods

we analyzed data from 431 COPD participants to the 2007–2010 National Health and Nutrition Examination Surveys who were followed for a median time of 36 months. COPD was defined as post-bronchodilator forced expiratory volume in 1 second (FEV1) and forced vital capacity ratio <0.70. Weibull survival analysis adjusted for covariates was performed to calculate the risk of mortality associated with the biomarkers and C-statistics was used to assess their added predictive value.

Results

During follow-up, 38 of the 431 participants died. Participants with high CRP, eosinophil count <2%, hypoalbuminemia, and hypovitaminosis D had worse baseline FEV1 and subsequently higher mortality compared to controls. In adjusted analysis, increasing CRP (hazard ratio [HR]: 4.45, 95% CI: 1.91–10.37) and neutrophil count (HR: 1.07, 95% CI: 1.03–1.11) as well as decreasing eosinophil count (HR: 7.03, 95% CI: 2.05–24.01) were associated with an increased risk of mortality. The addition of CRP with eosinophil and/or neutrophil count significantly improved a base model for the prediction of mortality which included age, gender, race/ethnicity, body mass index, smoking, poverty income ratio, asthma, diabetes, hypertension, and history of stroke or myocardial infarction.

Conclusion

high CRP and neutrophils as well as low eosinophils are predictive of poor COPD prognosis. They also add significant value to prediction models of mortality in COPD.