Predictive role of neutrophil‐percentage‐to‐albumin, neutrophil‐to‐lymphocyte and eosinophil‐to‐lymphocyte ratios for mortality in patients with COPD: Evidence from NHANES 2011–2018

BACKGROUND AND OBJECTIVE: This study evaluated the predictive roles of hematologic inflammatory biomarkers including neutrophil-percentage-to-albumin ratio (NPAR), neutrophil-to-lymphocyte ratio (NLR) and eosinophil-to-lymphocyte ratio (ELR) for mortality in community-dwelling individuals with chronic obstructive pulmonary disease (COPD). METHODS: This longitudinal study extracted data of adults 40-79 years who had physician-diagnosed COPD from the United States (US) National Health and Nutrition Examination Survey (NHANES) 1999-2018. Cox regressions determined the associations between NPAR, NLR, ELR and their components, with all-cause mortality, cardiovascular disease (CVD) mortality and mortality from chronic lower respiratory disease (CLRD). Receiver operating characteristic (ROC) curve analysis estimated the predictive performances of these biomarkers for 5-year all-cause mortality. RESULTS: Data of 1158 subjects were analysed. After adjustment, higher NPAR was significantly associated with increased all-cause and CVD mortality, and mortality from CLRD (adjusted hazard ratio [aHR] = 1.14, 1.15 and 1.16). Higher NLR was associated with an increased all-cause and CVD mortality (aHR = 1.16 and 1.29). Higher neutrophil was associated with increased all-cause mortality and mortality from CLRD (aHR = 1.13 and 1.34). Albumin was associated with decreased all-cause and CVD mortality (aHR = 0.91 and 0.86). ELR, eosinophil or lymphocyte was not significantly associated with either mortality outcomes. Adjusted AUC of NPAR and NLR in predicting 5-year all-cause mortality were 0.808 (95% CI: 0.722-0.845) and 0.799 (95% CI: 0.763-0.835), respectively. CONCLUSION: In community-dwelling US adults with COPD, increased NPAR and NLR are associated with mortality risks. NPAR outperforms the other hematologic inflammatory biomarkers in predicting 5-year all-cause mortality.