title: Relationship between blood eosinophils and clinical characteristics in a cross-sectional study of a US population-based COPD cohort.
abstract: BACKGROUND
  Current evidence suggests that blood eosinophil levels (Eos) are associated with chronic obstructive pulmonary disease (COPD) treatment response and natural history. This analysis investigated the relationship between Eos levels and clinical characteristics in a representative cohort of US subjects with spirometry-defined COPD.
  
  
  METHODS
  Cross-sectional data from the National Health And Nutrition Examination Survey (NHANES 2007-2010) of subjects ≥ 40 years with spirometry-defined COPD and Eos data (n = 948) were analyzed. Differences in clinical characteristics by Eos level (≤ 2%, > 2%) were compared using chi-square tests. Characteristics associated with Eos > 2% were identified using multivariate logistic regression modeling. Characteristics associated with Eos >2% among subjects with normal lung function, plus other cut-points among the COPD population, were evaluated post hoc.
  
  
  RESULTS
  Most participants had Eos >2%; 70.7% with spirometry-defined COPD and 65.5% with normal lung function. Older age, male gender, and severe current asthma were significantly associated with Eos >2% in COPD subjects. The Eos ≤ 2% COPD group had higher reported rates of previous heart attack and anemia. Among participants with normal lung function, Eos > 2% was associated with being male, being overweight/obese, older age, hay fever, and congestive heart failure.
  
  
  CONCLUSIONS
  In this large US-based cohort, Eos > 2% was prevalent in participants with COPD and normal lung function. Among participants with COPD, Eos > 2% was associated with specific characteristics including lower rates of some co-morbidities; however, the clinical implications and relationships between Eos levels, COPD mechanisms, and risk of outcomes require further evaluation.
authors.affiliation: Worldwide Epidemiology, GSK, 5 Moore Drive, Research Triangle Park, NC 27709, USA.
authors.forename: Rachael L
authors.initials: RL
authors.lastname: DiSantostefano
authors.affiliation: Worldwide Epidemiology, GSK, 1250 South Collegeville Road, Collegeville, PA 19426, USA. Electronic address: David.R.Hinds@gsk.com.
authors.forename: David
authors.initials: D
authors.lastname: Hinds
authors.affiliation: Worldwide Epidemiology, GSK, 5 Moore Drive, Research Triangle Park, NC 27709, USA; PAREXEL International, Research Triangle Park, Durham, NC 27713, USA.
authors.forename: Hoa Van
authors.initials: HV
authors.lastname: Le
authors.affiliation: Respiratory Research & Development, GSK, Stockley Park, Uxbridge, Middlesex, UB11 1BT, UK; William Harvey Institute, Barts and the London School of Medicine and Dentistry, John Vane Building, Charterhouse Square, London, EC1M 6BQ, UK.
authors.forename: Neil C
authors.initials: NC
authors.lastname: Barnes
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001249:Asthma / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology; D016022:Case-Control Studies; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004802:Eosinophilia / Q000453:epidemiology* / Q000276:immunology; D004804:Eosinophils / Q000276:immunology; D005260:Female; D005541:Forced Expiratory Volume; D006333:Heart Failure / Q000453:epidemiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009749:Nutrition Surveys; D009765:Obesity / Q000453:epidemiology*; D050177:Overweight / Q000453:epidemiology; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology*; D012720:Severity of Illness Index; D012737:Sex Factors; D014481:United States / Q000453:epidemiology
keywords: Biomarkers; Chronic obstructive pulmonary disease; Eosinophils; NHANES