title: Biomarkers to identify sputum eosinophilia in different adult asthma phenotypes.
abstract: Several biomarkers have been used to assess sputum eosinophilia in asthma. It has been suggested that the diagnostic accuracy of these biomarkers might differ between asthma phenotypes. We investigated the accuracy of biomarkers in detecting sputum eosinophilia (≥3%) in different adult asthma phenotypes.Levels of eosinophils in blood and sputum, exhaled nitric oxide fraction (FeNO) and total immunoglobulin (Ig)E from 336 adult patients, enrolled in three prospective observational clinical trials and recruited at five pulmonology outpatient departments, were analysed. Areas under the receiver operating characteristics curves (AUC) for detecting sputum eosinophilia were calculated and compared between severe and mild, obese and nonobese, atopic and nonatopic and (ex-)smoking and never-smoking asthma patients.Sputum eosinophilia was present in 116 patients (35%). In the total group the AUC was 0.83 (95% CI 0.78-0.87) for blood eosinophils, 0.82 (0.77-0.87) for FeNO and 0.69 (0.63-0.75) for total IgE. AUCs were similar for blood eosinophils and FeNO between different phenotypes. Total IgE was less accurate in detecting sputum eosinophilia in atopic and obese patients than in nonatopic and nonobese patients.Blood eosinophils and FeNO had comparable diagnostic accuracy (superior to total IgE) in identifying sputum eosinophilia in adult asthma patients, irrespective of asthma phenotype such as severe, nonatopic, obese and smoking-related asthma.
authors.affiliation: Department of Respiratory Medicine, Academic Medical Centre, Amsterdam, the Netherlands g.a.westerhof@amc.nl.
authors.forename: Guus A
authors.initials: GA
authors.lastname: Westerhof
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Daniël A
authors.initials: DA
authors.lastname: Korevaar
authors.affiliation: Department of Respiratory Medicine, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Marijke
authors.initials: M
authors.lastname: Amelink
authors.affiliation: Department of Respiratory Medicine, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Selma B
authors.initials: SB
authors.lastname: de Nijs
authors.affiliation: Department of Respiratory Medicine, Medical Centre Leeuwarden, Leeuwarden, the Netherlands.
authors.forename: Jantina C
authors.initials: JC
authors.lastname: de Groot
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Respiratory Medicine, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Els J
authors.initials: EJ
authors.lastname: Weersink
authors.affiliation: Department of Respiratory Medicine, Medical Centre Leeuwarden, Leeuwarden, the Netherlands.
authors.forename: Anneke
authors.initials: A
authors.lastname: ten Brinke
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Bossuyt
authors.affiliation: Department of Respiratory Medicine, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Elisabeth H
authors.initials: EH
authors.lastname: Bel
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001249:Asthma / Q000175:diagnosis* / Q000235:genetics*; D015415:Biomarkers / Q000032:analysis; D002986:Clinical Trials as Topic; D004804:Eosinophils; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis*; D007958:Leukocyte Count; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009426:Netherlands; D009569:Nitric Oxide / Q000032:analysis*; D010641:Phenotype; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D012720:Severity of Illness Index; D013183:Sputum / Q000166:cytology
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide; D007073:Immunoglobulin E