Association of elevated fractional exhaled nitric oxide concentration and blood eosinophil count with severe asthma exacerbations

Research output: Contribution to journalArticle

Abstract

Background: Blood eosinophil count (BEC) and fractional exhaled nitric oxide (FeNO) concentration are established biomarkers in asthma, associated particularly with the risk of exacerbations. We evaluated the relationship of BEC and FeNO as complementary and independent biomarkers of severe asthma exacerbations. Methods: This observational study included data from the Optimum Patient Care Research Database. Asthma patients (18-80 years) with valid continuous data for 1 year before FeNO reading, ≥ 1 inhaled corticosteroid prescription, and BEC recorded ≤ 5 years before FeNO reading were separated into cohorts. Categorisation 1 was based on the American Thoracic Society criteria for elevated FeNO concentration (high: ≥ 50 ppb; non-high: < 25 ppb) and BEC (high: ≥ 0.300 × 109 cells/L; non-high: < 0.300 × 109 cells/L). Categorisation 2 (FeNO concentration, high: ≥ 35 ppb; non-high: < 35 ppb) was based on prior research. Reference groups included patients with neither biomarker raised. Results: In categorisation 1, patients with either high FeNO or high BEC (n = 200) had a numerically greater exacerbation rate (unadjusted rate ratio, 1.31 [95% confidence interval: 0.97, 1.76]) compared with patients in the reference group. Combination of high FeNO and high BEC (n = 27) resulted in a significantly greater exacerbation rate (3.67 [1.49, 9.04]). Similarly, for categorisation 2, when both biomarkers were raised (n = 53), a significantly greater exacerbation rate was observed (1.72 [1.00, 2.93]). Conclusion: The combination of high FeNO and high BEC was associated with significantly increased severe exacerbation rates in the year preceding FeNO reading, suggesting that combining FeNO and BEC measurements in primary care may identify asthma patients at risk of exacerbations.

Details

Authors
  • David B. Price
  • Sinthia Bosnic-Anticevich
  • Ian D. Pavord
  • Nicolas Roche
  • David M.G. Halpin
  • Leif Bjermer
  • Omar S. Usmani
  • Guy Brusselle
  • Simon Wan Yau Ming
  • Sarang Rastogi
Organisations
External organisations
  • Observational and Pragmatic Research Institute Pte Ltd
  • University of Aberdeen
  • University of Sydney
  • University of Oxford
  • Paris Descartes University
  • Royal Devon & Exeter Hospital
  • Imperial College London
  • Ghent University Hospital
  • AstraZeneca, UK
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Respiratory Medicine and Allergy

Keywords

  • Asthma, Blood eosinophils, Exhaled airway markers, Nitric oxide
Original languageEnglish
Article number41
Number of pages18
JournalClinical and Translational Allergy
Volume9
Issue number1
Publication statusPublished - 2019 Aug 21
Publication categoryResearch
Peer-reviewedYes