Markers of airway inflammation and airway hyperresponsiveness remain stable in untreated asthmatics over time

Introduction: Airway hyperresponsiveness (AHR) and airway inflammation are important hallmarks of asthma that may be used in asthma monitoring, but may also vary between asthmatics as a potential indication of different clinical asthma phenotypes. The aim of this study was to assess whether two commonly used measures, AHR to mannitol and exhaled NO (eNO), were stable over a period of time in asthma patients who were not treated with steroids. Materials and methods: A total of 54 non-smoking, asthmatics not treated with steroids were enrolled in the study and assessed at baseline and again three to six months later, where spirometry, skin prick test and induced sputum was performed as well as measurements of hyperresponsiveness to mannitol and eNO. Subjects were excluded if they experienced a worsening of their asthma or commenced on steroid treatment. Results: A total of 41 subjects (21 females, mean age; 41 years, 70,70% atopics) completed both visits. Mean FEV1% predicted at baseline was 94,13% (SD 17,71).There was a significant correlation between the degree of AHR, defined by the Response Dose Ratio (RDR:% change/mg mannitol) at visit 1 and visit 2 (LogRDR, r = 0,80, p Conclusion: In asthmatics not treated with steroids, markers of AHR and airway inflammation remains at the same level over a three to six months period of observation, suggesting that these are stable markers of clinical disease.