Long-term adjustment of stable asthma treatment with fractional exhaled nitric oxide and sputum eosinophils

Current approaches to control asthma do not involve direct assessment of airway inflammation. The aim of this study is to assess whether the therapeutic adjustments of steroid treatment according to a stepwise algorithm based on sputum Eosinophils (sEos) and fractioned exhaled Nitric Oxide (FeNO) were effective in maintaining the stability of a group of stable asthmatic patients during a twelve-month follow-up. Fourteen asthmatic patients, treated for asthma according to a previously published protocol, were enrolled in the study. The patients underwent clinical evaluation, pulmonary function tests, measuring of airway hyperresponsiveness to methacholine, and determination of FeNO and sEos at visit 1. These procedures were repeated after 6 and 12 months (Visits 2 and 3, respectively). Symptoms score gradually improved during the study (p=0.008), no changes were observed in the frequency of clinical asthma exacerbations or in airway hyperresponsiveness to methacholine. At the end of the study both sEos and FeNO were significantly improved (p=0.011 and p=0.003, respectively) and at visit 3 the median steroid dose was reduced (p=0.039) in accordance with the improving of symptoms score, FeNO and sEos values. A direct relationship was observed between the difference of FeNO values and the difference of sEos registered between visits 1 and 2 (r²=609, p<0.001) and between visits 2 and 3 (r²=646, p<0.001). In conclusion, long-term titration of asthma inhaled steroid treatment based on sEos and FeNO values was able to provide long-term clinical stability and improvement to the asthmatic patients studied, without significant increases in the steroid dose.