F_eNO-based asthma management results in faster improvement of airway hyperresponsiveness

Abstract

Asthma is characterised by inflammation and respiratory symptoms. Current asthma treatment is based on severity of asthma symptoms only. Exhaled nitric oxide fraction (FeNO) is not recommended by the Global Initiative for Asthma guidelines. The aim was to compare the usefulness of a FeNO guided versus symptom-based treatment in achieving improved asthma control assessed by airway hyperresponsiveness (AHR).80 asthmatic patients were included in a double-blinded, parallel, randomised controlled trial with follow-up visits after 8, 24 and 36 weeks. Treatment was tailored using either a FeNO or Asthma Control Questionnaire (ACQ) based algorithm. Inclusion criteria were asthma symptoms and a provocative dose causing a 15% fall in forced expiratory volume in 1 s <635 mg mannitol. At each visit AHR, FeNO, ACQ and blood tests were performed.No differences between the two groups were found at inclusion. AHR from 8 to 24 weeks was improved in the FeNO group compared to the ACQ group (response dose ratio (RDR) geometric mean (95% CI): 0.02 (0.01–0.04) versus 0.05 (0.03–0.07), respectively, p=0.015). AHR to mannitol at 36 weeks showed no differences between the two groups (mean difference RDR (95% CI): −0.02 (−0.05–0.02), p=0.3). Total doses of inhaled steroid and number of exacerbations were similar (p>0.05).When using FeNO as a treatment management tool, lowering of airway responsiveness occurred earlier than using ACQ. However, airway responsiveness and asthma control after 9 months were similar.

Use of Fractional Exhaled Nitric Oxide to Guide the Treatment of Asthma: An Official American Thoracic Society Clinical Practice Guideline

“…The largest effect favoring FE NO -based care was in a trial that enrolled patients with markedly uncontrolled asthma at the onset of the study, with this study reporting a significant difference in the ACQ-7 results when using FE NO -based care; however, the differences in the ACQ-7 scores between the groups were fairly small relative to the marked improvement in asthma control identified in both treatment groups (82). The two other studies did not reveal a difference with FE NO -based care, although asthma control was much better at baseline in one study (83); in the other study, the score on the ACQ-7 was used as part of the algorithm to adjust asthma care (84).…”

“…Three studies evaluated quality of life, but data could not be combined because the studies used slightly different outcome measures. None of the studies showed a significant difference in quality of life with the intervention (83,84,96) (83). No data were identified on the effects on daily activity, exercise, or sports participation.…”

Treatment Response Biomarkers in Asthma and COPD

“…A number of randomized, clinical trials (RCTs) have assessed FeNO as a tool for guiding asthma treatment [ 62 , 63 ]. In an Australian RCT including 220 pregnant, non-smoking asthmatic women, the exacerbation rate was lower in the FeNO-group than in the control group in which the treatment was adjusted according to clinical symptoms, incidence rate ratio 0.47 (0.33–0.76), p = 0.001 [ 62 ].…”

“…In an Australian RCT including 220 pregnant, non-smoking asthmatic women, the exacerbation rate was lower in the FeNO-group than in the control group in which the treatment was adjusted according to clinical symptoms, incidence rate ratio 0.47 (0.33–0.76), p = 0.001 [ 62 ]. A 36-week RCT including 80 asthmatic Danish adults assessed the utility of a FeNO-guided versus symptom-based treatment algorithm [ 63 ]. The decrease in airway hyperresponsiveness (AHR) from week 8 to 24 was significantly different in the FeNO-group compared with the control group, suggesting that the use of FeNO resulted in an earlier lowering of AHR.…”

“…In a more recent double-blind, randomized, placebo-controlled multicentre study, the baseline level of FeNO predicted the response to treatment with extrafine ICS in terms of significant changes in Asthma Control Questionnaire 7 (ACQ-7): for every 10-ppb increase in baseline FeNO, the change in ACQ-7 was greater in the treatment group than in the placebo group (difference between groups 0.071 (0.002-0.139), p = 0.04) [61]. [62,63]. In an Australian RCT including 220 pregnant, nonsmoking asthmatic women, the exacerbation rate was lower in the FeNO-group than in the control group in which the treatment was adjusted according to clinical symptoms, incidence rate ratio 0.47 (0.33-0.76), p = 0.001 [62].…”