Personalised exhaled nitric oxygen fraction (<i>F</i>_ENO)-driven asthma management in primary care: a<i>F</i>_ENOsubgroup analysis of the ACCURATE trial

Abstract

Background The aim of this study was to identify patients who benefit most from exhaled nitric oxide fraction ( F ENO )-driven asthma management in primary care, based on prespecified subgroups with different levels of F ENO . Methods We used data from 179 adults with asthma from a 12-month primary care randomised controlled trial with 3-monthly assessments of F ENO , asthma control, medication usage, costs of medication, severe asthma exacerbations and quality of life. In the original study, patients were randomised to either a symptom-driven treatment strategy (controlled asthma (Ca) strategy) or a F ENO +symptom-driven strategy (FCa). In both groups, patients were categorised by their baseline level of F ENO as low (&lt;25 ppb), intermediate (25–50 ppb) and high (&gt;50 ppb). At 12 months, we compared, for each prespecified F ENO subgroup, asthma control, asthma-related quality of life, medication usage, and costs of medication between the Ca and FCa strategy. Results We found a difference between the Ca and FCa strategy for the mean dosage of beclomethasone strategy of 223 µg (95% CI 6–439), p=0.04) and for the total costs of asthma medication a mean reduction of US$159 (95% CI US$33–285), p=0.03) in patients with a low baseline F ENO level. No differences were found for asthma control, severe asthma exacerbations and asthma-related quality of life in patients with a low baseline F ENO level. Furthermore, in patients with intermediate or high level of F ENO , no differences were found. Conclusions In primary care, F ENO -driven asthma management is effective in patients with a low F ENO level, for whom it is possible to down-titrate medication, while preserving asthma control and quality of life.