Fractional exhaled nitric oxide (FeNO) suppression with directly observed inhaled corticosteroid therapy: does it make a difference to patient outcomes?

Objectives: Suppression of FeNO following a week of directly observed inhaled corticosteroid (ICS) therapy can provide objective evidence of non-adherence. We report the effect of demonstrating this on long-term clinical outcomes. Methods: Consecutive patients adherent to prescribed therapy based on clinical assessment, with FeNO levels greater than 45 ppb on two occasions and meeting criteria for biological therapy trials, underwent supervised directly observed ICS therapy over 8 days. In this, patients existing ICS/LABA inhalers were changed to once daily fluticasone / vilanterol (Relvar 184/22). Inhaled therapy technique was taught by and taken under direct supervision of a specialist nurse; in person or remotely via Skype. FeNO, spirometry and the Asthma Control Questionnaire -7 (ACQ-7) were recorded on the first and last days. Those identified as non-adherent (≥42% FeNO suppression at day-8) were appropriately educated. Initiation of biological therapy at 6 months or more of follow up is presented. Results: Of 46 (males 23, mean age 49) subjects 19 (males 7, mean age 41) were identified as non-adherent. Of these 19 subjects, 14 did not need to progress to biological therapies. FeNO levels significantly decreased from baseline to day 8 (p Conclusion: Combining once-daily ICS with remote access technology, FeNO suppression is a feasible objective test in routine clinical practice and demonstrating non-adherence may lead to sustained improvement in asthma control.