Benefit of daily FeNO measurement in asthmatics over 12 weeks: adherence, handling and overall satisfaction in the FeNO@home observational study.

<bold>Rationale:</bold> FeNO has diagnostic/prognostic value and improves therapeutic monitoring in asthma. Home-based, daily FeNO over longer periods may be more reflective of inflammation versus single-point, cross-sectional data. <bold>Objectives:</bold> To study feasibility and clinical benefits of the "Vivatmo me" FeNO device after 12 weeks daily domiciliary measurements. <bold>Methods:</bold> This multinational, 12-week observational study measured device adherence/handling, global satisfaction, and variability of daily FeNO in relation to other outcomes in asthma patients of different severities and background medications. FeNO, PEF, and asthma symptoms were collected daily by patients, spirometry and ACQ was performed at clinic visits (enrollment and after 12 weeks). <bold>Results:</bold> We enrolled n=85 asthmatics of different control levels (median age 48 yrs, 42% males), 23 GINA Step 1 (mean ACQ 0.6±0.6, FEV1% pred. 91), 37 Step 2-3 (ACQ 1.1±1.2; FEV1 90%), and 25 Step 4-5 (ACQ 2.1±0.9, FEV1 82%); 71% were on ICS background medication. Overall, FeNO adherence was excellent, with 71% subjects covering >80% of measurement days. Device handling by patients was excellent (95% rating “neutral/somehow easy” or “easy/very easy”). Key physicians’ expectations towards daily FeNO were primarily “therapy optimization”, “therapy control” and “self-management”. At week 12, physicians’ expectations were “neutral/somehow met” in 13% and “met/fully met” in 87% of cases. <bold>Conclusions:</bold> Daily FeNO measurements with a home-based device ("Vivatmo me") are feasible, and adherence rates over 12 weeks were high. Physicians’ ratings underline the potential of daily FeNO over extended periods to support long-term asthma management.