BACKGROUND: Fractional exhaled nitric oxide (FENO) is a non invasive method to assess airway inflammation and its levels are associated with worsening of asthma control and exacerbations, while they tend to rapidly reduce when a proper asthma treatment is established. FENO iswidely used in the asthma management, but classically during visits at asthma centers, and therefore not able to give a continous monitoring of airway inflammation.

AIM OF THE STUDY:To collect data about the potential benefits,feasibility/usability and compliance of regular FENO measurements at home for both patients and physicians, and to investigate FENO variability (inter- and intra-individual variation, and variations by period) in patients with asthma.

METHODS: Multicenter observational study in which a total of 120 patients are expected to be enrolled. Patients of 3 different groups will be enrolled: A) 40 patients with GINA 1 step of severity; B) 40 patients with GINA 2 or 3 steps of severity; C) 40 patients with uncontrolled (ACQ >1.5) GINA 4 or 5 steps of severity. All patients will be evaluated for asthma control, spirometry and opinion/expectation about FENO home monitoring, at baseline (V1) and after 12 weeks (V4). After one week (V2) and 6 weeks (V3) from enrollmentpatients will be evaluated for asthma control and exacerbations. Asthma symptoms and medication use will be assessed daily from V1 to V4 by an electronic patient diary. From V1 to V4 patients will be invited to assess daily FENO and PEF by a portable devices.

We expect that home monitoring of FENO will be feasible, well accepted and useful for both patients and physicians, therefore improving asthma management.