The role of Fraction Exhaled Nitric Oxide (FeNO) in asthma management: an Italian consensus statement on clinical and economic aspects

Background: Chronic respiratory diseases cause significant global morbidity and mortality, with asthma being a major contributor. Globally, 461,000 asthma-related deaths and a prevalence of 262 million subjects were estimated in 2019. The objective of this paper is to summarize experts' opinions in the field of asthma to produce evidence on the clinical and economic impact of FeNO test in asthma management, as well as on its standard operational procedures. Methods: The analysis conducted is based on a literature review of the FeNO test's role in asthma, focusing on its clinical and economic impact, strengths and limitations. Insights were gathered through interviews with ten Key Opinion Leaders in asthma management from various Italian regions. Their thoughts were summarized into key-messages and discussed in a joint meeting. A final document consolidating these discussions was outlined and approved by the experts involved. Results: The FeNO test is crucial in the clinical management of asthma, aiding in phenotypic classification and guiding therapeutic decisions, particularly in severe cases. The value of FeNO assessment is supported by extensive literature evidence and recommended by international guidelines. Moreover, published economic analyses highlight the sustainability of the initial investment in FeNO technology thanks to a reduction of short-term medical costs for National Health Services by decreasing hospital admissions, specialist visits, and exacerbations related to asthma management. The test should be conducted at the first visit at the asthma centre and then regularly during follow-ups to monitor therapy adherence, adjust treatments, and predict response to drugs. FeNO testing facilitates early detection of bronchial inflammation, shortening the time for patients to access appropriate therapy. Despite its ease of use, interpreting the results requires specialist oversight due to potential confounding factors. Conclusions: FeNO testing significantly improves asthma management by aiding in phenotyping, therapeutic strategy formulation, and monitoring. It enhances disease control, accelerates patient care, and offers economic benefits by reducing hospital admissions and treatment needs. However, practical and economic barriers can limit its adoption. Standardized test execution and result interpretation by specialists are essential for accurate patient management. The inclusion of FeNO assessment among exempt services for asthma patients would at last promote its equitable access.