Evaluating adherence to Non-Invasive Ventilation (NIV): findings from a validation study among patients with obstructive or restrictive respiratory conditions

<bold>Background:</bold> The current state-of-the-art in Non-Invasive Ventilation (NIV) focuses on identifying predictors of NIV failure, yet modest attention has been given to NIV adherence, which is crucial for successful outcomes, highlighting the need for standardized instruments to assess adherence and close monitoring to prevent delays in intubation. <bold>Aims:</bold> The main aim of this study was to validate the Belief about Ventilation Questionnaire (BVQ), developed to screen for potential adherence to NIV and the related beliefs. <bold>Methods:</bold> The themes that emerged from the qualitative interviews with respiratory disease patients' statements, supplemented with scientific literature and clinical experience, were used to develop the content of the questionnaire. After completing a pilot phase, the questionnaire was distributed to 399 individuals (mean age=69.7; SD=13.1) diagnosed with obstructive or restrictive respiratory diseases and recruited at IRCCS Fondazione Don Carlo Gnocchi, in Milan (Italy). Structured equation models and factor analysis were used to analyse the data that were gathered. <bold>Results:</bold> The Confirmatory Factor Analysis (CFA) demostrated good convergent validity, and acceptable test-retest reliability. Internal consistency, as measured by Cronbach’s alpha, exceeded the threshold of 0.725, indicating good reliability. Model fits were ascertained using two fit indexes such as Root Mean Square Error of Approximation (RMSEA) and Comparative Fix Index (CFI). <bold>Conclusions:</bold> The BVQ can represent a valuable tool to assess beliefs and adherence to NIV. It is expected to be validated also in English, French, Spanish and German.