Development and validation of a simple tool for the assessment of home noninvasive ventilation: the S-NIV questionnaire.

Patient-centred outcomes are significantly modified by long-term home noninvasive ventilation (NIV), but a short, self-administered, specific tool for routine clinical assessment is lacking. The aim of this study was to develop and validate the S-NIV questionnaire, a short questionnaire to measure respiratory ymptoms, leep quality and NIV-related ide effects.Patients with stable disease who were under long-term home NIV were recruited from three outpatient NIV services. Questionnaire development consisted of a selection of core items for analysis, followed by item reduction, validation and test-retest reliability.338 patients completed a 22-item questionnaire. 11 items were removed because of non-scalability (n=2), redundancy (n=8) and lack of fit (n=1). The final version of the S-NIV questionnaire consisted of 11 items covering two dimensions: "respiratory symptoms" (Cronbach's α=0.84) and "sleep & NIV-related side effects" (Cronbach's α=0.77). Convergent validity was high between the "respiratory symptoms" subscale of the S-NIV questionnaire and the St George's Respiratory Questionnaire (rho= -0.76, p<0.001), and between the "sleep & NIV-related side effects" subscale and the Quebec Sleep Questionnaire (rho=0.51, p<0.001). The S-NIV questionnaire had good test--retest reliability after 4 weeks (intraclass correlation coefficient=0.72).The S-NIV questionnaire is a short, valid and repeatable self-completed tool for the routine clinical assessment of patients undergoing home NIV.