Validity and reliability of the Dutch version of the S3-NIV questionnaire to evaluate long-term noninvasive ventilation

Objectives: Noninvasive ventilation (NIV) is an effective treatment for chronic respiratory failure (CRF). Patient-centered outcomes need to be evaluated regularly and the S ³-NIV questionnaire seems an applicable tool. We translated this short, self-administered questionnaire into a Dutch version and tested its construct validity and reliability. Methods: An observational study was conducted, including 127 stable long-term NIV users with CRF or complex sleep related breathing disorders due to different underlying diseases: chronic obstructive pulmonary disease (25%), slowly progressive neuromuscular disorders (35%), rapidly progressive neuromuscular disorders (12%) and ‘other disorders’ (28%) including complex sleep apnea and obesity hypoventilation syndrome. Construct validity and reliability were tested. Results: The Dutch version of the questionnaire was obtained after a translation and back-translation process. Internal consistency of the total score was good (Cronbach’s α coefficient of 0.78) as well as for the ‘respiratory symptoms’ subdomain and the ‘sleep and side effects’ subdomain (Cronbach’s α coefficient of 0.78 and 0.69, respectively). The reproducibility was excellent with an intraclass correlation of 0.89 (95% CI 0.87-0.93). Construct validity was good for the ‘respiratory symptoms’ subdomain. Conclusion: The Dutch S ³-NIV questionnaire is a reliable and valid tool to evaluate symptoms, sleep, and NIV related side effects in long-term NIV users.