Validation of the telephone version of S3-non-invasive ventilation questionnaire in patients with chronic obstructive pulmonary disease

Aim: This study aimed to validate the telephone administration of the S3-NIV questionnaire, a patient-reported outcome measure assessing the impact of NIV on patients' quality of life, in a Portuguese cohort of patients with chronic obstructive pulmonary disease (COPD) and chronic respiratory failure (CRF) under NIV. Methods: We conducted a prospective observational study with patients with COPD and CRF at a Portuguese tertiary hospital, including participants who completed both paper and telephone versions of the S3-NIV in randomized order within ten days. Results: Internal consistency was good in both telephone and paper versions: S3NIV-total (α=0.78 and 0.74), S3NIV-respiratory symptoms (α=0.78 and 0.74), and S3NIV-sleep and side effects (α=0.68 and 0.62). Moderate to strong convergent validity was found (S3NIV-total – rs=0.75, S3NIV-respiratory symptoms – rs=0.73, S3NIV-sleep and side effects – rs=0.67). Relative reliability was good in all scores: S3NIV-total (ICC 0.74 [95%CI 0.61; 0.83]), S3NIV-respiratory symptoms (ICC 0.74 [95%CI 0.61; 0.83]), and S3NIV-sleep and side effects (ICC 0.65 [95%CI 0.50; 0.77]). Bland-Altman plots demonstrated reasonable agreement, with most differences within acceptable limits and a minor bias. Conclusion: The telephone-administered S3-NIV is a valid, reliable tool for assessing NIV's impact on quality of life in patients with COPD, supporting its use in remote clinical settings.