Purpose: Patients with advanced-stage COPD often experience severe hypoxemia. Treatment with long-term oxygen therapy (LTOT) may relieve patients' symptoms and increase survival. As COPD is incurable, improving patients' health-related quality of life is important. The Chinese version of the Severe Respiratory Insufficiency Questionnaire (SRI) is valid for patients with hypercapnic COPD undergoing noninvasive positive airway pressure ventilation at home. However, the reliability and validity of the Chinese SRI for patients with COPD undergoing LTOT have not been investigated.
Patients and methods: We analyzed reliability using Cronbach's α coefficient. Construct validity was assessed with principal, exploratory, and confirmatory factor analysis. Concurrent validity was evaluated through the correlation between SRI domains and Chronic Respiratory Disease Questionnaire (CRQ) domains. Content validity was assessed by calculating the correlation between each SRI item score and the total score for the relevant domain.
Results: In total, 161 patients participated in this study. The Cronbach's α coefficient for all SRI domains was >0.7, except for the attendant symptoms and sleep domain. Exploratory and confirmatory factor analysis showed a good model fit for each domain, but the factors extracted from each domain were correlated. SRI and CRQ domains correlated well with respect to similar aspects of health-related quality of life, indicating good concurrent validity. Content validity was indirectly shown by a good correlation between each item score and the total score of the relevant domain.
Conclusion: The Chinese version of the SRI has a good reliability and validity for patients with COPD undergoing LTOT in China.
Keywords: chronic obstructive pulmonary disease; health-related quality of life; long-term oxygen therapy; severe respiratory insufficiency questionnaire.