Validation of the English Severe Respiratory Insufficiency Questionnaire

Assessment of health-related quality of life in patients with respiratory failure on home ventilation requires appropriate and highly specific measurement tools. We attempt to validate the English version of the Severe Respiratory Insufficiency Questionnaire (SRI). Psychometric properties of the SRI in 152 patients established on home ventilation were assessed. Cronbach's alpha ranged between 0.77 and 0.89 for the seven subscales and and was 0.93 for the summary scale. Principal components analysis revealed a one-factor solution for four and two factors for three subscales. Confirmatory factor analysis revealed a two-factor solution for six subscales, but these factors were dependent on each other. One factor was extracted out of the subscales confirming one summary scale accounting for 70% of the total variance. Correlation analysis between scales of the SRI and the Medical Outcome Study 36-item short-form health survey demonstrated highest correlations between comparable subscales. Chronic obstructive pulmonary disease patients had lower summary scale scores than patients with restrictive chest wall diseases, neuromuscular disorders and obesity hypoventilation syndrome. The English SRI has high internal consistency reliability, clearly established construct and concurrent validity, and is capable of differentiating between different diseases. It is now validated for use in research involving patients receiving home ventilation.