Validation of the Japanese Severe Respiratory Insufficiency Questionnaire in hypercapnic patients with noninvasive ventilation.
OBJECTIVE Home mechanical ventilation is used with patients with severe, chronic respiratory failure, a condition that has a serious impact on quality of life. The aim of this study was to produce a translation and cultural adaptation of the Severe Respiratory Insufficiency. Questionnaire for the Spanish population, the first health-related quality of life questionnaire specifically designed for patients receiving home mechanical ventilation. METHODS Four bilingual German-Spanish translators were used to translate and back-translate the questionnaire. Meetings were held with the translators following each step of the translation process to produce a single version that could be used in the next step. At the end of the process, the questionnaire was piloted to assess its comprehensibility. A scoring system using a scale of 1 (lowest) to 10 (highest) was used to rate both translation difficulty and the naturalness of the language produced. The equivalence of the original and translated items was also evaluated. RESULTS Three Spanish versions of the questionnaire were produced. Task difficulty was rated as quite low: the mean (SD) ratings were 1.4 (0.6) for translation and 2.2 (1.1) for back translation. The naturalness of the translated items was rated as very high, with scores improving with the successive versions (version 1, 8.4; version 2, 8.7; version 3, 9.1; P< .001). Thirty of the questionnaire items (61.2%) were judged to be fully equivalent, 13 (26.5%) to be similar, and 6 (12.2%) to be non-equivalent. The meaning conveyed by 5 of the items was changed or clarified during piloting. CONCLUSIONS The translation of the questionnaire using the translation-back-translation procedure has produced a version that is both comparable to the original and accessible to the Spanish population. Its validity is currently being tested in a multicenter study.