Translation and validation of the German version of the Bournemouth questionnaire for low back pain

BACKGROUND: Finding the best outcome measures for research and quality assurance purposes in terms of validity, sensitivity to change, length and ease of completion is crucial. The Bournemouth questionnaire for neck pain patients was recently translated and validated into German and found to be more sensitive to change than other commonly used questionnaires. However, the low back pain version is not yet available in German. Therefore the purpose of this study was to translate and validate the Bournemouth Questionnaire (BQ) for low back pain (LBP) into German. METHODS: The translation was done in 4 steps, translated and back-translated by two independent people and adapted and approved by an expert committee. Face validity was then done by 30 people who checked the questionnaire for comprehension. Test-retest reliability (reproducibility) was tested using 30 stable back pain patients. Internal consistency was tested using 108 low back patients. External construct validity, external longitudinal validity and responsiveness was tested against the German versions of the Oswestry Disability Index (ODI) and the SF-36 questionnaire using 108 patients from 5 different chiropractic clinics. RESULTS: The BQ showed high test-retest reliability (ICC > 0.91) for all items and strong internal consistency (Cronbachs alpha = 0.86 at baseline and 0.94 at 4 weeks). The BQ demonstrated good external construct and longitudinal construct validity with established measures. The effect sizes of the BQ were high and comparable with established measures. External construct validity and external longitudinal construct validity showed significant correlation for all 7 scales of the BQ with the relevant scales of the other questionnaires with one exception. External responsiveness results showed higher effect sizes for the BQ items and total score indicating better sensitivity to change than the compared measures. CONCLUSION: The BQ for LBP was successfully translated and adapted into German. It was successfully tested for validity, consistency, and responsiveness against the German versions of the ODI and the SF-36. It is shorter, covers more domains than the ODI and is more sensitive to change than the other questionnaires.