Cross-cultural adaptation of a German version of the Oswestry Disability Index and evaluation of its measurement properties

Study Design. Psychometric testing of a translated, culturally adapted questionnaire. Objectives. Cross-cultural adaptation of a German version of the Oswestry Disability Index (ODI) and evaluation of its measurement properties. Summary of Background Data. The ODI, one of the most popular questionnaires for chronic low back pain (LBP), has been valid, reliable, and responsive. Recently, a Swiss version of the ODI has been published, but there is no validated version for Germany to date. Methods. The translated and adapted German version of the ODI (ODI-G) was validated in inpatients with chronic LBP during 3 weeks' medical rehabilitation care. The ODI-G was completed at admission, 1 day later, and at discharge. Comparison with both a generic and chronic LBP-specific measure (the SF-36 and Hannover Functional Ability Questionnaire) assessed criterion validity. Results. A very high level of test-retest-reliability was found (r = 0.91). Criterion validity showed high correlations between the ODI-G on 1 side, and the SF-36 and Hannover Functional Ability Questionnaire on the other. Standardized response means showed significant changes when health status improved (1.38) or deteriorated (1.35). Conclusions. The ODI-G is valid, reliable, and responsive. It may be used to measure current state as well as changes in health status, and allows for cross-cultural comparisons. Further research comparing the 2 versions in German language seems to be necessary.