RESUMO
STUDY DESIGN: Validation of a translated, culturally adapted questionnaire. OBJECTIVE: To translate and culturally adapt a Polish version of the Oswestry Disability Index (ODI) and to validate its use in Polish patients. SUMMARY OF BACKGROUND DATA: The ODI is among the most popular questionnaires used to evaluate back pain-related disability. To our knowledge no validated Polish version of the index was available at the time our study was initiated. METHODS: The questionnaire was translated and culturally adapted by 2 independent translators and approved by expert committee. Final version was included in the booklet consisting in addition of a previously validated Roland-Morris disability questionnaire, VAS for low back and leg and 3 Likert scale questions (pain medications, pain frequency, disability). It was tested on 169 patients with chronic low back pain, 164 (97%) of them were enrolled, and 84 of 164 (53%) returned the completed retest booklet within 2 to 14 days after the baseline test. There were no differences between the 2 groups in demographic and clinical parameters. Test-retest reliability, internal consistency, and construct validity were investigated. RESULTS: The mean ODI (standard deviation [SD]) was 48.45 (18.94); minimum 2, maximum 94. The Cronbach α for baseline questionnaires (n = 164) was 0.90. Concurrent validity, measured by comparing ODI responses with the results of the Roland-Morris disability questionnaire score was very good (r = 0.607, P < 0.001). The correlation with VAS back was fair (r = 0.37, P < 0.001) and with VAS leg was good (r = 0.56, P < 0.001). The tested ODI had excellent test-retest reliability, the intraclass correlation coefficient was 0.97 and standard error of measurements was 3.54, the resulting minimal detectable changes at the 95% confidence level was 10. CONCLUSION: The results of this study indicate that the Polish version of the ODI is a reliable and valid instrument for the measurement of disability in Polish-speaking patients with lower back pain.