Validation and cross-cultural adaptation of the Polish version of the Oswestry Disability Index.

ABSTRACT

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.