Reliability and validity of the Yoruba version of the Oswestry disability index.

CONTEXT: Low back pain (LBP) is a major cause of disability, and the Oswestry Disability Index (ODI) is a validated assessment tool for evaluating disability in LBP patients. Cross-cultural adaptation of the ODI is important because not all populations are proficient in English. The Yoruba language is an indigenous language spoken by 40 million people in the Western part of Nigeria and some countries in West Africa and Latin America. Currently, no validated Yoruba version of ODI is available.

AIMS: The aim of the study was to translate, culturally adapt and validate the ODI in Yoruba language for participants with LBP.

SUBJECTS AND METHODS: The ODI was translated into Yoruba, and this translated version was analysed in terms of semantics and linguistics. Then, the Yoruba version was translated back into English and both versions administered to 160 participants with LBP. The internal consistency using Cronbach's alpha coefficient, criterion validity and test-retest reliability were assessed using Spearman's rank correlation with significance set at P< 0.05. The inter-rater reliability was evaluated by two different observers and the intra-rater reliability was determined by the same observer, a week apart.

RESULTS: The internal consistency of the Yoruba ODI with Cronbach's alpha was 0.97, the intrarater reliability yielded an intraclass correlation coefficient of 0.93 and criterion validity assessed using Spearman's rank correlation was r = 0.92 for highest score and 0.63 for lowest score.

CONCLUSION: The Yoruba ODI is a reliable and valid tool for assessing functional disability in LBP patients.