Cross-Cultural Adaptation, Reliability and Validity of the Yoruba Version of the Roland Morris Disability Questionnaire.

Study Design. A translation, cross-cultural adaptation, and psychometric analysis.Objective.The aim of this study was to translate, cross-culturally adapt, and validate the Yoruba version of the RMDQ. Summary of Background Data. The Roland-Morris Disability Questionnaire (RMDQ) is a valid outcome tool for low back pain (LBP) in clinical and research settings. There seems to be no valid and reliable version of the RMDQ in the Nigerian languages. Methods. Following the Guillemin criteria, the English version of the RMDQ was forward and back translated. Two Yoruba translated versions of the RMDQ were assessed for clarity, common language usage, and conceptual equivalence. Consequently, a harmonized Yoruba version was produced and was pilot-tested among 20 patients with nonspecific long-term LBP (NSLBP) for cognitive debriefing. The final version of the Yoruba RMDQ was tested for its construct validity and re-retest reliability among 120 and 87 patients with NSLBP, respectively. Results. Pearson product moment correlation coefficient (r) of 0.82 was obtained for reliability of the Yoruba version of the RMDQ. The test-retest reliability of the Yoruba RMDQ yielded Cronbach alpha 0.932, while the intraclass correlation (ICC) ranged between 0.896 and 0.956. The analysis of the global scores of both the English and Yoruba versions of the RMDQ yielded ICC value of between 0.995 (95% confidence interval 0.996-0.997), with the item-by-item Kappa agreement ranging between 0.824 and 1.000. The external validity of RMDQ using Quadruple Visual Analogue Scale was r=-0.596 (P=0.001). The Yoruba version of the RMDQ had no floor/ceiling effects, as no patient achieved either of the maximum or the minimum possible scores. Conclusion. The Yoruba version of the RMDQ has excellent reliability and validity and may be an appropriate outcome tool for clinical and research purposes among Yoruba- speaking patients with LBP.