Cross-cultural Adaptation and Validation of the Hausa Version of the Oswestry Disability Index 2.1a for Patients With Low Back Pain Aisha S. Adamu, PT, BPT, Aminu A. Ibrahim, PT, MPT, Rufa’i Y. Ahmad, PT, PhD, Mukadas O. Akindele, PT, PhD, Bashir Kaka, PT, PhD, and Naziru B. Mukhtar, PT, MSc Study Design. Validation of a translated, culturally adapted questionnaire. Objective. To translate the Oswestry Disability Index (ODI) version 2.1a into Hausa Language and to validate its use in a cohort of patients with low back pain (LBP). Summary of Background Data. The ODI is one of the most commonly used condition-specific questionnaires for assessing functional disability in patients with LBP, yet, no formal cross- culturally adapted and validated Hausa version exists. Methods. The Hausa version of the ODI 2.1a (ODI-H) was developed according to established guidelines. Validation was performed among 200 patients with LBP recruited from both rural and urban Nigeria. Reliability was assessed using internal consistency (Cronbach a), test–retest reliability by computing intraclass correlation coefficient, standard error of measurement, and minimal detectable change. Convergent validity was assessed by correlating the ODI-H with Visual Analogue Scale for pain, Fear-Avoidance Beliefs Questionnaire, and finger-floor distance test. Divergent validity was assessed by correlating the ODI-H with age, educational level, and occupational status. Exploratory factor analysis (EFA) and confirmatory factor analysis were also performed. Confirmatory factor analysis was per- formed with three models: 1) one-factor theory-driven model, 2) two-factor theory-driven model (dynamic and static factors), and 3) a model based on our EFA. Results. The ODI-H had high internal consistency (Cronbach a ¼ 0.87) and excellent test–retest reliability (intraclass correla- tion coefficient ¼ 0.937) with standard error of measurement and minimal detectable change being 3.69 and 10.2 respec- tively. The construct validity (convergent and divergent validity) is supported as all (6:6, 100%) the a priori hypotheses were confirmed. The EFA yielded a two-factor model explaining 54.3% of the total variance but demonstrated poor fit. The one- factor and two-factor theory-driven model had acceptable fit but the one-factor theory-driven model was better. Conclusion. The ODI-H version 2.1a was transculturally equiv- alent, reliable, and valid tool for assessing functional disability among Hausa-speaking patients with LBP. The use of this tool can be recommended for future clinical and research purposes. Key words: cross-cultural adaptation, functional disability, Hausa, low back pain, Oswestry disability index, reliability, validity. Level of Evidence: 3 Spine 2019;44:E1092–E1102 L ow back pain (LBP) is a common and costly muscu- loskeletal condition affecting many people at some time in their lifetimes. It is the leading cause of years lived with disability in both high and low-income countries, and causes substantial socioeconomic burden. 1,2 In Nigeria, the annual prevalence of LBP was estimated to be 33% to 74%, 3 which is disproportionally higher than the 20% to 56% estimated for Western societies. 2 This indicates that the occurrence of LBP among Nigerians is on the increase and affected individuals are likely to experience high levels of LBP-related disability. In view of the negative impact of LBP especially in its chronic state on functioning in both daily living and work, the assessment of limitation in functional status (disability) is crucial in LBP research and routine clinical practice. This would necessitate the use of valid and reliable patient self- report measures of disability. There is no ‘‘gold standard’’ to assess disability in LBP, 4 but the Oswestry Disability Index (ODI) is one of the most commonly used condition-specific From the Department of Physiotherapy, Faculty of Allied Health Sciences, College of Health Sciences, Bayero University Kano, Kano State, Nigeria. Acknowledgment date: October 11, 2018. First revision date: December 8, 2018. Second revision date: March 7, 2019. Acceptance date: March 25, 2019. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No relevant financial activities outside the submitted work. Address correspondence and reprint requests to Aminu A. Ibrahim, PT, MPT, Department of Physiotherapy, Faculty of Allied Health Sciences, College of Health Sciences, Bayero University Kano, P.M. B 3011, Kano State, Nigeria; E-mail: amenconafs@gmail.com DOI: 10.1097/BRS.0000000000003068 E1092 www.spinejournal.com September 2019 SPINE Volume 44, Number 18, pp E1092–E1102 ß 2019 Wolters Kluwer Health, Inc. All rights reserved. HEALTH SERVICES RESEARCH Copyright © 2019 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.