Urdu Version of Oswestry Disability Index; A Reliability and Validity Study

Abstract Background:Although Oswestry Disability Index (ODI) is broadly used in clinical and research settings for assessing the disability level in patients with lumbar radiculopathy but it has not been translated into Urdu language according to the pre-established translation guidelines as well as the validity and reliability of ODI Urdu version has not been tested yet. The aim of this study was to translate ODI in native Urdu language (ODI-U) according to recommended guidelines and to measure its psychometric properties in Urdu speaking patients suffering from lumber radiculopathy. Methods: The ODI-U was developed through previously described translation procedures. 108 participants were recruited, out of which 54 were healthy and 54 were patients of lumber radiculopathy. ODI-U was filled by all participants. However, the patients were administered through ODI-U and visual analogue scales for disability (VAS disability) and pain intensity (VAS pain) at baseline and after 3 days. Reliability was investigated through test-retest method, internal consistency, standard error of measurement (SEM) and smallest detectable change (SDC) at 95% confidence level. ODI-U was assessed for exploratory factor analysis, construct (convergent and discriminative) validity and content validity. Alpha level <0.05 was considered statistically significant and psychometric standards were evaluated contrary to priori hypothesis.Results: The culturally adapted ODI-U revealed excellent test-retest reliability for total score (ICC=0.95) and for all item (ICC=0.72-0.98). Cronbach’s alpha of 0.89 showed excellent internal consistency and a moderate correlation between ODI-U total score and each item was observed through spearman’s correlation coefficient (r=0.51 to 0.76). One factor structure was created for ODI-U explaining 52.5% variance. There was no floor and ceiling effect of total ODI-U score showing good content validity. The discriminative validity was assessed by independent sample t-test which indicated significant difference in ODI-U total score between healthy and patients (P<0.001). The convergent validity was evaluated through Pearson’s correlation showing moderate correlation between ODI-U and VAS pain (r=0.49) as well as VAS disability (r=0.51).Conclusion: ODI-U showed adequate psychometric properties. ODI-U was found to be a reliable and a valid tool to measure the level of disability in Urdu-speaking patients with lumber radiculopathy.