Validation of the Tswana Versions of the Roland-Morris Disability Questionnaire, Quebec Disability Scale and Waddell Disability Index

Abstract

The use of reliable and valid outcome measures inclinical research as well as clinical practice is very important. Selfreported questionnaires are widely used as outcome measures to assessthe subjective perception of disability caused by low back pain (LBP).The Roland Morris Disability Questionnaire (RMDQ), Quebec DisabilityScale (QDS) and Waddell Disability Index (W DI) have been identifiedas reliable and valid instruments for assessing disability caused by LPBin English speaking patients. The fact that we do not yet have a validatedand published version of the RMDQ, QDS and W DI in a local SouthA frican language was the motivation to undertake this study.  The threequestionnaires were translated, back-translated and tested in a final version for use with Tswana speaking subjects. The questionnaires were tested on one hundred respondents, who metthe inclusion criteria, at five hospitals in Tswana speaking areas. Of the one hundred respondents 31 were retested 24 hours later. The Visual A nalogue Pain Intensity Scale (VA S-Pain) and Disability Rating Index (DRI) were used ascorrelation tools. There was moderate correlation between the RMDQ and the DRI (0.74) and the W DI and the DRI(0.63). The correlation between the QDS and DRI was strong (0.85). The RMDQ, QDS and W DI correlated moderatelywith the VA S-Pain (0.63, 0.68 and 0.74, respectively). The RMDQ, QDS and W DI appeared to be internally consistentscales with Cronbach’s alpha values of 0.92, 0.95 and 0.75, respectively. The RMDQ, QDS and W DI showed excel-lent test-retest reliability with intra-class correlation coefficient values of 0.93, 0.91 and 0.84, respectively. The resultssuggest that the Tswana versions of the RMDQ, QDS and W DI validated in this study are easy to understand, validand reliable instruments for the measurement of functional disability caused by LBP in a Tswana speaking population.Therefore these translated instruments may be useful clinical instruments for collecting standardised data on activitylimitations resulting from LBP in a Tswana speaking population.