Translation, Cultural Adaptation, and Validation of the Sinhala Version of the Roland-Morris Disability Questionnaire among patients with Chronic Low Back Pain in Sri Lanka

Background: Chronic low back pain (CLBP) is a leading cause of disability worldwide. Impacting the physical-psycho-social well-being, CLBP causes a major socio-economic influence on the individual, family, and the country as a whole. The Roland-Morris Disability Questionnaire (RMDQ) has been translated and widely used globally to measure CLBP-associated disability across multiple domains in the individual, using 24 items. Due to the strong psychometric properties of the questionnaire, the tool can be used to monitor patient outcomes in response to treatment and the progress of the disease. Assessment of disability in native languages proves accurate and guides treatment.
Objectives: The study aimed to translate, culturally adapt, and validate the RMDQ among Sinhala-speaking patients with CLBP in Sri Lanka.
Methods: A descriptive, cross-sectional validation study was conducted at a Sri Lankan tertiary care pain clinic, following consecutive sampling of Sinhala-speaking patients with CLBP lasting for six months or more. CLBP due to trauma, surgery, or malignancy was excluded.  The Sinhala version of the RMDQ was developed through forward-backward translation and three rounds of Delphi techniques. Validity was assessed using Exploratory Factor Analysis (Varimax rotation), and reliability through Cronbach’s alpha.
Results:  Validation study included participants (n=240) aged 18-70 years (mean 55.2; SD±12.0).  The 24-item RMDQ was applied as a whole, without separating into subdivisions, to ensure consistency with the original questionnaire. EFA extracted seven factors that collectively explained 53.23% of the total variance. The first, second, and third factors accounted for a variance of 9.95%, 7.41%, and 5.71%, respectively, with additional factors contributing progressively smaller amounts of eigenvalues above one. The alpha coefficient of 0.818 suggests the relatively high internal consistency.
Conclusion: The Sinhala translated RMDQ (RMDQ-Sinhala) is a reliable and valid instrument for assessing disability in Sinhala-speaking patients with CLBP, suitable for both research and clinical use.