Introduction: The aims of this study were to cross-culturally adapt and evaluate the validity of the Singaporean Malay and Tamil versions of the EQ-5D. Materials and Methods: The EQ5D was cross-culturally adapted and translated using an iterative process following standard guidelines. Consenting adult Malay- and Tamil-speaking subjects at a primary care facility in Singapore were interviewed using a questionnaire (including the EQ-5D, a single item assessing global health, the SF-8 and sociodemographic questions) in their respective language versions. Known-groups and convergent construct validity of the EQ-5D was investigated by testing 30 a priori hypotheses per language at attribute and overall levels. Results: Complete data were obtained for 94 Malay and 78 Indian patients (median age, 54 years and 51 years, respectively). At the attribute level, all 16 hypotheses were fulfilled with several reaching statistical significance (Malay: 4; Tamil: 5). At the overall level, 42 of 44 hypotheses related to the EQ-5D/ EQ-VAS were fulfilled (Malay: 22; Tamil: 20), with 21 reaching statistical significance (Malay: 9; Tamil: 12). Conclusion: In this study among primary care patients, the Singapore Malay and Tamil EQ-5D demonstrated satisfactory known-groups and convergent validity.
The EQ-5D is a widely used preference-based instrument (available in at least 60 language versions and used in more than 800 published studies to date1 ) that provides both a health profile (for assessing health status) and health utility index for individuals or groups, thus allowing clinical and economic evaluation of medical interventions.2 Each language version of the EQ-5D needs to be cross-culturally adapted and to demonstrate satisfactory psychometric properties before routine use in any given socio-cultural setting.3,4 The purpose of this paper is thus to report on the cross-cultural adaptation and construct validation of Singapore Malay and Tamil language versions of the EQ5D in Singapore, an island state in Southeast Asia, an ethnically and linguistically diverse region with a population of 443 million,5 which is seeing an increasing stream of pharmacoeconomics and outcomes research-related activities.6
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