Introduction: Although the EQ-5D questionnaire is widely used to measure health status internationally, there is little evidence of its content validity in Asian populations. This qualitative study aimed to explore the content validity of the EQ-5D in Singapore. Materials and Methods: Sixty Singaporeans (Chinese: 20; Malay: 20; Indian: 20) completed semi-structured interviews in which they were asked about health concepts which were important to them and the relevance and comprehensiveness of the EQ-5D descriptive system (DS). Thematic analysis employing open, focused and axial coding was used to identify the themes and subthemes from the interviews. Results: A total of 70 health concepts were identified which fall into the broad categories of ‘physical health’, ‘mental well-being’, ‘social relationships’, ‘medical conditions and treatment’, and ‘health promotion knowledge and behaviours’. The 5 dimensions in the EQ-5D DS were among the health concepts nominated by participants. Some participants suggested that content validity could be improved by adding social relationships, medical conditions and treatment, and health promotion knowledge and behaviours to the EQ-5D DS. Conclusions: This study confirmed that EQ-5D dimensions are important and relevant aspects of health to Asians in Singapore, although some dimensions that could be important to Singaporeans are absent.
EQ-5D is a tool to measure and value health status. It is a standardised questionnaire that comprises 2 components: a Descriptive System (DS) on the first page and a hash-marked visual analogue scale (EQ-VAS) on the second page. Importantly, responses to the DS can be converted into a utility score to indicate the value of the described health state according to the health preferences of the general public in a given country or region. This utility score is widely used to estimate quality-adjusted life years (QALYs) in the economic evaluation of health interventions or programs.
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