Estimating an EQ-5D value set for Malaysia using time trade-off and visual analogue scale methods

OBJECTIVES: To estimate a EQ-5D value set for Malaysia by using time trade-off (TTO) and visual analogue scale (VAS) valuation methods.
METHODS: TTO and VAS valuations were obtained from face-to-face surveys of a convenience sample of patients, caregivers, and health professionals conducted at nine government hospitals in 2004 and 2005. Forty-five EQ-5D questionnaire health states were valued, divided into five sets of 15 health states. Analysis was conducted by using linear additive regression models applying N3 and D1 specifications. Model selection was based on criteria of coefficient properties, statistical significance, and goodness of fit.
RESULTS: One hundred fifty-two respondents were interviewed, yielding 2174 TTO and 2265 VAS valuations. Respondents found TTO valuations to be more difficult than VAS valuations, and there were more inconsistencies in TTO valuations. All the independent variables in the models were statistically significant and consistent with expected signs and magnitude, except for the D1 specification modeled on TTO valuations. The N3 model provided the best fit for the VAS valuation data, with a mean absolute error of 0.032.
CONCLUSION: This study provides a Malaysian EQ-5D questionnaire value set that can be used for cost-utility studies despite survey limitations.
Study site: convenience sampling from three categories of respondents (patients undergoing dialysis, patients’ carers, and dialysis center staff) from public hospitals