Estimating population-based values for EQ-5D health states in Thailand.

OBJECTIVE: To derive EuroQol five-dimensional (EQ-5D) health states values from the Thai general population. METHODS: Forty-eight trained individuals successfully conducted interviews with a representative sample of 1409 respondents in 2007. A total of 12 sets of health states were used with one set allocated to each respondent. A respondent was requested to assign values for 11 states using the ranking and visual analogue scale methods and 10 states using the time trade-off method. The variables from the three existing models were used in model specifications and the best model was chosen on the basis of the extent of logical inconsistency in the estimated scores, predictive performance, parsimony, and sensitivity to changes in health. RESULTS: Eighty-six health states were valued. The mean age of respondents was 44.6 years old. The highly consistent respondents tend to give higher scores for mild states and lower scores for severe states, compared with those given by the highly inconsistent respondents. The best model used variables from the Dolan 1997 study and estimated from the scores given by the respondents with fewer than 11 inconsistencies. The estimated scores are completely consistent, R(2) is 0.448. The second highest score was 0.766 given to state 11112 and the lowest score was -0.454 for state 33333. CONCLUSION: Values for EQ-5D health states were estimated from the Thai general population. This is the first Thai generic health state value results to be used in evaluating health interventions in Thailand.