Valuing EQ-5D health states for Sri Lanka

The aim of this study was to derive an algorithm to estimate utility values for the EQ-5D-3L health states based on the preferences of a population sample from Sri Lanka.

The time trade-off method was used to directly value 198 EQ-5D-3L health states in a general population sample (n = 780) from Sri Lanka. Stratified cluster sampling with random selection within clusters was used to select the sample from four districts. Each participant valued 15 health states via face-to-face interviews. The best fit model was selected using consistency, parsimony, and goodness of fit. Based on logical inconsistency, numerous sub-samples were also used for model specification. For each model, the numbers of illogical orderings in the resulting value set were also examined.

Generalised least squares with random effects were found to be the best specification. The sub-sample consisting of participants with less than seven logical inconsistent observations produced no illogical ordering in the final value set and is considered the preferred model. Compared to value sets in other countries, a high disutility is associated with level 3 deficits in the mobility dimension. More than 50 % of health states in the Sri Lankan value set are deemed worse than death health states.

Sri Lankan utility values for EQ-5D-3L states deviate markedly from existing values for upper middle and high-income countries. It is important to have country-specific utility values to conduct cost-utility analysis.