Valuation of Quality Weights for EuroQol 5-Dimensional Health States With the Time Trade-Off Method in the Capital of Iran

Abstract

Background: The EuroQol 5-dimension (EQ-5D) is a standard instrument that is widely used for measuring health-related quality of life and quality-adjusted life years in economic evaluation of healthcare interventions.

Objective: To estimate a preference valuation set for EQ-5D 3-level (3L) health states from the perspective of the general population in the capital of Iran.

Methods: Eight hundred seventy adults aged ≥18 years were interviewed in Tehran (Iran's capital) from July to November 2013. The participants were selected by a stratified random sampling method and were interviewed face-to-face at their usual residence. Forty-two health states were selected and valued from the 243 states derived from the EQ-5D-3L instrument. Each respondent valued 11 health states using the time trade-off method. Generalized least squares regression with random effect was used to predict values for health states.

Results: The analysis was performed for 846 respondents. The final model yielded the best fit for the time trade-off value at the individual level with an overall R² of 0.45 and a mean absolute error of 0.214. The mean values for the 42 health states ranged from 0.934 for state 11121 to -0.142 for state 33333.

Conclusions: This study provided for the first time a value set for calculating quality-adjusted life years from the EQ-5D instrument in Iran. The Iranian EQ-5D-3L value set slightly differs from the value sets of the UK and the United States.

Keywords: EQ-5D-3L; general population; preference-based measures; time trade-off; value set.