RESUMEN
The aim of this study was to estimate the monetary value of a QALY among patients with heart disease and to identify its determinants. A cross-sectional survey was conducted through face-to-face interview on 196 patients with cardiovascular disease from two heart hospitals in Tehran, Iran, to estimate the value of QALY using disaggregated and aggregated approaches. The EuroQol-5 Dimension (EQ-5D) questionnaire, Visual Analogue Scale (VAS), Time Trade-Off (TTO) and contingent valuation WTP techniques were employed, first to elicit patients' preferences and then, to estimate WTP for QALY. The association of patients' characteristics with WTP for QALY, was assessed through Heckman selection model. The Mean willingness to pay per QALY, estimated by the disaggregated approach ranged from 2,799 to 3599 US dollars. It is higher than the values, estimated from aggregated methods (USD 2,256 to 3,137). However, in both approaches, the values were less than one Gross Domestic Product (GDP) per capita of Iran. Significant variables were: Current health state, education, age, marital status, number of comorbidities, and household's cost group. Our results challenge two major issues: the first, is a policy challenge which concerns the WHO recommendation to use less than 3 GDP per capita as a cost-effectiveness threshold value. The second, is an analytical challenge related to patients with zero QALY gain. More scrutiny is suggested on the issue of how patients with full health state valuation should be dealt with and what arbitrary value could be included in the estimation value of QALY when the disaggregated approach used.