Monetary value of quality-adjusted life years (QALY) among patients with cardiovascular disease: a willingness to pay study

The aim of this study was to estimate monetary value of a QALY among heart disease patients and to identify its determinants.A cross-sectional survey with face-to-face interview was conducted with 196 cardiovascular disease patients from two heart hospitals in Tehran, Iran, to estimate the value of QALY using disaggregated and aggregated approaches. The Euro Qol -5d (EQ-5D) questionnaire, visual analogue scale (VAS), time trade-off (TTO) and contingent valuation WTP techniques were employed to, first, elicit patients’ preferences and to estimate WTP for QALY. The association of patients’ characteristics with WTP for QALY was assessed using the Heckman selection model. 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 (2,256 to 3,137 USD). 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 on using 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 and with what arbitrary value could be included in the estimation value of QALY when disaggregated approach was used.