Abstract
Background. The cost-effectiveness threshold represents the maximum monetary amount per health outcome considered acceptable for adopting a new intervention or technology. It serves as a straightforward decision-making tool to determine cost-effective interventions. Different jurisdictions apply this tool to optimize monetary investments to provide patients with additional quality-adjusted life years (QALYs). The willingness-to-pay approach-used in this study to project the monetary worth of a QALY- is one way to derive this cost-effectiveness threshold.
Methods. This cross-sectional study, conducted in 2019, was tailored to Iran’s socioeconomic context. It comprised a survey in Tabriz, a metropolitan city, with a sample size of 304 participants without any particular disorders. The study employed the contingent valuation method and the willingness-to-pay approach. The data were acquired by interviews, and a researcher-designed questionnaire. Data analysis was conducted using Excel 2010 and STATA 16 software, employing the Weibull regression model.
Results. The results revealed that the median willingness to pay among Tabriz citizens in 2019 for one QALY was 715,001,033 rials. This figure is 1.05 times Iran's 2017 per capita GDP, less than the upper limit of the World Health Organization (WHO)'s recommended cost-effectiveness level. Key factors in the study were household income, level of education, and number of children. Other variables, such as gender, employment status, age, and marital status, did not significantly impact the willingness to pay.
Conclusion. Based on the results of this study, the threshold obtained is lower than that proposed by the WHO. Our findings align with those of other studies and can serve as crucial input for economic evaluation studies.
Extended Abstract
Background
A cost-effectiveness analysis, a type of economic evaluation, compares the cost and effectiveness of different interventions to achieve desirable health outcomes. To determine the cost per unit of effectiveness, a specific cost-effectiveness threshold must be established to make efficient decisions about adopting or rejecting a particular intervention or program.
The cost-effectiveness threshold represents the maximum monetary value per health outcome that justifies adopting a new intervention or technology. It is a simple decision-making tool for identifying cost-effective interventions. Countries use this tool to optimize the monetary investment required to provide patients with an additional QALY. One way to derive this cost-effectiveness threshold is the willingness-to-pay approach. This study aimed to estimate the monetary value of a QALY using this technique.
Methods
This cross-sectional study was conducted in the metropolis of Tabriz, and data were collected from various health centers. Among Tabriz's 11 health centers, several were chosen randomly, and people attending these centers for medical treatment were interviewed. The required sample size, calculated at a 95% confidence level with a standard deviation for the pilot study and a given error level of 7%, was determined to be 304 participants. The participants’ age range was between 17 and 64. Data was collected using a questionnaire and face-to-face interviews based on the contingent valuation technique. The questionnaire consisted of three sections. The first part was demographic information such as age, education level, marital status, employment status, income, and the number of children in the household.
In the second part of the questionnaire, respondents' utility was elicited using the time trade-off method and the ping-pong technique. To achieve this goal, two hypothetical scenarios—one representing a severe disease condition and the other a mild disease condition—were presented to the respondents. They were asked to imagine themselves in these hypothetical health situations. Severe and mild disease conditions were designed based on EQ-5D questionnaire states and are listed in Appendix 1.
In the third part of the questionnaire, a hypothetical disease scenario and a payment card were presented to the respondents (payment card values were adjusted based on Iran’s GDP per capita in 2017). The respondents' maximum willingness to pay was measured using the contingent valuation and bidding game techniques. Data for this research were collected through interviews, and a researcher-designed questionnaire. The Weibull regression model was implemented to determine significant variables that influence respondents' willingness to pay, and data analysis was performed using Excel 2010 and STATA 16 software.
Results
The descriptive analysis of the research yielded the following results: The youngest respondent was 17 years old, and the oldest was 64. The average age of the respondents was 36.32 years. The age group with the highest frequency was 21 to 40 years.
The results showed that 58.88% of the respondents had an education level below a diploma, while the smallest percentage (1.4%) were illiterate.
Most respondents were unemployed. Regarding income, the highest percentage of respondents fell within the income range of 2,000,000 to 3,500,000 rials. Most respondents had two children (34.21%), and 0.65% had five children.
Most of the respondents were women (68.42%). In the analytical statistics section, the utility of willingness to pay to transition from a severe to a mild health condition was calculated as 0.746-0.262=0.484. Since the willingness-to-pay data is right-skewed, the mean is not a reliable indicator of the data. We employed the median—which stands for the midpoint value of the data—to guarantee that our reports stayed accurate. The median willingness to pay for the difference between two hypothesized severe and mild disease states is 346,060,500 rials. Therefore, the willingness to pay for one QALY equals 715,001,030 rials.
The Weibull regression model results showed that some variables were statistically significant. The education level was significant at the 5% level and had a positive relationship with willingness to pay. This indicates that individuals with higher education levels have a better understanding of their health, are more aware of their health status, and place greater importance on it, leading to a higher level of willingness to pay.
The monthly income variable, one of the most important and influential factors, was significant at the 5% level. This demonstrates that as people's income increases, so does their willingness to pay.
Additionally, the number of children variable was significant at the 5% level, indicating a tendency for larger families to be willing to pay more.
Conclusion
The study estimated people's willingness to pay per QALY. Seven independent variables were included: age, gender, level of education, marital status, monthly income, and the number of children. The data were analyzed using Weibull regression, which revealed how these variables impact people's willingness to pay.
The cost-effectiveness threshold estimated in this study, using the contingent valuation method and the willingness-to-pay approach, is about 1.05 times Iran’s GDP per capita (lower than the highest threshold suggested by the WHO). The findings of this study indicate that adherence to the current WHO threshold may result in the implementation of technologies or interventions that are not cost-effective, given the estimated threshold for this study. The findings align with previous contingent valuation studies, indicating that the willingness to pay per estimated QALY is lower than the threshold the World Health Organization suggested.
Practical Implications
A context specific cost-effectiveness threshold offers a more accurate reflection of individuals Willingness To Pay for a QALY, compared to a universal cost-effectiveness threshold. These estimations can be valuable in resource allocation and decision making regarding the adoption of health technologies.