The importance of perspective when eliciting preferences for health – A study of the willingness to pay for hepatitis C treatment

This report present the result of a study of the willingness to pay (WTP) for hepatitis C treatment from different perspectives, including who you pay for (yourself, others, yourself and others) and when you pay (when at risk, when assuming having hepatitis C). The study shows that the WTP varies significantly depending on the perspective used and shows the importance of considering the perspective used when designing and interpreting preference studies.

Background:
The second generation antiviral therapy for individuals with hepatitis C (HCV) has been found to be a cost-effective treatment, but would result in a high budget impact. The Swedish national government made an agreement with the regions to help funding the new treatment, implying a societal perspective where it is relevant to search for the consumer value of treatment. The aim of this study is to estimate the value of HCV treatment by performing a willingness to pay (WTP) study from different perspectives.

Methods:
The study is performed as a web-based survey of a sample from the Swedish general population (n=513), using the contingent valuation (CV) approach. A framework of perspectives was applied with respect to whom to pay for; her-or himself only (personal perspective), others only (social perspective), both her- or himself and others.

Results: 
The personal perspective resulted in the highest WTP estimates while the lowest WTP estimates was found for the social perspective. The WTP per HCV treatment varied between SEK 0.2 million and SEK 38 million. The WTP estimates were similar between the ex post perspective and ex ante perspective. Respondents believing that others would pay less than themselves had a higher WTP in all scenarios except the scenario with the social perspective.

Conclusion: 
This study shows that the value appears to be higher and more valid when individuals are asked to pay for themselves. This value may be driven by a will to secure access to the treatment when others are willing to pay less.

IHE Report 2022:7, IHE: Lund, Sweden