Willingness to pay for angiotensin-converting enzyme inhibitors as self-medication for primary prevention of stroke in Japan

Background : Lifestyle-related diseases are increasing in Japan, and the national medical expenditure is increasing. Converting prescription drugs to over-the-ounter (OTC) drugs would appear to be one solution to cut expenditure. The willingness to pay (WTP) of the Japanese public for OTC imidapril, an angiotensin-converting enzyme (ACE) inhibitor, as a healthcare-related item has not been evaluated. Objective : To measure the value of OTC imidapril as a health care-related item by investigating the public's WTP as self-medication for primary prevention of stroke, assuming that ACE inhibitors are switched from prescription-only to OTC status. Methods : A questionnaire was distributed among healthy individuals engaged in various jobs in office buildings (including a clinic) in Tokyo and Fukuoka, Japan. For the WTP question format, the double-bound dichotomous choice approach was employed. Participants were randomly assigned to 3 groups. Group A was provided with a starting price per month of ¥6,000, group B with ¥8,000, and group C with ¥10,000. Weibull regression analysis was used to investigate factors affecting WTP. Results : The questionnaire survey was completed correctly by 311 individuals (156 men, mean age 50 years), and the mean WTP was ¥7,237 per month. Weibull regression analysis showed that gender significantly affected WTP. The bid acceptance rates differed among the age groups of 20-39 years, 40-64 years, and 65 years. Conclusion : The public's WTP amount was approximately ¥7,000 per month, and the WTP based on the questionnaire responses was about 20% lower than the present cost for physician visits.