What Drives Responses to Willingness-to-pay Questions? A Methodological Inquiry in the Context of Hypertension Self-management

Background: The use of economic evaluation to determine the cost-effectiveness of health interventions is recommended by decision-making bodies internationally. Understanding factors that explain variations in costs and benefits is important for policy makers. Objective: This work aimed to test a priori hypotheses defining the relationship between benefits of using self-management equipment (measured using the willingness-to-pay (WTP) approach) and a number of demographic and other patient factors. Methods: Data for this study were collected as part of the first major randomised controlled trial of self-monitoring combined with self-titration in hypertension (TASMINH2). A contingent valuation framework was used with patients asked to indicate how much they were willing to pay for equipment used for self-managing hypertension. Descriptive statistics, simple statistical tests of differences and multivariate regression were used to test six a priori hypotheses. Results: Data for this study were collected as part of the first major randomised controlled trial of self-monitoring combined with self-titration in hypertension (TASMINH2). A contingent valuation framework was used with patients asked to indicate how much they were willing to pay for equipment used for self-managing hypertension. Descriptive statistics, simple statistical tests of differences and multivariate regression were used to test six a priori hypotheses. Conclusion: The majority of hypertensive patients who had taken part in a self-management study were prepared to purchase the self-monitoring equipment using their own funds, more so for men, those with higher incomes and those with greater satisfaction. Further research based on bigger and more diverse populations is recommended.