Costs of rheumatoid arthritis: new estimates from the human capital method and comparison to the willingness-to-pay method.

BACKGROUND: Individuals' valuation of changes in health states in monetary terms have been measured by examining changes in the direct and indirect costs of disease and by the willingness-to-pay (WTP) methodology. METHODS: In 2002, a 2-part study was conducted in Quebec. In one part of the study, 121 rheumatoid arthritis (RA) patients from the McGill University Health Centre were mailed the Stanford Cost Assessment Questionnaire, which enabled the elicitation of direct costs and indirect costs, according to the friction cost and the human capital methods. The other part was a phone survey conducted in a representative sample of the general population and in the same sample of patients, aiming to elicit the societal WTP for a complete cure of RA in the context of 2 different scenarios: a public coverage or private insurance. These estimates were then compared. RESULTS: Estimates of the cost of illness of RA ranged from 11,717 to 28,498 Canadian Dollars (CAD) depending on the method. These estimates are higher than those previously published in Canada from the 1990s, which is partly due to the recent and costly biological therapies and to a change in the measurement of productivity losses. These estimates are somewhat lower than the societal WTP elicited from the WTP survey, that is, 26,717 and 36,817 CAD per RA case, depending on the public or private health insurance context in which the cure would be available. CONCLUSION: Given that neither method is ideal, data from both methods would provide an important sensitivity analysis when monetary estimates of health state changes are required.

Valuing a hypothetical cure for rheumatoid arthritis using the contingent valuation methodology: the patient perspective.

OBJECTIVE: A willingness-to-pay (WTP) survey measures the value of a given intervention in money terms. We examined the WTP of Canadian patients with rheumatoid arthritis (RA) for a hypothetical cure for RA under private and public scenarios. The validity of the survey was explored by studying the association between WTP and variables thought to be associated with WTP and randomly-varied variables of the survey materials. METHODS: A telephone survey was carried out in a sample of 121 patients with RA from 5 rheumatologists affiliated with the McGill University Health Centre. In advance, patients had been sent a 4-page brochure providing a comprehensive description of the disease (including photos or no photos). The hypothetical cure for RA was presented through 2 scenarios: a private insurance implying an annual premium and a public coverage requiring additional income taxes. The survey included questions related to their WTP, socioeconomic status (ability to pay), general health, opinion about the performance of the healthcare system, and their opinion about the difficulty of the survey. For elicitation of WTP, patients were randomized to one of 3 payment cards. Mailed questionnaires concerning RA health status were also completed. A series of univariate comparisons and multivariate ordered logit regressions were carried out to examine the association of WTP and patient and study variables. RESULTS: Patients were willing to pay annually significantly more for the private program (mean 1190 Canadian dollars) than for the public program (mean 502 Canadian dollars). Annual WTP was associated with age, household income, site of care (private program), private health insurance, opinion about the performance of the public healthcare system (public program), and presence of brochure photos. The payment card did not affect WTP for either program. CONCLUSION: The WTP survey was well understood and accepted by the patients with RA. Although measures of RA-specific health status (e.g., Health Assessment Questionnaire) were not found to be associated with WTP, many variables thought to be associated with WTP were found to be related in the expected directions. Since WTP for the private program was higher than that for the public program, our study design did not fully capture altruistic valuations of RA patients. Thus, our estimates represent a lower bound on patients' WTP for an RA cure.