ASSESSING THE VALUE OF A NEW PHARMACEUTICAL - A FEASIBILITY STUDY OF CONTINGENT VALUATION IN MANAGED CARE

OBJECTIVES. The authors assessed the feasibility and construct validit y of the contingent valuation method for measuring the monetary value to healthy enrollees in a health maintenance organization of a new dru g, filgrastim, as prophylaxis against febrile neutropenia after chemot herapy treatment for cancer. METHODS. A random sample of 220 enrollees from a closed-panel staff-model health maintenance organization who d id not have cancer were interviewed. Chemotherapy, febrile neutropenia and filgrastim were described by video and decision board. Questions were asked in two different scenarios: (1) User-based: Assuming they w ere at the point of consumption and about to receive chemotherapy, wha t is the maximum they would be willing to pay to receive filgrastim? a nd (2) Insurance-based: Given they were at risk of cancer in the futur e, what is the maximum they would be willing to pay in additional mont hly insurance premiums to add filgrastim to the plan? In a second insu rance scenario where respondents were told that filgrastim was covered , what is the minimum reduction in premium that persons were willing t o accept to relinquish coverage of the drug? A 2 x 2 factorial design was used to contrast two bidding algorithms to test for starting point bias and two 5-yearly prior risks of cancer, 1/200 versus 1/100. Main effects were tested by ANCOVA controlling for age, sex, health, and i ncome. RESULTS. Demographics of experimental cells were similar. No ev idence was found of significant starting point bias. For user-based qu estions, as expected, willingness-to-pay increases with febrile neutro penia risk reduction, but at a declining marginal rate. Despite carefu l presentation of information to respondents, willingness-to-pay for i nsurance was higher in the lower prior risk group. Consistent with pre vious contingent valuation studies, the authors of the present study f ound evidence that willingness-to-accept exceeds willingness-to-pay fo r coverage of the same benefit. CONCLUSIONS. An insurance-based contin gent valuation study is feasible in a health maintenance organization. Construct validation evidence was encouraging, with the exception of the test for prior risk of cancer; however, this was a between-person contrast and may have been confounded by other factors.