A time-tradeoff method for cost-effectiveness models applied to radiology

Purpose. The wait tradeoff (WTO) is a simple time-tradeoff method designed for temporary health states that uses a realistic and intuitive interface f or the patient/subject. This method was tested by assessing patients' prefe rences for magnetic resonance angiography (MRA) versus x-ray angiography (X RA). Materials and methods. The WTO was tested by telephone interview in 38 patients with atherosclerotic peripheral vascular disease, all having prev iously undergone both MRA and XRA. At indifference point, patients were amb ivalent about having MRA or XRA and immediate treatment, versus having a wa iting period for test results and treatment after a hypothetical "ideal tes t" that entailed no pain or risk. Results. The patients were willing to wai t a mean of 42.1 days after the ideal test for results and treatment, as op posed to XRA. They were willing to wait only 16.1 days as opposed to MRA. T his difference in waiting times was significant (p = 0.0001) and indicates a clear preference for MRA, in agreement with known literature. Conclusion. The WTO method assesses preferences for these radiologic tests in an intui tive fashion that does not invoke artificial or irrelevant health states. T his approach may also prove useful for other testing situations or short-te rm treatments being evaluated for cost-effectiveness.