Measuring High-Risk Patients' Preferences for Pharmacogenetic Testing to Reduce Severe Adverse Drug Reaction: A Discrete Choice Experiment

Abstract

Objectives: To investigate patient preferences and willingness to pay (WTP) for a genetic test that can reduce the risk of life-threatening adverse drug reactions (ADRs). We hypothesize that test features (risk of developing the adverse reaction with and without testing, test cost, and treatment cost) and the choice context (physician recommendation and the most common choice made by peer patients) will influence choices.

Methods: A discrete choice experiment was conducted in which 189 patients at high risk for gout were asked to choose between treatment options that varied along key attributes. A latent class logit model was used to analyze the choice data and test the hypotheses.

Results: We identified two classes of patients: the risk-averse class and the cost-conscious class. The WTP to reduce the risk of life-threatening ADRs from 1 out of 600 to 1 out of 1 million was SGD1215 in the risk-averse class. In contrast, in the cost-conscious class, the WTP was insensitive to the extent of risk reduction. Overall, the predicted take-up rate for the test is 65% at a price of SGD400. If the test was recommended by a physician or was chosen by most of the patients, the take-up rate for the test would increase by 8.5 and 1.5 percentage points, respectively.

Conclusions: There is a potentially large demand for genetic tests that could reduce the risk of life-threatening ADRs. Physician recommendations and providing information on the choices of others are powerful influences on demand, even more so than moderate price reductions.

Keywords: discrete choice experiment; patients’ preferences; pharmacogenetics; willingness to pay.