A DISCRETE CHOICE EXPERIMENT (DCE) TO ELICIT PREFERENCES FOR ATTRIBUTES OF A BEDSIDE PHARMACOGENETIC TEST – PILOT TEST RESULTS

Purpose: To pilot test a DCE, developed to elicit preference weights (including a willingness to pay) for attributes of a bedside pharmacogenetic test for the CYP2C19*2 allele. The DCE will inform respondent preferences for sample extraction as well as turnaround time for result to a pharmacogenetic test. The willingness to pay will inform a cost benefit analysis.

Method: An internet-based survey tool was designed to include: initial demographics/patient characteristics, decision board and choice sets. Respondents were provided context by way of a decision board that offered three treatment alternatives for hypothetical acute coronary syndrome patients.  Only 1 of the three treatment options offered a pharmacogenetic test. Respondents who chose the pharmacogenetic option were then provided with 8 choice sets; each choice set presented the respondents with two alternatives. Each alternative was comprised of three attributes each with three levels. Attributes (levels) included: how sample was taken (cheek swab, finger prick or draw blood); turnaround time for results (1 hour, 3 days, 1 week), and cost expressed as an additional annual insurance premium in Canadian dollars (C$)(C$0, C$2, C$5). A full factorial design was implemented. Respondents were asked to choose between two alternatives A. conditional logit regression model, using main effects only, was used to analyze the responses. The survey was disseminated to a convenience sample (n=24) respondents in Ontario (Canada).

Result: 23 individuals provided responses for the analysis. 1 individual completed the survey but chose a treatment option that did not include a pharmacogenetic test. 184 choice sets were completed providing 368 observations.  Estimates (standard errors) are as follows, intercept: 0.947 (0.286) p<0.001 WTP: -0.145 (0.036), p <0.001; turnaround time -0.008 (.002) P < .001); Sample Cheek swab: 0.320 (0.319,p=.315); Sample finger prick -0.034 (0.325, p=.917). Results infer that the sample would be WTP C$2.13 in additional annual insurance premiums for a cheek swab over a blood test and C$3.55 more to have results in one hour rather than 3 days.   

Conclusion: Direction of the coefficients were as expected. Respondents were willing to pay slightly higher insurance premiums for quicker turnaround times for results and for a cheek swab compared to finger prick. The survey will be disseminated to 300 respondents.