Patient preferences for pharmacogenetic screening in depression
A Web-based discrete choice questionnaire was sent to 89 respondents, age 18–65. Four attributes were included: (i) shifts in antidepressant medication before symptom relief, (ii) time with antidepressant medication without symptom relief, (iii) time with antidepressant medication without symptoms but with adverse side-effects, (iv) cost of genetic screening.
We used a switching model with two scenarios, one representing patients’ own treatment history and the other a treatment scenario with genetic screening.
In a main-effects model involving the four attributes all coefficients had the expected sign, indicating that as the number of shifts, price or time without symptom relief, and/or dosage-adjustments increased, the likelihood of choosing the screening test decreased.
Price and number of shifts in medicine were significant. Marginal WTP for 5 percent probability of a reduction of one in antidepressant shifts was DKK2,599 (€350). Patients value reductions in shifts in antidepressants and price when choosing between genetic screening and no screening.
They do not focus on how the reductions are provided, nor do they value the genetic information the test provides irrespective of its effect on outcome. Given, that the test is able to provide a reduction of one shift in the number of antidepressant shifts with a probability of 5 percent, WTP for the test exceeds its cost.