Does pharmacogenetic testing for CYP450 2D6 and 2C19 among patients with diagnoses within the schizophrenic spectrum reduce treatment costs?

The effect of pharmacogenetic testing for CYP450 2D6 and 2C19 on treatment costs have not yet been documented. This study used Danish patient registers to calculate healthcare costs of treating patients with diagnoses within the schizophrenic spectrum for 1 year with or without pharmacogenetic testing for polymorphisms in the genes for the CYP2D6 and CYP2C19 enzymes. In a randomized, controlled trial, stratified with respect to metabolizer genotype, 104 patients were assigned to treatment based on pharmacogenetic testing and 103 patients to treatment as usual. Random exclusion of extensive and intermediate metabolizers was used to increase the frequency of extreme metabolizers (poor metabolizers and ultrarapid metabolizers for CYP2D6) to 20% in both groups. Cost differences were analysed at several levels including (i) overall healthcare expenditure, (ii) psychiatric hospital cost (iii) nonpsychiatric hospital cost, (iv) primary care spending and (v) pharmaceuticals. Statistically significant differences in costs of psychiatric care dependent on metabolizer status were found between intervention groups. Pharmacogenetic testing significantly reduced costs among the extreme metabolizers (poor metabolizers and ultrarapid metabolizers) to 28%. Use of primary care services and pharmaceuticals was also affected by the intervention.This study confirms earlier findings that extreme metabolizers (poor and ultrarapid metabolizers) incur higher costs than similar patients with a normal metabolizer genotype. However, this study shows that these excess costs can be reduced by pharmacogenetic testing. Pharmacogenetic testing for CYP2D6 and CYP2C19 could thus be considered as a means of curtailing high psychiatric treatment costs among extreme metabolizers.

Do guidelines recommending pharmacogenetic testing of psychiatric patients affect treatment costs and the use of healthcare services?

AIM: To identify the effects of local recommendations of pharmacogenetic testing in psychiatry with respect to treatment costs. METHODS: Based on Danish patient registers, individual treatment costs within a 365-day period at three psychiatric hospitals recommending and using pharmacogenetic testing is compared retrospectively with treatment costs at other Danish psychiatric hospitals using alternate treatment strategies. Primary outcome of interest is total direct costs analyzed by multilevel modelling. Secondary outcome measures are healthcare consumption within specific sectors analyzed by Tobitregressions. RESULTS: Costs among patients treated at hospitals recommending and using pharmacogenetic testing were not found to be statistically significantly different from costs among patients treated at sites using alternate treatment strategies. In spite of recommendations to test all patients the uptake of the test was, however, low (26-31 %). Treatment practice using routine therapeutic drug monitoring (in Ãrhus) shows a trend towards lower costs. CONCLUSIONS: Based on this natural experiment we were not able to document statistically significant differences in total costs between treatment sites that had guidelines recommending pharmacogenetic testing, relative to sites without such guidelines, over a period of one year. However, guidelines of pharmacogenetic testing and possibly also therapeutic drug monitoring seem to lead to reductions in costs for primary care services. In the case of the former, reductions do, however, seem to be outweighed by increases in costs for psychiatric and non-psychiatric inpatient stays. In conclusion, no statistically significant differences in total direct costs across sites with different treatment strategies were found.

Estimating the Danish populations' preferences for pharmacogenetic testing using a discrete choice experiment. The case of treating depression.

OBJECTIVE: The objective is to estimate willingness-to-pay (WTP) for pharmacogenetic testing in the treatment of depression. METHODS: In a web-based discrete choice questionnaire, four attributes were included: 1) number of changes in antidepressants before symptom relief; 2) time with dosage adjustments due to adverse side effects and/or lack of effects; 3) cost of pharmacogenetic testing; 4) probability of benefits from pharmacogenetic testing. Respondents were asked to choose between two scenarios; 1) pharmacogenetic testing; and 2) an opt-out option reflecting a scenario without pharmacogenetic testing. The indirect utility model was assumed to be multiplicative in probability of benefits and reduced time with dosage adjustments as well as reduced number of antidepressant changes. RESULTS: Most coefficients had the expected signs and were statistically significant. WTP for avoidance of one change in antidepressant medication is 1571 Danish Krone (DKK), whereas WTP for reducing the period with dosage-adjustments by 1 month is DKK604. Both were statistically significantly different from zero. CONCLUSION: If diagnosed with depression, peoples' WTP for pharmacogenetic testing appears to exceed its price as long as there is a reasonable probability for improvements in treatment (in the present case 10%). Utility is associated with outcomes only. Hence, other modes of provision of similar improvements in treatment may be valued equally highly. WTP estimates and the associated policy implications appear to be robust because they were unaffected by estimation model.

Patient preferences for pharmacogenetic screening in depression.

OBJECTIVES: The aims of this study were to estimate preferences and willingness-to-pay (WTP) for genetic screening for CYP2D6 polymorphisms among a group of former and currently depressed patients. METHODS: 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. RESULTS: 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 (euro350). CONCLUSIONS: 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.