Genetic testing for new warfarin patients is rare, but often inappropriate

SAN FRANCISCO, April 18, 2012 /PRNewswire/ -- Genetic testing to determine a more accurate initial dosing of warfarin, a drug used to prevent blood clots, remains rare, but is often done for inappropriate patients, according to a new study by Prime Therapeutics (Prime), a leading pharmacy benefit manager (PBM). The study will be presented on Friday, April 20, at the Academy of Managed Care Pharmacy (AMCP)'s 24th Annual Meeting & Expo in San Francisco.

The study found that genetic testing associated with warfarin is being performed at a rate of only 4 per 100 individuals, consistent with 2012 American College of Chest Physician guidelines which recommended against routine testing. Despite its rare use, nearly two-thirds of those patients on warfarin who received a genetic test were tested inappropriately, typically those who have already been on the drug for five days or more.

"Based on the increased prevalence of genetic testing, it is clear health plans need to ensure the right member is tested at the right time for the best outcomes," said Patrick Gleason, PharmD, director of clinical outcomes assessment at Prime. "Genetic testing for patients taking warfarin remains controversial and this study shows that while testing is rare, a large number of those being tested are not tested appropriately."

To identify warfarin genetic testing prevalence, appropriateness and cost, researchers from Prime in collaboration with Blue Cross and Blue Shield of Minnesota (BCBSM), reviewed integrated pharmacy and medical claims data from a 1.2 million member commercially insured population. This study emphasizes the value of health plan and PBM collaboration since combining medical and pharmacy data allows for comprehensive assessment of drug safety, effectiveness and total cost of care that ensures clinical pharmacy decisions reflect a complete view of utilization and costs.

There were 8,396 unique members with a warfarin claim during the study period. A genetic testing claim was found in 334 (4 percent) warfarin users and the total paid for genetic testing was $100,312 with a median cost of $152 per member. Researchers used Center for Medicaid and Medicare Services (CMS) criteria to define the appropriateness of testing and categorized the data into those whose tests were performed within five days of the warfarin index claim as appropriate, and greater than five days as inappropriate.

In 2009, CMS decided against covering genetic tests for warfarin use because there was not enough evidence that the tests improved patient health. CMS only reimburses for tests given as part of a clinical trial. Federally-funded clinical trials of genetic tests for warfarin users are currently under way.

Prime Therapeutics is a pharmacy benefit management company dedicated to providing innovative, clinically-based, cost-effective pharmacy solutions for clients and members. Providing pharmacy benefit services nationwide to nearly 20 million covered lives, its client base includes Blue Cross and Blue Shield Plans, employer and union groups, and third-party administrators. Headquartered in St. Paul, Minn., Prime Therapeutics is collectively owned by 13 Blue Cross and Blue Shield Plans, subsidiaries or affiliates of those Plans. Learn more at www.primetherapeutics.com.

SOURCE Prime Therapeutics