WASHINGTON, D.C. (July 19, 2016) – The Patient-Centered Outcomes Research Institute (PCORI) Board of Governors today approved $6.5 million to fund two studies that will compare the effectiveness of the newer as well as older blood-thinning medications in preventing dangerous blood clots in the veins and lungs. The awards were among 35 totaling $153 million approved today by the Board.

Blood thinners, or anticoagulants, prevent the production of certain proteins that are needed for blood to clot. They are used in hospitals to treat blood clots in the lung, or pulmonary embolism. It’s estimated that pulmonary embolisms cause up to half a million hospitalizations and 100,000 deaths every year in the U.S.

Four new clot-dissolving drugs -- apixaban, dabigatran, edoxaban, and rivaroxaban – are now available to treat clots in addition to the older drug warfarin. These anticoagulants are frequently used for longer than the standard three-month treatment period to prevent additional clots from forming, but the comparative safety and effectiveness of such extended use is not clear. Although effective treatments, these drugs also can cause serious bleeding, including in the brain.

  • A research team based at the University of California at San Francisco was approved for a $3.5 million award for a study that will review thousands of records of patients who either took one of the five drugs for extended periods of time as a preventive measure or stopped taking the drugs once their clots were resolved. It also will compare outcomes associated with each of the drugs and look at whether the benefits and harms differ for patients who are older, have impaired kidney function, or a higher risk of bleeding.

  • Another research team based at Brigham and Women’s Hospital in Boston was approved a $2.9 million award to compare the safety and effectiveness of each of the newer anticoagulants to one another and to warfarin when used for extended periods. Researchers will examine the outcomes experienced by patients being treated for the first time for clots.

"Blood clots in the veins and lungs can cause serious and sometimes deadly results such as organ damage, stroke, and heart attacks,” said PCORI Executive Director Joe Selby, MD, MPH. “The research we are supporting gives the patients a vital role in finding the evidence on these newer medications that they, along with their providers, can use to make treatment decisions.”

Each study is engaging key stakeholders, such as patient organizations and major professional societies and associations, in research design and implementation. Some of the partners include a national blood clot advocacy organization, representatives from health plans, and clinicians who specialize in treating clots. This kind of engagement can help ensure that the research addresses outcomes that matter most to patients and those who care for them and can facilitate quicker dissemination and application of study results.

The new studies are designed to address evidence gaps and questions that people who have had blood clots and other healthcare stakeholders identified as their top priorities through PCORI’s research prioritization process. A multi-stakeholder workshop in June 2015 brought together patients and participants representing groups advancing research on cardiovascular disease as well as clinicians, government agencies, industry, and health insurance plans to refine the questions that became the focus of PCORI’s funding announcement. 

All awards are approved pending completion of a business and programmatic review by PCORI staff and completion of a formal award contract.



The Patient-Centered Outcomes Research Institute (PCORI) is an independent, nonprofit organization authorized by Congress in 2010. Its mission is to fund research that will provide patients, their caregivers and clinicians with the evidence-based information needed to make better-informed healthcare decisions. PCORI is committed to continuously seeking input from a broad range of stakeholders to guide its work.


The Patient-Centered Outcomes Research Institute (PCORI) is the nation’s leading funder of patient-centered comparative clinical effectiveness research (CER). By comparing two or more health or healthcare approaches, CER generates evidence that helps people make better-informed decisions and improves healthcare delivery and outcomes. PCORI takes a holistic approach to its work, ensuring that patients and other health decision makers are engaged as partners throughout the research process, supporting dissemination and implementation of results in practice and strengthening clinical research infrastructure to advance patient-centered CER. PCORI is an independent, non-profit organization authorized by Congress.

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