VA Ann Arbor Study Helps Veterans Use Blood-Thinning Medicines More Safely

The project focused on Veterans taking newer oral anticoagulants, known as direct oral anticoagulants, or DOACs, who were also taking antiplatelet drugs such as aspirin. For some patients, that combination is necessary. But for many others, especially those with stable heart disease, the extra antiplatelet drug may increase bleeding risk without adding protection.

"Anticoagulants are essential medicines that help prevent dangerous clots and strokes, but they are also one of the leading causes of serious medication harm, especially bleeding," said Dr. Jacob Kurlander. "Our goal is to make sure every medicine has a clear purpose and to stop unnecessary antiplatelet therapy, which can significantly increase the bleeding risk."

The study, “Multilevel Stewardship Intervention for Use of Anticoagulation-Antiplatelet Therapy”, was published June 22 in JAMA Internal Medicine. Led by Kurlander, a physician at the VA Ann Arbor Healthcare System, the study evaluated a medication safety effort across seven VA health systems in Florida, South Georgia, Puerto Rico, and the U.S. Virgin Islands.

David Parra, PharmD, co-author and VISN 8 Clinical Pharmacy Program Manager in Cardiology and Anticoagulation, said the work grew out of a safety concern seen in everyday care. Some Veterans who had bleeding events while taking DOACs were also taking antiplatelet therapy that recent clinical trials suggested may no longer have been needed.

Parra said that created an opportunity to streamline care while improving safety.

The study examined more than 27,000 Veterans receiving DOACs at the seven intervention health systems and compared them with more than 250,000 similar patients at 128 other VA sites. Before the intervention, about one-quarter to one-third of DOAC patients were also taking an antiplatelet drug.

After VA introduced clinician education, electronic health records (EHR) changes, and enhancements to a pharmacist electronic dashboard tool, antiplatelet use fell faster at the intervention sites than in the rest of VA.

The effect was greatest for Veterans with stable coronary artery disease, in whom the interventions helped roughly one in every 18 eligible patients discontinue their antiplatelet medication every six months.

Kurlander said one encouraging finding was that each part of the strategy helped. Education and EHR changes made a difference, and the dashboard flag added further benefit.

“The best results come when you support clinicians at multiple levels: education, smart EHR design, and pharmacist-led population management,” Kurlander said. “That combination helps give Veterans safer, more streamlined care.”

Many people use the term blood thinner to describe several different kinds of medicines, but anticoagulants and antiplatelet drugs are not the same. Anticoagulants, including DOACs such as apixaban, rivaroxaban, dabigatran, and edoxaban, act on the blood’s clotting system to make clot formation less likely. 

Antiplatelet drugs work differently. Medicines such as aspirin and drugs known as P2Y12 inhibitors make platelets less sticky, making them less likely to clump together and form a clot. 

Sometimes, patients need both an anticoagulant and an antiplatelet medicine for a limited time, such as after a recent heart attack, stent, or bypass surgery. But for many patients with stable heart disease, staying on both types of medicine long term may raise the risk of serious bleeding without adding extra protection.

“Multiple studies have now demonstrated that many patients who are on a combination of a DOAC with an antiplatelet may no longer require the antiplatelet,” Parra said. “In short, there was no benefit and more harm.”

Patients should not stop any anticoagulant or antiplatelet medicine on their own. The goal is to make sure each medicine still has a clear purpose and that any changes happen with a clinician's guidance.

That balance can be difficult for clinicians. Anticoagulants help prevent blood clots that can cause strokes, block blood flow in the legs, or travel to the lungs. Because those events can be so serious, clinicians may hesitate to stop a medication that was once prescribed to prevent them, even when it may no longer be needed.

VA addressed the issue with both education and technology. A specially trained clinical pharmacist met with physicians and local pharmacists to review evidence and discuss real cases, an approach called academic detailing. This elbow-to-elbow coaching helped clinicians feel more confident deciding when two medicines were still needed and when it was safer to stop the extra antiplatelet drug.

VA also added prompts to the electronic health record and later introduced a dashboard flag. The flag alerted pharmacists when a patient was taking both a DOAC and an antiplatelet drug.

“Think of the dashboard as a high-tech safety checklist for thousands of patients at once,” Kurlander said.

The flag did not automatically stop any medication. Instead, it prompted a pharmacist to review the chart, contact the patient or clinician if needed, and help stop the extra medicine when appropriate.

The study estimated that for every 12 patients who can safely stop an unnecessary antiplatelet medication, one major or clinically important bleeding event may be prevented over about two years.

Changing prescribing habits across many hospitals and clinics takes time. Clinicians may worry that stopping aspirin could lead to a stroke or heart attack, and it can be unclear whether the cardiologist, primary care provider, or another specialist should make the decision.

Future dashboard flags could be more targeted, helping pharmacists focus on patients most likely to benefit while reducing alert fatigue. Expanding the model outside VA may also require adjustments, since not every health system has VA's integrated pharmacists, national data tools, and pharmacist prescribing authority.

Still, the findings are encouraging. Few real-world efforts to reduce unnecessary anticoagulant-antiplatelet combinations have worked at this scale. This project showed that education, EHR design, and pharmacist review can work together to reduce potentially harmful therapy across a large regional network.

“This study demonstrates that addressing combination therapy is feasible and has the potential to reduce medication burden for our Veterans while maintaining benefit and improving safety,” Parra said.

For Veterans, the message is simple: these medicines can be lifesaving, and the safest care is care that regularly checks whether each medicine is still needed and stops extra therapy that no longer adds benefit.