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• Posted December 8, 2021

What's the Best Blood Thinner for a Blood Clot in Your Legs?

For people suffering from clots in their legs, a new study finds that one of two commonly used blood thinners is safer and more effective than the other.

Venous thromboembolism (VTE) can cause clots to form in the deep veins in the legs, and if one breaks loose it can travel to the lungs and cause breathing problems and even death. In this study, researchers looked at the risks and benefits of two popular blood thinners -- apixaban (Eliquis) and rivaroxaban (Xarelto).

"In this real-world study of patients with VTE, treatment with apixaban was associated with lower rates of recurrent VTE and bleeding than treatment with rivaroxaban," said researcher Dr. Adam Cuker. He is an assistant professor of medicine at the Perelman School of Medicine at the University of Pennsylvania, in Philadelphia.

Clinicians and patients may select a blood thinner based on factors that include dosing (Xarelto is taken once daily and Eliquis is taken twice daily), cost and insurance coverage, he said.

"While direct comparisons of apixaban and rivaroxaban are lacking, our findings suggest that apixaban is superior to rivaroxaban with respect to effectiveness and safety," Cuker said. "Patients may wish to discuss these results with their provider and incorporate evidence about the comparative effectiveness and safety of different treatment options in their selection of an anticoagulant."

For the study, Cuker and his colleagues analyzed medical records of over 37,000 patients with VTE who were taking either Eliquis or Xarelto.

Among the more than 18,600 patients taking Eliquis, 475 had recurrent VTE and 386 had episodes of stomach or brain bleeding. But among the 18,600 patients taking Xarelto, 595 had recurrent VTE and 577 had episodes of stomach or brain bleeding, the researchers found.

Dr. Scott Woller, a professor of medicine at the University of Utah School of Medicine in Salt Lake City, and a specialist in VTE and anti-clotting drugs, said the latest findings line up with other studies.

"The actual difference observed between groups is small, yet these study results may be impactful when a physician is choosing between these drugs and all other things are equal," he said.

Woller does see some limitations in the study. For example, the researchers didn't account for other drugs patients were taking that can also increase the risk for internal bleeding, like aspirin. In addition, doctors may have chosen one over the other for reasons not directly linked to risk for internal bleeding.

The best anticoagulant is the one taken as prescribed, Woller said. "Therefore, anticipating barriers such as insurance coverage limitations, compliance with dosing, and individual patient characteristics, such as co-morbidities, is necessary to assure that patients receive necessary care," he said.

Studies have shown that Eliquis and Xarelto are better than the older drug warfarin in preventing clotting. But there has still been no head-to-head comparison of these newer drugs, added Dr. Aeshita Dwivedi, a cardiologist at Lenox Hill Hospital in New York City.

The variance in how these drugs perform may be due to differences in how they are metabolized in the body, she said.

"While this study is not practice-changing due to its design, it certainly sheds light on possible differences amongst the newer anticoagulants and calls for further investigation," Dwivedi said. "Comparison amongst the newer anticoagulants will become more evident once the results of the ongoing randomized trials become available."

The report was published online Dec. 6 in the Annals of Internal Medicine.

More information

For more on venous thromboembolism, head to the U.S. Centers for Disease Control and Prevention.

SOURCES: Adam Cuker, MD, assistant professor, medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia; Aeshita Dwivedi, MD, cardiologist, Lenox Hill Hospital, New York City; Scott Woller, MD, professor, medicine, University of Utah School of Medicine, Salt Lake City; Annals of Internal Medicine, Dec. 6, 2021, online