Each year in the U.S., approximately 950,000 people develop venous thromboembolism (VTE), which consists of both pulmonary embolism and deep vein thrombosis. Deep vein thromboses are blood clots that occur in the veins — typically in the legs — that can travel through the venous system and heart into the lungs, where the clot can damage the lungs. When a clot travels through the lungs and blocks arteries, it is called a pulmonary embolism.

“People with VTE are treated with anticoagulant drugs, and for decades, the only oral anticoagulant available in the U.S. was warfarin,” says Associate Professor Pamela Lutsey from the School of Public Health. “Warfarin has numerous food and drug interactions, and maintaining stable anticoagulation requires regular monitoring. Since 2010, several new direct oral anticoagulants have been approved by the FDA. These are thought to be easier for patients to use, however, there is limited information about their real-world effectiveness.”

Given the choice between the blood thinner warfarin and the new direct oral anticoagulants (DOACs), Lutsey recently conducted a study to find out what concerns and preferences patients have in using drugs to treat VTE. The results were recently published in the journal Thrombosis and Haemostasis.

“Overall, patients viewed the reversibility of an anticoagulant and the ability to monitor its levels as important,” says Lutsey. “Most patients did not consider regular monitoring and dietary restrictions onerous.”

Specifically, 53-percent of patients strongly preferred anticoagulants that can be reversible to prevent bleeding, and 30-percent said they want drugs that can be monitored through blood tests.

The study also showed that low percentages of patients were comfortable using the newest drug versus an established drug, found regular blood testing to be inconvenient or thought it difficult to change their diet to accommodate their anticoagulant.

“These findings bring into question whether the factors the medical community perceives as advantages of DOACs are also really viewed by patients as advantages,” says Lutsey. “They suggest that patients generally didn’t find the potential weaknesses of warfarin to be onerous, while warfarin’s advantages were viewed favorably. However, as there is more clinical experience with DOACs, it is possible that patient perceptions may change.“

Lutsey said more research is needed to evaluate the comparative effectiveness of DOACs versus warfarin in real-world settings. The clinical trials that have been conducted evaluating the comparative effectiveness of these drugs have been very rigorous, but questions still remain.

“For example, are the results generalizable across patient subgroups which were not well-represented in the trials? About one-third of VTE cases are provoked by cancer, but the trials contained very few cancer patients,” says Lutsey.

Lutsey is continuing her VTE research, this time examining the effectiveness of treatment strategies in a large patient-based sample and looking at whether there are differences in patient subgroups, such as people with cancer.