OUHSC Study Shows Blood Clots Can Be Prevented After Hospitalization

When patients are hospitalized for surgery or treatment of a medical condition, they face an additional concern: the risk of developing a blood clot. Because today’s hospital stays are much shorter than in the past, patients confront that risk after they return home. The risk for developing a clot remains for 90 days after discharge from the hospital and is particularly high in the first 45 days, when the majority of clots occur.

However, that risk may soon be significantly lower. A researcher at the OU Health Sciences Center, the academic partner of OU Medicine, has published a study in the New England Journal of Medicine showing that patients who are given a daily, low dose of an existing anti-clotting medication had significantly fewer blood clots for 45 days after leaving the hospital. The research is groundbreaking because it shows that blood clots can be prevented without causing excess bleeding.

The research was led by Gary Raskob, Ph.D., Dean of OU’s College of Public Health and Professor of Epidemiology and Medicine. He served as co-chair of the executive committee for the study, which studied 12,000 patients in 36 countries and more than 600 hospitals. When patients were discharged from the hospital, they were randomly assigned to receive the anti-clotting medication Rivaroxaban for 45 days, or an identical placebo.

In the general U.S. population, as well as in Oklahoma, blood clots affect two to three people per 1,000. In Raskob’s study, Rivaroxaban prevented two to three clots in every 1,000 patients, significantly reducing the risk in the qualified research study population. The study also evaluated the safety of giving Rivaroxaban to patients every day for 45 days. The primary risk of the medication is bleeding complications, but patients in the study showed no increase in risk of such problems.

“The study is important because we now have evidence that an oral anti-clotting medication, which is already available and used in a variety of settings, can safely prevent the development of clots in the legs and lungs,” Raskob said. “Losing someone suddenly to a blood clot is a tragedy. It’s rewarding to know that our research can be directly applied in clinical care.”

Raskob has studied blood clots for more than 25 years. Blood clots fall under the umbrella term of venous thromboembolism, which refers to clots that develop in the large veins of the leg or that move from the leg to the lungs. When clots develop in the leg, the condition is called deep vein thrombosis (DVT). When they move to the lungs, it is called pulmonary embolism (PE). The three primary risk factors for developing DVT or PE are admission to the hospital, surgery or cancer. About 70 percent of people who develop venous thromboembolism have an identifiable risk factor, and 30 percent have no identifiable risk factor but likely have a genetic predisposition to developing clots.

When DVT forms in the leg, it can obstruct blood flow and cause pain, tenderness and swelling of the leg. If clots move through the body’s circulation, passing through the heart and into the lungs, people experience chest pain, shortness of breath, rapid heart rate or passing out. A significant number of cases are fatal.

“The problem with pulmonary embolism is in a large number of cases, the first sign or symptom is a collapse or sudden death of the patient,” Raskob said. “While we have effective blood-thinning drugs to treat these patients, prevention is critical to reduce the poor health outcomes and death caused by this condition.”

Raskob’s study began in 2014 and concluded this spring. The findings can be translated efficiently from the research study to physicians’ practices, which is what sets OU Medicine apart in its health care delivery. Researchers across the OU Health Sciences Center are conducting studies that, like Raskob’s, will one day directly benefit patients.

“Research is what distinguishes an academic health system like OU Medicine,” said Jason Sanders, M.D., MBA, Senior Vice President and Provost of the OU Health Sciences Center and Vice Chair of OU Medicine. “Our leaders are developing evidence-based practices used across the world. Through the affiliation between our academic health center and OU Medicine, groundbreaking treatments and care are brought directly to Oklahoma patients.”