MONDAY, Feb. 25, 2008 (HealthDay News) -- People who develop a blood clot in their legs (deep vein thrombosis) or in their lungs (pulmonary embolism) are at risk of developing another blood clot within three years, a new study suggests.
Deep vein thrombosis and pulmonary embolism are known collectively as venous thromboembolism.
Researchers looked at 1,691 people, average age 65, in Worcester, Mass., diagnosed with pulmonary embolism (549) and isolated deep vein thrombosis (1,142) in 1999, 2001 or 2003. During the three-year study, 31 (5.7 percent) of the pulmonary embolism patients had a recurrent clot in the lung, 75 (13.7 percent) had a recurrence of either type of venous thromboemolism, and 82 (14.9 percent) had a major bleeding episode (one that required blood transfusion).
Among the 1,142 patients with isolated deep vein thrombosis, 64 (5.6 percent) developed a pulmonary embolism, 217 (19 percent) had recurrent venous thromboembolism, and 146 (12.8 percent) had a major bleeding episode.
Patients with pulmonary embolism were more likely than those with deep vein thrombosis to die after one month (13 percent vs. 5.4 percent), one year (26 percent vs. 20.3 percent), and three years (35.3 percent vs. 29.6 percent).
"Patients whose course was complicated by major bleeding were more likely to experience recurrent venous thromboemolism or to die at three years than those without these complications," wrote Dr. Frederick A. Spencer, of McMaster University Medical Center in Hamilton, Ontario, Canada.
"Patients who presented with pulmonary embolism had similar rates of subsequent pulmonary embolism or recurrent venous thrombosis compared with patients with isolated deep vein thrombosis," the study authors noted.
"However, rates of recurrent venous thromboembolism and major bleeding after deep vein thrombosis and pulmonary embolism remain unacceptably high in the community setting. Efforts are needed to identify patients most at risk for venous thrombosis-associated complications and to develop better anti-coagulation strategies conducive to long-term use in the community setting," they concluded.
The study was published in the Feb. 25 issue of the Archives of Internal Medicine.
The U.S. National Heart, Lung, and Blood Institute has more about deep vein thrombosis.