Mortality after a blood clot remains high

About one in four patients in a population-based study who were treated for blood clots in major blood vessels died within 1 year after their initial diagnosis, a mortality rate that investigators say is not much better than was observed in the 1980s.

Advances in the treatment blood clots "continue, and studies are ongoing to find better anticoagulants," lead researcher Dr. Frederick A. Spencer told Reuters Health.

"That said, we have pretty good treatment available right now," he added, "but if we can't replicate the successes seen in clinical trials in the community, it suggests that patients in the community don't necessarily mirror those enrolled in clinical trials, and that we have more to learn about using the therapies we already have in the typical patient."

To determine patient outcomes in the "real world," Spencer from McMaster University Medical Center in Hamilton, Ontario, Canada, and his associates obtained medical records of residents of Worcester, Massachusetts who were treated for blood clots during 1999, 2001, and 2003. Included were 549 patients with blood clots in the lungs (pulmonary embolism) and 1142 patients with isolated deep vein thrombosis, or DVT.

Their findings appear in the February 25th issue of the Archives of Internal Medicine.

"Rates of recurrent pulmonary embolism, DVT, bleeding, and mortality are unacceptably high in the community setting - much higher than those reported in clinical trials," Spencer stated.

Compared with patients with isolated DVT, patients who presented with pulmonary embolism had similar rates of subsequent pulmonary embolism, repeat venous thromboembolism, and major bleeding during 3 years of follow-up.

However, mortality was significantly higher at 1 month among patients with pulmonary embolism (13.0 percent vs 5.4 percent), a difference that persisted at 3 years (35.3 percent vs 29.6 percent). Major bleeding tripled the risk of recurrent DVT and raised mortality rates at 3 years by 30 percent.

"Future research needs to be done evaluating how to use the therapies we have in 'real-world' patients who tend to be older and sicker than those in clinical trials," Spencer said. "Trials of new anticoagulant strategies should consider including such patients either in the main trials or as specifically targeted subsets."

SOURCE: Archives of Internal Medicine, February 25, 2008.