Study: Men more at risk for recurrent blood clots

LONDON -- Among people who have had blood clots, men are twice as likely as women to have them again after treatment, according to an analysis of several studies.

``Gender may need to be considered when deciding how long patients should be treated with blood thinners," said Dr. Simon McRae, principal author of a paper published today in the medical journal Lancet.

McRae is a doctor with the department of hematology and oncology at Queen Elizabeth hospital in Woodville, Australia.

He and his colleagues analyzed 15 studies in a review that considered about 5,400 people who had discontinued medication three to six months after having a blood clot.

Blood clots, or thromboses, are thought to affect 1 in 1,000 people. The clots develop in veins of the legs, which then get dislodged and can travel to the heart or lungs, potentially causing cardiac or pulmonary failure.

The condition has also been called ``economy class syndrome," since remaining immobile for long stretches of time, like during long-haul flights, is a known risk factor.

The Lancet study concerns people only with a past record of blood clots.

There is no discernible difference in the risk of a first blood clot between men and women.

When it comes to recurrent clots, however, McRae concludes that men appear to be at higher risk statistically.