Factors increasing risk for recurrent blood clots

Reported by Susan Aldridge, PhD, medical journalist

A study shows that patients who have had one blood clot have a high risk of having another one, especially if they are male.
A blood clot in the arm or leg may break off and travel around the body, perhaps lodging in the lungs where it may have a potentially fatal effect. A team at the Leiden university Medical Center, The Netherlands, now reports on a follow-up of 474 patients aged 18 to 70 who had had a thrombotic event (clot).

The annual risk of recurrence was 2.6 per cent and the cumulative risk at five years was 12.4 per cent. At seven years, it was 16.5 per cent. The risk of recurrence was 2.7 times higher among men than women. And if there was no obvious cause for the first clot, the risk of recurrence was twice that for patients whose clot had a clear medical cause. Women using oral contraceptives were also more at risk.

These findings may be useful in guiding anti-thrombotic therapy, which is given to prevent recurrence. It looks as if laboratory tests may not be as useful as the risk factors discovered in this study when it comes to deciding what therapy to use.

Source
Journal of the American Medical Association 18th May 2005 Volume 293 pages 2352-2361