Long-term increase in mortality rate after thrombosis
Even years after a thrombosis, the mortality rate remains higher than average, according to an article by the Leiden University Medical Center in the scientific journal PloS Medicine. The cause is not a second thrombosis, but cancer, a heart attack or lung disease.
Long-term consequences
For approximately five years, the researchers followed almost five thousand patients who had suffered a deep vein thrombosis. This condition involves a blood clot becoming lodged in an arm or leg artery. In the months following the thrombosis, the mortality rate is increased, but little is known about the long-term effects. The researchers of the LUMC combined data from the so-called MEGA study, which started in 1999 to investigate the causes of thrombosis, with the Netherlands mortality records. They concluded that the mortality rate remained higher than average even up to eight years after a deep vein thrombosis.
Further research required
Ex-thrombosis patients are generally more likely to die of cancer. This is not so surprising, since thrombosis often occurs in cancer patients. But mortality as a result of heart attacks and lung diseases such as emphysema and pneumonia was also increased, which could not immediately be explained. ‘In the case of a heart attack you might think of an increased clotting tendency, which lies at the root of both conditions,’ says researcher Dr Suzanne Cannegieter. ‘But it might also be caused by common risk factors that underlie both thrombosis and other diseases. Think, for instance, of smoking or obesity.’ Since this is a purely descriptive study, causal relations can only be speculated on. Further research is required to come to a definitive answer.
Mortality
Incidentally, it was shown that the long-term mortality rate was only increased in cases of thrombosis with an unknown cause. If the thrombosis had a known cause – for instance an operation – then the long-term mortality rate did not increase.
Monitoring patients for longer
The standard treatment for thrombosis patients consists of anti-clotting drugs, which are usually prescribed for a period of three to six months. ‘On the basis of these results, doctors would be advised to monitor patients who have suffered an unexplained thrombosis for a much longer period of time,’ suggests researcher Linda Flinterman. ‘For instance by carrying out regular check-ups.’
(Source: 11 January 2012/LUMC)
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