THURSDAY, April 5 (HealthDay News) -- Infections, especially
among older adults, may increase the risk of developing potentially
dangerous blood clots, a new study suggests.
The clots are called venous thromboembolisms, and include the
deep vein thromboses (DVTs) that typically begin in the legs.
However, DVTs can also travel to the lungs where they form
potentially deadly pulmonary embolisms.
DVTs have been linked to prolonged sitting, gaining the nickname
"economy-class syndrome" after cases of passengers developing them
on long-haul flights.
But, the new study finds that if an older adult suffers an
infection (for example, a urinary, skin or respiratory infection)
after a stay in a hospital or nursing home, the risk of developing
a venous thromboembolism can rise nearly sevenfold. In people who
develop infections at home, the researchers found a threefold
increased risk of a clot within 90 days.
The report was published in the April 3 online edition of the
"Preventing infection can have long-term benefits, in ways that one may not expect," said lead study author Mary Rogers, a research assistant professor in internal medicine at the University of Michigan Medical School.
"This includes fewer problems with blood clots," she said. "If you do develop an infection -- and we all do at times -- be more vigilant regarding possible vascular effects. Keep hydrated. Walking helps. See your doctor if problems arise," said Rogers, who is also research director of the patient safety enhancement program at the University of Michigan Health System and the VA Ann Arbor Healthcare System
For the study, Rogers' team collected data on more than 16,700
people who took part in the Health and Retirement Study, which is a
sample of older Americans.
To find hospitalizations for venous thromboembolism, the
researchers linked these data with Medicare records from 1991 to
2007 and found 399 people, averaging 77 years of age, were
hospitalized for the condition during the period.
The most common trigger of hospitalization for venous
thromboembolism was infection, accounting for 52 percent of the
cases, the study authors found.
Besides infection, medications used to treat anemia and blood
transfusions were also associated with greater risk of venous
thromboembolism. Anemia drugs increased the risk ninefold,
according to the report.
Other risk factors included surgery, fractures, being immobile
and having had chemotherapy, the researchers pointed out.
Venous thromboembolism is a serious problem, with more than
330,000 Americans hospitalized for it each year, the authors
"Since infection can occur anywhere, it is important that people know that something this common can result in a blood clot," Rogers said.
Therefore, it is important that preventive measures are a part
of daily life, she added. "This includes getting your seasonal flu
shot and other recommended vaccinations. This also includes
practicing good hygiene and other measures to prevent infection,
such as covering your cough," Rogers advised.
In addition, treatments are available to prevent clotting,
including anticoagulants and compression stockings.
"Individuals who are already at higher risk of blood clots, for example, those who are overweight, older, had surgery or a bone fracture, or who have limited mobility, should take precautions," Rogers said.
Dr. Eric Gandras, associate chief of the division of
vascular/interventional radiology at North Shore University
Hospital in Manhasset, N.Y., said that "these researchers have
identified risk factors for venous thromboembolism that are
underappreciated compared to some of the other known risk
Increased awareness can lead to increased preventive measures
and more investigation of how infections result in venous
thromboembolism, he said.
Right now it isn't known whether infection is a cause of venous
thromboembolism or is associated with other mechanisms that result
in the condition, Gandras said. "We don't know in terms of direct
cause and effect what the exact relationship is," he said.
To learn more about venous thromboembolism, visit the
U.S. National Library of Medicine.