FRIDAY, Nov. 25 (HealthDay News) -- Patients hospitalized for
autoimmune disorders, like rheumatoid arthritis or Crohn's disease,
may be at greater risk for a life-threatening pulmonary embolism, a
clot in a main artery of the lung, a new study finds.
Reporting online Nov. 25 in
The Lancet, researchers warned that steps should be taken to prevent this condition among patients admitted to the hospital for autoimmune diseases.
In conducting the study, researchers analyzed data on more than
500,000 patients admitted to the hospital in Sweden for one of 33
autoimmune diseases, which can also include Grave's disease,
Hashimoto's thyroiditis and chronic rheumatic heart disease.
The team, led by Dr. Bengt Zoller of Malmo University Hospital
in Sweden, found the overall risk of pulmonary embolism in the 12
months following hospitalization to be six times higher for
patients with autoimmune diseases than for those without this type
of disorder.
They noted that all of the 33 autoimmune disorders included in
the study were associated with a significantly higher risk of
pulmonary embolism, although the most notable increases were
associated with immune thrombocytopenic purpura, a clotting
disorder, which carried an 11-fold increased risk; polyarteritis
nodosa, a form of vasculitis (13 times the risk); and polymyositis,
which involves chronic muscle inflammation (16 times the risk).
The rise in risk did decrease over time, however. Between one
and five years after hospitalization, overall risk dropped to a 50
percent increased risk for those with autoimmune disorders, the
researchers found. The risk dropped even further, to 15 percent
five to 10 years after admission, and fell to just 4 percent after
10 years or more.
The researchers pointed out the risks were the same for men and
women, and did not vary across age groups.
Zoller and colleagues said in a journal press release that
preventive measures against pulmonary embolism "could be warranted
in patients admitted with autoimmune disorders or at least for
those disorders for which the risk of pulmonary embolism was very
high. Further studies are needed to assess the potential usefulness
of such treatment."
In a journal commentary, Dr. Carani B Sanjeevi, of the
Karolinska Institute and Karolinska University Hospital in
Stockholm, said that a "clear link is shown between thrombosis and
inflammation" in the study. She agreed that "anti-inflammatory
drugs and thromboprophylaxis [prevention of clots] should be
considered to treat inflammation associated with autoimmune
disorders, particularly in those admitted to hospital."
Sanjeevi added that more research is needed to investigate the
link between inflammation and pulmonary embolism.
More information
The U.S. National Institutes of Health provides more information
on
autoimmune diseases.