-- Alan Mozes
FRIDAY, March 11 (HealthDay News) -- A simple and inexpensive
blood test designed to uncover early signs of emphysema may one day
find its place among the standard work-up that most Americans
undergo during their yearly physical, new research suggests.
Although the novel screening method has shown considerable
promise in preliminary investigations sponsored by the U.S.
National Institutes of Health, the researchers caution that more
studies are needed before the test could become available.
An easily administered test that could spot emphysema even
before symptoms show up would be an enormous boon to the care of
smokers, who are the most vulnerable to the onset of the disabling
and potentially deadly disease.
"We know from other studies that smokers who learn from objective evidence that their health is in danger are much more likely to quit," Dr. Ronald G. Crystal, chairman and professor of genetic medicine and internal medicine at Weill Cornell Medical College and the study's lead author, said in a news release. "That is the only thing that will help them avoid this deadly disorder."
"We need a blood test that can be administered to the 20 percent of American adults who smoke as well as nonsmokers exposed to secondhand smoke -- all who may not understand their risk of developing this progressive lung disease," he added.
Crystal, who also serves as chief of the division of pulmonary
and critical care medicine at New York-Presbyterian/Weill Cornell
Medical Center in New York City, reported his team's findings in
the March 14 online issue of the
American Journal of Respiratory and Critical Care
Emphysema and chronic bronchitis are the two main conditions of
chronic obstructive pulmonary disease (COPD). In the United States,
COPD is the fourth leading cause of death and has been projected to
increase as the American population ages.
The new screening mechanism for emphysema was designed to
measure the presence in the bloodstream of capillary debris, known
as endothelial microparticles, or EMP, that results from injury to
the lung's air sacs, called alveoli. The researchers noted that air
sacs are central to respiratory function, and their COPD-driven
deterioration ultimately shreds the lungs, producing the
Swiss-cheese appearance that's telltale of the disease.
When tested on healthy nonsmokers, healthy smokers and smokers
with signs of lung disease, the new test for EMP was found to be
nearly foolproof in detecting early signs of emphysema, compared
with the current emphysema screening method, known as DLCO, or lung
diffusion testing, which measures how well the lungs exchange
oxygen and carbon dioxide.
The new test, according to the researchers, also is better than
the current one at uncovering the earliest signs of disease and can
be done without the involvement of a pulmonologist.
In addition, they said, being able to easily diagnose emphysema
at an early stage could be the leg up that health practitioners
need to get their patients who smoke to finally kick the
Dr. Neil Schachter, a professor of pulmonary medicine at Mount
Sinai Medical Center in New York City, agreed.
"Only about 15 percent of smokers will go on to develop emphysema," he noted. "So if you're a gambler and a smoker, which most are in a very general sense, it may not feel that urgent to stop smoking if you think you have a better-than-even chance of beating the game. But if you know you're in that 15 percent, it certainly is a powerful argument that physicians can bring forth to help convince people to stop smoking."
"But even so, smoking is a terrible, huge addiction," Schachter stressed. "It's difficult to convince people to quit, even when they know they have symptomatic disease. So it's not clear this will actually make a difference."
Edmund J. Miller, head of the Center for Heart and Lung Research
at the Feinstein Institute for Medical Research in Manhasset, N.Y.,
echoed this reservation.
"Since the dangers of smoking have been emphasized in many ways, and many smokers do not quit even when the most severe symptoms have developed, it is perhaps unlikely that an individual will quit because of a blood test," Miller said. He added that biomarkers and early recognition of disease processes are valuable, however, and "the test may be useful in other settings where deterioration of lung function may be a late finding that perhaps could be prevented."
"This is a new finding in emphysema," Miller said, "but these particles [EMP] have been proposed as potential biomarkers for several other diseases, including sepsis and vasculitis."
Dr. Norman Edelman, chief medical officer of the American Lung
Association (ALA), agreed that it's unknown whether the new test
would prove to be a quit-smoking aid.
"I cannot predict whether this new test will be an important tool in helping doctors convince their patients to stop smoking," Edelman said. "The ALA recommends that doctors make strong efforts at smoking cessation for all of their smoking patients, as it is proven that doctors' intervention is an effective way to get people to make a serious attempt to quit." How much this test might add to either the quality of the doctors' efforts or the patients' response was uncertain, he noted.
But Schachter added that early detection can make all the
difference in managing emphysema.
"If you catch the disease early, while there may be some microscopic damage, you are still way ahead of the game," he said. "And if the person stops smoking and takes proper prevention measures, such as following a healthy lifestyle, you could probably slow down the disease and maintain it at a level as either asymptomatic as it is at the time of discovery or mildly symptomatic."
The Cleveland Clinic has more on
emphysema and COPD.
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