It's estimated that smoking will cause more than 8 million deaths a year around the world in the coming decades. In addition to cardiovascular disease and cancer, COPD is a major cause of death in heavy smokers. Yet, it is under-diagnosed, and deaths from it are increasing, the researchers noted.
CT-based lung cancer screening "may provide an opportunity to detect individuals with COPD at an early stage," said study author Dr Pim A. de Jong, a radiologist at the University Medical Centre Utrecht.
"Early cessation of smoking can prevent COPD progression, underscoring the importance of early detection," de Jong said. "This CT-based detection may provide a possibility to enhance the cost-effectiveness of lung cancer screening with CT."
The report was published in the issue of the Journal of the American Medical Association.
For the study, de Jong's team looked for COPD in more than 1,000 men who took part in an ongoing lung cancer screening trial, using CT scans, that ran from July 2007 to September 2008. The men also underwent lung function tests that are standard screens for diagnosing COPD.
Based on lung function tests, the researchers found 38% of the men had COPD.
Using CT scans, de Jong's group looked for emphysema, a common form of COPD, characterised by air trapped in the lungs. They also took into account the patient's weight and how many cigarettes each patient smoked a day and whether he had quit or still smoked.
Using this criteria, they identified about 275 men with COPD and 85 with false-positive results, meaning they did not actually have the condition. That means the CT test was able to correctly predict COPD 76 percent of the time, the researchers reported.
This included men with mild, moderate and severe COPD, they noted.
"Among men who were current or former heavy smokers, undergoing lung cancer screening with CT scanning identified a substantial proportion who had COPD, suggesting that this method may be helpful as an additional tool in detecting COPD," de Jong said.
Dr Neil Schachter, medical director of the respiratory care department at Mount Sinai School of Medicine in New York City, said heavy smokers should be screened for COPD.
"The question is, is CT a useful way to screen for COPD," he said. "On the one hand, you are using an expensive tool to make a diagnosis that you could make with a simpler, cheaper tool, namely spirometry."
Low-dose CT scans
However, with CT scans becoming a standard screen for diagnosing lung cancer, it might make sense to also use it to diagnose COPD, he said.
A study in the issue of the New England Journal of Medicine found that annual low-dose CT scans cut the death rate from lung cancer by 20% in heavy smokers and formerly heavy smokers, compared with those who get annual chest X-rays.
"Lung cancer [detection] with CT scans is poised to take off. It may take off like a flash or it may crash and burn, we don't know that yet," he said. "If people are going to have this test anyway, then it would make sense that they be screened for COPD," Schachter said. "But there are a lot of ifs here."
Schachter noted that COPD is the third leading cause of death in the United States, and of the 25 million with the condition only half know they have it. Diagnosing COPD early means earlier treatment and better outcomes, he said.
(HealthDay, Steven Reinberg, October 2011)
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