Spirometry doubles 'known' cases of COPD
April 19, 2004
NORTHBROOK, Ill. - Spirometry testing in a primary care setting significantly improves early identification of COPD, says a study published in the April issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians.
The study found that by using spirometry, the gold standard for diagnosing COPD, primary care physicians nearly doubled the number of "known" COPD cases. In addition, of all newly diagnosed cases of COPD, 42 percent would have remained undetected without the use of spirometry.
"Although there is no cure for COPD, early detection is important for effective disease management," said Johan Buffels, MD, Katholieke University, Leuven, Belgium. "A predominant number of patients with early stage COPD receive initial medical care through primary care physicians; however, many remain undiagnosed because their physicians do not regularly screen for the disease. Without the use of spirometry by primary care physicians, nearly half of our patients with COPD will remain undiagnosed."
In the study known as the DIDASCO project, researchers from Katholieke University compared the effectiveness and accuracy of office spirometry and a screening questionnaire as used by primary care physicians to detect early stages of COPD.
Primary care physicians, trained in the use of spirometry and the management of COPD and asthma, screened a total of 3,408 patients between the ages of 35 and 70 over a 12-week period. Of the patients screened, 250 were currently using bronchodilators and/or inhaled steroids, indicating a "known" condition of either asthma or COPD. The remaining 3,158 patients completed a screening questionnaire that identified 728 patients as having signs or symptoms suggesting a condition of COPD.
Spirometry tests were obtained from 703 of the symptomatic patients and 10 percent of asymptomatic patients. Among the group with symptoms, researchers confirmed 126 patients with formerly unknown airflow obstruction, as compared to the extrapolated number of 90 cases in the group without symptoms. The screening questionnaire was found to be insufficient for the detection of COPD, failing to identify 42 percent of all new cases of obstructive lung disease.
"Mild or moderate COPD often has few or no symptoms. Therefore, screening only patients with symptoms of COPD may result in missing an important number of people with obstructive lung disease," said Dr. Buffels. "As shown in our study, office spirometry nearly doubled the number of known cases of COPD in our target patient population, which reinforces the need for spirometry testing in general physician practice."
The majority of newly diagnosed patients presented with mild to moderate COPD. Of newly diagnosed patients, 45 percent were women, as compared to 15 percent among "known" COPD patients. The percentage of current smokers in the newly diagnosed group (48 percent) exceeded the number of smokers in the group with normal lung function (28 percent).
"COPD is the fourth leading cause of death in the United States, claiming the lives of over 117,000 Americans each year, yet COPD continues to be widely underdiagnosed in the primary care setting," said Richard S. Irwin, MD, FCCP, President of the American College of Chest Physicians. "Primary care physicians play a key role in the detection of COPD and should be encouraged to learn the technique of spirometry and incorporate the screening method into regular practice."