Researchers from dozens of leading institutions around that nation have proposed new criteria for diagnosing chronic obstructive pulmonary disease (COPD), the fourth leading cause of death in the United States. The proposal expands diagnostic criteria from a single measure of lung function to include environmental exposure, symptoms, and abnormal computed tomography (CT) scans. The new criteria could lead to new treatments aimed at slowing the disease’s progression, the researchers say.
For the study, the researchers evaluated nearly 9,000 smokers and former smokers enrolled in the COPDGene® study, whose goal is to discover the genetic factors that contribute to the development of COPD. The researchers documented patients' environmental exposures (smoking), symptoms (shortness of breath, chronic cough and phlegm), structural abnormalities on CT scans (emphysema, gas-trapping and airway wall thickness) and lung function or spirometry (total volume of air exhaled from the lungs, and the volume of air exhaled in one second). They then correlated those measures with mortality and loss of lung function five years later and compared them with smokers with none of the other criteria.
In general, the more diagnostic criteria that were included, the higher the probability of developing COPD. Those with all four diagnostic criteria were designated as having Definite COPD. They had a 188 percent greater chance of losing significant lung function over five years and more than 5 times the risk of dying.
The study, funded by the NHLBI, appeared in Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation.