SELECTED ARTICLES FROM THE RECENT LITERATURE 2004
8/19/04
Asthma as a risk factor for COPD
Summary
Background - Asthma has traditionally been considered as an entity separate from COPD. It is generally thought that asthma generally does not progress to COPD unless other factors, particularly tobacco smoking, are involved.
Findings - Silva et al of the Univ. of Arizona in Tucson, AZ determined whether there was an increased development of COPD in adults initially diagnosed as asthmatic among a population of 3,099 individuals followed over a period of 20 years with sequential respiratory questionnaires and pulmonary function tests. They found that subjects initially diagnosed with active asthma (n=192) had a 10 fold greater risk for developing chronic bronchitis and a 12.5 higher risk for eventually fulfilling criteria for a diagnosis of COPD than were non-asthmatics. These increased risk factors persisted even after adjusting for smoking history and other potential confounders. The authors concluded that physician-diagnosed asthma is significantly associated with an increased risk for chronic bronchitis and COPD.
Reference
Chest 2004;126:59-65
Editor's Comments
For years, most asthma specialists have assured their asthmatic patients that they were at little risk of developing irreversible airway diseases such as COPD if the patients did not smoke or get recurrent pneumonias. I think that this statement is still true for some, but maybe not all, asthmatics. There is increasing evidence that uncontrolled airways inflammation in asthma may lead to airways remodeling, with local fibrosis and other irreversible changes in the airways of such patients. Thus, some chronic asthmatics may ultimately exhibit elements of irreversibility and other features seen in COPD. Whether genetic or environmental factors determine which asthmatics are at particular risk for such irreversible charges is currently not well defined.
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