The Lung Health Study showed that spirometry screening in a selected population is an effective way to identify individuals at risk for COPD and to initiate effective interventions. Thus, it seems reasonable to conclude that a clinical profile of asymptomatic COPD can make screening feasible (Table 1).
Smoking is the key attribute of such a profile. In the Lung Health Study, smoking cessation led to initial absolute improvement of lung function and subsequent improvement in the rate of decline, whereas a steep rate of decline was seen in those who continued to smoke. Of the 73,694 smokers who were screened for COPD in this study, about 25% met the criteria for mild to moderate airflow obstruction (FEV1 to FVC ratio of less than 70%) . This prevalence is high compared with that reported in other studies but correlates well with the results of the Manchester study described above. It is of interest to note that participants in the study tended to be heavy smokers – 20 to 30 cigarettes/day.
Table 1. Clinical profile of asymptomatic chronic obstructive pulmonary disease
|Smoking history||Anthonisen et al Sherrill et al Buist and Ducic|
|Age (35 years and older)||Anthonisen et al Fletcher and Peto Burrows et al|
|Methacholine reactivity||Tashkin et al Vollmer et al Barter and Campbell|
|Environmental exposures||Tashkin et al Oxman et al Becklake|