Preventive Care

Hundreds of patients would need to undergo spirometry to defer a single acute exacerbation of COPD

A substantial number of smokers with severe airflow obstruction do not recognize or report respiratory symptoms to their doctor. This suggests that screening smokers for COPD might be beneficial. However, screening smokers for COPD using spirometry (which measures lung capacity when a patient breathes into a tube) is likely to identify mostly patients with mild to moderate airflow obstruction. For these patients, there is no evidence that medications are beneficial or that spirometry measurements motivate smokers to quit.

Since most COPD patients are older than 50, screening would not necessarily increase the number of patients recommended to receive annual flu shots. Even in the best case scenario, hundreds of patients would need to undergo spirometry to defer a single acute exacerbation of COPD, according to a new study by Kenneth Lin, M.D., and Mary Barton, M.D., M.P.P., of the Agency for Healthcare Research and Quality, and colleagues. They summarized the evidence on spirometry screening for COPD for the U.S. Preventive Services Task Force. They examined eight key questions on the benefits and harms of screening.

The evidence revealed that medications for COPD reduced acute exacerbations in patients with severe disease. However, severe COPD is uncommon in the general U.S. population. Potential harms from screening identified in studies reviewed by the authors include false-positive results and adverse effects from subsequent unnecessary therapy. One limitation was that no studies provided direct evidence on health outcomes associated with screening for COPD.

More details are in "Screening for chronic obstructive pulmonary disease using spirometry: Summary of the evidence for the U.S. Preventive Services Task Force," by Dr. Lin, Bradley Watkins, M.D., Tamara Johnson, M.D., M.S., Joy Anne Rodriguez, M.D, M.P.H., and Dr. Barton, in the April 1, 2008, Annals of Internal Medicine 148(7), pp. 535-543.

Reprints (AHRQ Publication No. 08-R058) are available from the AHRQ Publications Clearinghouse.

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