Screening for chronic obstructive pulmonary disease using spirometry: summary of the evidence for the U.S. Preventive Services Task Force.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. Fewer than half of the estimated 24 million Americans with airflow obstruction have received a COPD diagnosis, and diagnosis often occurs in advanced stages of the disease.
PURPOSE: To summarize the evidence on screening for COPD using spirometry for the U.S. Preventive Services Task Force (USPSTF). DATA SOURCES: English-language articles identified in PubMed and the Cochrane Library through January 2007, recent systematic reviews, expert suggestions, and reference lists of retrieved articles. STUDY SELECTION: Explicit inclusion and exclusion criteria were used for each of the 8 key questions on benefits and harms of screening. Eligible study types varied by question. DATA EXTRACTION: Studies were reviewed, abstracted, and rated for quality by using predefined USPSTF criteria. DATA SYNTHESIS: Pharmacologic treatments for COPD reduce acute exacerbations in patients with severe disease. However, severe COPD is uncommon in the general U.S. population. Spirometry has not been shown to independently increase smoking cessation rates. Potential harms from screening include false-positive results and adverse effects from subsequent unnecessary therapy. Data on the prevalence of airflow obstruction in the U.S. population were used to calculate projected outcomes from screening groups defined by age and smoking status. LIMITATION: No studies provide direct evidence on health outcomes associated with screening for COPD.
CONCLUSION: Screening for COPD using spirometry is likely to identify a predominance of patients with mild to moderate airflow obstruction who would not experience additional health benefits if labeled as having COPD. Hundreds of patients would need to undergo spirometry to defer a single exacerbation.