STHMA IS COMMON, AFFECTing 5% to 12% of the adult population. 1,2 In the United States alone, asthma affects more than 200 000 adults and accounted for approximately 465000 hospitalizations, 1.8 million emergency department visits, 10.4 million physician office visits, and 4487 deaths in 2000. 3 For largely unknown reasons, US women have a 30% higher prevalence and 40% more asthma attacks than men, and blacks have a 10% higher prevalence and 20% more asthma attacks than whites. 3 The prevalence of self-reported asthma has increased 74% over the past 2 decades, 2 with a doubling in the number of office visits and a 61% increase in asthma-related deaths. 2 The current total annual costs of asthma are $11 billion. 2-5 Asthma is characterized clinically by repeated episodes of wheezing, breathlessness, chest tightness, and coughing, usually in the presence of variable (and reversible) airflow obstruction. 6 Most patients also demonstrate air-Author Affiliations and Financial Disclosures are listed at the end of this article.

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