Problem/Condition: Asthma, a chronic disease occurring among both children and adults, has been the focus of clinical and public health interventions during recent years. In addition, CDC has outlined a strategy to improve the timeliness and geographic specificity of asthma surveillance as part of a comprehensive public health approach to asthma surveillance.

Reporting Period Covered: This report presents national data regarding self-reported asthma prevalence, school and work days lost because of asthma, and asthma-associated activity limitations (1980--1996); asthma-associated outpatient visits, asthma-associated hospitalizations, and asthma-associated deaths (1980--1999); asthma-associated emergency department visits (1992--1999); and self-reported asthma episodes or attacks (1997--1999).

Description of Systems: CDC's National Center for Health Statistics (NCHS) conducts the National Health Interview Survey annually, which includes questions regarding asthma and asthma-related activity limitations. NCHS collects physician office-visit data in the National Ambulatory Medical Care Survey, emergency department and hospital outpatient data in the National Hospital Ambulatory Medical Care Survey, hospitalization data in the National Hospital Discharge Survey, and death data in the Mortality Component of the National Vital Statistics System.

Results: During 1980--1996, asthma prevalence increased. Annual rates of persons reporting asthma episodes or attacks, measured during 1997--1999, were lower than the previously reported asthma prevalence rates, whereas the rates of lifetime asthma, also measured during 1997--1999, were higher than the previously reported rates. Since 1980, the proportion of children and adults with asthma who report activity limitation has remained stable. Since 1995, the rate of outpatient visits and emergency department visits for asthma increased, whereas the rates of hospitalization and death decreased. Blacks continue to have higher rates of asthma emergency department visits, hospitalizations, and deaths than do whites.

Interpretation: Since the previous report in 1998 (CDC. Surveillance for Asthma---United States, 1960--1995. MMWR 1998; 47 [No. SS-1]: 1--28), changes in asthma-associated morbidity and death have been limited. Asthma remains a critical clinical and public health problem. Although data in this report indicate certain early indications of success in current asthma intervention programs (eg, limited decreases in asthma hospitalization and death rates), the continued presence of substantial racial disparities in these asthma endpoints highlights the need for continued surveillance and targeted interventions.