Tracking asthma involves not only collecting data about people diagnosed and living with asthma but also collecting data about people who experience asthma attacks. This includes tracking the number of people ever told by a physician that they have asthma, the number of asthma-related physician visits, the number of hospital or emergency room visits, and the number of deaths due to asthma. Public health officials rely on many sources of data including:
- surveys of self-reported symptoms or diagnoses,
- medical encounters of people receiving care for asthma, and
- death certificates.
Each source gives a snapshot of different aspects of the burden of asthma. Hospitalizations, emergency room visits, and deaths represent more severe health outcomes associated with asthma. Such outcomes may be the result of poor asthma management, lack of access to healthcare, and exposure to known triggers. While we can use survey data to estimate the number of people suffering from asthma attacks, we do not have data on exactly when, where, and how often individuals have asthma attacks.
The Tracking Network includes data on asthma hospitalizations and asthma prevalence which is the number of people diagnosed with and living with asthma. These data are useful in providing estimates about the geographic distribution and effects of asthma among different populations. These estimates can be used to plan and evaluate asthma interventions.
The hospital admissions data available on the Tracking Network present state hospital discharge data which reflects more severe exacerbations of asthma. Persons who have to stay in the hospital because of asthma usually have more severe attacks than persons with asthma symptoms who are not hospitalized. The Tracking Network is using hospital admission dates while other public health programs use the hospital discharge dates to count asthma cases. This may cause a difference in asthma rates between the Tracking Network and other public health Web sites. For more information about the limitations of these data, visit the Hospitalizations for Asthma indicator page
The asthma prevalence data used on the Tracking Network are obtained from the BRFSS. BRFSS data are self-reported and reflect the perceptions of respondents. Self-reported data have some limitations because respondents may have difficulty recalling events and understanding questions. Furthermore, cultural and language barriers and limited health knowledge can affect the quality of self-reported data. For more information about the limitations of these data, visit the Asthma Prevalence among Adults and Children indicator pages.