Asthma Hospitalizations and Emergency Department (ED) Visits

Data Sources & Limitations

Hospitalization and Emergency Department Data

These figures are based on hospitalization and emergency department (ED) data from the Office of Statewide Health Planning and Development (OSHPD), which is responsible for routinely collecting data from hospitals in California.

The datasets include information like age, gender, race/ethnicity, and diagnosis. A case due to asthma is identified by looking at the principal diagnosis based on the International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM). A principal diagnostic ICD-9-CM code of 493 indicates a patient who was admitted to a hospital or visit an ED because of asthma.

Population Data

County-level population estimates are from the California Department of Finance (DOF). DOF uses year 2000 population data collected by the U.S. Census Bureau and takes into account survival rates, migration patterns, and fertility rates for California to project the California population by county, race/ethnicity, age, and gender for 2000-2050.

Zip code-level population estimates are based on 2000 population data collected by the U.S. Census Bureau, zip code routes from the U.S. Postal Service, and other data sources to estimate population counts at the zip code level. Please note that zip codes do not have exact spatial boundaries, change very frequently, and can cross city and county boundaries.

For more information on the data sources and limitations, go to the methods section.

Why Some Query Submissions Return No Results

Users request data by selecting from a number of choices, or parameters. For the Asthma data query, these parameters include indicator (e.g. hospitalizations), time period, race/ethnicity group, age group, gender, geographic unit, and calculation method.

Query results have been calculated ahead of time and entered into our data system. This allows the system to respond to query results more quickly. Once the query is submitted, results are provided to the user.

The query tool is designed to give the user maximum flexibility for requests. However, some combinations of parameters do not have corresponding results in our data system. This is why a data query may not return results.

There are a number of reasons why results may not be available for certain combinations of parameters. Most common reasons include:

• The data do not presently exist. Data availability is subject to resource and logistical limitations.
• We have not calculated results for the specific query combination. Calculating results requires time and resources. Therefore, we prioritized calculating results for the measures and parameter combinations that we anticipated would meet the most common needs and be of most interest to the public.

Frequently, user needs can be met by slightly altering the parameters in question. If this is not the case, please feel free to contact us with your specific data request: data@cehtp.org

Which Asthma Query Submissions Will Not Work

For the Asthma data query system specifically, the following combinations do not have results calculated:

• Selecting the "spatially modeled" calculation method for any single race/ethnic group will not produce results. These have not been calculated because few racial and/or ethnic groups are represented state-wide, which makes modeled rates difficult to interpret.

If you are interested in any of the parameter combinations that we have not yet calculated, it may be that you are pursuing questions that, although valid, have not occurred to us. Please feel free to contact us with your specific data request: data@cehtp.org