Interpreting the data
What these data tell us:
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The rates of hospitalizations and emergency department (ED) visits among Colorado residents over time and across counties.
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The rate is the number of hospitalizations or ED visits per state or county population in a calendar year.
What these data do not tell us:
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These data do not tell us the number of people who currently have or experience each condition. The data may reflect more severe cases of each condition. People who are hospitalized or admitted to the emergency room often have more severe illness.
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Comparisons of hospitalization and ED visits to environmental measures should be done with caution.
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Areas with higher environmental exposure and elevated rates of events do not necessarily mean the exposure is the cause.
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There may be other factors that lead to increased rates within an area. Rates may differ due to factors such as access to medical care. For example, lack of access to medical care can affect the likelihood of a person being hospitalized for asthma.
Numerator/denominator information
Event/numerator data:
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Hospital discharges, Hospital Discharge Data Set, Colorado Hospital Association.
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ED discharges, ED Discharge Data Set, Colorado Hospital Association.
Population/denominator data:
- Midyear resident population estimates. Source: State Demography Office, Colorado Department of Local Affairs.
Limitations of the data
The hospital and ED visits datasets do not include all cases. The following cases are not included in these datasets:
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Those who do not receive medical care.
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Those who receive medical treatment in outpatient settings (other than emergency department).
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Those who die without being admitted to a hospital.
Differences in rates by year or county may reflect changes in medical coding, billing, or access to medical care.
Although exact duplicate records are excluded, the measures are based upon events, not individuals. For example, if someone is admitted multiple times for a condition within one year, each visit is a separate event. If people are being counted more than once, the reported rate may be higher than the true rate.
Reporting rates at the state and county level is a broad measure. This means the data will not show the true disease burden at a more local level, such as the neighborhood. These data are not geographically specific enough to be linked with many types of environmental exposure.
Data not included
These data do not include hospital or ED discharges from federal facilities in Colorado. One federal facility is the U.S. Department of Veterans Affairs Medical Centers.
Calculation methods
Case definition for hospitalizations and ED visits occurring:
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before October 1, 2015 are based on diagnosis codes from the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9CM).
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on or after October 1, 2015 are based on diagnosis codes from the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10CM).
Age-specific rates in each age group and geographic population are calculated:
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per 10,000 population for asthma, chronic obstructive pulmonary disease (COPD), and heart attack.
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per 100,000 population for carbon monoxide poisoning and heat-related illness.
Age-adjusted rates are calculated:
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per 10,000 population for asthma, chronic obstructive pulmonary disease (COPD), and heart attack
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per 100,000 population for carbon monoxide poisoning and heat-related illness.
Rates are adjusted for differences across age and sex by the direct method using the Year 2000 U.S. Standard Population.