Interpreting the data
What these data tell us:
- These data tell us rates of hospitalizations and emergency department visits among Colorado residents over time and across counties. The rate is the number of hospitalizations or emergency department visits per state or county population in a calendar year.
What these data do not tell us:
- 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 since people who are hospitalized or admitted to the emergency room often have more severe illness.
- Comparisons of these rates of hospitalization and emergency department visits to environmental measures should be done with caution.
- Elevated rates of hospitalizations and emergency department visits in a geographic area with higher than average environmental exposure do not necessarily indicate that the environmental exposure is causing the higher rate.
- There may be other factors that lead to increased disease rates within a geographic area. Rates may differ due to factors such as access to medical care which can affect the likelihood of a person being hospitalized for asthma.
Numerator/denominator information
Event/numerator data:
- Hospital discharges, Hospital Discharge Data Set, Colorado Hospital Association.
- Emergency department discharges, Emergency Department 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 emergency department visits datasets do not include all cases. Those who do not receive medical care, receive medical treatment in outpatient settings (other than emergency department), or die without being admitted to a hospital are not included in these datasets.
Differences in rates by year or county may reflect differences or changes in medical coding or billing for hospitalizations and emergency department visits, or changes in access to medical care.
Although exact duplicate records are excluded, the measures are based upon events, not individuals. If the same person is admitted to the hospital or emergency department multiple times for the same condition in the same year, these events would be counted as separate events, even though it was the same person. 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, which may vary across the county.
Data not included
These data do not include hospital or emergency department discharges from Federal facilities in Colorado, such as U.S. Department of Veterans Affairs Medical Centers.
Calculation methods
Case definition for hospitalizations and emergency department visits occurring:
- before October 1, 2015 are based on diagnosis codes from the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9CM).
- 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:
- per 10,000 population for asthma, chronic obstructive pulmonary disease (COPD), and heart attack.
- per 100,000 population for carbon monoxide poisoning and heat-related illness.
Age-adjusted rates are calculated:
- per 10,000 population for asthma, chronic obstructive pulmonary disease, and heart attack
- 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.
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