Environmental Public Health Tracking: COPD Data

COPD stands for chronic obstructive pulmonary disease. 

COPD is a group of diseases that affects a person’s breathing and makes it hard for them to get oxygen to their lungs. COPD includes emphysema and chronic bronchitis. 

For people with COPD, the inside of their airways can become inflamed. This inflammation makes it harder to breathe, leading to shortness of breath. 

Although there is no cure for COPD, its symptoms can be treated.

To learn more about COPD, visit the CDC's (Centers for Disease Control and Prevention) COPD webpage.

The main cause of COPD is cigarette smoking. However, breathing in other lung irritants, such as air pollution, secondhand smoke, fumes, or dust over a long period of time can also cause it.

More information about COPD is available from the CDC’s COPD webpage.

There is strong evidence linking COPD to tobacco smoke and to indoor and outdoor air pollution. 

Research shows a connection between air pollution and increased hospital admissions and emergency department visits for COPD.

Gathering data on COPD trends allows public health professionals to identify high-risk groups and geographical areas, evaluate current prevention efforts, and plan programs and policies to reduce the burden of COPD.

With Wisconsin Tracking data, public health professionals can answer questions, such as:

• How many emergency department visits for COPD occur each year?
• How do hospitalizations or emergency department visits for COPD differ between counties?
• Are there disparities in COPD hospitalizations or emergency department visits among different age groups, races, ethnicities, and genders at the state level?
• Which populations are in greatest need of programs, policies, or other interventions to address COPD?
• How do levels of certain environmental exposures, such as particulate matter, relate to COPD hospitalizations and emergency department visits?

The source of these data is the Wisconsin Hospital Association Information Center, Inc. 

To calculate rates, these data are combined with population data from the National Center for Health Statistics.

• Annual number of hospitalizations and emergency department visits, by location
• Monthly number of emergency department visits
• Average daily number of hospitalizations and emergency department visits
• Annual unadjusted (crude) rate for COPD hospitalizations and emergency department visits, by location
• Annual age-specific rates of COPD hospitalizations and emergency department visits
• Annual age-adjusted rate of COPD hospitalizations and emergency department visits, by gender, race, ethnicity, and location

• Because these data are based on inpatient hospitalizations and emergency department visits, some people who experience symptoms are not included. These people include those who do not receive medical care; those whose care does not result in hospitalization; and those who die in settings, such as ambulances, nursing homes, or at home.
• These data do not include inpatient hospitalizations or emergency department visits at hospitals owned by the federal government. This includes Veterans Administration hospitals.
• Data from the year 2000 to present include hospitalizations among Wisconsin residents who were treated in Minnesota hospitals. In addition, data from the year 2005 to present include hospitalizations among Wisconsin residents who were treated in Iowa hospitals.
• Data from the year 2002 to present include emergency department visits among Wisconsin residents who were treated in Minnesota hospitals. In addition, data from the year 2005 to present include emergency department visits among Wisconsin residents who were treated in Iowa hospitals.
• Data users should keep in mind that many factors contribute to a disease. These factors should be considered when interpreting the data. Factors include:
  • Demographics (e.g., race, gender, age)
  • Socioeconomic status (e.g., income level, education)
  • Geography (e.g., rural, urban)
  • Changes in the medical field (e.g., diagnosis patterns, reporting requirements, coding changes, medical advances)
  • Individual behavior (e.g., diet, smoking)

• CDC – COPD
• American Lung Association – COPD
• National Heart, Lung, and Blood Institute – COPD

COPD emergency department visits

Number of emergency department visits for COPD

These data include emergency department visits for COPD and are collected from emergency room visit discharge records, for persons aged 25 years and older. Emergency department visits resulting in subsequent hospitalization are also included. Federally funded hospitals (for example, Veteran's Administration (VA) hospitals, which are exempt from state reporting requirements) are not included in these data. This measure includes emergency department visits with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Data are suppressed for counties with fewer than five visits to protect confidentiality. However, counties with zero cases are not suppressed. Please note that counts are a statistically limited way to consider emergency department visits because they do not allow for accurate comparison between counties. Counties with higher populations, such as Milwaukee, will have more emergency department visits simply because they have more people. An age-adjusted rate is a better measure for true comparison between counties. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

Crude rates of emergency department visits for COPD per 10,000 people

These data include emergency department visits for COPD and are collected from emergency room visit discharge records, for persons aged 25 years and older. Emergency department visits resulting in subsequent hospitalization are also included. Federally funded hospitals (for example, VA hospitals, which are exempt from state reporting requirements) are not included in these data. This measure includes emergency department visits with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2, Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Data are suppressed for counties with fewer than five visits to protect confidentiality. However, counties with zero cases are not suppressed. The crude rate is the number of emergency department visits divided by the total number of people in the area of interest (for example, a county). Population of interest is derived from census data (2000 standard population). This is expressed as a number per unit population such as "per 10,000 population." Crude rates do not take into account the differences in age distributions across counties and are therefore subject to bias. Use age-adjusted rates for a better standardized measure. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

COPD emergency department visits age-specific rates per 10,000 people

These data include emergency department visits for COPD and are collected from emergency room visit discharge records, for persons aged 25 years and older. Emergency department visits resulting in subsequent hospitalization are also included. Federally funded hospitals (for example, VA hospitals, which are exempt from state reporting requirements) are not included in these data. This measure includes emergency department visits with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Data are suppressed for counties with fewer than five visits to protect confidentiality and improve rate stability. However, counties with zero cases are not suppressed. The age-specific rate is the number of emergency department visits for a certain age group divided by the total number of people in that age group and area of interest (for example, a county). Population of interest is derived from census data (2000 standard population). This is expressed as a number per unit population such as "per 10,000 population." Ages are grouped into the following categories: 0-24 years, 25-44 years, 45-64 years, 65-84 years, and 85+ years. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

COPD emergency department visits age-adjusted rates per 10,000 people

These data include emergency department visits for COPD and are collected from emergency room visit discharge records, for people over the age of 25. Emergency department visits resulting in subsequent hospitalization are also included. Federally funded hospitals (for example, VA hospitals, which are exempt from state reporting requirements) are not included in these data. This measure includes emergency department visits with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Data are suppressed for counties with fewer than five visits to protect confidentiality and improve rate stability. However, counties with zero cases are not suppressed. An age-adjusted rate is a rate that is statistically modified to eliminate the potential biasing effect of different age distributions across different populations. In other words, the age-adjusted rate accounts for the possibility that emergency department visits for COPD may be more frequent among older individuals and the fact that some counties have older populations than others. Direct age-adjustment is conducted using the 2000 U.S. standard population. Note: Due to a number of cases where ethnicity was not collected for discharge records and is thus unknown, there are several years where the ‘combined’ age-adjusted rate for ethnicity is higher than the age-adjusted rates for both Hispanic and non-Hispanic populations. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

Average daily count for COPD emergency department visits

These data include emergency department visits for COPD and are collected from emergency room visit discharge records, for persons aged 25 years and older. This measure includes emergency department visits with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Average Daily Count was calculated by dividing the monthly count by the number of days in that respective month. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

COPD hospitalizations

Number of hospitalizations for COPD

These data include hospitalizations for COPD and are collected from inpatient hospital discharge records, for persons aged 25 years and older. This measure includes hospitalizations with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Data are suppressed for counties with fewer than five visits to protect confidentiality. However, counties with zero cases are not suppressed. Please note that counts are a statistically limited way to consider emergency department visits because they do not allow for accurate comparison between counties. Counties with higher populations, such as Milwaukee, will have more hospitalizations simply because they have more people. An age-adjusted rate is a better measure for true comparison between counties. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

Crude rates of hospitalizations for COPD per 10,000 people

These data include hospitalizations for COPD and are collected from inpatient hospital discharge records, for persons aged 25 years and older. This measure includes hospitalizations with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Data are suppressed for counties with fewer than five visits to protect confidentiality. However, counties with zero cases are not suppressed. The crude rate is the number of hospitalizations divided by the total number of people in the population of interest (for example, a county). Population of interest is derived from census data (2000 standard population). This is expressed as a number per unit population, such as "per 10,000 population." A crude rate does not take into account the differences in age distributions across counties and are therefore subject to bias. Use age-adjusted rates for a better standardized measure. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

COPD hospitalizations age-specific rates per 10,000 people

These data include hospitalizations for COPD and are collected from inpatient hospital discharge records, for persons aged 25 years and older. This measure includes hospitalizations with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Data are suppresses data for counties with fewer than five visits per 10,000 to protect confidentiality. However, counties with zero cases are not suppressed. The age-specific rate is the number of hospitalizations for a certain age group divided by the total number of people in that age group and area of interest (for example, a county). Population of interest is derived from census data (2000 standard population). This is expressed as a number per unit population such as "per 10,000 population." Ages are grouped into the following categories: 0-24 years, 25-44 years, 45-64 years, 65-84 years, and 85+ years. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

COPD hospitalizations age-adjusted rates per 10,000 people

These data include hospitalizations for COPD and are collected from inpatient hospital discharge records, for persons aged 25 years and older. This measure includes hospitalizations with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Data are suppressed for counties with fewer than five visits per 10,000 to protect confidentiality. However, counties with zero cases are not suppressed. An age-adjusted rate is a rate that is statistically modified to eliminate the potential biasing effect of different age distributions across different populations. In other words, the age-adjusted rate accounts for the possibility that hospitalizations for COPD may be more frequent among older individuals and the fact that some counties have older populations than others. Direct age-adjustment is conducted using the 2000 U.S. standard population. Due to a number of cases where ethnicity was not collected for discharge records and is thus unknown, there are several years where the "combined" age-adjusted rate for ethnicity is higher than the age-adjusted rates for both Hispanic and non-Hispanic populations. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

Average daily count for COPD hospitalizations

These data include hospitalizations for COPD and are collected from inpatient hospital discharge records, persons aged 25 years and older. This measure includes hospitalizations with any of the following ICD-9 codes in the principal diagnosis field: 490, 491, 492, 496, and 493.2. Cases with 493.2 as a primary diagnosis are excluded if none of the secondary diagnosis fields contain 490, 492, or 496. The measure also includes any of the ICD-10 codes J40-J44 in the principal diagnosis field. Average Daily Count was calculated by dividing the monthly count by the number of days in that respective month. In 2018 a new block group variable became available, for accuracy the new variable is now used to determine the county instead of the county variable.

Explore definitions and explanations of terminology found on the portal, like age-adjusted rate and confidence intervals.