Environmental Public Health Tracking: Heart Disease and Stroke Data

In the U.S., the most common type of heart disease is coronary artery disease (CAD, or ischemic heart disease), which can lead to heart attack.

A heart attack is a brief and severe health event in which the heart does not get enough oxygen. This decrease in oxygen is caused by blocked blood flow to the heart muscle. A heart attack is also called myocardial infarction (MI).

Nearly one million people in the US have heart attacks every year. Learn more about heart attack risk factors and prevention tips on the heart disease web page.

A stroke happens when a blood vessel carrying oxygen and nutrients to the brain is either blocked by a clot or bursts. When that happens, part of the brain cannot get the blood (and oxygen) it needs, and brain cells die. Strokes are the number five cause of death in the U.S. 80% of strokes are preventable. Learn more about how to prevent a stroke.

Exposure to small particles in the air, called particulate matter, is a risk factor for heart disease and stroke. A number of studies reported associations between some air pollutants and hospitalizations for heart attacks and stroke.

The Tracking data allow public health professionals to monitor trends over time. These data may also help with program planning, policy, and evaluation efforts. Tracking heart disease, heart attack, and stroke will help public health professionals identify:

• Heart attack and stroke hospitalization changes over time.
• Seasonal variations.
• Geographic differences in prevalence, hospitalizations, and mortality.
• Differences in heart attack and stroke mortality by age, gender, and race/ethnicity.
• Disparities in heart attack and stroke mortality by factors such as age, race/ethnicity, and gender.
• Populations in need of targeted interventions.

Heart attacks

• Hospitalizations: Wisconsin Tracking provides data about heart attack hospital admissions and emergency department visits. The source of these data is the Wisconsin Hospital Association Information Center, Inc.
• Mortality: These indicators used data collected by vital records from CDC’s National Center for Health Statistics. Rates are calculated with U.S. Census data.

Heart disease

• Mortality: This indicator includes vital records data from CDC’s National Center for Health Statistics. Rates are calculated with U.S. Census data.
• Prevalence: Data are collected from the Behavior Risk Factor Surveillance Survey (BRFSS), the 2010 Census population, American Community Survey estimates, and from CDC’s Population Level Analysis and Community Estimates (PLACES) Project.

Strokes

• Hospitalizations: These data come from hospitals, the Centers for Medicare and Medicaid Services, and CDC’s Atlas of Heart Disease and Stroke.
• Mortality: These indicators used data collected by vital records from CDC’s National Center for Health Statistics and CDC’s Atlas of Heart Disease and Stroke.
• Prevalence: Data are collected from the Behavioral Risk Factor Surveillance Survey (BRFSS), the 2010 Census population, American Community Survey estimates, and from CDC’s Population Level Analysis and Community Estimates (PLACES) Project.

Heart attack

• Hospitalizations:
  • Annual number of hospitalizations, by age, gender, and geography
  • Annual unadjusted (crude) rate of hospitalizations by age, gender, and geography
  • Annual age-adjusted rate of hospitalizations for ages 35+, by gender and geography
• Mortality:
  • Age-adjusted death rate among persons 35+ per 100,000 population by gender, race/ethnicity, and geography
  • Crude death rate among persons 35+ per 100,000 population by age group, gender, race/ethnicity, and geography
  • Number of deaths among persons 35+ by age group, gender, race/ethnicity, and geography

Heart disease

• Mortality:
  • Age-adjusted death rate for ages 35+ per 100,000 population by gender, race/ethnicity, and geography
  • Crude death rate for ages 35+ per 100,000 population by age group, gender, race/ethnicity, and geography
  • Number of deaths among persons 35+ by age group, gender, race/ethnicity, and geography
• Prevalence:
  • Age-adjusted prevalence for ages 18+
  • Crude prevalence for ages 18+

Stroke

• Hospitalization:
  • Average annual age-adjusted hospitalization rate per 1,000 Medicare beneficiaries 65+ by gender, race/ethnicity, and geography
• Mortality:
  • Average annual age-adjusted death rate for ages 35+ per 100,000 population by age group, gender, race/ethnicity, and geography
• Prevalence:
  • Age-adjusted prevalence for ages 18+
  • Crude prevalence for ages 18+

Heart attack

• Hospitalizations:
  • Because these data are based on hospital admissions, some people who experience symptoms are not included, such as those who do not receive medical care, those whose care does not result in hospitalization, and people who die in settings such as ambulances, nursing homes, or at home.
  • Data from year 2000 to the present include hospitalizations among Wisconsin residents who were treated in Minnesota hospitals. In addition, data from year 2005 to the present include hospitalizations among Wisconsin residents who were treated in Iowa hospitals. These data do not include hospitalizations among residents of Wisconsin who were treated in border states of Michigan and Illinois.
  • These data do not include inpatient admissions at hospitals owned by the federal government, such as Veterans Administration hospitals.
• Mortality:
  • Death investigation laws vary by locale. In addition, variations may occur between localities in how medical examiners/coroners/physicians assign cause of death.

Heart disease

• Mortality:
  • Death investigation laws vary by locale. In addition, variations may occur between localities in how medical examiners/coroners/physicians assign cause of death.

Stroke

• Hospitalizations
  • Because these data are based on hospital admissions, some people who experience symptoms are not included, such as those who do not receive medical care, those whose care does not result in hospitalization, and people who die in settings such as ambulances, nursing homes, or at home.
  • This measure is restricted to Medicare beneficiaries aged 65 and older with fee-for-service coverage only.

Overall considerations

• 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 (race, gender, age)
  • Socioeconomic status (income level, education)
  • Geography (rural, urban)
  • Changes in the medical field (diagnosis patterns, reporting requirements)
  • Individual behavior (diet, smoking)

• Wisconsin Heart Disease and Stroke Prevention Program – Cardiovascular Health
• Centers for Disease Control and Prevention – Division for Heart Disease and Stroke Prevention
• National Heart, Lung, and Blood Institute

Heart attack hospitalizations

Number of hospitalizations for heart attack among persons 35 and over

These data include hospitalizations for heart attack and are collected from inpatient hospital discharge records. This measure includes hospitalizations with an ICD-9 code of 410.0-410.92 or an ICD-10 code of I21.0-I22.9 in the principal diagnosis field. Starting in 2015, transfers between hospitals were excluded. Data are suppressed for counties with fewer than six hospitalizations to protect confidentiality. However, counties with zero cases are not suppressed. Please note that counts are a statistically limited way to consider hospitalization data 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.

Crude rates of hospitalizations for heart attack among persons 35 and over per 10,000 people

These data include hospitalizations for heart attack and are collected from inpatient hospital discharge records. This measure includes hospitalizations with an ICD-9 code of 410.0-410.92 or an ICD-10 code of I21.0-I22.9 in the principal diagnosis field. Starting in 2015, transfers between hospitals were excluded. Data are suppressed for counties with fewer than six hospitalizations 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 area of interest (for example, a county). 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.

Age-adjusted rates of hospitalization for heart attack among persons 35 and over per 10,000 people

These data include hospitalizations for heart attack and are collected from inpatient hospital discharge records. This measure includes hospitalizations with an ICD-9 code of 410.0-410.92 or an ICD-10 code of I21.0-I22.9 in the principal diagnosis field. Starting in 2015, transfers between hospitals were excluded. Data are suppressed for counties with fewer than six hospitalizations 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 heart attacks are more frequent among older individuals and some counties have more older individuals than others. Direct age-adjustment is conducted using the 2000 U.S. standard population.

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