Acute Myocardial Infarction (Heart Attack) Metadata: Hospitalizations


Hospitalization data are from the Maine Health Data Organization (MHDO). Population data are from the U.S. Census Bureau.

Dates Available:

2001 – 2014, 2016

Geographic Resolution:

State, County, Town


The Maine EPHT program receives hospitalization data annually, based on discharge date, from MHDO. Acute myocardial infarction (AMI) hospitalizations among Maine residents are analyzed and stratified by transfer status (whether transfers from one hospital to another were included or excluded), geographic resolution, age group, and sex.
The dataset contains the following measures:

  1. Crude rate of AMI hospitalizations per 10,000 population (transfers included/transfers excluded)
  2. Age-adjusted rate of AMI hospitalizations per 10,000 population (transfers included/transfers excluded)
  3. Number of hospitalizations for AMI (transfers included/transfers excluded)


This data set supports efforts to improve public health in Maine and contributes to the U.S. CDC’s National Environmental Public Health Tracking (EPHT) Network. A key activity of participants in this network is to track and make available environmental health measures on state and national data portals. Measures derived from the data set described here can be used to compare AMI visits across the state, between groups of people, over time, and in relation to risk factors, exposures, and health outcomes.

The Maine Tracking Network, a member of the National EPHT Network, connects communities, public health professionals, policy makers, state agencies, and others to the data they need to monitor public health, respond to health concerns, prioritize resources for public health action, and evaluate prevention activities. Maine tracks certain health effects, exposures, and environmental hazards that have known relationships, as well as some health effects and environmental hazards that have suspected relationships. By making health and environmental data available through the Maine Tracking Network, more people have access to data they need to think critically and hypothesize about health outcomes and their relationships to conditions in the environment.

Supplemental Information:

AMI is more commonly known as a heart attack. The Maine EPHT program analyzes AMI events among Maine residents by the year of hospital admission. Hospitalization data are de-duplicated within the hospital of care. Duplicate hospitalization records are excluded prior to analysis. From 2001 through September 2015, AMI hospitalizations are identified as Maine residents who are hospitalized at any non-federal hospital in Maine with a primary discharge diagnosis of AMI, defined by ICD-9-CM code 410 (including all sub variation codes 410.0-410.92). Beginning in October 2015, ICD-10-CM codes I21-I22 (including all sub variation codes) were used to define AMI. Hospitalization data for all of calendar year 2015 are omitted due to the change in discharge diagnosis coding practices from ICD-9-CM to ICD-10-CM.

Individuals admitted to an acute care hospital for a heart attack often require specialized medical care. Because of this, patients are often transferred to another facility within hours or days of a heart attack. Hospitalization rates that include transfers of heart attack patients could be considered an overestimate, because the same individual/heart attack is counted twice. AMI hospitalization measures are available with transfers included and excluded to identify geographic locations in the state that are more or less likely to transfer patients from one healthcare facility to another. Transfers are identified and de-duplicated (for measures with transfers excluded) using an approximate unique identifier created to identify and link patients with a primary discharge diagnosis of AMI who transfer from one hospital to another. The unique patient identifier is created using the patient’s date of birth, sex, and city/town of residence.

Entity and Attribute Overview:

This dataset contains the following fields: transfers included or excluded, admission year, geographic resolution, location, sex, age group, number of hospitalizations, population, rate per 10,000 (with accompanying 95% CI’s), age-adjusted rate per 10,000 (with accompanying 95% CI’s).

Data Limitations:

  • Only individuals who sought treatment for AMI at a hospital, and received a primary diagnosis of AMI, are included in the data.
  • Data represent the number of hospitalizations for AMI and not the number of individual people hospitalized.
  • Only Maine residents admitted to Maine hospitals are included in the analysis; the total number of AMI events, especially in areas served by hospitals in neighboring states or provinces, may be undercounted.
  • When comparing rates across geographic areas, a variety of factors, including socio-demographic characteristics and access to medical care, can impact the likelihood of persons being hospitalized for AMI.

Access Constraints:

Publicly available data are suppressed in accordance with the Maine CDC Privacy Policy to protect confidentiality.

Suggested Citation for Data Displays:

Maine Center for Disease Control and Prevention, Maine Tracking Network. Myocardial Infarction: Hospitalizations.  Available online:  Accessed on [date accessed].