Close search bar

30-Day Acute Myocardial Infarction Readmission

This indicator provides the risk-adjusted rate of urgent readmission following discharge for acute myocardial infarction (AMI).

Lower rates are desirable.

Data updated:
Data availability: to (fiscal years)
Geographic coverage
All provinces/territories
Reporting level
National, Province/Territory, Region, Neighbourhood Income Quintile
Calculation

Risk-adjusted readmission rate for each region = Observed number of readmissions for each region ÷ Expected number of readmissions for the region × Canadian average readmission rate

Unit of analysis: Episode of care

An episode of care refers to all contiguous inpatient hospitalizations and same-day surgery visits. For episodes with transfers within or between facilities, transactions were linked regardless of diagnoses. To construct an episode of care, a transfer is assumed to have occurred if either of the following conditions is met:

  1. An acute care hospitalization or a same-day surgery visit occurs less than seven hours after discharge from the previous acute care hospitalization or same-day surgery visit, regardless of whether the transfer is coded;
  2. An acute care hospitalization or same-day surgery visit occurs between 7 and 12 hours after discharge from the previous acute care hospitalization or same-day surgery visit, and at least one of the hospitalizations or visits has coded the transfer.
Denominator

Number of AMI episodes of care discharged between April 1 and March 1 of the fiscal year

Numerator

Cases within the denominator with a readmission for any reason within 30 days of discharge after the index episode of care

Download CSV Expand/collapse all All accordions expanded

Name

30-Day Acute Myocardial Infarction Readmission

Short/Other Names

Not applicable

Description

This indicator provides the risk-adjusted rate of urgent readmission following discharge for acute myocardial infarction (AMI).

For further details, please see the General Methodology Notes (PDF).

Rationale

Readmissions to acute care facilities are increasingly being used to measure institutional or regional quality of care and care coordination. Readmission rates after AMI can be influenced by a variety of factors, including the quality of inpatient and outpatient care, effectiveness of the care transition and coordination, or the availability of appropriate diagnostic or therapeutic technologies during the initial hospital stay. While not all urgent readmissions are avoidable, interventions during and after a hospitalization can be effective in reducing readmission rates.

Interpretation

Lower rates are desirable.

HSP Framework Dimension

Health system outputs: Appropriate and effective

Areas of Need

Getting Better

Targets/Benchmarks

Not applicable

Available Data Years

to (fiscal years)

Geographic Coverage

  • All provinces/territories

Reporting Level/Disaggregation

  • National
  • Province/Territory
  • Region
  • Neighbourhood Income Quintile

Indicator Results

Web Tool:
Health Indicators e-Publication
 

Update Frequency

Every year

Latest Results Update Date

Updates

Not applicable

Description

Risk-adjusted readmission rate for each region = Observed number of readmissions for each region ÷ Expected number of readmissions for the region × Canadian average readmission rate

Unit of analysis: Episode of care

An episode of care refers to all contiguous inpatient hospitalizations and same-day surgery visits. For episodes with transfers within or between facilities, transactions were linked regardless of diagnoses. To construct an episode of care, a transfer is assumed to have occurred if either of the following conditions is met:

  1. An acute care hospitalization or a same-day surgery visit occurs less than seven hours after discharge from the previous acute care hospitalization or same-day surgery visit, regardless of whether the transfer is coded;
  2. An acute care hospitalization or same-day surgery visit occurs between 7 and 12 hours after discharge from the previous acute care hospitalization or same-day surgery visit, and at least one of the hospitalizations or visits has coded the transfer.

Type of Measurement

Rate - per 100

Denominator

Description:

Number of AMI episodes of care discharged between April 1 and March 1 of the fiscal year

Inclusions:

  1.  
    1. Acute myocardial infarction (AMI) (ICD-10-CA: I21, I22; ICD-9/ICD-9-CM: 410) is coded as most responsible diagnosis (MRDx) but not also as a diagnosis type (2); or 
    2. Where another diagnosis is coded as MRDx and also as a diagnosis type (2), and a diagnosis of AMI is coded as a type (1) [type (C) for Quebec data] or (type (W), (X) or (Y) but not also as type (2)); or 
    3. Where coronary artery disease (ICD-10-CA: I25.0, I25.1, I25.8, I25.9; ICD-9/ICD-9-CM: 429.2, 414.0, 414.8, 414.9) is coded as MRDx, AMI as type (1) [type (C) for Quebec data] or type (W), (X) or (Y) but not also as type (2); along with revascularization procedure (percutaneous coronary intervention–CCI: 1.IJ.50^^ ; 1.IJ.57.GQ^^ [this code is used for 2002–2003 to 2017–2018 data only]; 1.IJ.54.GQ-AZ [this code is used for 2006–2007 to 2008–2009 data only]; 1.IJ.57.GT*; 1.IJ.57.GU*; CCP: 48.02, 48.03; ICD-9-CM: 36.01, 36.02, 36.05; or coronary artery bypass–CCI: 1.IJ.76^^ ; CCP: 48.1^; ICD-9-CM: 36.1^).
  2. Episodes involving inpatient care. An episode may start or end in a day surgery setting. Episodes that both start and end in day surgery settings are not included.
  3. Discharge between April 1 and March 1 of the following year (period of case selection ends March 1 to allow for 30 days of follow-up)
  4. Age 18 and older
  5. Sex recorded as male or female
  6. Urgent/emergent episodes (Admission Category Code = U in any records within an episode)

Exclusions:

  1. Records with an invalid health card number
  2. Records with admission category of cadaveric donor or stillbirth (Admission Category Code = R or S)
  3. Records with an invalid code for province issuing health card number
  4. Records with an invalid admission date or time
  5. Records with an invalid discharge date or time
  6. Episodes with discharge as death (DAD Discharge Disposition Code = 07, 72*, 73*, 74*; NACRS Visit Disposition Code = 10, 11, 71*, 72*, 73*, 74*)
  7. Episodes with length of stay less than 24 hours
  8. AMI episodes that are within 30 days of a previous AMI episode

    Note
    *2018–2019 data onward.

Numerator

Description:

Cases within the denominator with a readmission for any reason within 30 days of discharge after the index episode of care

Inclusions:

  1. Emergent or urgent (non-elective) readmission to an acute care hospital (Admission Category Code = U)

Exclusions:

  1. 2018–2019 data onward: Medical assistance in dying (MAID) (Discharge Disposition Code = 73)

Method of Adjustment

Logistic regression

Adjustment Applied

Covariates used in risk adjustment:

For a detailed list of covariates used in the model, please refer to the Model Specification (PDF) document.

Geographic Assignment

Place of residence

Data Sources

  • DAD
  • HMDB
  • NACRS

Caveats and Limitations

Patients can appear in the denominator more than once if they have multiple episodes of care between April 1 and March 1 of the fiscal year.

Planned readmissions reported as urgent admissions are included in the readmission rate.

Trending Issues

Not applicable

Comments

Not applicable

References

Ashton CM, Wray NP. A Conceptual Framework for the Study of Early Readmission as an Indicator of Quality of Care. Soc Sci Med; 1996; 43: 1533-1541.

Hosmer DW, Lemeshow S. Confidence Interval Estimates of an Index of Quality Performance Based on Logistic Regression Models. Stat Med 1995; 14: 2161-2172.

Krumholz HM, et al. Hospital 30-Day Acute Myocardial Infarction Readmission Measure: Methodology. Baltimore, MD: Centers for Medicare & Medicaid Services; 2008. Accessed September 24, 2024.

How to cite:

Canadian Institute for Health Information. 30-Day Acute Myocardial Infarction Readmission . Accessed April 25, 2025.