30-Day Acute Myocardial Infarction In-Hospital Mortality

This indicator calculates the risk-adjusted rate of all-cause in-hospital deaths occurring within 30 days of first admission with a diagnosis of 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

The risk-adjusted mortality rate (RAMR) is calculated by dividing the observed number of in-hospital deaths by the expected number of in-hospital deaths and multiplying by the Canadian average in-hospital death rate.

Unit of analysis for denominator cases: 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 7 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

Total number of first AMI episodes in an 11-month period

Numerator

Number of deaths from all causes occurring in hospital within 30 days of admission for AMI

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Name

30-Day Acute Myocardial Infarction In-Hospital Mortality

Short/Other Names

Not applicable

Description

The risk-adjusted rate of all-cause in-hospital death occurring within 30 days of first admission with a diagnosis of acute myocardial infarction (AMI)

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

Rationale

A lower risk-adjusted mortality rate following AMI may be related to quality of care or other factors. It has been shown that the 30-day in-hospital mortality rate is highly correlated (r = 0.9) with total mortality (death in and out of hospital) following AMI.

Variations in 30-day in-hospital mortality rates may be due to jurisdictional and institutional differences in care practices, as well as to other factors that were not included in the adjustment.

Interpretation

Lower rates are desirable.

HSP Framework Dimension

Appropriate and effective

Areas of Need

Getting Better

Targets/Benchmarks

Not applicable

Available Data Years

to

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

Beginning with the 2004 rates, AMI case selection criteria were revised to account for the fact that an increasing number of AMI patients are undergoing revascularization procedure (percutaneous coronary intervention or coronary artery bypass) at their index admission. In the case of revascularization procedure, AMI may not be coded as the most responsible diagnosis, and these cases were previously excluded from the indicator. In addition, exclusion criteria were revised and patients with a length of stay of less than three days and discharged alive are no longer excluded.

Prior to 2018–2019, indicator results by place of residence are based on 3 years of pooled data. Starting in 2018–2019, indicator results by place of residence are based on 1 year of data. Due to this change in reporting, trends over time should be interpreted with caution.

Description

The risk-adjusted mortality rate (RAMR) is calculated by dividing the observed number of in-hospital deaths by the expected number of in-hospital deaths and multiplying by the Canadian average in-hospital death rate.

Unit of analysis for denominator cases: 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 7 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:

Total number of first AMI episodes in an 11-month period

Inclusions:

    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 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.GT^^* ; 1.IJ.57.GU^^* ; 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]; 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 (Facility Type Code = 1). 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. Admission 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 at admission 18 years and older
  5. Sex recorded as male or female
  6. Urgent/emergent episodes (Admission Category Code = U in any records within an episode)

Note

*2018–2019 data onward.

Exclusions:

  1. Records with an invalid health card number
  2. Records with an invalid code for province issuing health card number
  3. Records with an invalid admission date
  4. Records with admission category of cadaveric donor or stillbirth (Admission Category Code = R or S)
  5. Records with a status of dead on arrival (Discharge Disposition = 11, 71* for NACRS)
  6. 2018–2019 data onward: Episodes with medical assistance in dying (MAID) (Discharge Disposition Code = 73)
  7. AMI episodes with length of stay less than 24 hours and patients alive at end of episodes
  8. Subsequent AMI episodes in the 11-month period (only the first AMI episode for a patient is included)

Note

*2018–2019 data onward.

Numerator

Description:

Number of deaths from all causes occurring in hospital within 30 days of admission for AMI

Inclusions:

  1. Discharges as deaths (Discharge Disposition Code = 07, 72*, 74*)
  2. Admission to an acute care institution (Facility Type Code = 1)
  3. (Discharge date on death record) − (Admission date on AMI record) less than or equal to 30 days

Note

*2018–2019 data onward.

Exclusions:

  1. Records with an invalid discharge date
  2. 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 or service

Data Sources

  • DAD
  • HMDB
  • NACRS

Caveats and Limitations

Not applicable

Trending Issues

Please refer to the Updates section for information on trending.

Comments

Indicator results are also available in

References

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

Tu JV, Austin P, Naylor CD, Iron, K, Zhang H. Acute Myocardial Infarction Outcomes in Ontario (Methods Appendix). Cardiovascular Health & Services in Ontario: An ICES Atlas (Technical and Methods Appendices). Eds. Naylor CD and Slaughter PM. Toronto, ON; Institute for Clinical Evaluative Sciences:1999.

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