Hospital Deaths (HSMR)
Lower is better. The HSMR is most useful to follow a hospital's performance over time.
The ratio of the actual number of in-hospital deaths to the expected number of in-hospital deaths, for conditions accounting for about 80% of inpatient mortality
Unit of Analysis: Hospitalization
Expected deaths, or number of deaths that would have occurred in a hospital or region had the mortality of these patients been the same as the mortality of similar patients across the country, based on the reference years (2018–2019 to 2020–2021)
HSMR case selection criteria:
Observed deaths, or actual number of in-hospital deaths that occurred in a hospital or region
Methodology
Name
Hospital Deaths (HSMR)
Short/Other Names
Hospital Standardized Mortality Ratio (HSMR)
Description
The ratio of the actual number of in-hospital deaths in a region or hospital to the number that would have been expected, based on the types of patients a region or hospital treats.
For further details, please refer to the following documents:
Rationale
The HSMR is a performance indicator that allows hospitals to measure and monitor their progress in quality of care.
Ever since the HSMR measure was first developed and disseminated by CIHI, many hospitals and health providers across Canada have been using it as part of their ongoing efforts to improve care.
The HSMR can be used to track the overall change in mortality resulting from a broad range of factors, including changes in the quality and safety of care delivered.
Interpretation
Lower is better. The HSMR is most useful to follow a hospital's performance over time.
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
Reporting Level/Disaggregation
- National
- Province/Territory
- Region
- Facility
Indicator Results
Update Frequency
Every year
Latest Results Update Date
Updates
The most recent changes to the HSMR methodology include the following:
- For COVID-19 patients only, 2 risk adjustment models were used to calculate the probability of in-hospital death. The first was used for all data years prior to and including 2021–2022; the second was used for 2022–2023 onward.
- Developed an updated top 80 list of diagnosis groups using 2018–2019 to 2020–2021 data; diagnosis group C80 was replaced with K83, R41 and U07.
- HSMR results are calculated with an updated baseline using 2018–2019 to 2020–2021 data. The previous baseline was calculated using 2015–2016 to 2017–2018 data.
Description
The ratio of the actual number of in-hospital deaths to the expected number of in-hospital deaths, for conditions accounting for about 80% of inpatient mortality
Unit of Analysis: Hospitalization
Type of Measurement
Ratio
Denominator
Description:
Expected deaths, or number of deaths that would have occurred in a hospital or region had the mortality of these patients been the same as the mortality of similar patients across the country, based on the reference years (2018–2019 to 2020–2021)
HSMR case selection criteria:
Inclusions:
- Admission to an acute care institution (Facility Type Code = 1)
- Discharge with diagnosis group of interest (i.e., one of the diagnosis groups that account for about 80% of in-hospital deaths, after excluding patients receiving palliative care)
- Age at admission between 29 days and 120 years
- Sex recorded as male or female
- Length of stay of up to 365 consecutive days
- Admission category recorded as urgent/emergent or elective (Admission Category Code = U or L)
Exclusions:
- Cadavers or stillborns (Discharge Disposition Code = 08 or 09, or Admission Category Code = R or S)
- Records with most responsible diagnosis (MRDx) of palliative care (ICD-10-CA: Z51.5). For Quebec data: records where Z51.5 coded as MRDx, or cancer (C00–C97) coded as MRDx and Z51.5 coded in any secondary diagnosis field
- Medical assistance in dying (MAID):
- 2016–2017 to 2017–2018 data only:
Discharge Disposition Code = 07 (in-hospital death) AND either 1 of the following 2:- Prefix = J in any field; OR
- 3 CCI codes: 1.ZZ.35.HA-P7, 1.ZZ.35.HA-P1, 1.ZZ.35.HA-N3 (all present on the same abstract)
- 2018–2019 data onward: Discharge Disposition Code = 73
- 2016–2017 to 2017–2018 data only:
Numerator
Description:
Observed deaths, or actual number of in-hospital deaths that occurred in a hospital or region
Inclusions:
Death (Discharge Disposition Code = 07, 72*, 74*)
Note
*2018–2019 data onward
Exclusions:
Same as for the denominator
Method of Adjustment
Logistic regression
Adjustment Applied
Covariates used in risk adjustment:
For each HSMR diagnosis group, the HSMR logistic regression models are fitted with age, sex, length-of-stay (LOS) group, admission category (urgent and elective), comorbidity (Charlson Index Score) group, transfers and COVID-19 as independent variables.
Geographic Assignment
Place of service
Data Sources
- DAD
- HMDB
Trending Issues
Not applicable
References
Alexandrescu R, Jen MH, Bottle A, Jarman B, Aylin P. Logistic versus hierarchical modeling: an analysis of a statewide inpatient sample. J Am Coll Surg 2011;213(3):392-401.
Bottle A, Jarman B, Aylin P. Hospital standardized mortality ratios: sensitivity analyses on the impact of coding. Health Serv Res 2011;46(6pt1):1741-1761.
Bottle A, Jarman B, Aylin P. Strengths and weaknesses of hospital standardised mortality ratios. BMJ 2011;342:c7116.
Breslow NE, Day NE. Statistical Methods in Cancer Research: Volume II: The Design and Analysis of Cohort Studies. Lyon: International Agency for Research on Cancer; 1987.
Jarman B, Gault S, Alves B et al. Explaining differences in English hospital death rates using routinely collected data. BMJ 1999;318(7197):1515-1520.
Jarman B, Bottle A, Aylin P, Browne M. Monitoring changes in hospital standardised mortality ratios. BMJ 2005;330(7487):329.
Quan H, Li B, Couris CM et al. Updating and validating the Charlson comorbidity index and score for risk adjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol 2011;173(6):676-682.
How to cite:
Canadian Institute for Health Information. Hospital Deaths (HSMR) . Accessed April 24, 2025.
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Comments
Further information is available in the Technical Notes and other HSMR resources.
Indicator results are also available in