Inflow/Outflow Ratio
A ratio of less than 1 indicates that health care utilization by residents of a region exceeded care provided within that region, suggesting an outflow effect. A ratio of greater than 1 indicates that care provided by a region exceeded the utilization by its residents, suggesting an inflow effect. A ratio of 1 indicates that care provided by a region was equivalent to the utilization by its residents, suggesting that inflow and outflow activity, if it existed at all, was balanced. A ratio of 0 is an indication that none of the institutions in the region provided the service and residents received care outside of their region.
The indicator is expressed as an overall ratio, calculated for discharges associated with any diagnosis or procedure (acute care discharges only) and separately for coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI), hip replacement, knee replacement and hysterectomy procedures. There are six inflow/outflow ratios:
- Overall
- CABG
- PCI
- Hip replacement
- Knee replacement
- Hysterectomy
Ratio = Number in numerator ÷ Number in denominator
Unit of Analysis: Single admission
Number of separations (discharges and deaths) from acute care/same-day surgery facilities generated by residents of the region for a given procedure
Number of separations (discharges and deaths) from acute care/same-day surgery facilities within a given region (including non-residents) for all cases and for a given procedure
Methodology
Name
Inflow/Outflow Ratio
Short/Other Names
Not applicable
Description
This indicator is a ratio, calculated as the number of separations (discharges and deaths) from acute care/same-day surgery facilities within a given region divided by the number of acute care/same-day surgery separations generated by residents of that region.
For further details, please see the General Methodology Notes (PDF).
Rationale
This indicator reflects the balance between the quantity of hospital stays provided to both residents and non-residents by all relevant facilities (acute care/same-day surgery) in a given region and the extent of utilization by residents of that region, whether they received care within or outside of the region.
Interpretation
A ratio of less than 1 indicates that health care utilization by residents of a region exceeded care provided within that region, suggesting an outflow effect. A ratio of greater than 1 indicates that care provided by a region exceeded the utilization by its residents, suggesting an inflow effect. A ratio of 1 indicates that care provided by a region was equivalent to the utilization by its residents, suggesting that inflow and outflow activity, if it existed at all, was balanced. A ratio of 0 is an indication that none of the institutions in the region provided the service and residents received care outside of their region.
HSP Framework Dimension
Health system outputs: Person-centred
Areas of Need
Getting Better
Targets/Benchmarks
Not applicable
Available Data Years
to (fiscal years)
Geographic Coverage
- All provinces/territories
Reporting Level/Disaggregation
- Region
Indicator Results
Web Tool:
Health Indicators e-Publication
Update Frequency
Every year
Latest Results Update Date
Updates
Not applicable
Description
The indicator is expressed as an overall ratio, calculated for discharges associated with any diagnosis or procedure (acute care discharges only) and separately for coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI), hip replacement, knee replacement and hysterectomy procedures. There are six inflow/outflow ratios:
- Overall
- CABG
- PCI
- Hip replacement
- Knee replacement
- Hysterectomy
Ratio = Number in numerator ÷ Number in denominator
Unit of Analysis: Single admission
Type of Measurement
Ratio
Denominator
Description:
Number of separations (discharges and deaths) from acute care/same-day surgery facilities generated by residents of the region for a given procedure
Inclusions:
CABG (acute care discharges only):
CCI: 1.IJ.76^^
PCI (acute care and same-day surgery discharges):
CCI: 1.IJ.50^, 1.IJ.57.GQ^^ (this code is used for 2017–2018 and earlier), 1.IJ.54.GQ-AZ (this code is used for 2006–2007 to 2008–2009 only), 1.IJ.57.GT (from 2018–2019), 1.IJ.57.GU (from 2018–2019)
Hip replacement (acute care and same-day surgery discharges):
CCI: 1.VA.53.^^ (excluding 1VA53LASLN and 1VA53LLSLN when intervention status attribute does not equal R), 1.SQ.53.^^
Knee replacement (acute care and same-day surgery discharges):
CCI: 1.VG.53.^^ (excluding 1VG53LASLN when intervention status attribute does not equal R), 1.VP.53.^^
Hysterectomy (acute care and same-day surgery discharges):
CCI: 1.RM.89^^, 1.RM.91^^, 1.RM.87.BA-GX, 1.RM.87.CA-GX, 1.RM.87.DA-GX, 1.RM.87.LA-GX with intervention extent attribute coded as SU
Note:
procedure codes may be recorded in any position.
Numerator
Description:
Number of separations (discharges and deaths) from acute care/same-day surgery facilities within a given region (including non-residents) for all cases and for a given procedure
Inclusions:
CABG (acute care discharges only):
CCI: 1.IJ.76^^
PCI (acute care and same-day surgery discharges):
CCI: 1.IJ.50^, 1.IJ.57.GQ^^ (this code is used for 2017–2018 and earlier), 1.IJ.54.GQ-AZ (this code is used for 2006–2007 to 2008–2009 only), 1.IJ.57.GT (from 2018–2019), 1.IJ.57.GU (from 2018–2019)
Hip replacement (acute care and same-day surgery discharges):
CCI: 1.VA.53.^^ (excluding 1VA53LASLN and 1VA53LLSLN when intervention status attribute does not equal R), 1.SQ.53.^^
Knee replacement (acute care and same-day surgery discharges):
CCI: 1.VG.53.^^ (excluding 1VG53LASLN when intervention status attribute does not equal R), 1.VP.53.^^
Hysterectomy (acute care and same-day surgery discharges):
CCI: 1.RM.89^^, 1.RM.91^^, 1.RM.87.CA-GX, 1.RM.87.DA-GX, 1.RM.87.LA-GX with intervention extent attribute coded as SU
Note that procedure codes may be recorded in any position.
Method of Adjustment
Not applicable
Adjustment Applied
None
Geographic Assignment
Place of residence or service
Data Sources
- DAD
- HMDB
- NACRS
Caveats and Limitations
Not applicable
Trending Issues
Not applicable
References
Heart and Stroke Foundation of Canada. The Growing Burden of Heart Disease and Stroke in Canada 2003. Available at http://publications.gc.ca/collections/Collection/H1-10-2003E.pdf. Accessed March 01, 2014.
Johansen HL, et al. Incidence, Comorbidity, Case Fatality and Readmission of Hospitalized Stroke Patients in Canada. Can J Cardiol. 2006;22:65-71.
Truelsen T, Bonita R and Jamozik K. Suveillance of Stroke: A Global Perspective. Int J Epidemiol. 2001;30:S11-S16.
World Health Organization. WHO STEPS Stroke Manual: The WHO STEPwise Approach to Stroke Surveillance. Geneva, Switzerland: WHO, 2006.
How to cite:
Canadian Institute for Health Information. Inflow/Outflow Ratio. Accessed April 24, 2025.
If you would like CIHI information in a different format, visit our Accessibility page.
Comments
Beginning with 2015-2016 data, cement spacers are excluded from hip and knee replacement cases when they are not revisions; comparability with previous years should not be affected.