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
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.