Definition

A readmission is a care event where a patient is admitted to any inpatient stay within 30 days of being discharged from an inpatient stay. Like this: INP D/C  INP (RE)Admission within 30 days.

The Trella Health Readmission Rate is a percentage measurement of readmissions against a select population. This rate can be calculated for either hospitals or post-acute agencies. Please see below for lots of information on calculation.

Usage

 Readmission rates are one of the most critical metrics for evaluating all facilities involved with a patient's care path. The ideal is for this rate to be low. Compare readmission rates between similar types of providers and against national or regional benchmarks. As always, you will want to compare your agency's readmission rates with your competitor's.

Calculation

Overview

All readmission metrics are calculated from multiple claim events. These combined events are considered a readmission when a patient is discharged from an inpatient stay and is readmitted to inpatient care again within 30 days. This readmission scenario could include a post-acute stay, or multiple post-acute stays during that 30 day period. 

 The following basic equation shows how this rate is calculated.

 A bunch of clarifications!

• "Applicable discharges" in this equation could be a variety of patient populations depending on the facility, agency, or focus of the specific metric. For example, the complete population could be:
  • A group of post-acute admission events. (that is, to hospice or home health.) We would not count a discharge that does not include a post-acute admission for a readmission rate for a post-acute agency.
  • Count of inpatient discharges - note that this is different from count of distinct discharged patients
• The numerator in this equation is limited to facilities identified under the taxonomies: General Acute, Rural, of Critical Access hospitals.
• Planned admissions are not counted as a readmission, and will not be counted in the numerator.
• Numerator - For any single discharge we we only count a single readmission event. This way, if a patient is in and out of inpatient care multiple times within 30 days, each "pair" of events only counts as one readmission.
• Denominator - when generating our "applicable discharges," we exclude patient discharges with a status code of "02" - transfer to another hospital.
• Inpatient Rehab Facilities stays are not counted in readmission metrics.

Reporting Periods

There are a number of different reporting periods that we use to generate our metrics. To calculate readmission rates we use offset two-year and offset one-year reporting periods. The reason we offset the reporting period is to allow a 30 day reference period for a readmission to take place after the initial inpatient discharge (see images below.)

 Our Process: To identify the matching claims that generate our readmission rates, we first look in a specified reporting period and identify inpatient discharges. Each inpatient discharge is an "index event." We then search through the following 30 day reference period to identify corresponding inpatient admissions. Once we find the pair of events, we have identified a readmission.

Reporting Period for most Readmission Rates

Most Readmission Rates in Marketscape use an offset two year reporting period. We identify inpatient discharges during this two-year (24 month) period. The end of this two-year period is offset from the end of the most recent data set by 30 days. In order to get a full 24 months of re-admissions, we use a 25 month reference period within which we identify the inpatient REadmission.

Trended Readmission Rates

The Trended Readmission Rates (found on the Analyze pages in the Utilization and Quality tab) are calculated using an offset one year reporting period. The end of this one-year period is offset from the end of the most recent data set by 30 days. In order to get a full 12 months of re-admissions, we use a 13 month reference period within which we identify the inpatient REadmission.

Because the trended readmission rates are calculated using a one year period, this metric will not match other readmission rates listed under the last reported quarter in other locations in Marketscape for the same organization. In addition, because of the shortened reporting period, you will notice a higher number of readmission rates that are not reported to comply with privacy suppression.

Inpatient versus post-acute readmission rates

Our discussion up to this point has been largely focused on readmission rates for inpatient hospitals.

We also calculate readmission rates for post-acute agencies. Here is how:

• Remember that we look for every readmission event; a combination of a INP D/C and a INP Admission within 30 days.
• We then compile every post-acute admission that happens between the two.
• As you can see from the image below, we have what we need for a post-acute readmission metric.

 The following equation shows the calculation:

 For this equation, PAC Admission would always be for the same post-acute facility.

Another way to visualize this is:

Numerator: INP D/C  PAC Adm  INP Adm within 30 days

Denominator: INP D/C  PAC Adm within 30 days

Deep in the weeds: Exceptions/Inclusions

 For a "set" of claims relative to a specific patient to be counted in an inpatient readmission rate, there does not need to be a post-acute admission between discharge and re-admission. Additionally, the "set" of claims could have multiple post-acute admissions in between and still apply. 

Examples of readmissions: (all claim events happen within 30 days of the first INP D/C)

INP D/C  INP Admission (Adm)

INP D/C  PAC Adm  INP Adm

INP D/C  HHA Adm  HOS Adm  INP Adm

Which PAC gets the "Credit" for a readmission?

The examples above are relative to understanding readmission rates for hospitals, that is, inpatient care. The metrics would be readmission rates for listed hospitals. When we calculate readmission rates for post-acute agencies, the claim for post-acute admission will occur in the sandwich between the inpatient discharge and readmission, as this image shows:

INP D/C  PAC Adm  INP Adm

In this case, the readmission rate for the post-acute care agency is limited to patients admitted to post-acute care at the specific agency. 

The following scenario is a bit more complicated. Imagine that a patient is admitted to two post-acute agencies between the inpatient discharge and readmission.

INP D/C  PAC1 Adm  PAC2 Adm  INP Adm

In this case, only the second post-acute agency gets a readmission count towards the final readmission rate. The reason we do this is to indicate a higher level of responsibility to the agency that provided the most recent care prior to the readmission.

Unique SNF metrics

 If you are digging around in our SNF Product, you will notice that we have a 60 day and 90 readmission rate. In short, we calculate these two metrics in the same way as the 30 day readmission rates, but use 60 and 90 day reference periods for identifying the corresponding inpatient REadmissions. The reporting periods for these metrics are also offset further from the end of the data set to provide the the 60 or 90 day reference period required.