WHA Risk-Adjusted All Cause Readmission Measure Specification Rev. Oct 2017 Table of Contents Section 1: Readmission Algorithm Summary... 1 Section 2: Risk Adjustment Method... 3 Section 3: Examples... 4 Appendix: Readmission Criteria Tables... 5 Section 1: Readmission Algorithm Summary This algorithm applies to inpatient admissions with a discharge date of 1/1/2017 or later. The methods used in this algorithm are based on the 2017 Measures Updates and Specifications Report for Hospital-Wide All- Cause Unplanned Readmissions, prepared for CMS. The report can be downloaded from this link. WHA/WHAIC modifications to this method include: Modification the measure will include all ages and payers Modification - the measure will not be risk adjusted. The Measures Team has studied the lack of risk adjustment and did not find a relationship between overall readmission rates and case mix index. Modification the measure will exclude patients admitted with an AODA primary diagnosis. The process first selects all inpatient admissions where the discharge date lies within the reporting quarter, and also those in the following quarter, since a readmission may occur outside the reporting quarter. Internally the admission records are assigned these True/False fields: IsExcluded, IsIndex, and HasReadmission. Excluded records are ignored. Only index admissions are examined for having a readmission. Admissions are organized by the Unique Case Identifier (UCID) field which identifies a specific patient. If an inconsistent gender or date of birth is found within the records for a specific UCID, or if an overlapping admit/discharge date is found in those records, all of the records for that UCID are marked excluded. Non-excluded records are considered index admissions unless one or more of these conditions applies: Discharge status 20: Expired. Discharge status 07: Discharged against medical advice. Discharge status 02, 05 or 66: Discharged to non-acute care setting. The principal diagnosis is for a primary psychiatric diagnosis. See Section 3, Table D.1. The principal diagnosis is for rehabilitation, defined as diagnosis CCS 254. The principal diagnosis is for a primary AODA diagnosis. See Section 3, Table D.2. The principal diagnosis is for cancer treatment. See Section 3, Table D.3. The admission is considered a transfer, as defined below. Transfers cannot be index admissions. These conditions constitute transfers: Existence of a readmission to another hospital within one day of discharge, regardless of the disposition of the previous admission. Existence of a readmission to the same hospital on the same day of discharge for the same principal diagnosis. 1
Existence of a readmission to the same hospital on the same day of discharge, where the discharge status of the first admission is 65 or 93, indicating a transfer to an in-hospital psychiatric unit. When a transfer is found to have occurred, check for another transfer. Keep checking until no further transfers are found. The last admission is considered to be the index. Once the index admissions are determined, each is examined and compared to the next admission for that patient. The comparisons below are done in order: 1. If no later admission was found, or the next admission was more than 30 days after the previous discharge, no readmission applies. 2. If the principal procedure on the readmission indicates a bone marrow, kidney or other organ transplant, Cesarean section, forceps, vacuum or breech delivery, the readmission is considered planned and is not counted in the numerator. See Section 3, Table PR.1 3. If the principal diagnosis on the readmission indicates maintenance chemotherapy, rehabilitation, forceps or normal delivery, the readmission is planned and is not counted in the numerator. See Section 3, Table PR.2 4. If a principal or secondary procedure on the readmission appears in the Potentially Planned Procedure Category list (Section 3, Table PR.3), and the principal diagnosis is not an acute diagnosis or complication of care (Section 3, Table PR.4), the readmission is planned and is not counted in the numerator. 5. If none of the above applies, the readmission is unplanned and HasReadmission is set to True on the index admission. A hospital s readmission rate is the count of records for that hospital where HasReadmission is True, divided by the count of records where IsIndex is True. A readmission can be considered a new index admission if it meets the criteria. 2
Section 2: Risk Adjustment Method Risk-adjusted (RA) All Cause Readmission (ACR) rate can be interpreted as the rate for a hospital if it treated an average mix of APRDRG-Severities. A hospital experiencing below-average readmission rates for the APRDRG-Severities of the patients it treated will show the overall statewide readmission rate, but reduced accordingly. Hospitals of average performance will show RA rates closer to the statewide average (normative) rate. APRDRG, severity score (1, 2, 3 or 4), numerator and denominator for the ACR measure are provided by Wisconsin Hospital Association Information Center from its discharge data collection. RA rates then are calculated as follows: 1. Statewide normative readmission rates are calculated as an aggregate for all hospitals for each APRDRG-Severity combination: Normative Rate = (sum of numerators) / (sum of denominators) 2. Expected Numerators are calculated for each hospital-aprdrg-severity combination using the appropriate normative rate: Hospital Expected Numerator = (Normative Rate * denominator) 3. A hospital s overall observed rate for each APRDRG-Severity combination is calculated: Hospital Observed Rate = numerator / denominator 4. Expected numerators are summed for each hospital and divided by their observed denominators to calculate an overall hospital expected rate: Hospital OA Expected Rate = (sum of expected numerators) / (sum of denominators) 5. An overall normative rate is calculated for all APRDRG-Severity combinations: OA Normative Rate = (sum of numerators) / (sum of denominators) 6. Overall RA hospital rate is then calculated by scaling it for each hospital according to their performance: Hospital RA Rate = (Hospital OA Observed Rate/ Hospital OA Expected Rate) * OA Normative Rate 3
Section 3: Examples These hypothetical cases are all for the same patient. Hospital Admit Date Discharge Date Principal Diagnosis Principal Procedure Is Index Has Readmission Comments 1 1/1/2016 1/5/2016 P0718 0VTTXZZ True False 1 3/1/2016 3/2/2016 I222 False False 1 3/2/2016 3/3/2016 I222 False False 2 3/4/2016 3/4/2016 I222 5A02210 False False 3 3/20/2016 3/22/2016 N179 True True 3 3/22/2016 3/24/2016 S72146A 0QSC06Z True False 3 3/28/2016 3/29/2016 Z44009 0HBQXZZ False False 4 4/15/2016 4/28/2016 F10129 False False 5 5/15/2016 5/22/2016 I2510 4A023N7 True False 5 5/29/2016 6/4/2016 I2510 02104ZC True True 5 7/1/2016 7/1/2016 A419 0JHP3XZ False False Index admission. No readmission because the next admission was more than 30 days after discharge. Not an index because the next admission was to the same hospital, on the same day of discharge, for the same principal diagnosis. Considered a transfer. Not an index because this is considered a transfer to hospital 2, since next admission was within one day of discharge. Had discharge status 02 indicating transfer. Not an index, regardless of the next admission. Next admission is to the same hospital, same day of discharge, but different principal diagnosis. Treat as index and readmission. Does not have readmission because next admission was planned. Principal diagnosis is in CCS 254 (rehabilitation) which is considered always planned. Also, CCS 254 means this visit cannot be a new index admission. Principal diagnosis is in CCS 660 (AODA) so it cannot be an index. New index, but next admission was planned. Principal procedure is in CCS 44, considered potentially planned. Principal diagnosis is in CCS 101, not in the acute diagnosis list. Considered a planned readmission to 5/15. Is also considered a new index, with a readmission on 7/1. Had discharge status 20 indicating patient expired. Not an index admission. 4
Appendix: Readmission Criteria Tables These tables reference the HCUP/AHRQ Clinical Classification Software tables. Click on the links for CCS maps to ICD-10 diagnosis and procedure codes. Table D.2 AODA Discharge Diagnosis Categories Excluded from the Measure AHRQ Diagnosis CCS Description 660 Alcohol-related disorders 661 Substance-related disorders 5
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