Table 1.
Inclusion criteria | Rationale |
---|---|
1. Enrolled in Medicare fee-for-service | Hospital claims data are regularly available only for Medicare fee-for-service beneficiaries. |
2. Age 65 or older | Medicare patients younger than age 65 qualify for Medicare due to severe disability, making them distinctly different from the elderly Medicare population. |
3. Discharged from a non-federal acute care hospital alive | Only those patients who are alive at time of hospital discharge are eligible for a readmission. |
4. Enrolled in Parts A and B Medicare for the 12 months prior to the date of the index admission | Including Medicare Part A beneficiaries ensures there are no Medicare Part C (Medicare Advantage patients) in the data. Enrollment in Medicare in the 12 preceding months ensures 1 year of administrative data for risk adjustment purposes. |
5. Have a qualifying elective primary THA/TKA procedure, without any of the following: | Elective primary THA/TKA is the procedure of interest in this study. |
(a) Femur, hip or pelvic fractures coded in the principal or secondary discharge diagnoses fields of the index admission | Procedures to correct an orthopedic fracture are considered non-elective. Patients with orthopedic fracture tend to have higher mortality, complication and readmission rates. |
(b) Partial hip arthroplasty procedures with concurrent THA/TKA | Partial hip arthroplasty are primarily indicated for hip fractures. |
(c) Revision procedures with a concurrent THA/TKA | Few hospitals perform THA/TKA revision procedures and are associated with higher mortality, complication and readmission rates. |
(d) Resurfacing procedures with a concurrent THA/TKA | Resurfacing procedures are distinctly different than THA/TKA and are primarily indicated for younger, healthier patients. |
(e) Mechanical complication of the pelvis, sacrum, coccyx, lower limbs, or bone/bone marrow or disseminated malignant neoplasm coded in the principal discharge diagnosis field | A mechanical complication was likely present on admission and may require more technically complex procedures to correct. Patients with malignant neoplasms undergoing a THA/TKA are likely not elective and the patients are more likely to have a readmission. |
(f) Removal of implanted devices/prostheses | Removal of implanted device/prostheses may be more complicated. |
(g) Transfer from another acute care facility for THA/TKA | Transfers from another acute care facility for THA/TKA is likely not elective. |
Exclusion criteria | |
1. Without at least 30 days post-discharge enrollment in fee-for-service Medicare | Since readmissions are identified using claims data, 30 days of post-discharge enrollment in Medicare fee-for-service is required. |
2. Discharged against medical advice (AMA) | Patients leaving AMA may not allow providers to deliver complete and full care to prepare the patient for discharge. |
3. Admitted for the index procedure and subsequently transferred to another acute care facility | Including these cases in the readmission measure makes it difficult to determine to which hospital the readmission outcome should be attributed. |
4. With more than two THA/TKA procedure codes during the index hospitalization | More than two THA/TKA procedures likely reflects an error in coding. |
Source: Suter et al. [10].