The Association Between Hospital Length of Stay and 90-Day Readmission Risk Within a Total Joint Arthroplasty Bundled Payment Initiative

To curb the unsustainable rise in health care expenses, health care payers are developing programs to incentivize hospitals and physicians to improve the value of care delivered to patients. Payers are utilizing various metrics, such as length of stay (LOS) and unplanned readmissions, to track progression of quality metrics. Relevant to orthopedic surgeons, the Centers for Medicare and Medicaid Services announced in 2015 the Comprehensive Care for Joint Replacement Payment Model—a program aimed at improving the quality of health care delivered to patients by shifting more of the financial risk of patient care onto providers.

We analyzed the medical records of 1329 consecutive lower extremity total joint patients enrolled in Centers for Medicare and Medicaid Services’ Bundled Program for Care Improvement treated over a 21-month period. The goal of this study was to ascertain if hospital LOS is associated with unplanned readmissions within 90 days of admission for a total hip or knee arthroplasty.

After controlling for multiple demographic variables including sex, age, comorbidities and discharge location, we found that hospital LOS greater than 4 days is a significant risk factor for unplanned readmission within 90 days (odd ratio = 1.928, P = .010). Total knee arthroplasty (TKA) and discharge to a location other than home are also independent risk factors for 90-day readmission.

Our results demonstrate that increased LOS is a significant risk factor for readmission within 90 days of admission for a hip or knee arthroplasty in the Medicare population.