Do Patients Who Have Medicare Advantage Have Differing Lengths of Stay Following Hip and Knee Arthroplasty Procedures Compared to Traditional Medicare?

Abstract

Traditional Medicare (MC) and Medicare Advantage (MADV) differ in payment models and care coordination, which may influence hospital utilization. This study compared lengths of stay (LOS) among patients undergoing hip and knee arthroplasty procedures with MC versus MADV coverage. A single-center retrospective cohort study was performed including 1,104 hip and knee arthroplasty procedures in patients insured by MC or MADV between January 1, 2018 and December 31, 2022, including primary, revision, fracture, and infection cases. There were 739 patients who were covered by MC and 365 by MADV. The LOS was calculated as the difference between calendar dates of admission and discharge. Comparisons were made between insurance groups, with subgroup analyses for elective versus non-elective procedures and discharge disposition. There were 739 patients who were covered by MC and 365 by MADV. The mean LOS was 1.88 (range, one to 12) days for MC and 2.20 (range, one to 12) days for MADV (P = 0.0062). Among elective procedures, patients who were covered by MC had a shorter LOS compared to patients who were covered by MADV (1.37 versus 1.58 days; P = 0.0104). There was no significant difference in LOS observed for non-elective procedures (3.88 versus 4.18 days; P = 0.32). The two-way analyses of variance demonstrated discharge disposition as a strong predictor of LOS (P < 0.0001). While the main effect of insurance type was not significant (P = 0.16), a significant interaction between insurance type and discharge disposition was observed (P < 0.0001), indicating variation in the relationship between insurance coverage and LOS across discharge categories. Medicare Advantage coverage was associated with a longer LOS following elective lower extremity arthroplasty compared to Traditional Medicare, while no difference was observed for non-elective procedures. Discharge disposition significantly modified the relationship between insurance type and LOS, suggesting that differences in post-acute care pathways may contribute to observed LOS variation.