Risk of 30-day Readmission After Knee or Hip Replacement in Rheumatoid Arthritis and Osteoarthritis by Non-Medicare and Medicare Payer Status.

Objective: To determine the indication and risk of 30-day rehospitalization after hip or knee replacement among patients with rheumatoid arthritis (RA) and osteoarthritis (OA) by Medicare and non-Medicare status.

Methods: Using the Nationwide Readmission Database (2010-2014), we defined an index hospitalization as an elective hospitalization with a principal procedure of total hip (THR) or knee replacement (TKR) among adults aged ≥ 18 years. Primary payer was categorized as Medicare or non-Medicare. Survey logistic regression provided the odds of 30-day rehospitalization in RA relative to OA. We calculated the rates for principal diagnoses leading to rehospitalization.

Results: Overall, 3.53% of 2,190,745 index hospitalization had a 30-day rehospitalization. Patients with RA had a higher adjusted risk of rehospitalization after TKR (OR 1.11, 95% CI 1.02-1.21) and THR (OR 1.39, 95% CI 1.19-1.62). Persons with RA and OA did not differ with respect to rates of infections, cardiac events, or postoperative complications leading to the rehospitalization. After TKR, RA patients with Medicare had a lower venous thromboembolism (VTE) risk (OR 0.58, 95% CI 0.58-0.88), whereas those with RA had a greater VTE risk (OR 2.41, 95% CI 1.04-5.57) after THR.

Conclusion: Patients with RA had a higher 30-day rehospitalization risk than OA after TKR and THR regardless of payer type. While infections, postoperative complications, and cardiac events did not differ, there was a significant difference in VTE as the principal diagnosis of rehospitalization.