Risk Adjustment Is Necessary in Value-Based Payment Models for Arthroplasty for Oncology Patients

Value-based payment models such as bundled payments have been introduced to reduce costs following total hip arthroplasty (THA). Concerns exist, however, about access to care for patients who utilize more resources. The purpose of this study is thus to compare resource utilization and outcomes of patients undergoing THA for malignancy with those undergoing THA for fracture or osteoarthritis.

We queried the American College of Surgeons National Surgical Quality Improvement Program database to identify all hip arthroplasties performed from 2013 to 2016 for a primary diagnosis of malignancy (n = 296), osteoarthritis (n = 96,480), and fracture (n = 13,406). The rates of readmissions, reoperations, comorbidities, mortality, and surgical characteristics were compared between the 3 cohorts. To control for confounding variables, a multivariate analysis was performed to identify independent risk factors for resource utilization and outcomes following THA.

Patients undergoing THA for malignancy had a longer mean operative time (155.7 vs 82.9 vs 91.0 minutes, P < .001), longer length of stay (9.0 vs 7.2 vs 2.6 days, P < .001), and were more likely to be discharged to a rehabilitation facility (42.1% vs 61.8% vs 20.2%, P < .001) than patients with fracture or osteoarthritis. When controlling for demographics and comorbidities, patients undergoing THA for malignancy had a higher rate of readmission (adjusted odds ratio 3.39, P < .001) and reoperation (adjusted odds ratio 3.71, P < .001).

Patients undergoing THA for malignancy utilize more resources in an episode-of-care and have worse outcomes. Risk adjustment is necessary for oncology patients in order to prevent access to care problems for these high-risk patients.