Minority patients are at higher risk for complications and readmissions after total hip and knee arthroplasty. They are also more likely to undergo joint replacement in lower volume centers, which is associated with poorer outcomes. It is unknown whether these disparities simply reflect disproportionate use of lower volume centers. This study evaluates the impact of hospital volume on racial differences in outcomes following joint replacement.
Patients who underwent total hip or knee arthroplasty between 2006 and 2013 in New York and Florida were identified through the Healthcare Cost and Utilization Project State Inpatient Databases. Complications, readmissions, and emergency department (ED) visits within 90 days were compared by hospital volume. Relative risks were calculated with generalized estimating equations for risk factors associated with adverse outcomes.
Race/ethnicity was not associated with readmission following hip replacement. Black race was associated with readmission following knee replacement (relative risk [RR] 1.16). Black race was associated with ED visits following hip replacement (RR 1.29) and knee replacement (RR 1.33). Hispanic ethnicity was associated with ED visits following knee replacement (RR 1.15), but not hip replacement. These associations did not change after adjusting for hospital volume.
Adjusting for hospital volume does not alter the risk of readmissions and ED use associated with minority race/ethnicity, suggesting that hospital volume alone may be insufficient to explain racial differences in outcome.