Background/Purpose: To assess whether race/ethnicity is associated with differences in discharge disposition after elective primary total knee arthroplasty (TKA), and if discharge disposition is associated with 90-day hospital readmission.

Methods: This was an observational cohort study that used the Pennsylvania Health Care Cost Containment Council (PHC4) Database, which includes all patient discharges from 170 non-governmental acute care hospitals in the State of Pennsylvania. We examined the association of race/ethnicity with discharge disposition after elective primary TKA, using multivariable logistic regression models, which were adjusted for patient-level and facility-level variables.
Results: Between 2012 and 2015, there were 107,768 eligible primary TKAs had identifiable race/ethnicity. In study cohort, 7,287 (6.8%) were African-Americans; 63.4% were female, 43.1% were younger than 65 years, 40.2% had private, 3.6% Medicaid and 56.3% Medicare insurance. The 30-, 60- and 90-day readmission rates were 5.3%, 7.5% and 9.4%, respectively. Compared to younger than 65 years, 30-, 60- and 90-day readmission rates were higher in adults 65+ years.

Younger than 65 years. Compared to whites, African-Americans were more likely to be discharged to skilled nursing facility (SNF) or inpatient rehabilitation facility (IRF), but not home health care, 2.49 (95% CI, 1.42, 4.36), 3.91 (95% CI, 2.17, 7.06) and 1.30 (95% CI, 0.91, 1.88), respectively.

65 years or older. Compared to whites, African-Americans were more likely to be discharged to SNF but not IRF or home health care, 3.30 (95% CI, 1.81, 6.02), 1.64 (95% CI, 0.91, 2.97), and 1.06 (95% CI, 0.68, 1.65), respectively.

Younger than 65 years. Compared to home self-care, discharge to IRF or SNF, but not home health care, were each associated with higher odds ratios of 90-day readmission: 3.62 (95% CI, 2.33, 5.64), 1.91 (95% CI, 1.37, 2.65) and 1.08 (95% CI, 0.96, 1.22), respectively.

65 years or older. Similarly, in multivariable-adjusted model, compared to home self-care, discharge to IRF or SNF, but not home health care, were each associated with higher odds ratios of 90-day readmission: 2.85 (95% CI, 2.25, 3.61), 1.55 (95% CI, 1.27, 1.89) and 0.96 (95% CI, 0.82, 1.12), respectively.

Sensitivity analyses by inverse probability weighting (IPW) method confirmed these findings with minimal accentuation of odds ratios, but no change in significance or interpretation of findings.
Conclusion: African-Americans were more likely than whites to be discharged to IRF and SNF.  Discharge to IRF or SNF, but not home health care, were each associated with higher odds ratios of 90-day readmission. These findings indicate that race/ethnicity may predict higher utilization, and further insights into modifiable attributes associated with this higher utilization are needed.