Disparities in 30-Day Readmissions After Total Hip Arthroplasty

Policymakers have expanded readmissions penalties to include elective total hip arthroplasties (THA), but little is known whether disparities exist on the basis of race, socioeconomic status, or payer.

To identify disparities in elective primary THA readmissions based on race, socioeconomic status, and type of insurance.

This analysis is a retrospective cohort study of patients discharged for an elective THA. The Healthcare Cost & Utilization Project's State Inpatient Database from California was used to identify index hospitalizations for elective primary THA and rehospitalizations within 30 days of discharge. We used multivariate logistic regression to examine differences in readmissions by race, socioeconomic status, and insurance.

Subjects included patients discharged from California hospitals from 2009 through 2011 after THA.

Risk-adjusted odds of all-cause 30-day readmission.

The overall rate of unplanned 30-day all-cause readmissions was 4.6%. African American [odds ratio (OR)=1.38; 95% confidence interval (CI), 1.16-1.64] and Hispanic (OR=1.16; 95% CI, 1.00-1.34) patients had a higher risk of readmission than white patients after THA, when accounting for comorbidities and hospital factors. The observed difference for Hispanic patients, however, was null after adjusting for socioeconomic status and payer. Lower socioeconomic status was associated with higher odds of readmission (OR=1.24; 95% CI, 1.10-1.39). Compared with private insurance, Medicare (OR=1.26; 95% CI, 1.13-1.43), Medicaid (OR=1.86; 95% CI, 1.49-2.32), and uninsured status (OR=1.31; 95% CI, 1.01-1.69) were also associated with increased readmission risk.

We found significant differences in the odds of 30-day readmissions on the basis of race, socioeconomic status, and payer. As readmissions penalties become widely adopted, payers need to be mindful of their effects on vulnerable populations.