Socioeconomic Disparities in Outcomes Following Primary Total Hip Arthroplasty: A Large Database Analysis of 2,280,000 Procedures

BACKGROUND: Total hip arthroplasty (THA) is one of the most common and cost-effective orthopaedic procedures in the United States, yet disparities in access, complication rates, and discharge disposition persist across socioeconomic groups. Although racial disparities after THA are well described, the influence of socioeconomic status (SES)-particularly income and insurance type-on in-hospital outcomes during the index admission remains less clearly defined. Clarifying these relationships is essential for improving equity in joint arthroplasty care. METHODS: A retrospective cohort study was conducted using a large national database to identify adults undergoing elective primary THA from 2016 to 2021. Approximately 2.28 million weighted THA cases were included in the analysis. The SES indicators included ZIP code-based income quartiles and primary payer category (e.g., private, Medicare, Medicaid, self-pay, and other). Survey-weighted descriptive statistics characterized demographic and clinical patterns. Multivariable logistic regression, adjusted for age, sex, race, comorbidity burden, and admission type, evaluated associations between SES and prolonged length of stay, discharge disposition, in-hospital complications, and mortality. RESULTS: Routine home discharge declined from 38.6% in the lowest income quartile (Q1) to 33.6% in the highest (Q4), with Q1 patients demonstrating higher adjusted odds of home discharge (odds ratio (OR) 1.42, 95% confidence interval 1.33 to 1.51, P < 0.001). Medicare (OR 0.84, P < 0.001) and Medicaid (OR 0.89, P < 0.001) coverage were associated with reduced odds of home discharge compared with private insurance. Income quartile did not significantly predict perioperative complications; however, Medicaid (OR 1.36, P < 0.001) and self-pay (OR 1.50, P < 0.01) patients had increased risk. In-hospital mortality was rare (< 0.2%), with elevated odds in lower-income groups largely attributable to comorbidity severity. Lower SES and public insurance coverage were also associated with modest increases in length of stay. CONCLUSIONS: Socioeconomic disadvantage influences inpatient outcomes following THA. Lower-income and publicly insured patients experience longer hospitalizations, higher complication risk, and distinct discharge patterns. Incorporating social and payer-based risk factors into perioperative planning and value-based payment models may improve equity in joint arthroplasty care.