Exploring the determinants of racial and ethnic disparities in total knee arthroplasty - Health insurance, income, and assets

Objective: To estimate national total knee arthroplasty (TKA) rates by economic factors, and the extent to which differences in insurance coverage, income, and assets contribute to racial and ethnic disparities in TKA use. Data Source: US longitudinal Health and Retirement Study survey data for the elderly and near-elderly (biennial rounds 1994-2004) from the Institute of Social Research, University of Michigan. Study Design: The outcome is dichotomous, whether the respondent received first TKA in the previous 2 years. Longitudinal, random-effects logistic regression models are used to assess associations with lagged economic indicators. Sample: Sample was 55,469 person-year observations from 18,439 persons; 663, with first TKA. Results: Racial/ethnic disparities in TKA were more prominent among men than women. For example, relative to white women, odds ratios (ORs) were 0.94, 0.46, and 0.79, for white, black, and Hispanic men, respectively (P < 0.05 for black men). After adjusting for economic factors, racial/ethnic differences in TKA rates for women essentially disappeared, while the deficit for black men remained large. Among Medicare-enrolled elderly, those with supplemental insurance may be more likely to have first TKA compared with those without it, whether the supplemental coverage was private [OR: 1.27; 95% confidence interval (CI): 0.82-1.96] or Medicaid (OR: 1.18; 95% CI: 0.93-1.49). Among the near-elderly (age 47-64), compared with the privately insured, the uninsured were less likely (OR: 0.61; 95% CI: 0.40-0.92) and those with Medicaid more likely (OR: 1.53; 95% CI: 1.03-2.26) to have first TKA. Conclusions: Limited insurance coverage and financial constraints explain some of the racial/ethnic disparities in TKA rates.