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 nearelderly (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.Total knee arthroplasty (TKA) is increasingly common with over 431,000 procedures performed nationwide in 2004. 1 For persons with severe and potentially disabling osteoarthritis, TKA is "efficacious and cost-effective …[it] relieves pain and reduces functional disability." 2 As the US population ages, growth in TKAs is expected to accelerate. A study of Canadians aged 55 or older concluded that those with less education and lower income were more likely to need TKA and similarly willing to undergo TKA as those with more education or income. 20 To the extent that these findings apply to the United States, lower TKA utilization among minorities with lower SES is not necessarily due to unwillingness to undergo TKA.A related study of disparities in joint (knee and hip) replacement based on a nationally representative (US) longitudinal survey sample of 6159 Medicare-enrolled adults (age 69 or older) found that those with supplementary Medigap coverage were more likely to have a joint replacement compared with those without. 21 The apparent difference with Skinner et al 6 may be due to the more detailed individual-level financial and insurance coverage measures in Dunlop et al. 21 Although the data used in this study are from the same survey source [Health and Retirement Study (HRS)] as ...