Racial, ethnic, and geographic disparities in rates of knee arthroplasty.

BACKGROUND There are large variations in the use of knee arthroplasty among Medicare enrollees according to race or ethnic group and sex. Are racial and ethnic disparities more pronounced in some regions than in others, and if so, why? METHODS We used all Medicare fee-for-service claims data for 1998 through 2000 to determine the incidence of knee arthroplasty according to Hospital Referral Region, sex, and race or ethnic group. A total of 430,726 knee arthroplasties were performed during the three-year study period. RESULTS At the national level, the annual rate of knee arthroplasty was higher for non-Hispanic white women (5.97 procedures per 1000) than for Hispanic women (5.37 per 1000) and black women (4.84 per 1000). The rate for non-Hispanic white men (4.82 procedures per 1000) was higher than that for Hispanic men (3.46 per 1000) and more than double that for black men (1.84 per 1000). The rates were significantly lower for black men than for non-Hispanic white men in nearly every region of the country (P<0.05). For the Hispanic population and for black women, racial or ethnic disparities at the national level were due in part to geographic differences rather than to differences in the rates for different racial and ethnic groups within geographic areas. Residential segregation and low income levels contributed to racial and ethnic disparities in arthroplasty rates. CONCLUSIONS In the Medicare population, the rate of surgical treatment for osteoarthritis of the knee varies dramatically according to sex, race or ethnic group, and region. These variations underscore the importance of geography and sex in determining racial or ethnic barriers to health care.