Age and racial/ethnic disparities in arthritis-related hip and knee surgeries

Abstract

Background: Nearly 18 million Americans experience limitations due to their arthritis. Documented disparities according to racial/ethnic groups in the use of surgical interventions such as knee and hip arthroplasty are largely based on data from Medicare beneficiaries age 65 or older. Whether there are disparities among younger adults has not been previously addressed.

Objective: This study assesses age-specific racial/ethnic differences in arthritis-related knee and hip surgeries.

Design: Longitudinal (1998-2004) Health and Retirement Study.

Setting: National probability sample of US community-dwelling adults.

Sample: A total of 2262 black, 1292 Hispanic, and 13,159 white adults age 51 and older.

Measurements: The outcome is self-reported 2-year use of arthritis-related hip or knee surgery. Independent variables are demographic (race/ethnicity, age, gender), health needs (arthritis, chronic diseases, obesity, physical activity, and functional limitations), and medical access (income, wealth, education, and health insurance). Longitudinal data methods using discrete survival analysis are used to validly account for repeated (biennial) observations over time. Analyses use person-weights, stratum, and sampling error codes to provide valid inferences to the US population.

Results: Black adults under the age of 65 years report similar age/gender adjusted rates of hip/knee arthritis surgeries [hazard ratio (HR) = 1.43, 95% confidence interval (CI) = 0.87-2.38] whereas older blacks (age 65+) have significantly lower rates (HR = 0.38, CI = 0.16-0.55) compared with whites. These relationships hold controlling for health and economic differences. Both under age 65 years (HR = 0.64, CI = 0.12-1.44) and older (age 65+) Hispanic adults (HR = 0.60, CI = 0.32-1.10) report lower utilization rates, although not statistically different than whites. A large portion of the Hispanic disparity is explained by economic differences.

Conclusions: These national data document lower rates of arthritis-related hip/knee surgeries for older black versus white adults age 65 or above, consistent with other national studies. However, utilization rates for black versus white under age 65 do not differ. Lower utilization among Hispanics versus whites in both age groups is largely explained by medical access factors. National utilization patterns may vary by age and merit further investigation.