Racial differences in performance‐based function and potential explanatory factors among individuals with knee osteoarthritis

OBJECTIVE: In people with knee osteoarthritis (OA), self-reported physical function is poorer in Blacks than Whites, but it is unclear whether this holds true for objective assessments. This study examined racial differences in performance-based physical function as well as potential underlying factors contributing to these racial differences. METHODS: Participants with knee OA from a randomized controlled trial (ClinicalTrials.gov number NCT02312713) completed the 2-minute step tests (2MST), timed-up-and-go (TUG), and 30-second chair stands (30s-CST) at baseline. Race differences in performance-based function were assessed by logistic regression. Separate models were adjusted for sets of demographic, socioeconomic, psychological health, and physical health variables. RESULTS: In persons with knee OA (n=322; women: 72%, Black: 22%, age=66±11 years, BMI=31±8 kg/m2 ), Blacks (vs. Whites) had greater unadjusted odds of poorer function (30s-CST: OR [95% CI] = 2.79 [1.65-4.72]; 2MST: 2.37 [1.40-4.03]; TUG: 3.71 [2.16 - 6.36]). Relationships were maintained when adjusted for demographic and psychological health covariates, but they were either partially attenuated or non-significant when adjusted for physical health and socioeconomic covariates. CONCLUSION: Black adults with knee OA had poorer unadjusted performance-based function than Whites. Physical health and socioeconomic characteristics diminished these differences, emphasizing that these factors may be important to consider in mitigating racial disparities in function. This article is protected by copyright. All rights reserved.