Objective: To determine race- and sex-specific rates of total knee arthroplasty (TKA) and to document independent effects of demographic factors on TKA incidence in a population with radiographically confirmed osteoarthritis (OA).
Methods: We used data from the Osteoarthritis Initiative, a US-based, multicenter longitudinal study of knee OA. We selected subjects with radiographic symptomatic OA at baseline and determined TKA incidence rates (ratio of TKAs to time at risk for TKA) over 84 months of followup. We used multivariable Poisson regression to identify independent associations between demographic factors and TKA utilization.
Results: During the study period there were 223 TKAs among 1,915 subjects for an incidence of 1.9% (95% confidence interval [95% CI] 1.7-2.2%). The overall rate was 1.9% (95% CI 1.5-2.3%) in men versus 2.0% (95% CI 1.7-2.3%) in women, and 2.2% (95% CI 1.9-2.6%) in whites versus 1.0% (95% CI 0.7-1.5%) in nonwhites. We observed a statistically significant interaction between sex and age (stratified at <65 and ≥65 years at end of followup), wherein male sex was associated with decreased risk of TKA for younger participants (relative risk [RR] 0.32) but not for older participants. Nonwhite race was associated with a decreased risk of TKA for both younger (RR 0.32) and older (RR 0.43) participants.
Conclusion: Our finding that nonwhites were less likely to undergo TKA than whites in adjusted analyses confirms racial differences observed in population-based studies and underscores the need for interventions to address lower use of TKA among nonwhites with OA.
Trial registration: ClinicalTrials.gov NCT00080171.
© 2016, American College of Rheumatology.