Geographic region, socioeconomic position and the utilisation of primary total joint replacement for hip or knee osteoarthritis across western Victoria: a cross-sectional multilevel study of the Australian orthopaedic association national joint replacement registry

Summary Compared to urban residents, those in rural/regional areas often experience inequitable healthcare from specialist service providers. Independent of small between-area differences in utilisation, socially advantaged groups had the greatest uptake of joint replacement. These data suggest low correlation between ‘need’ vs. ‘uptake’ of surgery in rural/regional areas. Background and purpose Compared to urban residents, those in rural and regional areas often experience inequitable healthcare from specialist service providers, often due to geographical issues. We investigated associations between socioeconomic position (SEP), region of residence and utilisation of primary total knee replacement (TKR) and/or total hip replacement (THR) for osteoarthritis. Design and methods As part of the Ageing, Chronic Disease and Injury study, we extracted data from the Australian Orthopaedic Association National Joint Replacement Registry (2011–2013) for adults that utilised primary TKR (n = 4179; 56% female) and/or THR (n = 3120; 54% female). Residential addresses were matched with the Australian Bureau of Statistics (ABS) 2011 census data: region of residence was defined according to local government areas (LGAs), and area-level SEP (quintiles) defined using an ABS-derived composite index. The ABS-determined control population (n = 591,265; 51% female) excluded individuals identified as cases. We performed multilevel logistic regression modelling using a stratified two-stage cluster design. Results TKR was higher for those aged 70–79 years (AOR 1.4 95%CI 1.3–1.5; referent = 60–69 years) and in the most advantaged SEP quintile (AOR 2.1, 95%CI 1.8–2.3; referent = SEP quintile 3); results were similar for THR (70–79 years = AOR 1.7, 95%CI 1.5–1.8; SEP quintile 5 = AOR 2.5, 95%CI 2.2–2.8). Total variances contributed by the variance in LGAs were 2% (SD random effects ± 0.28) and 3% (SD ± 0.32), respectively. Conclusion Independent of small between-LGA differences in utilisation, and in contrast to the expected greater prevalence of osteoarthritis in disadvantaged populations, we report greater TKR and THR in more advantaged groups. Further research should investigate whether more advantaged populations may be over-serviced.