DOS 2019

DOS Kongressen 2019 · 173 Effect of growing population and obesity primary total knee arthroplasty rates in Sweden Anders Overgaard Parker Institute, Bispebjerg og Frederiksberg hospital Background: Obesity is the major risk factors for developing and progression of knee osteoarthritis that may lead to the need for arthroplasty surgery. As obesity among the population increases the number of operations is expected to follow similar patterns. The increasing strain on public healthcare costs from treating late- stage osteoarthritis patients, yields a need for studies on the as- sociation between obesity and the need for total joint arthroplasty. Purpose / Aim of Study: This study aims to quantify the relative risk for total knee arthroplasty in the Swedish population for specific body mass index cat- egories and age intervals to investigate whether the TKA use is attributable to changes in the prevalence of obesity and the growing elder-population. Materials and Methods: The Swedish Nationwide Health Survey (SNHS) pro- vided BMI data for a representative sample of the Swedish population and the Swedish Knee Arthroplasty Register (SKAR) to calculate Relative Risk (RR) of TKA surgery by age and BMI. Age groups of interest are middle-aged 45- 64 and elderly 65-84 years of age and patients were divided according to BMI cat- egories (BMI 18.5-24.9 normal-weight; BMI 25.0-29.9 over- weight; BMI>30 obese). The RR for TKA surgery was applied to the demographic forecasts for the Swedish population as a forecasting model. We assumed unchanged indica- tions and utilization patterns for TKA among obese and non-obese individuals. Findings / Results: There was observed increases in population size of 5.1% from 2009 to 2015 (roughly 40.000 middle- aged and 250.000 elderly) and an increase in prevalence of obesity from 16 to 18% in the two age categories. Compared to normal-weight, the RR for TKA was 2.7 higher for over-weight and 7.3 higher for persons classified as obese, aged 45-64. The corresponding figures for individuals aged 65-84 were 2.1 higher and 4.0 higher respectively. Applying the RR to the demographical changes in prevalence of obesity and an increase in the elderly population accounted for an estimated increase of ap- proximately 1300 TKAs. Conclusions: The increase in the prevalence of obesity and the number of middle-aged and elderly in the population may to some extent explain the rapid increase in TKAs in Sweden over the last seven years. 129.