Knee replacement incidence and social deprivation: results from a French ecological study.

OBJECTIVES: Temporal and geographic variations in knee osteoarthritis (OA) incidence occur worldwide. Regional variations also exist for socioeconomic status. We analyzed the association between socioeconomic deprivation (SED) and knee replacement (KR) incidence and assessed the proportion of KR associated with affluence. METHODS: Patients aged 15 years and over hospitalized for KR in 2013 were included. We linked each patient to a municipality of residence. Municipalities were matched to the 2011 European Deprivation Index score for SED analysis. Poisson regression was performed to examine the association between KR incidence and EDI adjusted for age and sex. The Population Attributable Fraction (PAF) was measured to calculate the proportion of excess of KR associated with social affluence. RESULTS: We included 77 597 KR. KR incidence decreased with increasing SED index. The EDI was significantly associated with KR incidence (P < 0.0001). The risk of KR is 2.36 times higher for persons living in the most affluent area compared to those living in the most underprivileged area. The PAF was 28.3%. CONCLUSIONS: The French administrative municipalities with the highest SED have the lowest age- and sex-adjusted KR incidence. It cannot be excluded that patients living in more privileged areas are overtreated. Complementary studies are necessary to define all the individual factors that limit or increase the access to knee replacement.