The Utility of the Social Vulnerability Index as a Proxy for Social Disparities Following Total Knee Arthroplasty

Abstract

BackgroundIn 2021, alternative payment models accounted for 40% of traditional Medicare reimbursements. As such, we sought to examine health disparities through a standardized categorization of social disparity using the social vulnerability index (SVI). We examined (1) risk factors for SVI ≥ 0.50, (2) incidences of complications, and (3) risk factors for total complications between patients who have SVI < 0.50 and SVI ≥ 0.50 who had a total knee arthroplasty (TKA). MethodsPatients who underwent TKA between January 1, 2022 and December 31, 2022 were identified in the state of Maryland. A total of 4,952 patients who had complete social determinants of health data were included. Patients were divided into 2 cohorts according to SVI: < 0.50 (n = 2,431) and ≥ 0.50 (n = 2,521) based on the national mean SVI of 0.50. The SVI identifies communities that may need support caused by external stresses on human health based on 4 themed scores: socioeconomic status, household composition and disability, minority status and language, and housing and transportation. The SVI theme of household composition and disability encompassed patients aged 65 years and more, patients aged 17 years and less, civilians who have a disability, single-parent households, and English language deficiencies. The higher the SVI, the more social vulnerability or resources are needed to thrive in a geographic area. ResultsWhen controlling for risk factors and patient comorbidities, the theme of household composition and disability (odds ratio 2.0, 95% confidence interval 1.1 to 5.0, P = .03) was the only independent risk factor for total complications. Patients who had an SVI ≥0.50 were more likely to be women (65.8% versus 61.0%, P < .001), Black (34.4% versus 12.9%, P < .001), and have a median household income < $87,999 (21.3% versus 10.2%, P < .001) in comparison to the patients who had an SVI < 0.50, respectively. ConclusionsThe SVI theme of household composition and disability, encompassing patients aged 65 years and more, patients aged 17 years and less, civilians who have a disability, single-parent households, and English language deficiencies, were independent risk factors for total complications following TKA. Together, these findings offer opportunities for interventions with selected patients to address social disparities.