Social Vulnerability Is Associated with Worse Two-Year Survival after Lower Extremity Bypass

INTRODUCTION: Socioeconomic (SES) disparities in lower extremity bypass (LEB) outcomes for chronic limb threatening ischemia (CLTI) are well-documented. Multiple geospatial SES metrics are available, but there’s lacking guidance on their relative performance. We hypothesized the Social Vulnerability Index (SVI) would poorly correlate with other metrics and be associated with worse survival following LEB for CLTI. METHODS: A single-center retrospective analysis of LEB for CLTI from 2012-2020 was performed. The SVI uses census tract, Area Deprivation Index (ADI) block groups, and the Distressed Community Index (DCI) zip-codes. Higher scores suggest increased disadvantage. Raw scores and top quintiles of disadvantage were assessed using Pearson’s correlation. Cox multivariable analysis assessed each metric for association with 2-year survival. RESULTS: Within 308 cases, median age was 70.5 years (IQR: 61.7-79.3), 59% male, and 62% white. The median SVI score was 53 (IQR: 28-76), ADI 16 (IQR: 5-41), and DCI 34 (IQR: 18-57). Raw SVI correlated with ADI (0.60) and DCI (0.48) (p < 0.01). Top SVI quintile correlated with ADI (0.51) and DCI (0.39) (p < 0.01). Two-year survival differed by metric and only SVI was associated with worse 2-year survival (17% vs 8%, p = 0.04) (Fig. 1). On Cox multivariable analysis, the top SVI quintile was independently associated with 2.2 times the hazards of death (95% CI: 1.0-4.6, p = 0.04) (Fig. 1).Figure 1CONCLUSION: SVI may be a superior SES metric in LEB for CLTI. While other SES metrics have moderate correlation with raw SVI, heterogeneity persists in identifying highly vulnerable groups. SVI’s increased geographic granularity may contribute to the differential survival after LEB for CLTI compared to other SES metrics.