Impact of Dual Eligibility on Surgical Outcomes After Lower Extremity Bypass or Peripheral Vascular Intervention

Abstract

Dual eligibility for Medicare and Medicaid is more common among Black and lower socioeconomic status patients than traditional Medicare and has been associated with worse health outcomes. Given that peripheral artery disease (PAD) disproportionately affects this underserved population, we sought to assess the impact of dual eligibility on surgical outcomes after lower extremity bypass (LEB) or peripheral vascular intervention (PVI) for PAD. A retrospective analysis was conducted of all LEB and PVI procedures between 2010 and 2018 with Medicare-match data in the VQI-VISION (Vascular Quality Initiative Vascular Implant Surveillance and Interventional Outcomes Network) database. The sample was restricted to first-record LEB or PVI procedures in fee-for-service beneficiaries over the age of 65 who were either covered by traditional Medicare alone or were dually eligible for Medicare and Medicaid. The two groups were compared with identify baseline demographic differences. Inverse probability weighting with Cox regression was used to determine adjusted associations with death, major amputation, and amputation-free survival (AFS), for which, the time to major amputation was calculated with death as a competing risk. Of 46,032 patients in our sample, 12,872 (28.0%) were dually eligible for Medicare and Medicaid, whereas 33,160 (72.0%) had traditional Medicare only. Similar proportions of dually eligible and traditional Medicare patients underwent LEB (18.5%) and PVI (81.5%) for PAD. Before inverse probability weighting, dually eligible patients were more likely than traditional Medicare patients to be female (48.0% vs 37.9%, P < .00001), Black (25.1% vs 10.0%, P < .00001), and have lower median household income ($50,885 vs $60,306, P < .0001). On unadjusted analysis, rates of long-term mortality (42.3% vs 35.1%, P < .0001) and major amputation (19.4% vs 10.7%, P < .0001) were higher in the dually eligible cohort. After inverse probability weighting, dually eligible patients had a higher hazard of death relative to traditional Medicare patients after LEB or PVI for PAD (hazard ratio [HR]: 1.39 [95% confidence interval (CI): 1.34-1.45], P < .0001) as well as a higher hazard of major amputation (HR: 1.27 [95% CI: 1.19-1.36], P < .0001). On Fine-Gray analysis of AFS, dually eligible patients were found to have a 21% higher hazard of amputation or death (HR: 1.21 [95% CI: 1.14-1.27], P < .0001) (Fig). Findings were similar when LEB and PVI were analyzed separately. Compared with traditional Medicare, dual eligibility was associated with higher hazards of death and major amputation and lower AFS after LEB or PVI for PAD. This suggests possible deficiencies in insurance coverage or coordination for dually eligible patients with PAD, requiring further investigation.