Abstract
BACKGROUND: After the Centers for Medicare and Medicaid Services modified reimbursement rates for outpatient peripheral vascular intervention in 2008 with the intent of improving access to care, providers began to increasingly perform peripheral vascular interventions in privately owned office-based clinics. Little is known about the characteristics of patients treated in this setting and their long-term outcomes as compared with those treated in hospital-based centers.
METHODS: In this retrospective cohort study, Medicare beneficiaries ≥66 years undergoing outpatient femoropopliteal peripheral vascular interventions in office-based clinics and hospital-based centers from 2015 to 2017 were identified. Sociodemographics, comorbidities, and institutional characteristics were compared across sites. Multivariable Cox proportional hazards models were used to estimate the adjusted associations between practice site location and outcomes. The primary outcome was the composite of major amputation or death analyzed through the end of follow-up.
RESULTS: Among 134 869 patients, 29.9% were treated in office-based clinics and 70.1% in hospital-based centers. Patients treated in office-based clinics were more often Black (16.9% versus 11.9%), dually enrolled in Medicaid (26.3% versus 19.6%), and residents of lower-resourced regions (32.6% versus 25.6%). Over a median follow-up time of 800 days (interquartile range, 531-1119 days), patients treated in office-based clinics had reduced risks of major amputation or death compared with outpatients treated in hospital-based centers (hazard ratio, 0.92 [95% CI, 0.89-0.95]). They also had lower adjusted all-cause mortality (hazard ratio, 0.93 [95% CI, 0.90-0.96]), major lower extremity amputation (hazard ratio, 0.84 [95% CI, 0.79-0.89]), and all-cause hospitalization (hazard ratio, 0.86 [95% CI, 0.84-0.88]). These findings persisted after stratification by critical limb ischemia, race, dual enrollment, and regional socioeconomic status, as well as among operators treating patients in both clinical settings.
CONCLUSIONS: In this large nationwide analysis of Medicare beneficiaries, office-based clinics treated a more socioeconomically disadvantaged population compared with hospital-based centers. Long-term outcomes were comparable between locations. As such, these clinics appear to be selecting lower-risk patients for outpatient peripheral vascular interventions, although there remains the possibility of unmeasured confounding.