Geographic and Socioeconomic Disparities in Major Lower Extremity Amputation Rates in Metropolitan Areas
What superb work by our colleagues Fanaroff and coworkers. Further evidence that the ZIP code lottery for amputation includes rural and urban areas. This article was featured on the American Limb Preservation Society (ALPS) site.
Geographic and Socioeconomic Disparities in Major Lower Extremity Amputation Rates in Metropolitan Areas
CLINICAL PERSPECTIVE
What Is New?
• Though amputation rates are higher in rural areas, more than three quarters of patients with peripheral artery disease undergoing lower ex- tremity amputation live in metropolitan areas.
• In metropolitan areas, ZIP codes with markers of low socioeconomic status and greater pro- portions of Black people had amputation rates comparable to those in rural communities.
What Are the Clinical Implications?
- Geographic proximity to subspecialty peripheral artery disease care within metropolitan areas is not adequate to ensure access to high-quality care.
- Strategies targeted to communities with high amputation rates in urban areas are needed to reduce disparities in peripheral artery disease outcomes.
Abstract
Background
Rates of major lower extremity amputation in patients with peripheral artery disease are higher in rural communities with markers of low socioeconomic status, but most Americans live in metropolitan areas. Whether amputation rates vary within US metropolitan areas is unclear, as are characteristics of high amputation rate urban communities.
Methods and Results
We estimated rates of major lower extremity amputation per 100 000 Medicare beneficiaries between 2010 and 2018 at the ZIP code level among ZIP codes with ≥100 beneficiaries. We described demographic characteristics of high and low amputation ZIP codes, and the association between major amputation rate and 3 ZIP code–level markers of socioeconomic status—the proportion of patients with dual eligibility for Medicaid, median household income, and Distressed Communities Index score—for metropolitan, micropolitan, and rural ZIP code cohorts. Between 2010 and 2018, 188 995 Medicare fee‐for‐service patients living in 31 391 ZIP codes with ≥100 beneficiaries had a major lower extremity amputation. The median (interquartile range) ZIP code–level number of amputations per 100 000 beneficiaries was 262 (75–469). Though nonmetropolitan ZIP codes had higher rates of major amputation than metropolitan areas, 78.2% of patients undergoing major amputation lived in metropolitan areas. Compared with ZIP codes with lower amputation rates, top quartile amputation rate ZIP codes had a greater proportion of Black residents (4.4% versus 17.5%, P<0.001). In metropolitan areas, after adjusting for clinical comorbidities and demographics, every $10 000 lower median household income was associated with a 4.4% (95% CI, 3.9–4.8) higher amputation rate, and a 10‐point higher Distressed Communities Index score was associated with a 3.8% (95% CI, 3.4%–4.2%) higher amputation rate; there was no association between the proportion of patients eligible for Medicaid and amputation rate. These findings were comparable to the associations identified across all ZIP codes.
Conclusions
In metropolitan areas, where most individuals undergoing lower extremity amputation live, markers of lower socioeconomic status and Black race were associated with higher rates of major lower extremity amputation. Development of community‐based tools for peripheral artery disease diagnosis and management targeted to communities with high amputation rates in urban areas may help reduce inequities in peripheral artery disease outcomes.
For earlier work in Los Angeles by Stevens and coworkers, click here.
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