Poverty plays growing role in major amputation risk

Major lower extremity amputations were once heavily concentrated in a narrow band of under-resourced, safety-net hospitals. A three-decade national study now shows that burden has spread well beyond those settings and that poverty is a more powerful predictor of limb loss today than it was a generation ago. 

The findings, published in the Journal of Vascular Surgery, draw on nearly 2.8 million inpatient admissions from the National Inpatient Sample between 1993 and 2021.  

Researchers identified clear inflection points around 2010 for below-knee amputations (BKA) and 2012 for above-knee amputations (AKA), after which both incidence and the distribution of risk changed markedly across hospital types and patient income groups. 

“Our study builds on prior work that was among the first to identify alarming inflections toward increasing amputation incidence,” said lead author Sherene E. Sharath, PhD, MPH, associate professor of surgery at SUNY Downstate Health Sciences University. “The primary objective was to investigate potential drivers of these trends from a social and systems perspective, specifically whether rising amputation incidence was associated with patient-level socioeconomic factors and hospital resources, represented by hospital Medicaid burden.” 

Across the full study period, 348,036 major amputations were recorded — roughly 57% BKA and 43% AKA. Nearly 79% of all major amputations by 2021 were performed at hospitals with moderate to high Medicaid burden. From a patient socioeconomic standpoint, approximately 42% of both BKA and AKA procedures occurred among patients in the lowest income quartile, with another roughly 26% in the second-lowest quartile. Patients undergoing amputation at higher Medicaid burden hospitals were also notably younger than those treated at lower-burden facilities. 

The pre- and post-inflection findings told two distinct stories. Before the inflection points, amputation risk increased in a fairly linear fashion as a hospital's Medicaid proportion rose. After the inflection, that pattern shifted in a way that raised concern about how broadly the burden had spread. 

“In the pre-inflection periods, risk of amputation increased progressively as the proportion of Medicaid patients at a hospital rose,” said Sharath. “After the inflection, amputation risks started converging, affecting hospitals serving moderate to high proportions of Medicaid patients, indicating that more resource-constrained hospitals were experiencing disproportionately higher amputation risk. In terms of patient income, the protective effect of higher income widened after the inflection, meaning that economic advantages became even more strongly associated with lower amputation risk over time.” 

The pattern is consistent for both amputation types and points to something more systemic than a shift in surgical case mix or referral patterns. 

“Risk that was previously concentrated in a relatively small number of extreme, highly disadvantaged settings has shifted to a broader pattern that spans more hospital systems and communities,” said Sharath. “This diffusion reflects increasing pressure on resource-constrained hospitals and a clearer, more pronounced link between personal economic hardship and limb loss than before.” 

The racial disparity dimension of the findings also persisted across both time periods. Black patients carried the highest amputation risk both before and after the inflection points for BKA and AKA, underscoring that the diffusion of risk does not erase longstanding inequities. 

For the field, the implications push beyond individual clinical decision-making. Sharath said the findings point to a need for structural changes at the hospital and policy levels that parallel any advances in limb-salvage care. 

“Improving amputation outcomes will require more than better individual care, advanced treatments, or treatment algorithms,” said Sharath. “It also demands attention to the systems within which care is delivered and to patient circumstances that extend beyond hospital walls. As risk spreads, strengthening capacity in resource-constrained hospitals and reducing economic and access barriers become central to lowering amputation risk and incidence.” 

The study's conclusions point toward community- and policy-level engagement as the necessary next step. The authors note that future interventions will need to reach the community stakeholders and policymakers whose decisions shape the conditions in which amputation risk takes hold. 

“The key takeaway is that who you are and where you receive care matter increasingly for whether you lose a limb,” said Sharath. “Reducing amputation incidence will hinge on how well we strengthen vulnerable hospitals and support vulnerable patients, not just on improving clinical treatments.”