Multidisciplinary approach to decreasing major amputation, improving outcomes, and mitigating disparities in diabetic foot and vascular disease

Abstract

Major nontraumatic lower extremity amputation (LEA) is a morbid complication of longstanding or poorly controlled diabetes and/or end-stage peripheral artery disease. Incidence of major LEAs consistently declined during the 1990s and 2000s, but rates have plateaued or increased in many regions during the past decade. Marked racial, ethnic, socioeconomic, and geographic disparities in risk of LEA persist and are related to inequalities in access to care and differential rates of attempted limb preservation. Multidisciplinary diabetic foot care (MDFC) is increasingly recognized as a necessary model for optimal management of patients with diabetic foot and vascular disease. This article reviews the role of MDFC in reducing major LEAs and the specific ways in which MDFC can mitigate disparities in care delivery and limb preservation outcomes. Access to MDFC among vulnerable populations remains a significant barrier to systematic reduction in major LEAs.

1. Introduction

Nontraumatic lower extremity amputation (LEA) is a highly morbid late-stage complication of diabetes and peripheral artery disease (PAD), and marked racial and ethnic, socioeconomic, and geographic disparities in LEAs exist. Most major LEAs are avoidable with appropriate preventive care and management of incident diabetic foot ulcers (DFUs). This review summarizes the epidemiology of DFUs and PAD, recent trends in LEA incidence, and the role of multidisciplinary diabetic foot care in reducing major LEAs, especially in populations that are disproportionately affected by LEAs.

2. Epidemiology of diabetes, PAD, and diabetic foot disease

PAD and diabetes are the primary drivers of foot ulceration and LEAs in the United States, and together they represent a major source of preventable morbidity, mortality, and health care utilization [1]. Diabetes affects more than 37 million US adults, and this number is rising rapidly, driven primarily by an increase in type 2 diabetes [1]. The estimated US prevalence of PAD is 8 million to 12.5 million people [2], although this likely underestimates the prevalence of asymptomatic disease. Diabetes is an independent risk factor for PAD, and 20% to 30% of people with diabetes have received a PAD diagnosis [2]. These rates as are as high as 50% in older adults with diabetes [2]. Chronic limb-threatening ischemia (CLTI) represents approximately 11% of PAD and is associated with frequent hospitalizations, de novo tissue loss, LEA, and a 5-year mortality rate >50% [3]. Diabetes-related PAD and CLTI characteristically present with medial arterial calcification in tibial and pedal arteries and long-segment arterial occlusions. This calcification pattern leads to noncompressible arteries and limits the diagnostic accuracy of ankle brachial index; long-segment occlusions, small vessel disease, and limited collateralization, especially in pedal circulation, present unique therapeutic challenges for successful revascularization [3].

DFUs precede minor and major LEAs in most cases [4,5]. Lifetime prevalence rates of DFUs are rising as life expectancy and medical complexity in people with diabetes increases [4]. Up to 34% of people with diabetes will develop a diabetic foot complication during their lifetime, and approximately 20% of people with DFUs will require a minor or major LEA [4,5]. Macro-ischemia are micro-ischemia are estimated to play a causal role in the development of 50% to 70% of DFUs [6]. The presence of macrovascular PAD is associated with development of DFUs, poor outcomes in ulcer healing, a 2- to 4-fold risk of LEA, and a 5-year mortality rate approaching 70% [5,6].

Rates of any LEAs among people with diabetes in the United States declined steadily during the 1990s and 2000s to a nadir incidence near 0.3% per year [7,8]. During this time, there was also a shift toward a higher proportion of minor LEAs and a lower proportion of major LEAs [7,8]. These trends corresponded with rapid expansion of endovascular interventions for PAD and increasing emphasis on multidisciplinary diabetic foot care (MDFC). In the past decade, however, retrospective series have reported up to a 60% increase in minor and 30% increase in major LEAs among people with diabetes, with highest increases noted among younger people and in racial and ethnic minority groups in some regions [7,9]. More than 150,000 major and minor LEAs were performed in US adults with diabetes in 2018, representing a crude annual US incidence near 0.6% [1].

3. Differences and disparities in the risk of LEA

There are several well-defined clinical risk factors for DFUs and diabetes-related LEAs, most of which are related to longstanding disease and/or poor glycemic control. Racial and ethnic minority populations and people with low socioeconomic status experience higher rates of diabetes and risk-associated comorbidities, including cardiovascular disease, PAD, neuropathy, and chronic kidney disease, compared with White people and those with high income levels [1,10,11]. Even after adjusting for clinical risk, Black and Hispanic populations have 1.5- to 5-fold higher rates of any LEA, major LEA, and primary LEA [8,10]. Low rates of revascularization and higher likelihood of LEA within 1 year of DFU diagnosis compared with non-Hispanic White people suggest systematic inequities in limb preservation [8,10,12,13].

Racial and ethnic disparities in LEA are inextricably linked to socioeconomic and geographic disparities [8,10,12]. Area deprivation (a composite, ZIP code-based measure of community resources), low income, and less favorable insurance status (eg, Medicaid or no insurance) are associated with higher likelihood of advanced-stage and infected ulcer at presentation [8,12,14]. Low socioeconomic status and worse insurance status are also linked to lower rates of revascularization, higher rates of LEA after revascularization, and higher rates of minor and major LEAs regardless of PAD status [13,14]. Geographic variation in LEA consistently shows clustering of poor outcomes in areas with high socioeconomic deprivation and racial and ethnic minority populations [12,15]. Limited access to care and structural disparities in care delivery are implicated [10,16]. The remainder of this review describes the core components of MDFC and the ways in which this model can improve outcomes for all patients, especially those who face disproportionate DFU and LEA morbidity.

4. Components of MDFC

Multiple society guidelines recommend management of DFU and PAD in a multidisciplinary care setting [3,17], although no clear data exist on the requisite components of MDFC. Most described models include vascular surgery, podiatry, and a diabetologist, at minimum (Table 1) [18]. The inclusion of podiatry, specifically, has been found to improve limb preservation rates [18]. MDFC should be capable of specialty wound care, but whether wound care is driven by surgeons or non-surgeon wound care specialists does not seem to be important [5,18,19]. Additional subspecialty providers and ancillary team members have independent value and are often included in larger tertiary MDFC settings [5,18]. This frequently includes infectious disease, physical medicine and rehabilitation, orthopedics, and plastic surgery.

Table 1 –

Provider components of a multidisciplinary foot care team.

Specialty/provider	Diabetes surveillance and management	Screening, surveillance, and medical management of PAD	Complex wound evaluation, advanced wound care	Offloading, custom footwear/ devices, gait training	Endovascular or surgical intervention for PAD/ ischemia	Lower extremity amputation and/or recon struction	Screening with or without management of other DFU risk factorsa
Vascular surgery		x	x	x	x	x	x
Podiatry			x	x		x	x
Endocrinology	x						x
Additional nonsurgical specialist providers
Internal medicine	x	x					x
Infectious disease							x
Vascular medicine	x	x					x
Additional surgical specialist providers
Orthopedic surgery			x	x		x
Plastic surgery			x	x		x
Additional ancillary services
Specialist wound care nursing	Manage simple and complex wounds, evaluate wound progress, and determine need for change in regimen. Perform advanced wound care (eg, NPWT).
Physical and/or occupational therapy	Provide gait (re)training, strength, and endurance therapy. Promote comfort with and adherence to offloading devices, maximize pre- and post-intervention functional status.
Orthotists/ prosthetists	Create custom footwear, insoles, or other orthotics for pressure offloading in pre-ulcerative, post-healing, or active DFU, provide prosthetics to improve QoL and functional status after amputation.
Mental health providers	Screen for clinical depression or anxiety (worsened during DFU and associated with poor self-care). Promote cognitive and behavioral coping strategies to reduce symptoms of depression and anxiety and improve compliance with self-care.
Dedicated patient educators	Design and implement patient education on foot care, offloading, glucose control and other global diabetes and cardiovascular health topics.
Social work	Connect patients to additional resources for transportation, nutrition, financial assistance, social and emotional support, minimize barriers to care access and healing.

Abbreviations: DFU, diabetic foot ulcer; NPWT, negative pressure wound therapy; PAD, peripheral artery disease; QoL, quality of life.

^aFor example, peripheral neuropathy, non-PAD cardiovascular disease, smoking/smoking cessation, and chronic kidney disease.

4.1. Evaluation of the diabetic foot

Delayed diagnosis of DFUs in disadvantaged groups drives disparities in major LEAs [14,20]. A complete and standardized foot examination, including evaluation of sensation, perfusion, and presence of infection, is central to both preventive and therapeutic diabetic foot care [5,17]. The use of guideline-directed screening and surveillance in MDFC serves to standardize and improve foot evaluation and outcomes [3,5,19]. Current Society for Vascular Surgery guidelines provide clear recommendations for DFU screening and surveillance based on patient risk [17]. There is special emphasis on the use of toe pressures and transcutaneous oximetry, due to their improved sensitivity for PAD in patients with diabetes, which may not be readily available outside the context of vascular specialist clinics or MDFC [17,20]. Noncompressible arteries at the ankle limit the utility of ankle brachial index, and pedal microvascular disease may result in distal and/or angiosome-specific ischemia, despite palpable pedal pulses, both of which contribute to underestimation of PAD in people with diabetes [2,17]. Evidence of ischemia in people who may be candidates for revascularization should trigger step-up diagnostic imaging with duplex ultrasound, computed tomography angiography, and catheter-based digital subtraction angiography, the latter especially for distal tibial and pedal arteries [3]. Routine use of advanced imaging, particularly digital subtraction angiography, before nonemergent LEA has been shown to reduce major amputation rates [8]. Use of these modalities are inherent to MDFC and, compared with settings where separate referrals are required, MDFC leads to decreased delays in care [3].

Many classification systems exist for evaluating and staging DFU and/or threatened limbs. The Society for Vascular Surgery’s Wound, Ischemia, and Foot Infection (WIfI) classification is unique in its interrater reliability, prognostic value, and utility to aid clinical decision making regarding the benefit of revascularization [21]. Its wide use in MDFC allows for further standardization of wound severity and limb threat, and more appropriate comparison of outcomes between groups and across time.

The Infectious Disease Society of America guidelines on management of diabetic foot infection and diabetic foot osteomyelitis is another diagnostic algorithm tied to clinical decision making [22]. Patients with mild or moderate infection may be managed successfully on an outpatient basis; patients with severe infection or moderate infection and complicating factors (eg, PAD, hyperglycemia, or socioeconomic and psychosocial factors that may preclude adherence to a treatment regimen without support) generally require hospital admission [5,22]. Early recognition of diabetic foot infection and diabetic foot osteomyelitis, especially in people with PAD, is critical for appropriate triage [6,21]. Foot infection at presentation is more common among racial and ethnic minority groups and people who are economically disadvantaged, and severe infection independently predicts LEA [6,23]. Limiting variation in early diagnosis and treatment of infection has the potential to improve limb preservation outcomes in these high-risk groups [6,21,22].

4.2. Medical management of diabetes, PAD, and associated comorbidities

The importance of glycemic control and cardiovascular risk factor management to prevent diabetic foot ulcers and slow the progression of PAD cannot be overstated. Racial and ethnic minority groups in the United States and United Kingdom receive lower rates of guideline-directed care and are less likely to meet diabetes-related targets, including hemoglobin A1c and blood pressure [11]. These indicators suggest limited access to care that likely contributes to the more advanced stage of wound at presentation and the excess morbidity associated with DFUs and PAD in racial and ethnic minority groups. MDFC settings have shown improvement in process measures, including more frequent hemoglobin A1c measurements and increased use of guideline-directed antihypertensives and lipid-lowering medications [24].

MDFC settings also achieve improved and equitable adherence to elements of guideline-directed medical therapy in PAD. Armstrong et al [25] reported odds of smoking cessation, antiplatelet, angiotensin-converting enzyme inhibitor, and statin use in an MDFC setting that were even higher among racial and ethnic minority patients than among White patients in the same cohort [25]. Adherence to all four guideline-directed medical therapy elements in this study was associated with lower risk of major LEA or mortality, reinforcing the potential of medical management within MDFC models to prevent morbidity in high-risk groups [25].

5. Multidisciplinary approach to treatment of diabetic foot ulcers

Complete wound healing as quickly as possible and achieving optimal functional status of the limb and patient are generally considered the driving goals of DFU treatment. These are sometimes at odds (eg, a trial of prolonged wound care for an ulcer with questionable healing potential to avoid a minor amputation that may not significantly affect functional status), in which case shared decision making between patient and providers is essential. Treatment of DFUs is founded on the following basic principles: debridement and local wound care; diagnosis and management of infection; pressure offloading; evaluation for and management of ischemia; reconstruction, if necessary, for complex wounds; and global medical and nutritional optimization [3,5,17]. Management can be highly nuanced based on wound and patient complexity, and the value of a multidisciplinary team is largely in its ability to manage the breadth of DFU treatment with expertise.

5.1. Glycemic control

A goal hemoglobin A1c of ≤ 7.0% is a well-established target for preventive care, with some variation based on the patient’s ability to achieve lower goals, but aggressive glucose control during wound episodes has not been demonstrated to promote wound healing. A recent meta-analysis of glycemic control in people with DFUs found that hemoglobin A1c ≤ 8.0% during wound healing is likely sufficient to reduce risk of nonhealing and LEA [26], and baseline hemoglobin A1c does not appear to be associated with DFU outcomes. Furthermore, a decrease in hemoglobin A1c in people with DFUs whose hemoglobin A1c was <7.5% at baseline was associated with relatively worse healing outcomes compared with a slight increase in hemoglobin A1c in a retrospective cohort study, and intermittent hypoglycemia due to tight glucose control has been proposed as a mechanism for this finding [27]. Intermittent hypoglycemia and treatment-related neuropathy in strict glucose control have been proposed as causal mechanisms. MDFC settings, where patient and limb can be monitored in parallel, are ideal to manage the nuances of glucose control in people with active DFU.

5.2. Offloading

Offloading is an essential component of DFU treatment and of both primary and secondary prevention [5,17]. Provider surveys have shown broad understanding of the importance of offloading, but there is wide variability in offloading practices [5,17]. Barriers to offloading device access and adherence, including socioeconomic factors and patient education, are also significant [5,28]. MDFC settings with integrated podiatry have demonstrated improvement in timeliness, uniformity, and adherence to offloading compared with standard of care (pre-MDFC), and have shown that these changes result in improved DFU healing [18]. Patient education on the importance of offloading is another central component of offloading, especially among those who require removable offloading devices [5]. Multilevel reinforcement from providers and dedicated educators can address patient education gaps. Mechanisms to ensure insurance coverage or other financial assistance for offloading equipment are additional elements frequently found in MDFC that can serve to limit disparities related to socioeconomic deprivation [5].

5.3. Advanced wound care

Basic wound care using sharp debridement of devitalized tissue and callus and topical therapy to maintain an ideal wound bed are mainstays of management of DFUs [17]. It should be noted that aggressive local debridement in a dysvascular limb can lead to wound deterioration and should be postponed until revascularization is performed and perfusion is optimized. Advanced wound therapies are considered if at least 4 weeks of standard wound care fails to achieve >50% reduction in the wound area in an otherwise optimized limb [17]. In longstanding DFU, referral for advanced wound therapy is associated with up to 30% absolute improvement in wound healing, but is associated with delays outside the context of MDFC [29].

The spectrum of advanced wound care is broad and often requires specialized provider training and intensive patient surveillance. The most robust evidence exists for negative pressure wound therapy, with multiple randomized controlled trials reporting improved healing time and rates, reduced amputation, and higher patient satisfaction and quality of life [17,29,30]. Additional biologic, hyperbaric oxygen, and tissue matrix technologies have limited large-scale data and require experience and expertise, but have demonstrated excellent efficacy in healing high-risk wounds in multidisciplinary settings [17]. One center reported 79% and 93% 12- and 18-month healing rates, respectively, of complex infected and/or ischemic DFUs (most were WIfI stage 3 to 4) with combined dermal regeneration template and negative pressure wound therapy, and split-thickness skin grafting or hyperbaric oxygen in select cases [30]; WIfI stage 3 to 4 wounds, heel wounds, and wounds involving osteomyelitis all demonstrated healing similar to less-high-risk wounds. These healing rates are approximately 20% higher than those historically reported for similar wound types and result in fewer than expected LEAs based on WIfI stage [30]. Adults from racial and ethnic minority groups are more likely to present with ischemic and infected wounds [10,14]; thus, expert advanced wound care in an MDFC setting presents a major opportunity to prevent amputation in this population.

5.4. Evidence-based revascularization

Variability in patterns of revascularization in diabetic foot and vascular disease lead to disproportionately fewer revascularization attempts in non-White patients and patients who are socioeconomically disadvantaged, and subsequently to increased rates of major amputation in these groups [13,15,31]. Although anatomic data are lacking in most studies evaluating these differences, they are demonstrated consistently and are almost uniformly not attenuated by controlling for gangrene or patient comorbidities [31]. The 2019 Global Vascular Guidelines and the Global Anatomic Limb Staging System (GLASS) aimed to better standardize revascularization strategies based on patient fitness for open surgical intervention, anatomic pattern of ischemic lesions, and best options for re-establishing in-line pulsatile flow to the threatened extremity [3].

In MDFC settings, both Global Vascular Guidelines–guided and more aggressive use of endovascular revascularization strategies resulted in excellent limb preservation rates across GLASS stage, with WIfI continuing to better predict wound healing and amputation [32]. Complex tibial and pedal disease poses significant challenges to successful revascularization in diabetic foot and vascular disease, especially in patients who are poor candidates for open bypass. Stratified according to GLASS, several MDFC groups have shown similar rates of patency and 1-year major amputation rates between GLASS stage 1 and GLASS stage 3 infrapopliteal lesions presenting with tissue loss, including with tibial endovascular interventions [33,34]. This demonstrates that complex and/or severe tibial arterial disease can be managed successfully in MDFC settings to achieve limb preservation. Given the disproportionately high rates of complex tibial and pedal disease at presentation in Black and Hispanic patients, which is often cited as a reason for fewer revascularization procedures [35], more aggressive attempts at tibial interventions are a potential target for decreasing major amputation rates in this population. Ongoing validation of additional calcium-based and pedal-specific scoring systems may provide further evidence for best practices revascularization in these groups [36].

6. MDFC and preserving the functional limb

Retrospective center-based cohort studies almost universally demonstrate improvement in both process measures and outcomes after implementation of an MDFC model, and a recent systematic review by Musuuza and colleagues [19] reported that 94% of included publications examining pre–post MDFC outcomes found a reduction in major LEAs. Centers in underserved urban areas have demonstrated excellent healing, limb preservation, and functional outcomes among populations with significant socioeconomic deprivation that are comparable with outcomes among people with mid- to high-level socioeconomic status [37]. In similar MDFC settings, neither race nor insurance was associated with adverse outcomes, including ulcer recurrence, unplanned readmission, or loss of functional status after treatment for complex DFUs [38-40]. Together, these highlight the potential for MDFC to attenuate racial, ethnic, and socioeconomic disparities in outcomes (Fig. 1).

Fig. 1 –

Multidisciplinary diabetic foot care. CVD, cardiovascular disease; DFU, diabetic foot ulcer; LEA, lower extremity amputation; PAD, peripheral artery disease; PN, XXXX.

6.1. Wound healing and recurrence

Wound healing rates are difficult to compare in MDFC and pre- or non-MDFC settings due to variable use of classification schema before WIfI and increasing medical complexity of the population with diabetes, which affect wound healing potential. In modern MDFC series, wound healing is reliably predicted by WIfI stage; mean healing time for stage 1 is generally 1 to 3 months and for the more variable stage 4 is 3.5 to 9 months [41,42]. WIfI stage 4 wounds at high risk for amputation have reported healing rates between 60% and 75% [21,30,41]. Although WIfI was initially designed and validated to predict risk of LEA, a recent retrospective series of mostly non-White and Medicaid patients in an MDFC setting found WIfI predicted healing but not major amputation [41]. These findings reinforce the potential of MDFC models to reduce the risk of major LEAs in high-stage DFUs, even in populations at disproportionately high risk.

Surveillance in MDFC after wound healing results in reduced morbidity of recurrent ulcers. Although some centers report as much as a 40% reduction in ulcer recurrence rates, this is not demonstrated consistently, and may be related to disparate protocols for following patients after healing [39,43]. Multiple studies have shown that for patients followed in MDFC after ulcer healing, recurrent ulcers are a lower stage, smaller, and have reduced healing times [39,43], with similar ulcer recurrence rates and healing outcomes among Black and White patients [39].

6.2. LEA, amputation-free survival, and preserving the functional limb

A reduction in major LEAs is perhaps the most consistently reported finding in pre–post MDFC outcomes studies. The implementation of an MDFC model is associated with up to 51% absolute reduction in major LEAs [5,19,44]. Although differences in wound stage–adjusted major LEAs by race or ethnicity are often not reported, centers serving high proportions of racial and ethnic minority patients report outcomes similar to those serving largely White populations. Rates of minor LEAs are not necessarily reduced and, in several studies, minor LEA incidence increases, consistent with national trends in LEAs. However, this appears to reflect higher rates of limb preservation and specifically of preserved functional status, especially for high-stage wounds [40].

Amputation-free survival is consistently improved in MDFC settings [19], and MDFC is associated with up to a 50% reduction in early mortality and better than expected 5- and 10-year mortality rates among patients with advanced-stage DFUs [44]. In the context of complex diabetic foot and vascular disease, however, primary amputation is sometimes appropriate for unsalvageable (WIfI stage 5) limbs, for patients with poor baseline functional status, or for patients with severe comorbidities and limited life expectancy. A shift toward prioritizing patient-centered outcomes, including wound healing, ambulatory status, and independence in activities, recognizes this distinction, and some have proposed the addition of a functional component to the WIfI score [45].

Complex DFUs in people with baseline ambulatory functional status are an important target of MDFC. A recent evaluation of patient-centered clinical success (defined as wound healing, limb salvage and maintenance of ambulatory status at 1 year, and survival to 6 months) in adults with diabetes, CLTI, and tissue loss or gangrene reported a 71% clinical success rate after revascularization and wound care, almost double the rates of similar composite outcomes reported historically in non-MDFC settings [40]. Similarly, results in maintaining ambulatory status have been achieved in hospitalized patients presenting with CLTI, tissue loss, and high WIfI stage, confirming the feasibility of functional limb preservation as a primary goal of MDFC in this population [42].

Functional status and patient-reported quality of life are closely related, and both are relevant measures of successful diabetic limb care. Patients affected by DFUs and LEAs consistently report poor physical health–related quality of life [46]. Self-reported functional status improves after wound healing, with no significant difference in return to baseline quality of life between those who heal primarily and those who heal with minor amputation [46]. Quality of life studies in this population are limited by lack of data on the differential impact of diabetic foot and vascular disease on functional status and quality of life based on race, ethnicity, or socioeconomic status, which might better quantify the DFU burden on quality of life in these groups.

7. Cost-effectiveness of MDFC

Diabetic foot complications result in annual excess health care expenditures of 50% to 200% above the baseline costs of diabetes-related care [44]. Direct treatment costs correlate with increasing WIfI stage, and WIfI stage 4 wounds are estimated to cost at least $50,546 ± $4,887 from diagnosis to healing or LEA [42,47,48]. Pre–post historical analyses of MDFC have shown cost reductions of up to 20% per wound episode, primarily driven by fewer inpatient admissions; other studies have reported stable costs despite intensive multispecialty care and better outcomes [44,47]. Current payment models do not sufficiently support multidisciplinary DFU care, and improved reimbursement of outpatient services may further incentivize widespread implementation of MDFC paradigms, especially for costly to treat, high-stage wounds [47,48]. Indirect costs of DFUs and LEAs are difficult to measure, but improved limb preservation and functional outcomes in MDFC result in reduced long-term disability, minimizing the indirect economic burden of diabetic foot disease.

8. Barriers to MDFC access and implementation

MDFC are collaborative, often centralized care models in which referrals are inherently streamlined. Inability to access timely specialist care is a strong predictor of poor outcomes associated with non-White race and ethnicity and low income, but can be mitigated by standardized referral pathways to and within MDFC [14,20]. Large academic and tertiary MDFC settings tends to be found in urban locations and therefore are well-positioned to serve racial and ethnic minority and low-income urban communities where diabetes and PAD-related LEA rates are highest [12].

Despite excellent reported outcomes in limb preservation for racial and ethnic minority, low-income individuals treated with MDFC, rates of LEA in socioeconomically deprived urban neighborhoods remain high [12], suggesting that gaps remain between availability and utilization of MDFC. A compelling geographic analysis by Fanaroff and colleagues [12] reported urban clusters of high major LEA rates corresponding to low neighborhood median income and a high proportion of Black residents in cities with large academic medical centers, suggesting delayed or limited access to tertiary care. Rural populations are at especially high risk of delays in specialist care, and rurality is associated with higher rates of advanced-stage ulcer at presentation and major LEAs [12,20]. These data indicate that feasible access to MDFC (either through geographic proximity or referral) is necessary but not sufficient to guarantee equity in high-quality, population-based limb care. Community-based screening, outreach, and referral networks, and urban–rural referral partnerships are necessary to improve utilization among high-risk populations that will most benefit from MDFC.

9. Conclusions

Diabetic lower extremity complications, including major LEAs, are increasingly common, highly morbid, and largely preventable. Longstanding structural disparities in access to preventive and therapeutic care result in a disproportionately high burden of major LEAs among racial and ethnic minority groups and socioeconomically deprived populations, and meaningful reductions in major LEAs cannot be achieved without addressing these inequities. Disparities in process and outcome measures of DFU care are minimized by experienced multidisciplinary teams, where variability in care is limited and aggressive pursuit of functional limb preservation is standard. Treatment of patients with diabetes and PAD should be managed in an MDFC environment with vascular surgery, podiatry, endocrinology, and expertise in advanced offloading and wound care as minimum team requirements. Community-based outreach is necessary to improve MDFC access in underserved urban environments where the need for and potential impact of MDFC are high. Strong referral networks to ensure timely evaluation of DFUs by specialists and adequate funding and reimbursement of these complex care models are essential for sustained widespread MDFC adoption.