Prevention of Lower Extremity Amputations due to Nontraumatic Loss of Sensation and Loss of Circulation

  • Date: Oct 26 2021
  • Policy Number: 20212

Key Words: Diabetes, Cardiovascular Disease

Abstract
Nontraumatic lower extremity amputations (NTLEAs) have been identified as a major public health burden causing reduced ambulatory independence, decreased quality of life, and reduced life expectancy. NTLEAs result in a significant financial strain on the health care system. The cost of diabetes and its complications is estimated at $327 billion. Although NTLEAs are often observed in combination with diabetes, they are not dependent on the presence of diabetes. Peripheral neuropathy and peripheral vascular disease are also prominent drivers of NTLEAs, and their estimated annual costs are $10.9 billion and $7.3 billion, respectively. In addition to their financial burden, NTLEAs are twice as likely in African American and Hispanic populations than among Caucasians, highlighting an area of health care disparity in our system. Guidelines from the Lower Extremity Amputation Prevention program are simple steps providers can take to prevent NTLEAs at early stages. The first step is for at-risk individuals to become familiar with clinical signs and symptoms to reduce their risk of an NTLEA via regular foot screenings. For higher-risk individuals, timely referral to a multidisciplinary care team may be needed to prevent worsening complications. It is essential to incorporate guidelines regarding access to care and payment for preventative services nationwide. Providing lower extremity screenings and payment benefits from Medicare, Medicaid, and other insurance providers to eligible beneficiaries will reduce health disparities and encourage providers to engage in primary prevention measures. Because of the financial burden and increasing incidence of lower extremity amputations, APHA recommends this policy statement for adoption.

Relationship to Existing APHA Policy Statements
There are no existing policy statements addressing the public health problem identified in this statement. APHA Policy Statement 20002 (Reducing the Incidence of Blindness, Lower Extremity Amputation, and Oral Health Complications in Minority Populations Due to Diabetes) addressed the topic of lower extremity amputations in diabetic populations but was archived in 2019. Several existing APHA policy statements discuss relevant broad topics, such as access to care and social determinants of health, but not in the context of prevention of nontraumatic lower extremity amputations (NTLEAs). These statements include the following:

  • APHA Policy Statement 20189: Achieving Health Equity in the United States
  • APHA Policy Statement 201011: Reforming Primary Health Care: Support for the Health Care Home Model
  • APHA Policy Statement 20161: Access to Integrated Medical and Oral Health Services
  • APHA Policy Statement 20204: A Call for Adult Dental Benefits in Medicaid and Medicare
  • APHA Policy Statement 20109: Health Literacy: Confronting a National Public Health Problem
  • APHA Policy Statement 20023: Support of Healthy Aging through Health Promotion and Prevention of Disease and Injury

Problem Statement 
Epidemiology of NTLEA: Lower extremity amputations are the result of either traumatic (e.g., motor vehicle accident) or nontraumatic (e.g., severe infection, gangrene or ischemia, nonfunctional limb) etiologies. NTLEAs commonly arise as a complication of diabetes, which is believed to affect more than 30 million people in the United States, and/or chronic limb-threatening ischemia (CLTI), which may affect 8.5 to 12 million Americans.[1] Peripheral arterial disease (PAD) is also a known risk factor for NTLEA, with studies showing 78 times greater odds[2] of amputation among people with PAD versus those without PAD. Approximately 20% to 30% of people with PAD have concomitant diabetes mellitus, increasing the risk of amputation twofold to fourfold when both conditions are present[3]; however, the two conditions are considered independent risk factors for amputation on their own. 

There are known precursors to NTLEA that are often present in adults with diabetes or PAD such as diabetic foot ulcers (DFUs), tissue breakdown, and infection. As many as half of NTLEAs are preceded by an underlying loss of protective sensation, which in turn leads to foot ulceration.[4] Another risk factor for NTLEA is neglected PAD, which may lead to a more severe, end-stage condition (CLTI).[5] Consequently, approximately 50% of all NTLEAs are caused by diabetes.[4] According to data from the Nationwide Inpatient Sample of the Agency for Healthcare Research and Quality, age-adjusted NTLEA rates per 1,000 adults decreased 43% between 2000 and 2009 and then increased 50% between 2009 and 2015. The recent increase was driven by a larger number of NTLEAs among younger and middle-aged adults, a 62% rise in the rate of minor NTLEAs, and a 29% increase in the rate of major NTLEAs.[6] Reasons for the uptrend are unclear but are likely multifactorial. A possible explanation is that preventative practices are not currently being employed,[6] despite the large body of evidence that supports the effectiveness of prevention strategies.  

Financial burden: The costs associated with NTLEAs include the initial cost of surgery, acute in-hospital care, long-term care (e.g., care at a skilled nursing facility, physical therapy), and costs for surgical complications (e.g., wound healing) and prosthetics.[7] Medical care costs for Medicare and Medicaid beneficiaries with dysvascular amputations were estimated to exceed $4.3 billion in 1996. Acute hospital care expenses accounted for the largest portion of medical care costs, while physician and outpatient care accounted for the second largest component.[8] The costs associated with NTLEAs are expected to increase as a result of the growing prevalence and substantial economic impact of diabetes, CLTI, and DFUs.[9–11] For instance, the total cost of diabetes-related preventable hospitalizations increased by approximately $20 billion between 2002 and 2017.[11] Furthermore, annual health care costs due to CLTI (a known precursor to NTLEA) were estimated to be greater than $4 billion,[12] in addition to estimates between $9 and $13 billion for DFUs (another known precursor to NTLEA),[13] $7.3 billion for PAD,[14] $10.9 billion for peripheral neuropathy,[15] and an enormous $327 billion for diabetes.[16] 

Social and mental burden: NTLEA has been identified as a major public health burden leading to reduced ambulatory independence, significant mental health consequences, decreased quality of life, and reduced life expectancy.[17] The mental health impact on individuals who undergo an amputation has been historically underappreciated by health care providers. We now understand that there are stages of grief associated with the loss of a limb. These stages include denial, anger, bargaining, depression, and eventual acceptance. Surgeons should be aware of these stages and offer psychiatric help to individuals who will have or have undergone an NTLEA.[18] In a recent study assessing suicide ideation among adults with NTLEAs resulting from PAD, the authors noted that 15.71% of people expressed suicidal ideation one year after surgery.[19] Also, more than 30% of individuals may suffer from decreased self-esteem and introversion after amputation.[20] Mental health problems can interfere with rehabilitation if a mental health professional is not involved early in the postoperative phase. In addition, mental health professionals should be a part of the multidisciplinary team when an individual experiences an NTLEA.

Disparities in NTLEAs: Not only do NTLEAs cause a significant financial strain on our health system, they disproportionately affect minorities and those of lower socioeconomic status and are known to be a preventable complication.[21] In a recent population study involving 155,647 U.S. veterans, African American veterans had a higher prevalence of diabetes than their White counterparts (51.6% versus 44.1%). The risk for major amputation was significantly higher among African Americans—in fact, twice as high—than White patients.[21] After adjustment for socioeconomic status and preexisting comorbidities, African Americans still experience almost twice the risk of an NTLEA.[21] In another recent population study, the risks of major amputation among those diagnosed with diabetic foot infections were significantly higher among Black, Hispanic, and American Indian/Alaska Native patients than among White patients.[22]

Among patients diagnosed with PAD, African Americans are less likely to avoid an amputation following a revascularization procedure than their White counterparts; furthermore, the racial disparity in amputation-free survival after revascularization increases over time.[23] One study demonstrated that amputation rates in the United States were up to nine times higher among African Americans with diabetes in certain rural regions relative to urban regions.[4] Similarly, amputation rates vary by hospital referral region, with some clustering in the southeastern United States, and by the location of initial care of the diabetic foot problem.[23] 

Some authors have offered suggestions for why these racial disparities in outcomes exist. A common theme is that socioeconomic status may play a key role regarding risk factors for NTLEAs. In the study examining veterans mentioned above, African Americans were more likely to live in regions of lower socioeconomic status and regions with lower median household incomes ($40,000 or below), high neighborhood poverty, and higher area deprivation indices.[21] As a result of these findings, the authors concluded that race is an independent risk factor for NTLEAs. 

Limitations in access to care: The inability of patients to access the proper care continues to be an important problem in the U.S. health care system across all conditions. Podiatrists are the primary provider of preventive foot care services for many patients; however, these services are currently considered optional under many state Medicaid programs if they performed are by a podiatrist. Although such services would be considered “covered” if performed by a physician or optometrist, the time constraints surrounding outpatient appointments force providers to rely on podiatrists to provide preventive foot care. The result of this “optional services categorization” for podiatrists is that access to preventive foot care is often variable or absent based on year-to-year fiscal policies. Currently, nine states do not cover preventive foot care services by podiatrists for all qualified Medicaid beneficiaries, and 23 states require out-of-pocket expenses for such services.[24] 

Evidence suggests that significant differences exist across urban and rural areas in Medicare beneficiaries’ ability to access the required vascular testing and intervention necessary to prevent NTLEAs. A recent study among Medicare beneficiaries showed that ankle-brachial index testing (a basic screening test for PAD) was conducted among only 47.5% of patients within one year prior to undergoing an NTLEA and that testing rates were lower in rural than urban locations.[9] A separate study conducted in a rural community hospital revealed that testing levels were similarly low (preamputation ankle-brachial index testing was performed among only 49%–59% of patients) and that 66% of amputations occurred without any attempt at revascularization.[10] The study authors noted that among patients with already amputated limbs, only 27% had mild or moderate peripheral vascular disease and 90% had healthy healing tissue at the surgical site, suggesting that these limbs could have possibly been saved.[10] While some studies in urban settings have reported that 91% of patients undergoing NTLEAs had at least one diagnostic imaging study and a consultation with a vascular surgeon prior to the amputation, population studies in the United States suggest a strong inverse correlation between the intensity of vascular care (i.e., revascularization attempts and diagnostic vascular testing) and NTLEA rates even after adjustment for patient demographics and socioeconomic status.[9,11,25]

Delays in referrals to multidisciplinary care teams have been identified in the literature as a possible contributing factor leading to the worsening complications that precede lower extremity amputations.[26] The symptoms associated with PAD are variable, with up to 12% of asymptomatic patients having unrecognized PAD.[27] In addition, these delays may be due to misunderstanding among patients of their condition, inaccurate assessment of symptoms, and confusion about the need for specialist care.[28,29] With the projected rise in PAD, there is a need for improved education and symptom recognition to reduce the risk of lower extremity amputations caused by PAD complications. 

Therapeutic shoes, prescribed by podiatrists and other qualified specialists, play an important role in preventing foot ulcerations, infections, and subsequent NTLEAs.[30–32] However, the process to acquire a pair of therapeutic shoes is complicated, time consuming, and sometimes costly for both Medicare beneficiaries and nonbeneficiaries. In addition, podiatrists, among the more common suppliers of therapeutic shoes, are not able to complete the required Centers for Medicare & Medicaid Services (CMS) certificate of medical necessity, leaving the task for medical doctors and a small population of nurse practitioners. As a result, there was a decrease in the frequency of therapeutic footwear services rendered between 2013 and 2018 according to Medicare Part B data. The American Podiatric Medical Association is working to clarify and strengthen coordination of care in the Medicare therapeutic shoe program.[33]

Opposing Arguments/Evidence 
Conflicting evidence against major amputation prevention: There is some evidence to suggest that a lower extremity amputation may be warranted as a primary treatment option in patients with diabetes and PAD to avoid excessive costs to the health care system and the burden associated with long-term care. Khan et al. suggested that baseline functional status may dictate whether major amputation is the best option to provide better quality of life, particularly among patients with compromised lower extremity vascular status or poor functional status.[53] In that review article, the authors proposed that functional ambulatory status and ability to recover postoperatively may be important preoperative criteria in terms of who may benefit from primary amputation, therefore enabling an optimal patient-centered outcome that does not compromise a patient’s current functional status. In addition, individuals with advanced peripheral vascular disease in emergency situations (e.g., septicemia, severe limb-threatening infections) may require an amputation with few or no other options. While this policy statement opposes these scenarios, such conditions and situations are often determined by health care providers on a case-by-case basis.[54] Consequently, epidemiological data and true rates of medically necessary NTLEAs are not readily available to our knowledge. Although there is a literature suggesting that primary amputation may be worthwhile in some populations, these studies do not consider the long-term costs, societal costs, or mental health impacts of the procedure. As mentioned, a recent study among adults with NTLEAs resulting from PAD showed that approximately 15% of people expressed suicidal ideation one year after surgery.[19] It should also be noted that the five-year mortality rate after an NTLEA is approximately 50%, suggesting that primary NTLEAs may be contributing to a significant loss of valuable years of life when they are employed as a core treatment option,[55]

Conflicting evidence on the cost savings of multidisciplinary care teams for NTLEA prevention: From a health care system’s cost perspective, some literature has suggested that primary below knee amputations may be cost-effective relative to the implementation of a multidisciplinary care team if the initial cost of amputation is low (approximately $12,000). In the United States, where costs of below knee amputation are often greater than $35,000, multidisciplinary care teams have proven to be worthwhile to avert these costs.[56] However, if the cost of amputation were to drop below $12,000, as is the case in some European countries such as Russia, multidisciplinary care teams would fail to remain cost-effective.[17,57] Nonetheless, in the United States multidisciplinary care teams remain the standard of care in preventing NTLEAs in at-risk groups and are supported by several governing medical organizations. In addition, a recent study incorporating data from the Centers for Disease Control and Prevention on the cost-effectiveness of current interventions to manage diabetes suggested that comprehensive foot care, including patient education (a current primary prevention recommendation), is not only a cost-effective measure but has the ability to be cost saving.[36]

Conflicting government efforts on NTLEA prevention: Despite the efforts from various stakeholders to prevent NTLEAs, there may be examples of structural inequities embedded in current public insurance preventing such efforts. A recent study showed that Medicaid reimbursement in Texas is significantly lower for lower extremity vascular procedures and preventive foot care/reconstruction procedures than for amputations.[58] Such a reimbursement structure does not appear to incentivize limb salvage; ethical considerations and concern for patient well-being should outweigh any misaligned financial incentives in determining whether NTLEA or limb salvage is the optimal option.

Evidence-Based Strategies to Address the Problem 
Primary prevention: Several strategies have been described in the literature to prevent NTLEAs in adults who have been deemed “at risk” (i.e., adults with diabetes, neuropathy, and/or PAD). Primary prevention of amputations (which will occur after a diabetes or PAD diagnosis but before a foot ulcer develops) can be simplified through the five-step LEAP (Lower Extremity Amputation Prevention) program of the Health Resources and Services Administration.[34] This program outlines important steps providers and patients can take before the known precursors to amputation have developed. These steps include (1) an annual foot screening with PAD evaluation, (2) patient education, (3) daily self-inspection, (4) footwear selection, and (5) management of simple foot problems, suggesting that both the patient and the provider play a vital role in preventing the precursors to amputation. This five-step approach offers a framework for keeping our “at-risk” population healthy and well. Patient and provider education has been shown to be particularly worthwhile as a primary prevention tool, especially in terms of educating patients on proper shoe gear, foot hygiene, signs of infection, and so forth. Education is both low cost and simple to employ. For example, the Step-by-Step Diabetic Foot Project in Tanzania focused its prevention measures solely on foot education for providers and patients. Without using any costly interventions, it was able to reduce amputation rates by two standard deviations below the mean within three years of program implementation.[35] Primary prevention measures consisting of foot screenings and patient education have been identified as one of the only cost-saving measures currently employed for diabetes prevention[36]; however, despite this evidence, such measures continue to be among the most inconsistent and least used services rendered.[37] 

How and when to perform foot screenings: Since peripheral neuropathy and vascular disease are common pathways to developing DFUs,[38] foot screenings should be aimed at identifying a loss of protective sensation with monofilament testing and identifying signs of early PAD. Patients with diabetes are advised to have their feet evaluated at least once annually, with more frequent evaluations recommended for at-risk groups who have underlying PAD and/or end-stage renal disease.[39,40] The International Working Group on the Diabetic Foot, which produces evidence-based guidelines on the prevention and management of diabetic foot disease through the periodic comprehensive diabetic lower extremity evaluation/examination preventive service model, recommends that patients with loss of protective sensation or PAD and a history of a foot ulcer, a lower extremity amputation, or end-stage renal disease receive a foot screening from a podiatrist or other diabetes specialist as often as every one to three months.[2] In addition, as part of its primary prevention efforts, the American Diabetes Association suggests screening for PAD among adults with diabetes older than 50 years and those younger than 50 years with risk factors for PAD (e.g., smoking, high blood pressure, high cholesterol, or duration of diabetes greater than 10 years).[41] Vascular lab studies evaluating circulation to the toes and foot may prevent an amputation if vascular surgical intervention can restore adequate blood flow before tissue damage occurs.[5]

Patient education on smoking cessation is also a key component of preventive visits. The link between smoking status and diabetic foot amputation has been well established.[42] A pooled analysis showed that patients with diabetes who were smokers were 65% more likely to undergo an amputation than patients with diabetes who were nonsmokers. Patient education should also focus on performing daily foot exams. Providers should help engage patients in being equal members of the care team and reinforce that early detection of changes in their feet can help prevent serious complications.[43] Therapeutic footwear has been shown to reduce the risk of ulceration among adults with peripheral neuropathy and should be employed for at-risk patients.[44,45] Finally, management of simple foot problems such as the dry, cracked skin seen in autonomic neuropathy can prevent foot wounds and infections that can lead to more severe complications. 

Secondary prevention: Use of multidisciplinary care teams has been shown to reduce the risk of amputation by 39% to 56%,[46] and thus such teams have become a vital component of secondary prevention measures (i.e., after a foot ulcer develops in the presence of arterial disease and/or peripheral neuropathy). These care teams typically include a combination of several specialists (e.g., primary care, endocrinology, vascular surgery, podiatry, endovascular, and infectious disease specialists) and often incorporate community health workers.[46] Although several articles describing these care teams point to podiatrists or vascular surgeons serving as team leaders since neuropathy and arterial disease are the prominent drivers in the pathway to amputation, literature suggests that an interactive team approach in general, regardless of the providers involved, leads to a reduced risk of amputation overall.[46] Multidisciplinary care teams may also possess the ability to address the medical, mental health, and social struggles that high-risk diabetic patients may face, ensuring that a more comprehensive, patient-specific treatment strategy is employed.[45,47] Accumulating evidence has suggested that, in the United States, the multidisciplinary approach is cost-effective relative to preventive measures implemented by a single provider.[46] Barshes et al. demonstrated that multidisciplinary care teams aimed at limb preservation for patients with critical limb ischemia and nonhealing foot wounds were generally cost-effective.[48] The relative cost-effectiveness of these efforts seems to improve and even reach cost savings for frail and/or elderly patients. Multidisciplinary care teams are quickly becoming the standard of care for U.S. patients with active DFUs and are supported by multiple professional organizations including the American Diabetes Association, the Society for Vascular Surgeons, the American Podiatric Medical Association, and the International Working Group on the Diabetic Foot. Health care systems that have been successful in implementing multidisciplinary care teams have introduced the concept of “centers of excellence,” which can be defined as centers with personnel from multiple disciplines dedicated to working toward a common, patient-centered goal. These centers employ outcome monitoring, quality improvement, and benchmarks to ensure efficiency and effective and seamless communication between providers and patients. Although currently these centers of excellence are found only in large academic centers, they have become an example for health systems looking to make use of multidisciplinary care teams.

Among people with diagnosed PAD, reestablishing circulation, whether surgically and/or endovascularly, has become a mainstay in secondary prevention and has been shown to reduce the odds of NTLEA by 48%.[49] Unfortunately, despite a stable major amputation rate over time (approximately 250 per 100,000 admissions), revascularization procedures are declining in many regions of the United States.[49] Various studies have demonstrated that the regions of the country with the highest amputation rates typically have an approximately 50% lower rate of revascularization procedures, suggesting that vascular surgeons may not be available or that access to care is a barrier.[50] Increasing patient access to vascular specialists capable of performing such interventions, especially in rural and medically underserved areas, is a critical component of increasing attempts at revascularization and ultimately reducing NTLEAs. Financial incentives, specifically loan repayment programs such as the National Health Service Corps (NHSC), have been found to be an effective method to increase physician recruitment to medically underserved areas.[51] Currently, such programs are available only to primary care providers, and thus specialists with expertise in lower extremity and/or revascularization procedures such as podiatrists, vascular surgeons, and interventional radiologists are not included.

Solutions for increased access to care: Evidence suggests that inclusion of preventive foot care services for state Medicaid beneficiaries may substantially reduce lower extremity complications, including NTLEAs. A study by Skrepnek et al. showed that eliminating podiatric services from the Arizona Medicaid program resulted in a 36.7% increase in DFU-associated hospital admissions, a 22.5% increase in lengths of stay, and a 49.0% increase in lower extremity amputations.[52] The authors noted that for every $1 saved by the elimination of podiatric services, there was a $48 increase in hospitalization charges for complications related to diabetic foot ulcerations, resulting in a net loss of $47 per admission.[52] 

Poorly fitting footwear has been shown to be a key factor in the causal pathway to foot ulcerations, which later can lead to lower extremity amputations. A recent systematic review including six randomized controlled trials demonstrated that therapeutic footwear can improve healing of neuropathic ulcers by redistributing pressure across the plantar foot.[32] In addition to being an important method of offloading current ulcerations, therapeutic footwear can be a valuable tool for prevention of re-ulceration and first-time ulceration in high-risk groups.[47] In light of this evidence, CMS has included therapeutic footwear as a covered entity for its beneficiaries who meet certain criteria; however, issues have been identified in the current coverage policy resulting in the inability of many beneficiaries to receive this service. Barriers include lack of shoe providers and arduous coordination of care requirements. The Medicare requirement of having Certificates of Medical Necessity along with additional documentation from a primary provider who is a physician, optometrist, or nurse practitioner and is enrolled in the Primary Care First demonstration project involves significant staff time to coordinate. Physician assistants and nurse practitioners who are not independently licensed to practice require cosigning of their notes to be in compliance with Medicare policy, which also involves increased staff coordination. This documentation is in addition to the doctor of podiatric medicine’s documentation of the medical necessity of ordering footwear.

Action Steps
Significant areas for improvement exist across all levels of NTLEA prevention. The following action steps outline feasible strategies, based on the published scientific literature discussed here, that APHA believes will significantly lower NTLEA rates in the United States.

  • APHA urges health care associations and providers to support federal legislation and regulatory efforts to expand access to screening (using the periodic comprehensive diabetic lower extremity evaluation/examination preventive service model) and preventive foot care services. Examples include amending the Medicaid statute (Title XIX) to incorporate coverage of foot and ankle care services provided by a doctor of podiatric medicine and removing insurance benefit limitations on frequency of preventive foot care visits for high-risk individuals.[33,59,60]
  • APHA urges CMS and Congress to increase access to vascular testing and referrals to vascular specialists by focusing on lowering out-of-pocket expenses for noninvasive screening of high-risk patient groups, including those older than 50 years and those younger than 50 years with risk factors for PAD.[5,59–61]
  • APHA urges CMS and Congress to decrease the administrative barriers that currently impact the access of individuals with diabetes and PAD to the therapeutic shoe program. For example, doctors of podiatric medicine should be included as prescribing providers within the program, and coverage should be expanded to high-risk patients.
  • APHA urges all state and federal health care systems to financially support the development and implementation of centers of excellence with the goal of limb preservation.[46,62]
  • APHA urges Congress to expand the NHSC to include doctors of podiatric medicine and increase financial incentives for specialists to practice in rural or medically underserved areas of the United States through expansion of NHSC loan repayment programs.
  • APHA urges the National Institutes of Health to increase research funding directed toward primary prevention of foot ulcers, PAD, peripheral neuropathy, and NTLEAs. 
  • APHA urges health care professional associations (e.g., American Medical Association, American Board of Internal Medicine, American Academy of Family Physicians, American Mental Health Counselors Association) and individual providers to increase timely referrals to appropriate specialists before foot complications develop. 

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