Peripheral arterial disease (PAD) is a growing public health problem that results in significant morbidity and mortality, reduced quality of life, and substantial healthcare costs. The prevalence and incidence of PAD vary among different ethnic groups and those of socioeconomic disadvantage. Ethnic minority populations in the United States are undergoing rapid growth. However, ethnic disparities in PAD have not been well characterized. The purpose of this review is to examine the literature on how ethnicity influences the risk and management of PAD.
Ethnic Disparities in Risk Factors
To date, a number of reports, systematic reviews, and meta-analyses undertaken in different countries have consistently shown an association between non-white ethnicity and increased risk of lower limb amputation. Given the heterogeneity of definition and classification of ethnicity in these studies, and that this risk of amputation tends to be a surrogate measure of advanced PAD, it is reasonable to postulate that there are specific risk factors associated with ethnicity that are independent of established cardiovascular risk factors. This section will explore the evidence for ethnic disparities in PAD and the potential risk factors involved.
Ethnicity is defined as a common ancestral background shared by a group of people. Members of the group identify themselves, and are identified by others, as members of a separate group. Importantly, the group’s identity is based on shared social and cultural heritage that is passed from one generation to the next. Measured at the population level, ethnicity is a socio-demographic variable which tends to manifest, at least in part, as a result of culture, behavior, or socially determined factors. At an individual level, such factors have the potential to impact health status and healthcare.
Prevalence of Risk Factors
The reasons for the higher prevalence of PAD among ethnic minorities are not completely understood at this time. Minority populations in the United States share a disproportionate burden of PAD. According to NHANES data, the age-adjusted prevalence of PAD was 12.1% in non-Hispanic blacks and 8.4% in Mexican Americans compared to 5.4% in non-Hispanic whites. Similarly, the rate of PAD hospitalization and lower extremity amputation have been shown to be higher among ethnic minority groups. Overall, there is a two-fold higher rate of amputation among elderly black and Hispanic Medicare patients compared to white patients.
Results from the National Health and Nutrition Survey III (NHANES III) indicated that the prevalence of PAD was 6.3% among the general United States population age 40 years and older (approximately 7.1 million individuals). The prevalence increased sharply with age, affecting 1% of those age 40-49, and rising to 20% of those age 75 and older. PAD is also a common disease among individuals with other existing cardiovascular diseases, affecting 1 in 3 adults over the age of 50. These statistics may actually underestimate the true extent of PAD in the US population. In a recent analysis of the United States Medicare data, prevalence estimates were 12.5% overall and increased from 5.7% in those aged 65-69 years to 20.5% in those over age 85. The higher prevalence estimates in Medicare patients may reflect the higher prevalence of PAD among elderly persons.
Impact of Genetic Factors
Gene association studies have identified certain genes that may influence the development of PAD. A study of Chinese patients with type 2 diabetes found that those with diabetic foot disease had a higher frequency of a certain gene polymorphism than those without diabetic foot disease. This suggests that certain genes may predispose patients with diabetes to foot complications, including critical limb ischemia. Stepwise progression of PAD from claudication to critical limb ischemia or acute limb ischemia has been associated with certain genetic markers. Patients with critical limb ischemia were found to have a higher frequency of a specific gene polymorphism compared with patients with intermittent claudication and a higher frequency than a control population without PAD.
The direct impact of genes on the development of PAD is difficult to study, but useful information can be gained by comparing the disease frequency in monozygotic twins and dizygotic twins. If genes have a significant impact on the development of a disease, the disease frequency in monozygotic twins should be higher than in dizygotic twins. In a study of male twin pairs in the United States, Scotland, and Australia, involving almost 7500 participants, the disease rate in dizygotic twins was 24% compared with 73% in monozygotic twins. This suggests that genetic factors have a strong impact on the development of PAD.
Socioeconomic Factors and Access to Healthcare
The INSIGHT trial analyzed the response of 632 Black and White participants with peripheral artery disease to two different antiplatelet therapies. After adjusting for socioeconomic variables and comorbidities, Black race was associated with a higher risk of major cardiovascular events, with a hazard ratio of 1.65. These results suggest that there are ethnic differences in cardiovascular disease that cannot be explained solely by known risk factors and comorbidities. The higher risk experienced by individuals of black ethnicity may be attributed to a higher genetic predisposition.
Low SES is often also associated with migration and the acculturation process, and specific risk factors may be associated with the migratory experience. In a study of Black and White men of low SES, black race was a strong predictor of peripheral artery disease, with an odds ratio of 2.24, independent of lifestyle factors and cardiovascular risk factors.
Limited access to healthcare services because of socioeconomic factors is a key issue for health disparities among ethnic groups. Lower socioeconomic status (SES) is usually associated with a higher incidence of cardiovascular disease. This can be attributed to a higher prevalence of risk factors, unfavorable psychosocial and behavioral factors, as well as a lower standard of living. In Western multiethnic societies, much of the excess risk of cardiovascular disease among lower SES groups is borne by ethnic minority communities.
Ethnic Disparities in Disease Management
Currently, there are no published data on the influence of ethnicity on PAD management. However, inferences can be drawn from studies on cardiovascular disease management. Studies in other cardiovascular diseases have shown that African Americans and Hispanic Americans receive fewer revascularization procedures than whites, are more likely to undergo amputation, and are less likely to be referred to supervised exercise programs. The same pattern has been observed in other populations worldwide, suggesting that ethnic disparities in PAD management do exist. Differences in surgical rates may be due to variations in disease severity or patient preference, although several studies have found that these variables do not always account for the disparity in revascularization procedures. Economic status has been identified as a significant determinant of receiving vascular surgery in PAD patients, and may also influence access to supervised exercise programs. Restrictions in insurance coverage and choice of physician may further limit the treatment options available to minority populations. The finding that patients from ethnic minorities receive more amputations and less revascularization may indicate an underlying bias resulting from physician perception of futile revascularization in patients with poor functional status or coexisting comorbidities. This possibility is supported by evidence that African Americans with critical limb ischemia are less likely to see a vascular surgeon and if they do, are less likely to undergo amputation preventing revascularization procedures. Clearly, efforts must be taken to eliminate these disparities in PAD management and ensure that all patients, regardless of ethnicity, receive the most appropriate treatment for their condition.
Screening and Diagnosis
The existence of ethnic disparities in the utilization of ABI testing and imaging tests for PAD has not been directly studied, but is evident from differences in rates of lower extremity revascularization and amputation, which are indirect indicators of the diagnosis and severity of PAD. ABI testing is reimbursable by Medicaid and Medicare, and a better understanding of the reasons for underutilization of the ABI test can help to reduce disparities in the diagnosis of PAD. This issue will be discussed in the following section on treatment approaches.
Despite these recommendations, PAD continues to be highly underdiagnosed in the United States, as ABI measurements are only taken in 35-50% of individuals with clinically evident PAD. Low utilization of the ABI test is particularly common among African American and Hispanic individuals, and among individuals with diabetes, PAD, coronary heart disease, or cerebrovascular disease. This is a cause of concern as these are the groups that are at particularly high risk for adverse outcomes related to PAD. Olin et al showed that among high-risk individuals, the presence of PAD was documented in less than 50% of patients in the medical record. This study demonstrated a failure to diagnose PAD among the very individuals who are at high risk for adverse outcomes of the disease.
Screening for PAD is done simply by measuring the ankle-brachial index (ABI), which is the ratio of the systolic blood pressure in the ankle to the systolic blood pressure in the arm. An ABI value of less than 0.90 is abnormal and is diagnostic of PAD. The United States Preventative Services Task Force (USPSTF) strongly recommends that clinicians screen for PAD in asymptomatic individuals with ABI measurements. Clinical signs and symptoms of PAD, such as intermittent claudication, are used to identify individuals at high risk for PAD, and the USPSTF also strongly recommends that clinicians use non-invasive imaging tests to diagnose PAD in individuals with clinical signs and symptoms of the disease.
A patient cannot benefit from therapeutic interventions for PAD if the disease is not diagnosed, and earlier identification of PAD is strongly associated with the quality of care.
Treatment Approaches
Upon presentation of the ischemic leg with PAD, a careful etiologic assessment should be made. Patients with a pure nerve symptom, such as rest pain, that is reproducible with nerve palpation and is ameliorated within 10 minutes by removing the provocative stimulus, are most likely related to peripheral nerve ischemia. This type of ischemia is best managed with simple analgesics such as aspirin or acetaminophen. Although patients with nerve claudication and minimal functional impairment may be treated expectantly, those with functional disability due to muscle ischemia should be considered for revascularization. When severe limb-threatening ischemia is present, the characteristic intermittent claudication or limb-threatening ischemia, attempts at revascularization are almost always indicated. This is due to the fact that while all patients with PAD have an increased cardiovascular mortality and morbidity, most patients with intermittent claudication can be managed medically and have long-term survival similar to that of the general population. In addition to this, a discussion of the absolute and relative contraindications to revascularization must take place. The patient’s co-morbid medical conditions may greatly affect this decision. Those with poor life expectancy and severe functional limitation due to systemic disease may be best managed with exercise and pharmacologic therapy. In such cases, consideration should be made for meticulous risk factor modification and aggressive cardiovascular event prophylaxis. A small percentage of patients are not suitable candidates for any form of revascularization due to an unacceptably high surgical risk and poor long-term prognosis. In summary, the decision whether to manage limb ischemia invasively or conservatively should be individualized for each patient, taking into account the nature and severity of the limb ischemia, the patient’s functional status and life expectancy, and the risks and benefits of the chosen therapy.
Patient Education and Support
Patient education is a vital part of the medical system in any culture. However, there is some evidence to suggest that ethnic minorities may not be obtaining all the information they need. This has been shown in the Japanese population, with 49% of patients with PAD and 27% of people without PAD reporting that they had never received information on the disease from healthcare professionals. If people are not well informed about the disease, then they are not going to be actively seeking treatment. This is important because the BARI 2D trial showed that patients with good knowledge of the disease were more likely to choose a treatment strategy aimed at reducing symptom burden and preventing future disease progression. Unfortunately, ethnic minorities are less likely to receive information from healthcare professionals. In a study of 1325 patients with type 2 diabetes, less well-educated and non-white patients were less likely to receive disease-specific information from healthcare professionals.
Addressing Ethnic Disparities in Peripheral Arterial Disease
Implications of disparities in the rates of lower extremity amputation due to peripheral arterial disease among different ethnic groups in New York City. This essay presents a proposal to decrease the burden of PAD among minority populations by increasing awareness of the disease, improving screening and early diagnosis, and ensuring that all patients have access to appropriate medical and endovascular/surgical therapies. It focuses on improving outcomes and eliminating disparities for the most severe and at-risk patients, those with significant lower extremity ischemia. Although the causes of disparities in amputation rates are multifactorial, access to care and quality of care are the most significant and are potentially modifiable with effective public health strategies and health policy. This proposal was developed under the auspices of the Association of Black Cardiologists and the Cardiovascular Research Foundation and informed by the experiences of an AB panel of experts in PAD and health disparities, focus group sessions with PAD patients, and review of relevant medical literature and public policy research.
Culturally Sensitive Healthcare Practices
To that finish, we carried out focus teams of African-American sufferers with PAD and their caregivers to determine their precise experiences with healthcare suppliers and to find out their perceptions of cultural sensitivity throughout the healthcare setting. Preliminary findings from these focus teams have demonstrated that there could also be a divergence between the perceptions of suppliers and sufferers concerning cultural sensitivity and that a supplier’s skill to ascertain cultural sensitivity is essentially influenced by the power to know the particular person’s lived experiences, be open to discussing the affect of tradition on the particular person’s well being behavior and be prepared to include such information into the supply of care. By figuring out these key elements of cultural sensitivity, we are going to be capable to develop and implement interventions and teaching programs that may instruct suppliers find out how to higher perceive and care for sufferers with PAD from numerous ethnic and racial backgrounds.
A basic approach to begin addressing ethnic disparities within the remedy of sufferers with PAD is to implement culturally sensitive healthcare practices. Cultural sensitivity will be outlined as “the provision of health care with out a private bias, however with an intentional consciousness and incorporation of the affected person’s cultural beliefs and practices”. Culturally sensitive healthcare has been proposed as an efficient and environment friendly technique to enhance healthcare supply and outcomes for ethnic and racial minority groups. Nevertheless, there may be paucity of data relating to which explicit practices or approaches represent cultural sensitivity and find out how to finest apply these methods within the care of sufferers with PAD and different heart problems.
Community Outreach and Education
Firstly, community resources and attitudes must be assessed in order to plan an effective intervention. Types and level of existing PAD awareness in the community will vary greatly, and only by targeting communities with little existing awareness can PAD become a perceived public health priority. An assessment of PAD knowledge and attitudes among community members and leaders can be made using focus groups and surveys. These are useful tools in gaining qualitative and quantitative insights into how PAD is conceptualized within the community, and can aid in identifying influential individuals who could assist in promoting PAD awareness. Such assessments will also provide feedback on how the community views the best ways of receiving health information, thereby aiding in the tailoring of an intervention to community preferences.
In this context, PAD is often overshadowed by other chronic diseases such as diabetes and arthritis: diseases which carry strong negative connotations and may be perceived as more severe than PAD. PAD has been shown to be under-diagnosed and under-treated, and efforts are needed to increase its priority within primary care. Considering the strong associations between lower levels of education and income with prevalent PAD, community-based initiatives will be the most effective way of reaching high-risk groups. The successful development and implementation of community outreach programs and education initiatives requires a series of methodical steps.
Despite being aware of the potential consequences of PAD, communities who are at higher risk of developing the disease are often left out of both research and treatment efforts. There is a clear need to better understand their attitudes and behaviors surrounding PAD and its risk factors, in order to address disparities in disease prevalence, treatment, and outcomes. Cultural-specific interventions to raise awareness of PAD, its risk factors, and effective treatments among these groups can be developed only with an in-depth understanding of their perceptions of the disease.
Collaborative Efforts and Policy Changes
Collaborative efforts between healthcare providers, researchers, and policymakers are essential for reducing ethnic disparities in PAD. One example of a successful collaboration is the San Diego Preventive Amputation Group. By using community-based research methods, they have improved awareness of diabetes-related lower limb amputation, reduced the disparity of amputation rates between whites and minorities, and have decreased the actual number of amputations in San Diego County. This was done through a variety of methods including improving podiatry services for the uninsured, providing culturally sensitive diabetes education, and increasing the usage of revascularization procedures. These are the types of efforts that lead to meaningful changes in health disparities. By improving awareness and professional knowledge of the disease process and treatment options among high-risk minority populations, there can be a shift in overall treatment and outcomes for PAD.
Policy changes in the United States healthcare system have been largely responsible for improved health outcomes for racial and ethnic minority persons. Policy has the ability to affect care at many levels; it can create a supportive environment for the delivery of care, eliminate disparities in care, and improve access to care. In 2000, the US Department of Health and Human Services launched Healthy People 2010, which contained 28 objectives directly addressing disparities in health and healthcare. One of the overarching goals is to eliminate health disparities among racial and ethnic groups. Although they did not specifically address PAD, several of the goals are directly related to the improvement of PAD outcomes for minority persons. Establishment of these types of initiatives helps to provide a blueprint for future research and policy decisions.
