Neuropathy in Minority Populations

Another goal of Healthy People 2010 is to eliminate health disparities in minority populations. Over the past 10 years, the growing number of persons with diabetes, particularly within certain racial and ethnic groups, suggests that targeted strategies are needed to prevent the escalating number of new cases of diabetes and the associated complications.

Diabetes, the seventh leading cause of death in the United States, has been identified as one of the six major contributors to the disparity between African Americans and white U.S. death rates. The incidence of diabetes is 1.5 times greater in African Americans than in whites, and disproportionately affects African American women. The rates of long-term complications of diabetes including retinopathy, neuropathy, and nephropathy are higher in adult African Americans compared to whites, particularly in diabetic end-stage renal disease where rates are 3.2 to 6.6 times higher in African American persons.

Diabetes mellitus is the leading cause of non-traumatic lower-extremity amputations (LEA) in the United States. Increased rates of amputations suggest a higher incidence of neuropathy in minorities since neuropathy is found to contribute to amputations 87% of the time. The age-adjusted rates for hospital discharge for non-traumatic LEA per 1,000 for the diabetic population is 10.2 for African Americans compared to 7.1 for whites. LEAs are more prevalent in African Americans, more costly, and require longer hospital stays than whites. The current LEA rate of 10.1 per 1000 in African Americans has been targeted for a reduction to 5 per 1000 in the goals of Healthy People 2010.

Even though the impact of diabetes and its complications are disproportionately represented in African-Americans, few studies exist describing neuropathy and its impact on sensation and skin blood flow and how it affects the quality of life in African-Americans with diabetes. These facts underscore the need to understand the etiology of diabetes and its complications since lower extremity amputations (LEAs) are more prevalent in African-Americans.

The Strelitz Diabetes Institutes set out initially to determine the nature and extent of the problem in the Hampton Roads area of Virginia. In its HUD funded projects, a total of 1,342 respondents were surveyed at 29 health fairs and other community-based events in Hampton Roads between March 1999 and October 2000. Study sites included commercial stores, minority churches, hospital diabetes health fairs, YMCAs, employer health fairs, fundraiser health fairs, two HBCUs (Historically Black Colleges and Universities), and various other locations around Hampton Roads. SDI researchers found a lower rate of neuropathy in the African American than the white population of the area in the face of higher ulceration and amputation rates for minority populations suggesting that minorities with neuropathy are at much higher risk of developing limb complications that require intervention.

If these findings hold true, those minority patients with neuropathy are at about 4 times the risk of their white counterparts without neuropathy, and they, nonetheless, comprise at least 13% of the people in their groups. That neuropathy is so lethal and impacts the quality of life (QOL) and activities of daily living (ADL) makes clinical identification of these patients a much higher priority than previously deemed necessary. Preventive care and patient education before the gross limb complications develop is now the order of the day.

SDI faculty have developed direct, non-invasive techniques to evaluate cognitive function and measures of skin blood flow abnormalities. They have also developed a tool that allows quantification of quality of life and activities of daily living ADL that has been validated and is being used in national and international studies on diabetic neuropathy.

The SDI is now poised to easily identify African-American diabetic patients at risk for the development of impaired blood flow and nerve damage. The skin blood flow response (alluded to above) appears to be blunted in African Americans compared to Caucasians. Existing technologies to detect skin blood flow abnormalities have the potential to detect sub-clinical manifestations and risk for the development of foot ulceration, gangrene and ultimately amputation.

Faculty at SDI believe that the combination of reduced warm thermal perception and reduction in the thermal and nociceptor-mediated vasodilation contributes to the development of foot ulceration and gangrene. As the number of African Americans suffering from foot ulcers and lower extremity amputations continues to rise disproportionately, the need to document racial differences and develop more sensitive sub-clinical techniques to better detect African-Americans at risk for neuro-ischemic foot complications and the impact on QOL and ADL is imperative to introducing appropriate interventions directed towards achieving the goal for Healthy People 2010.

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