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Diabetic Foot Neuropathy

People with diabetes are at an increased risk for foot injury due to decreased sensation and increased blood sugar levels.  For people with diabetes, the risk of developing a diabetic foot ulcer ranges from 15- 25% (AMA).  Thirty percent of diabetics over 40 years of age develop lower extremity disease, which includes peripheral arterial disease, peripheral neuropathy, foot ulceration, or lower extremity amputation.

Unfortunately, many diabetic foot injuries and ulcers lead to amputation.  “Diabetes underlies up to 8 of 10 nontraumatic amputations, of which 85% follow a foot ulcer” (AMA).  A 2000 Swedish study in found the cost of treating a diabetic foot ulcer was $18,000 (no amputation) and $34,000 (with amputation).

Because of the tremendous financial and emotional cost of diabetic foot amputations, it is crucial to note that they are preventable.  A 2005 review by the American Medical Association (AMA) provides and evaluates recent evidence on identifying diabetic persons at risk for developing a foot ulcer, and of interventions to prevent their formation.

Background Information

Foot ulcers are caused by peripheral neuropathy (decreased nerves/ sensation), excess pressure on the foot, and trauma (including cutting toenails).  Persons with atherosclerotic peripheral vascular disease, which is twice as common in diabetics than those without diabetes, will have a very difficult time healing a foot injury, even a small one caused by cutting one’s toenails.  Diabetic wounds are also difficult to heal because of their impaired collagen formation and immune system deficiencies.  Many diabetics are obese and have poor vision, which will negatively affect their ability to care for foot injuries.

Screening

The AMA’s report recommends that primary care physicians prevent foot ulcers by screening for those at risk.  They provide a formula to calculate this risk, which includes previous foot ulcers, prior lower extremity amputation, more than ten years with diabetes, poor blood sugar control, and impaired vision.  The AMA also says that physician should examine the feet for “structural abnormalities, reduced joint mobility, dry or fissured skin, tinea, or onychomycosis.”

Interventions

The AMA review found there was an increase in foot screenings (15% to 76%) when physicians used a computer registry to calculate the patient’s risk status for lower extremity amputation.  Project LEAP (Lower-Extremity Amputation Prevention) was developed by the US Department of Health and Human Services.  It is a one-day workshop for physicians on diabetic foot care, and resulted in an increase of foot care education by physicians from 38% to 62%.

Since one of the causes of foot ulcers is pressure on the foot, the AMA recommends prescription shoes for diabetics who are at high risk for developing ulcers.  Such shoes have “a deep, wide toe box and ample padding” (AMA).  Additionally, shoe inserts cushion the foot and redistribute pressure over a greater area.

New Developments

A new agent by David Stern and Ann Marie Schmidt promises to be a “Method for treating symptoms of diabetes.”  (Patent Number 6790443).  The specific symptom this drug allegedly treats is ineffective wound healing.

The mechanisms for wound healing include the presence of inflammatory cells, the formation of collagens, and the removal of necrotic tissue.  Many previous studies have found that diabetics have deficiencies in these processes, which make ulcers almost impossible to heal.

Accumulation of AGE has been found in tissues of diabetics and is linked to secondary complications.  AGE interferes with homeostasis by binding to receptor sites for some white blood cells, smooth muscle cells, and neurons.  This in turn prevents new connective tissue from being formed, thus preventing wound healing.

The Patented drug administers sRAGE, which “inhibits binding of advanced glycation endproducts (AGE) to any receptor for advanced glycation endproducts (RAGE) so as to treat symptoms of diabetes,” including alleviating inflammation.

The sRAGE provides a place for AGE to bind, which diminishes the amount of AGE in cells.  The study found that sRAGE “improved wound healing in genetically-diabetic mice.”  This is very promising information, as the AGE mechanism is now a “feasible target for intervention in diabetic wound healing.”

Even if this new patent does not provide a drug to treat diabetes, the identification of the AGE mechanism is hope for further research.