About 21 million Americans have diabetes mellitus.1 In 2002, an estimated $92 billion, or nearly 11% of health care costs in the United States, was spent on the treatment of diabetes and diabetic complications.2 Approximately one fourth of this amount was used in the management of foot and leg problems.3 Diabetic foot wounds are the leading cause of lower extremity amputations in the United States.4 Yet, when effective preventive measures are implemented, many such wounds can be avoided. With prompt and aggressive therapy, most diabetic foot and leg wounds that do occur can be resolved.
Here we discuss the various causes of diabetic foot problems and describe interventions that can prevent wounds from occurring.
CAUSES OF DIABETIC FOOT PROBLEMS
Indirect causes. Neuropathy and peripheral vascular disease are indirect causes of many diabetic foot wounds (Table 1). The absence of pain can result in a patient's failure to recognize a problem or to appreciate a problem's significance. Peripheral vascular disease can impair healing and promote infection; thus, a minor wound can progressively worsen, often to the point where it does not heal.
Many experts believe that sensory neuropathy is responsible for the majority of diabetic foot wounds; however, sensory neuropathy must be placed in perspective. Wound recurrences are rare in motivated patients who have been educated about diabetic foot care—regardless of the degree of neuropathy. Treatment failure and leg amputation most often result from severe peripheral vascular disease, not from neuropathy.
Other conditions that can contribute to treatment failures include uncontrolled edema, capillary basement membrane thickening (a component of microangiopathy), impaired red blood cell deformability, autosympathectomy, hypoxia at the microcirculation level that results in a chemically mediated reperfusion insult, and the osmotic and glycosylation effects of hyperglycemia. Vasoconstriction resulting from cigarette smoking also interferes with blood flow and wound oxygenation.
1. Centers for Disease Control and Prevention. 2005 National Diabetes Fact Sheet. Available at: http://www.cdc.gov/diabetes/pubs/estimates05.htm. Accessed November 3, 2006.
2. American Diabetes Association. Direct and Indirect Costs of Diabetes in the United States. Available at: http://www.diabetes.org/diabetes-statistics/cost-of-diabetes-in-us.jsp. Accessed November 3, 2006.
3. Gordois A, Scuffham P, Shearer A, et al. The health care costs of diabetic peripheral neuropathy in the US. Diabetes Care. 2003;26:1790-1795.
4. Agency for Healthcare Research and Quality. Economic and Health Costs of Diabetes: HCUP Highlight 1. AHRQ Publication 05-0034, January 2005. Rockville, Md: Agency for Healthcare Research and Quality. Available at: http://www.ahrq.gov/data/ hcup/highlight1/high1.htm. Accessed November 3, 2006.
5. Hunt TK, Zederfeldt B, Goldstick TK. Oxygen and healing. Am J Surg. 1969;118:521-525.
6. Strauss MB. Diabetic foot and leg wounds: principles, management and prevention. Primary Care Reports. 2001;7:187-198.
7. Strauss MB, Hart JD, Winant DM. Preventive foot care: a user-friendly system for patients and physicians. Postgrad Med. 1998;103:223-245.
8. Balanced Budget Act of 1997. Washington, DC: US Government Printing Office. Publication 869-033-00034-10.
9. Strauss MB, Hart JD. "KISS" (Keep It Simple and Speedy) procedures for problem foot wounds. Undersea Hyperb Med. 2001;28(suppl):35-36.
10. Strauss MB. Surgical treatment of problem foot wounds in patients with diabetes. Clin Orthop Relat Res. 2005;439:91-96.