Study Raises Questions on Widespread Prescribing of Diabetic Footwear

Medicare pays for therapeutic footwear for thousands of people with diabetes each year, but researchers report in the May 15 Journal of the American Medical Association that for many of these patients regular good-quality shoes may work just as well in preventing foot ulcers. "The results were surprising," said principal investigator Gayle E. Reiber, MPH, PhD, of the Veterans Affairs (VA) Puget Sound Health Care System and the University of Washington.

"The popular notion among foot specialists is that therapeutic shoes and inserts should be prescribed freely to all patients with diabetes and prior foot ulcers. However this study did not provide evidence to support this practice."

Reiber said the study suggests that careful attention by health care professionals may be more important than therapeutic footwear in preventing ulcers. Patients not receiving this level of care, she said, may in fact benefit from special footwear.

The study randomized 400 men and women with diabetes and a prior foot ulcer into three groups. One group wore extra-depth study therapeutic shoes with customized cork inserts. A second group wore special, therapeutic shoes with non-custom polyurethane inserts. The third group served as controls and wore their own shoes.

After two years, ulcer rates were similarly low in all three groups: 15, 14, and 17 percent, respectively. The study did not include those five percent of diabetic patients with severe foot deformities or other special problems who may benefit from custom-made footwear.

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The reulceration rates reported in the study were strikingly lower than those found in several earlier European studies. Reiber cited two possible explanations for the lower rates. First, all study participants were provided specially designed slippers to wear when not in their shoes, to prevent non-shoe-related injuries and ulcers. Second, all participants had access to good-quality health care, as patients of either the VA Puget Sound Health Care System or the Seattle-based Group Health Cooperative.

Study participants made visits every 17 weeks to a study team that included a foot care specialist. Patients and their health care providers were informed about any foot lesions, and the patients were referred to the providers for treatment.

Reiber noted that the extra attention given the study participants may have contributed to the overall low rate of ulcers in all three groups, regardless of what kind of shoes they wore.

It is estimated that about 17 million Americans have diabetes. Footwear is a concern for those with diabetes because the condition may cause peripheral nerve damage and poor blood circulation, leaving patients with little to no feeling in their feet. As a result, pressure from shoes and minor trauma are more likely to lead to ulcers.

Half of U.S. adults with diabetes have one or more foot risk conditions and 10 percent of these adults report a prior foot ulcer, similar to the study population. These ulcers can become severe enough to require amputation. People with diabetes account for more than 90,000 of the roughly 134,000 lower-limb amputations performed yearly in the United States. About half these diabetes-related amputations are attributed to poorly fitting footwear.

Foot care specialists routinely recommend that patients with diabetes and foot risk factors buy special "depth" shoes with extra room in the toes. Since Medicare adopted the Therapeutic Shoe Bill in 1993, the cost of these shoes, along with insertsup to $318 per yearis covered for certain patients who do not have severe foot deformities.

"The evidence suggests that a shift in the diabetic foot care paradigm may be in order," said co-principal investigator Douglas Smith, MD, of the University of Washington. In light of the findings, he suggested the clinical emphasis should be on ensuring that all persons with diabetes and foot risk conditions have adequate footwear and regular access to their health care providers.

Funding for the study was provided by VA, the National Institute of Diabetes and Digestive and Kidney Diseases, and the Centers for Disease Control and Prevention. Collaborating on the study with Reiber and Smith were Carolyn Wallace, PhD, of VA; Katrina Sullivan, DPM, of the Joslin Diabetes Center at Swedish Medical Center in Seattle; Shane Hayes, CPed, and Christy Vath, BS, of VA; Matthew L. Maciejewski, PhD, Onchee Yu, MS, and Patrick J. Heagerty, PhD, all of VA and UW; and Joseph LeMaster, MD, of UW.

Source: VA Research Communications Service