If the Shoe Fits...

Study shows special footwear less helpful than good foot care for diabetic ulcers

TUESDAY, May 14, 2002 (HealthDayNews) -- Special shoes and inserts that shield the feet of diabetics reduce the risk of ulcers that may require amputation -- but just by inches.

A new study, which appears in tomorrow's Journal of the American Medical Association, found that two kinds of inserts -- one cork and one polyurethane -- offered only a slight edge over conventional shoes at preventing return ulcers in diabetics with a history of the dangerous sores.

Gayle Reiber, a University of Washington foot expert and the study's lead author, says the findings support the notion that good, routine foot care trumps special interventions to avoid ulcers.

"In populations that receive excellent foot care, the therapeutic footwear may not be as important," Reiber says. "People with a foot-risk condition [such as a deformity or vessel trouble] really don't have to be constrained by buying the more expensive therapeutic shoes and inserts," as long as they're getting frequent checkups.

Reiber cautions, though, that those with dead nerves in the ulcerated area -- a condition called peripheral neuropathy that's common among diabetics -- must talk with their doctor about more aggressive measures.

Special shoes, which have shanks and wider and deeper toe wells, and custom-made inserts can run many hundreds of dollars, experts say.

However, Dr. Lee Sanders, a Pennsylvania podiatrist and past president for health care and education at the American Diabetes Association, says the new study doesn't suggest diabetics don't need sensible shoes.

"It's very clear that improper footwear is a very significant cause of foot lesions leading to ulcers and amputation," Sanders says. "Many of the lesions created by shoes lead to amputation."

However, the study does indicate other factors are important, too, Sanders says. Doctors must educate their diabetic patients not only about why they need to wear comfortable shoes that don't hurt, but also about the dangers of sensory loss in the lower extremities.

The Centers for Disease Control and Prevention (CDC) reported last fall that diabetes accounted for 44 percent to 85 percent of all preventable leg, foot and toe amputations in this country in 1997. People with the blood-sugar disorder were nearly 30 times more likely to undergo amputations of their lower extremities not related to trauma, with men, blacks and the elderly bearing the biggest burden.

The rate of amputations among people 65 and older was about three to five times greater than that among Americans under age 45, according to the CDC.

Because nerve and vessel damage can render the feet insensitive, diabetics may not know when they've suffered an injury. As a result, a simple stubbed toe can wind up as a gangrenous ulcer that ultimately claims much of the lower leg and requires amputation to prevent further damage.

So, many doctors routinely prescribe special shoes, along with inserts that offer an additional layer of protection, to their diabetic patients.

In the new study, Reiber and her colleagues followed 400 diabetics with a history of foot ulcers. One group was given therapeutic shoes and custom inserts made of cork and covered by neoprene. Another group received the same shoes with pre-fab inserts of polyurethane encased in nylon. A third group was told to wear regular footwear.

All the patients received routine foot exams, and were sent home with specially designed slippers to wear around the house. The percentage of volunteers who complied with the shoe regimens was in the mid-80s.

After two years, ulcers returned in 15 percent of the patients with the cork inserts, and 14 percent of those with the high-tech synthetic guards. But the rate among the other group was 17 percent, only marginally higher than for the others. All of the cases of ulcers in the patients who wore inserts, and nearly 90 percent among those who wore their own shoes, occurred in people who had trouble feeling their feet.

The researchers didn't consider sores that cleared up within 30 days -- an accounting that might have masked some of the benefit of the protective shoes and inserts, Sanders says.

However, Reiber disagrees.

Dr. Brent Nixon, chief of podiatry at the VA Medical Center in Tucson, Ariz., calls the latest findings an "eye-opener," and agrees they justify a certain minimal level of foot care for diabetics.

In his own patient population of veterans, Nixon says, many are so obese they can't cut their own toenails. And a surprisingly high percentage -- he's now organizing a study to figure out just how high -- wear shoes that are either too small or too large, either of which can lead to ulcers. Help with either or both of these problems might make a dent in their risk of foot sores, he says.

Nixon and his colleagues are also studying whether pre-emptive surgery to correct foot deformations might help avoid ulcers from appearing in the first place.

What To Do: For more on diabetes and its complications, try the American Diabetes Association. You can also visit the American Academy of Family Physicians or the American Orthopaedic Foot and Ankle Society.

SOURCES: Gayle Reiber, Ph.D., professor, epidemiology and health services, University of Washington, VA Puget Sound Health Care System, Seattle; Lee Sanders, D.P.M., chief, podiatry, VA Medical Center, Lebanon, Pa.; Brent Nixon, D.P.M. chief, podiatry, Southern Arizona Veterans Affairs Health Care System, Tucson; May 15, 2002, Journal of the American Medical Association
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