WASHINGTON — The use of therapeutic shoes and the home monitoring of foot skin temperature by diabetic patients who are at high risk for foot ulceration are two simple, low-tech, preventive measures that could greatly reduce costs and improve patient outcomes if adopted more widely, according to Lawrence A. Lavery, D.P.M.
A foot ulcer is one of the most common precursors to the more than 100,000 diabetes-related amputations performed in the United States every year. Yet simple measures that can reduce the rate of foot ulceration are not being done, he said at the annual meeting of the American Association of Diabetes Educators.
“Prevention is a low-tech process,” said Dr. Lavery of the department of surgery at Texas A&M University, Temple.
Prevention efforts should focus on patients who are at greatest risk. In a study of 1,666 diabetic patients, Dr. Lavery and his associates stratified the risk classification beyond the current system that was established by an international working group (Diabetes Care 2001;24:1442–7).
Over a mean follow-up of 27 months, the risk of ulceration for patients with no peripheral neuropathy or peripheral vascular disease (PVD) was 2%, whereas those with neuropathy alone had a 4.5% risk and those with neuropathy plus a foot deformity had a 3% ulceration risk. High rates of ulceration occurred in patients with a history of PVD (14% risk) and in those with a previous ulcer or a history of amputation (14% risk) (Diabetes Care 2008;31:154–6).
Hospitalization rates, which were 1% for patients with neuropathy alone and 2% for those with a deformity, jumped to 16% for patients with PVD, 8% for those with a history of ulceration, and 50% for those with a previous amputation. Amputation rates were relatively low: from 0% in those with no disease or neuropathy alone to 0.7%-2.2% among those with deformity, PVD, and ulcer history. But “just 20% of the patients account for 70% of the ulcers and 90% of the amputations and hospitalizations. This tells us where to focus our educational efforts appropriately,” said Dr. Lavery, coauthor of a new task force report on foot assessment from the American Diabetes Association.
For patients at risk, elimination of the shoe as a source of pathology is a simple yet underutilized measure. About 20% of foot ulcers are triggered by ill-fitting shoes, mostly among women. “The easiest thing to do is just look at their shoes,” Dr. Lavery noted.
Since 1995, Medicare has covered therapeutic footwear and insoles for patients who are at risk for ulceration, but fewer than 3% of eligible patients receive the benefit. This is presumably because of a lack of awareness among providers as well as the cumbersome paperwork involved. “This is a simple, low-tech, very effective intervention that we don't do,” he said.
Even when physicians are diligent about checking the feet and shoes of their diabetic patients at every office visit, the transformation from injury to ulceration occurs far too rapidly to be left to examinations at 3-month intervals. That's why it's essential for patients to check their feet at home on a daily basis.
But about 54% of patients can't see the bottoms of their feet, because of impaired vision, obesity, limited joint mobility, or a combination of those factors (Arch. Intern. Med. 1998;158:157–62).
“About half of patients whom we're asking to inspect their feet haven't been able to see their feet in the last several years,” Dr. Lavery remarked.
Moreover, the cardinal signs of inflammation that precedes ulceration—including pain, loss of function, edema, redness, and heat—can go unnoticed, particularly among patients who have neuropathy. Indeed, “even trained health care professionals probably cannot identify subtle precursors to ulceration,” he said.
Of the five factors, heat may be the easiest to identify. In three published studies, a long-armed handheld infrared skin thermometer called TempTouch (www.temptouch.com
In the initial pilot study, 85 patients with either neuropathy and foot deformity, or previous history of ulceration or partial foot amputation, were randomized to standard therapy—including therapeutic footwear, diabetic foot education, and regular foot evaluation by a podiatrist—or to “enhanced” therapy, which included the standard measures plus twice-daily use of the dermal thermometer device at six sites on each foot. Patients were instructed to contact a study nurse and to minimize walking if they detected a temperature difference of more than 4° F. in the corresponding sites of the two feet.
At 6 months, there were nine foot complications, including seven ulcers and two Charcot's fractures, among the 44 patients in the standard therapy group (20%), compared with just one ulcer (2%) in the 41 patients who used the thermometer, Dr. Lavery and his associates reported (Diabetes Care 2004;27:2642–7).