Studies spotlight American outcomes
By Jordana Bieze Foster
For years, the amputation prevention literature has been dominated by studies performed outside the United States. Two recent studies, however, have served notice that that trend is starting to change.
At this year’s Diabetic Foot Global Conference (DF-Con), attendees heard from Gerry Rayman, MD, head of service for the Ipswich Diabetic Foot Unit at Ipswich Hospital in the U.K., who oversaw the precipitous drop in amputation rates described in the January 2008 issue of Diabetes Care. Hermelinda C. Pedrosa, MD, director of the Department of the Diabetic Foot for the Brazilian Diabetes Society, missed her scheduled presentation due to a travel snafu, but more than one lecturer throughout the course of the conference referred to the 77.8% decrease in amputation rates that Pedrosa and colleagues reported in the July-August 2004 issue of the International Diabetes Monitor.
Similar achievements have been documented in Finland, the Netherlands, Italy, Sweden, and other countries. American outcomes have been harder to come by. Perhaps the most notable was a February 2005 retrospective study in Diabetes Care, which found an 82% decrease in lower extremity amputations following the implementation of a multidisciplinary Limb Preservation Service at Madigan Army Medical Center in Tacoma, WA.
But in the March-April issue of the Journal of the American Podiatric Medical Association, researchers reported that an amputation prevention program at a country hospital in Iowa decreased the high-low amputation ratio eightfold. And in the July-August issue of the same journal, the Madigan research team published evidence that the limb preservation team approach resulted in twice the frequency of “minor” amputations and more than double the survival rate compared to conventional care.
The Iowa study analyzed amputation rates at Broadlawns Medical Center in Des Moines before and after implementation of a multidisciplinary amputation prevention program. The prevention efforts centered around a six-step protocol for treatment of patients with wounds: identification and management of infection, identification and management of ischemia, offloading pressure, wound debridement, promotion of granulation, and wound closure.
In the year immediately preceding the program’s implementation, the ratio of high (above knee and below knee) amputations to low (partial-foot) amputations was 0.41. In the program’s first year, the corresponding ratio was 0.05. By comparison, the national average high-low amputation ratio among Medicare enrollees was been reported to be 1.35 in 1996-1997.
In the July-August issue of JAPMA, the Madigan researchers randomly selected 485 patients from their diabetic patient population and compared the 311 patients who were treated by the limb preservation team with the 174 patients who were referred to the limb preservation team but ended up receiving nonspecialty care.
The limb preservation team includes podiatric and vascular surgery, pedorthics, a wound-care nurse, and a research unit. Treatment included advanced wound-care management, medical and surgical management of infection, clinical visits at least quarterly, educational programs for patients and families, orthotic devices, and extra-depth and custom shoes as needed.
In the limb preservation group, 53 patients underwent a minor (toe or transmetatatarsal) amputation; minor procedures accounted for two-thirds of all procedures in this cohort. In the nonspecialty group, minor procedures were performed in just 27 patients, and accounted for only one-third of all procedures. Survival rates were also significantly higher in the limb preservation group (19.5% vs 7.7%) during the study period, which included follow up of at least three years for each patient. The authors of both studies suggested that higher numbers of “minor” or “low” amputations reflected more aggressive care and resulted in greater functionality for the patient.
Look for future studies of amputation prevention to come from Valley Presbyterian Hospital in Los Angeles, where both authors of the Iowa paper are now employed. Valley Presbyterian unveiled its own dedicated amputation prevention center in March.
Ulcer-depression research emphasizes major symptoms, risk of primary lesions
Screening for depression in patients with diabetes may help reduce the risk of foot ulcers, according to separate studies from the University of Washington and Yeshiva University.
Researchers from the University of Washington in Seattle analyzed 3474 patients with diabetes and no previous history of foot ulcer; mean follow up was 4.1 years. They found that major depression, according to the Patient Health Questionnaire-9 assessment tool, was associated with two times the risk of foot ulceration compared to patients with no depressive symptoms. However, minor depression was not associated with a significantly increased risk of ulceration. Those findings were published in the August issue of the American Journal of Medicine.
In the second study, researchers from Yeshiva University in the Bronx, NY, followed 333 patients with diabetic peripheral neuropathy but no peripheral vascular disease for 18 months. They found that increasingly severe symptoms of depression were predictive of developing a first foot ulcer (hazard ratio of 1.68) but not ulcer recurrence. The results were e-published in Diabetologia on June 17.
Analysis finds variation in prescription of antibiotics for infected foot ulcers
A health services research analysis from the Boston area reveals a striking amount of variation in the way antibiotics are prescribed for diabetic foot infections in a national Veterans Administration population, raising questions as to which regimens may be the most cost-effective.
Investigators from the Center for Health Quality Outcomes and Economic Research at the Edith Nourse Rogers Memorial Veterans Hospital in Bedford, MA, analyzed information on antibiotic treatment of cellulitis in a diabetic foot ulcer for 3792 patients identified from the national VA Diabetes Epidemiology Cohorts database.
Nearly all infected foot ulcers (98.9%) were treated with antibiotics, but 40.7% of cases did not meet the study definition of a regimen (an unmodified course of treatment for five days or more). A total of 199 different antibiotic regimens were used, with 17 regimens used in more than 1% of patients. The most popular regimens were piperacillin-tazobactam alone, piperacillin-tazobactam with vancomycin, ampicillin-sulbactam alone, and vancomyclin alone.
The findings were published on July 6 in the online journal BMC Health Services Research.