Cath Lab Digest

David G. Armstrong, DPM, PhD: Diabetes is a growing epidemic in both the developed and developing world. Lower extremity disease is particularly common and problematic among people with diabetes. We know that foot infection is the most common reason for hospital admission in the diabetic population. This amounts to many billions of dollars every year in the United States alone. Unfortunately, even when these patients are admitted to hospitals, they are often treated less than adequately. It is not that that we don’t have the tools with which to treat these patients. It is more due to perhaps a lack of appreciation and even a lack of understanding of the very concrete mechanisms that cause all of these problems.

Benjamin A. Lipsky, MD: The International Diabetes Federation designated 2005 as the Year of the Diabetic Foot. For the first time in its history, the Federation dedicated an entire year, rather than just a day, to a diabetes-related complication. There were discussions, symposia and ceremonies around the world throughout the year to highlight the problem of foot complications in people with diabetes.

The specific complication of foot infection is among the most important for people with diabetes because it is the final step for most patients who require a lower extremity amputation. In the past 10 to 15 years, we have learned these infections are typically caused by aerobic organisms, most commonly gram-positive cocci, and particularly Staphylococcus aureus. However, many of these infections are polymicrobial with the causative organisms including gram-negatives and anaerobes as well. In light of the varied microbiology of these infections, selecting proper antibiotic therapy is crucial to good outcomes.

However, antibiotic therapy is only a part of the approach to treating these complex problems. It is also important to recognize the need for various forms of surgical intervention, such as incision and drainage, as well as the need for appropriate weight offloading, proper wound dressings and various adjunctive measures when necessary.

In the last few years, two groups have gotten together to publish guidelines on treating diabetic foot infections. The International Diabetes Federation published guidelines in May 2003 that have been accepted by over 80 different countries and are now published in over 25 different languages.1 The Infectious Diseases Society of America (IDSA) also published a set of guidelines in Clinical Infectious Diseases in the fall of 2004 and these guidelines are posted on the IDSA Web site.2 These guidelines were reprinted in the Journal of the American Podiatric Medical Association, and are now widely used throughout North America and elsewhere.3

Currently, we recognize that the overall outcomes in treating diabetic foot infections are still suboptimal and several things need to be improved in order to obtain better results. This certainly includes educating clinicians about selecting more appropriate antimicrobial regimens. Not only do we have to select antibiotic regimens that properly cover the likely pathogens but we must also select regimens that do not unnecessarily cover pathogens that are not clinically important. This is crucial because overuse of antibiotics drives resistance and the problem of antibiotic resistance has become a major concern in most developed countries.

Warren S. Joseph, DPM: In addition to choosing appropriate antibiotic therapy, there are still questions about the routes that you can use in therapy and the duration of therapy for these infections. There is also the question of osteomyelitis and what the duration of therapy should be for this condition. These are all areas that are somewhat controversial in the treatment of diabetic foot infections and there are still a lot of questions that need to be answered with good data.