Can A Diabetic Foot Surgery Classification System Help Predict Complications?

By Brian McCurdy, Associate Editor

Various classification systems categorize diabetic wounds and infections. One system, devised in 2003, categorizes different levels of non-vascular diabetic foot surgery. How effective is such a system? A recent study, the first to evaluate the system’s effectiveness, suggests including various risk factors in the system may better predict surgical complications. The study, presented as an abstract at the American College of Foot and Ankle Surgeons Annual Scientific Meeting, evaluates the classification system’s four categories: elective, prophylactic, curative and emergency surgery. Researchers from the Center for Lower Extremity Ambulatory Research (CLEAR) examined the records of 180 patients with diabetes without critical limb ischemia. There was an equal number of patients in the four categories. The study detected a “highly significant trend” toward increasing risks of ulceration and reulceration, peri-postoperative infection, amputation at all levels and major amputation that corresponded to the severity of the surgery. Researchers concluded that a non-vascular surgical classification system — including variables such as neuropathy, open wound and acute infection — may help predict peri- and postoperative complications. Such variables may help surgeons identify potential risk when selecting a surgical procedure for patients with diabetes, note the authors. As far as diabetic foot surgery, David G. Armstrong, DPM, PhD, the lead author of the study, cites a “tremendous rise in procedures being performed and what some of us believe is a real ill-defined melange of indications and contraindications. “When the patient asks the surgeon, ‘Doc, what are the chances my leg is still going to be on my body in six months?’, the surgeon should be able to offer at least a qualified answer, based not only on experience but also on some evidence,” notes Dr. Armstrong, the Director of CLEAR at the William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine and Science. “A classification of risk simply helps direct thought and therapy into something that can be better communicated among all members of the team, especially the patient.” While Dr. Armstrong believes the non-vascular diabetic foot surgery classification system’s framework may predict risk for complications such as amputation and infection, it is important for the system to continually evolve. Dr. Armstrong has been involved with teams that have proposed overall classification systems for foot risk and wound classification, and maintains these systems have evolved over time. He also cautions clinicians against relying too much on one classification system. “Just as it is best for one to be conversant in more than one language, it is best to be fluent in numerous classification systems,” says Dr. Armstrong, an immediate past member of the National Board of Directors of the American Diabetes Association. “I do believe that some (systems) are more descriptive than others but that knowledge only comes from immersing oneself in as many as possible.” Transmetatarsal Amputations: What A New Study Reveals By Brian McCurdy, Associate Editor A new study in the Journal of Foot and Ankle Surgery (JFAS) tracks the mortality and morbidity of those who had undergone transmetatarsal amputations and investigates predictive factors for complications. As part of the retrospective study, researchers reviewed medical records of 90 patients who had undergone 101 transmetatarsal amputations. The mean follow-up period was 2.1 years. Eighty-eight patients developed post-op complications and two patients died within 30 days following the surgery, according to the study. As senior author Graham Hamilton, DPM, notes, the population of patients with diabetes has changed significantly since the last extensive study, done 50 years ago by McKittrick, on surgical outcomes with this procedure and complications. Although patients are living longer with the disease, Dr. Hamilton notes many are experiencing chronic complications such as chronic renal failure and peripheral vascular disease, which have had a great impact on healing potential. The study notes no significant difference in healing times between the 88 patients with diabetes and the 13 without the disease. While this finding is consistent with other studies, the JFAS study notes that some studies have noted a difference in healing times between the two populations. Why the variation? Dr. Hamilton says it is difficult to answer that question but posits that “the greatest single determinant of healing after this procedure is vascular status, whether the patient is diabetic or not.” End-stage renal disease (ESRD) and palpable pedal pulses are predictors for failure to heal after a transmetatarsal amputation, according to the study. Using these two predictive factors can be advantageous because they facilitate more informed pre-patient counseling, according to Dr. Hamilton, the Director of Research for the Kaiser Permanente San Francisco Bay Area Foot and Ankle Residency Program. Dr. Hamilton advises patients with ESRD that they have a 50 percent chance of healing after a transmetatarsal amputation surgery. Accordingly, Dr. Hamilton says some of those patients choose to have a more proximal amputation. In contrast, Dr. Hamilton counsels patients that having one palpable pedal pulse increases the possibility of healing the amputation. Given the high rates of complication following transmetatarsal amputations, are any adjunctive technologies effective in reducing complication rates? Vacuum Assisted Closure (VAC Therapy, KCI) has had a “major impact” on podiatric surgery, according to Dr. Hamilton. While this was not the focus of the study, Dr. Hamilton notes that researchers used VAC therapy on many stumps that showed delayed healing (there was a 55 percent incidence of dehiscence) and were able to achieve healing in some patients. However, he notes that other patients, given their poor pedal perfusion, failed even with the addition of this modality. Study Conveys Continued Rise Of Community-Acquired MRSA By Brian McCurdy, Associate Editor Given the rising prevalence of methicillin resistant Staphylococcus aureus (MRSA), clinicians face questions of how to prevent the spread of infection and which antibiotics may be helpful in treatment. In a recent study, researchers identified the community-acquired MRSA USA 300 clone as the predominant cause of community-onset S. aureus skin and soft tissue infections, and emphasized the appropriate use of empiric antibiotics. The study, which was recently published in the Annals of Internal Medicine, tracked 389 people infected with S. aureus in an Atlanta-area hospital. Approximately 72 percent of the patients had MRSA and 87 percent of those with MRSA had acquired it in the community, according to the study. Researchers identified the following factors as independently associated with community-acquired MRSA: African-American race, female gender and hospitalization within the last year. Basic infection control measures, such as hand washing and disinfecting devices such as stethoscopes between patients, are the best way to stem the rising tide of MRSA infections, according to Warren Joseph, DPM, an Attending Podiatrist at the Coatesville Veterans Affairs Medical Center in Coatesville, Pa. Although isolating MRSA patients has been shown to be effective, Dr. Joseph notes this is not efficient when over 70 percent of Staph infections are MRSA. However, many new hospitals that are being built will have a private room model rather than shared rooms, according to Dr. Joseph, a Fellow of the Infectious Diseases Society of America. He notes that private hospital rooms have been shown to decrease rates of nosocomial infection. Additionally, Dr. Joseph points out that routine screening of preoperative patients for MRSA has been attempted but may not always be practical. Recommendations For Appropriate Antibiotics The study’s authors advocate the empirical use of agents active against community-acquired MRSA for those with serious skin and soft tissue infections. When it comes to mild infections with community-acquired MRSA, Dr. Joseph says one can use oral agents such as trimethoprim/sulfa or one of the tetracyclines, including doxycycline or minocycline. Dr. Joseph maintains that clinicians should stop thinking of vancomycin as the “gold standard” for severe infections. He notes recent studies have shown vancomycin is unable to clear MRSA in between 25 and 50 percent of complicated skin infections. Dr. Joseph says agents such as linezolid (Zyvox, Pfizer) daptomycin (Cubicin, Cubist) and tigecycline (Tygacil, Wyeth) are superior to vancomycin. He notes that a new drug, dalbavancin (Zeven) should be available by the summer and adds that it has the advantage of IV dosing once a week. However, do patients with community-acquired MRSA even need to be treated with specific anti-MRSA therapy? Dr. Joseph says some data suggest that patients who grow community-acquired MRSA from a mixed culture of a skin infections do equally well if they have received specific anti-MRSA therapy or therapy that does not cover MRSA. “I absolutely feel that the overuse of broad spectrum antibiotics, especially beta-lactams, in the community has contributed to this problem,” says Dr. Joseph of the rising MRSA rates. He adds that some quinolones have been shown to select out for MRSA. In addition, he says patients may fail to take the correct drug for the length of the prescription. “Many just take an antibiotic until they feel better. This also may select out MRSA,” says Dr. Joseph. Depression Therapy: Can It Facilitate Improved Self-Care Among People With Diabetes? By Brian McCurdy, Associate Editor Diabetes and depression can be a particularly troubling combination and research suggests that depression can make a patient less likely to comply with diabetes treatment. A recent study in the Annals of Family Medicine examines whether depression treatment would enhance the self-care of patients with diabetes. The study randomized 329 patients with diabetes in nine facilities into two groups. The first group received collaborative depression treatment, which included pharmacotherapy, problem-solving or a combination of both, while the second group received only usual primary care. Over a year, researchers compared the two groups’ adherence to diabetes therapy. Researchers of the study found that depression care was not associated with improved self-care for diabetes in regard to improved nutrition, cessation of smoking and improved physical activity. Compared to those who only received standard primary care, those undergoing depression care reported a small decrease in body mass index, averaging 0.70 kg/m2, and a higher rate of non-adherence to oral anti-hyperglycemic agents. Researchers concluded that adherence to lipid-lowering agents and anti-hypertension medications was similar between the two groups. In his experience, Eric Espensen, DPM, says he has seen many patients with diabetes and some degree of depression, particularly when patients were faced with a major problem such as gangrene. The majority of patients receive depression treatment from their primary care physicians. “I will note that for many patients, once their depression is improved, overall health is improved. A depressed patient seems to experience more complications and often demonstrates a lack of self care,” says Dr. Espensen, who practices at Burbank Foot Care Center in California. Does Depression Therapy Have Intangible Benefits? Even though the study notes no difference in diabetes self-care for those receiving depression treatment, does such treatment still provide a benefit? Dr. Espensen notes that first-line treatment is often not completely beneficial but it will aid patients. For depressed patients, continued treatment is necessary along with fine-tuning and close monitoring to reach a statistically significant benefit, according to Dr. Espensen, who has an undergraduate degree in psychology. “Just because a pilot study fails to show benefit, there are intangibles present that are often noted by the researchers,” he comments. As the study says, future research efforts need to assess whether self-care interventions targeted to specific conditions, combined with care for depression, can lead to better outcomes for patients with diabetes and depression. Dr. Espensen concurs with the need for further research, suggesting that a more long-term study, perhaps focusing on patients receiving two years of therapy modification, would be helpful. “Regardless, I feel that research must continue and as depression treatment improves, I believe that a strong link will surface,” says Dr. Espensen. Do Combination Supplements Reduce Cardiovascular Risk In Vascular Disease Patients? By Brian McCurdy, Associate Editor Many patients with vascular disease take supplemental vitamins to reduce homocysteine and decrease the risk of cardiovascular events. However, a recent study in the New England Journal of Medicine (NEJM) concludes that these supplements have no impact in reducing major cardiovascular risk among patients with vascular disease. The randomized study examined over 5,500 patients over the age of 55 who had a history of diabetes or vascular disease. Patients received either a placebo or a combination of 2.5 mg of folic acid, 50 mg of vitamin B6 and 1 mg of vitamin B12, once a day for an average of five years. In the group that took the combination supplement, the mean plasma homocysteine levels decreased by 0.3 mg/L in comparison to a 0.1 mg/L decrease in the placebo group, according to the study. The study notes that in the active treatment group, 519 patients (18.8 percent) died of cardiovascular disease or had a myocardial infarction or stroke in comparison to 547 patients (19.8 percent) in the placebo group. John Hahn, DPM, ND, a member of the American Association of Naturopathic Physicians, says a combination of folic acid and vitamins B6 and B12 does decrease homocysteine, which is known to exhibit toxic effects on vascular endothelial cells by increasing oxidation and damaging connective tissues. However, the NEJM study concluded that patients with vascular disease using the combination supplement to reduce homocysteine did not have a lower risk of cardiovascular events. Dr. Hahn cites several issues with the study. He notes that a majority of those in the treatment and placebo groups had a history of disease. For example, he points out that 82.8 percent of the supplement group and 83.8 percent of the placebo group had preexisting coronary artery disease. In addition, Dr. Hahn notes that 54 percent of each group had a history of myocardial infarction. Dr. Hahn adds that 11 percent of each group were smokers and notes that smoking will reduce serum B6 levels. He also points out the fact that several medications that patients in both groups were taking contained hormones and yellow dye 5, which also reduce B6 levels. Other Factors In Measuring Cardiovascular Risk Although previous studies have shown the homocysteine levels to be an independent risk factor for cardiovascular disease, Dr. Hahn believes “this one blood level measurement does not tell the whole story. “It would be foolish to rush to the assumption that homocysteine is an independent risk factor and the vitamin combination does not appear to reverse existing coronary artery disease, and that you should discontinue using this proven vitamin combination when multiple studies show a correlation between elevated homocysteine and cardiovascular events and, more recently, peripheral neuropathy” says Dr. Hahn. Although the NEJM study concludes that patients did not see a reduction in cardiovascular events when taking supplements, Dr. Hahn opines that researchers did not test other laboratory factors that would have provided a more accurate picture on the overall cardiac risk of these patients prior to the study. He says other factors, like heavy metal poisoning, toxic elements in the body and cardiac calcium scores, were not evaluated. Dr. Hahn says these are independent risk factors for cardiovascular disease. Dr. Hahn observes that many patients in both groups were taking statin drugs that deplete the muscle mitochondria of both skeletal muscle and smooth muscle of CoQ-10, which is essential for proper cardiac muscle function. As he points out, there was no supplementation of CoQ-10 for patients on statin drugs. Dr. Hahn says CoQ-10 is essential for proper muscle functioning and contraction, especially the heart muscle. The study also did not take into account lipid scores including HDL and LDL cholesterol, apoproteins, proteins A and B, lipoprotein A and triglycerides as independent risk factors, according to Dr. Hahn. As he notes, higher LpA levels have been correlated with an increased risk of coronary artery disease whereas lipoprotein protein A is protective in preventing cardiovascular events. In Brief For the fifth year, PRESENT Courseware will be putting on its Step into Your Future Practice Management Workshops at podiatry schools around the country. Organizers note that workshops will include lectures on transitioning from a student to a resident to a practicing podiatrist. Upcoming dates are May 2 at Temple University School of Podiatric Medicine in Philadelphia, June 1 at the New York College of Podiatric Medicine and June 13 at the Ohio College of Podiatric Medicine in Cleveland. For more info, go to Healthpoint Tissue Management recently named Rob Bancroft as its Senior Vice President of Sales and Marketing. Bancroft was most recently a Vice President of Marketing at the company.

Add new comment