A comparison of two diabetic foot ulcer classification systems: the Wagner and the University of Texas wound classification systems

Risk factors for primary major amputation in diabetic patients

CONTEXT AND OBJECTIVE

Diabetic patients present high risk of having to undergo minor or major amputation during their lifetimes, because of ischemia or infection. The aim of this study was to identify and quantify risk factors for major amputation in diabetic patients with foot infections.

DESIGN AND SETTING

Retrospective clinical-surgical trial at the Vascular Surgery Service of Santa Casa de São Paulo.

METHODS

Ninety-nine patients with diabetic foot infections who underwent 129 hospitalizations in the Vascular Surgery Unit were analyzed in accordance with a pre-established protocol to compare two groups of diabetic patients: one that underwent major amputations and the other that underwent minor amputations or debridements. The patients were predominantly male, in their sixth decade of life, and had type 2 diabetes mellitus. Chronic arterial insufficiency, age, diabetes mellitus duration, ascending lymphangitis, calcaneal lesions, Wagner's classification, laboratory tests and different microorganisms in deep tissue cultures were the risk factors evaluated in all patients.

RESULTS

The statistically significant risk factors for major amputation included age, ascending lymphangitis (odds ratio, OR: 2.5), calcaneal lesions (OR: 10.5), Wagner grade 5 lesions (OR: 3.4), chronic arterial insufficiency without possibility of revascularization (OR: 5.4) and diabetes duration. Presence of Gram-positive microorganisms was associated with the need of major amputation. The serum urea, creatinine, glucose and white blood cell levels were not significant risk factors for major amputation.

CONCLUSIONS

The risk factors for major amputation were: age, ascending lymphangitis, calcaneal lesions, Wagner grade 5 lesions, arterial insufficiency, diabetes duration and Gram-positive microorganisms in cultures.

Second-line treatment of limb-threatening diabetic foot infections with intravenous fosfomycin

Diabetic foot infections (DFI) expanding to bones and joints are associated with a poor prognosis of limb salvage. The bactericidal epoxide fosfomycin accumulates in inflamed soft and bone tissue, and may represent a potential treatment option for targeting severe DFI. Fifty-two patients (35 men, 17 women, mean age 62.9 +/- SD 9.2 years) with limb-threatening DFI (that is, Wagner grade 3 and higher) were enrolled in a multi-center compassionate use program of fosfomycin. Twenty-two patients (42.4%) had unsuccessfully been pretreated with other antimicrobials. Besides standard treatment (topical wound care and surgical debridement), eligible subjects received a combination of 8 to 24 g fosfomycin daily, and a conventional antibiotic agent, usually a beta-lactam compound. Treatment duration averaged 14.4 +/- 8.3 days. Limb-sparing surgery was possible in 48 patients (92.3%, 95% confidence interval 81.5-97.9%). Only four participants faced mild drug-related side effects (nausea, rash). Logistic regression analysis showed a trend towards better results with prolonged treatment, whereas a dose increase above 12 g daily did not affect outcomes. In DFI being resistant to conventional antibiotic agents, intravenous fosfomycin offers an effective treatment choice that may increase the likelihood of limb preservation. The present data warrant a larger comparative trial to stabilize effect estimates.

The global burden of diabetic foot disease

Diabetic foot problems are common throughout the world, resulting in major economic consequences for the patients, their families, and society. Foot ulcers are more likely to be of neuropathic origin, and therefore eminently preventable, in developing countries, which will experience the greatest rise in the prevalence of type 2 diabetes in the next 20 years. People at greatest risk of ulceration can easily be identified by careful clinical examination of the feet: education and frequent follow-up is indicated for these patients. When assessing the economic effects of diabetic foot disease, it is important to remember that rates of recurrence of foot ulcers are very high, being greater than 50% after 3 years. Costing should therefore include not only the immediate ulcer episode, but also social services, home care, and subsequent ulcer episodes. A broader view of total resource use should include some estimate of quality of life and the final outcome. An integrated care approach with regular screening and education of patients at risk requires low expenditure and has the potential to reduce the cost of health care.

Treatment for diabetic foot ulcers

People with diabetes develop foot ulcers because of neuropathy (sensory, motor, and autonomic deficits), ischaemia, or both. The initiating injury may be from acute mechanical or thermal trauma or from repetitively or continuously applied mechanical stress. Patients with clinically significant limb ischaemia should be assessed by a vascular surgeon to determine the need for angioplasty, stenting, or femorodistal bypass. When infection complicates a foot ulcer, the combination can be limb or life-threatening. Infection is defined clinically, but wound cultures reveal the causative pathogens. Tissue specimens are strongly preferred to wound swabs for wound cultures. Antimicrobial therapy should be guided by culture results, and should aim to cure the infection, not to heal the wound. Alleviation of the mechanical load on ulcers (off-loading) should always be a part of treatment. Neuropathic ulcers typically heal in 6 weeks with total contact casting, because it effectively relieves pressure at the ulcer site and enforces patient compliance. The success of other approaches to off-loading similarly depends on the patients' adherence to the effectiveness of pressure relief. Surgery to heal ulcers and prevent recurrence can include tenotomy, tendon lengthening, reconstruction, or removal of bony prominences. However, these procedures may result in secondary ulceration and other complications. Ulcer recurrence rates are high, but appropriate education for patients, the provision of posthealing footwear, and regular foot care can reduce rates of re-ulceration.

Autologous transplantation of granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cells improves critical limb ischemia in diabetes

OBJECTIVE

To assess the application of autologous transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (PBMNCs) in the treatment of critical limb ischemia (CLI) of diabetic patients and to evaluate the safety, efficacy, and feasibility of this novel therapeutic approach.

RESEARCH DESIGN AND METHODS

Twenty-eight diabetic patients with CLI were enrolled and randomized to either the transplant group or the control group. In the transplant group, the patients received subcutaneous injections of recombinant human G-CSF (600 microg/day) for 5 days to mobilize stem/progenitor cells, and their PBMNCs were collected and transplanted by multiple intramuscular injections into ischemic limbs. All of the patients were followed up after at least 3 months.

RESULTS

At the end of the 3-month follow-up, the main manifestations, including lower limb pain and ulcers, were significantly improved in the patients of the transplant group. Their laser Doppler blood perfusion of lower limbs increased from 0.44 +/- 0.11 to 0.57 +/- 0.14 perfusion units (P < 0.001). Mean ankle-brachial pressure index increased from 0.50 +/- 0.21 to 0.63 +/- 0.25 (P < 0.001). A total of 14 of 18 limb ulcers (77.8%) of transplanted patients were completely healed after cell transplantation, whereas only 38.9% of limb ulcers (7 of 18) were healed in the control patients (P = 0.016 vs. the transplant group). No adverse effects specifically due to cell transplantation were observed, and no lower limb amputation occurred in the transplanted patients. In contrast, five control patients had to receive a lower limb amputation (P = 0.007, transplant vs. control group). Angiographic scores were significantly improved in the transplant group when compared with the control group (P = 0.003).

CONCLUSIONS

These results provide pilot evidence indicating that the autologous transplantation of G-CSF-mobilized PBMNCs represents a simple, safe, effective, and novel therapeutic approach for diabetic CLI.

Changing perspectives in diabetic foot ulcer management

Diabetic foot ulceration is a serious complication of diabetes mellitus; it is the cause of more than half of nontraumatic lower limb amputations. Diabetic foot ulcers are the major cause of hospital admission for diabetic patients. Treatment costs are high. There have been advances in managing diabetic foot ulceration with the development of new dressings, growth factors, skin substitutes, and other novel approaches to stimulating wound healing. The management of vascular disease in the patient with diabetes mellitus is an essential and important consideration. However, the need for a multidisciplinary team to provide good foot care to diabetic patients is still vital for the prevention and treatment of diabetic foot ulceration.

Optimal treatment of infected diabetic foot ulcers

Foot ulceration can lead to devastating consequences in diabetic patients. They are not only associated with increased morbidity but also mortality. Foot infections result as a consequence of foot ulceration, which can occasionally lead to deep tissue infections and osteomyelitis; both of which can result in loss of limb. To prevent amputations prompt diagnosis and treatment is required. Understanding the pathology of the diabetic foot will help in the planning of appropriate investigations and treatment. Clinical diagnosis of infection is based on the presence of discharge from the ulcer, cellulitis, warmth and signs of toxicity; though the latter is uncommon. Deep tissue samples from the ulcer and/or blood cultures should be taken before, but without delaying the start of antibacterial treatment in limb and life-threatening infections. In milder infections wound sampling may direct appropriate antibacterial treatment. Staphylococcus aureus, followed by streptococci are the most common organisms causing infection and antibacterial treatment should be targeted against these organisms in mild infection possibly with monotherapy. But in serious infections combination therapy is required because these are usually caused by multiple organisms including anaerobes. Drug-resistant organisms are becoming more prevalent and methicillin-resistant infections can be treated effectively with a number of oral antibacterials either as monotherapy or in combination. Surgical treatment with debridement, for example, callus removal or drainage of pus form an important part of diabetic foot ulcer management especially in the presence of infection. Occasionally limited surgery including dead infected bone removal may be necessary for resolution of infection. Amputation is sometimes required as a last resort for limb or life preservation.

Reducing amputation rates in patients with diabetes at a military medical center: the limb preservation service model

OBJECTIVE

To describe and evaluate the Limb Preservation Service (LPS), a multidisciplinary, state-of-the-art, foot care clinic for patients with diabetes at Madigan Army Medical Center (MAMC). Evaluation criteria include the overall incidence of lower-extremity amputation (LEA) and the distribution of the anatomic level of amputation between 1999 and 2003.

RESEARCH DESIGN AND METHODS

This is a retrospective study of the incidence and types of LEAs performed in patients with diabetes at MAMC. Patients with diagnosed diabetes and LEA procedures were identified by ICD-9-Clinical Modification (CM) codes. Hospital and clinic characteristics that are integral to the success of the program are described.

RESULTS

The number of patients at MAMC with diagnosed diabetes increased 48% from 1999 to 2003; however, the number of LEAs decreased 82% from 33 in 1999 to 9 in 2003. Amputations of the foot, ankle, and toe comprise 71% of amputations among patients with diabetes.

CONCLUSIONS

The results of this study provide evidence of the value of a focused multidisciplinary foot care program for patients with diabetes. Associations between the creation of the LPS and LEA rates are discussed.

Are granulocyte colony-stimulating factors beneficial in treating diabetic foot infections?: A meta-analysis

OBJECTIVE

To assess the value of granulocyte colony-stimulating factor (G-CSF) as adjunctive therapy for diabetic foot infections.

RESEARCH DESIGN AND METHODS

We systematically searched the medical literature (including Medline, Embase, LookSmart, and the Cochrane Library) for prospective randomized studies that used G-CSF as an adjunct to standard treatment for diabetic foot infections. Using a conventional meta-analysis, we pooled the relative risks (RRs) for outcomes of interest, including resolution of infection, wound healing, duration of antibiotic therapy, and need for various surgical interventions, using a fixed-effects model.

RESULTS

Five randomized trials, with a total of 167 patients, met our inclusion criteria. The methodological quality of the studies was satisfactory. The investigators administered various G-CSF preparations parenterally for between 3 and 21 days. The meta-analysis revealed that adding G-CSF did not significantly affect the resolution of infection or the healing of the wounds but was associated with a significantly reduced likelihood of lower extremity surgical interventions (RR 0.38 [95% CI 0.20-0.69], number of patients who needed to be treated: 4.5), including amputation (0.41 [0.17-0.95], number of patients who needed to be treated: 8.6). There was no evidence of heterogeneity among the studies or of publication bias, suggesting that these conclusions are reasonably generalizable and robust.

CONCLUSIONS

Adjunctive G-CSF treatment does not appear to hasten the clinical resolution of diabetic foot infection or ulceration but is associated with a reduced rate of amputation and other surgical procedures. The small number of patients who needed to be treated to gain these benefits suggests that using G-CSF should be considered, especially in patients with limb-threatening infections.

It's not what you put on, but what you take off: techniques for debriding and off-loading the diabetic foot wound

The basic etiology of neuropathic diabetic foot wounds involves pressure in conjunction with cycles of repetitive stress, leading to failure of skin and soft tissue. The central tenet of any treatment plan addressing neuropathic diabetic foot wounds is the appropriate debridement of nonviable tissue coupled with adequate pressure relief (off-loading). Although numerous advances have been made in the treatment of diabetic foot wounds, including bioengineered tissues, autologous and exogenous cytokine delivery systems, and potentially effective topical antimicrobial modalities, none will succeed without addressing effective debridement and off-loading. Specific debridement and off-loading techniques are discussed, along with available supporting evidence. This includes the use of the "instant" total contact cast, among other modalities.

Diabetic foot ulcer and multidrug-resistant organisms: risk factors and impact

AIMS

The primary objective was to characterize factors allowing the colonization of diabetic foot wounds by multidrug-resistant organisms (MDRO), and the secondary objective was to evaluate the influence of MDRO colonization/infection on wound healing.

METHODS

In 180 patients admitted to a specialized diabetic foot unit, microbiological specimens were taken on admission. Potential risk factors for MDRO-positive specimens were examined using univariate and multivariate analyses. Prospective follow-up data from 75 patients were used to evaluate the influence of MDRO colonization/infection on time to healing.

RESULTS

Eighteen per cent of admission specimens were positive for MDRO. MDRO-positive status was not associated with patient characteristics (age, sex, type of diabetes, complications of diabetes), wound duration, or wound type (neuropathic or ischaemic). In the multivariate analysis, the only factors significantly associated with positive MDRO status on admission were a history of previous hospitalization for the same wound (21/32 compared with 48/148; P = 0.0008) or the presence of osteomyelitis (22/32 compared with 71/148; P = 0.025). In the longitudinal study of 75 wounds, MDRO-positive status on admission or during follow-up (6 months at least or until healing, mean 9 +/- 7 months) was not associated with time to healing (P = 0.71).

CONCLUSION

MDROs are often present in severe diabetic foot wounds. About one-third of patients with a history of previous hospitalization for the same wound, and 25% of patients with osteomyelitis, had MDRO-positive specimens. This suggests that hygiene measures, or isolation precautions in the case of admission of patients presenting with these characteristics, should be aggressively implemented to prevent cross-transmission. Positive MDRO status is not associated with a longer time to healing.

The DEPA scoring system and its correlation with the healing rate of diabetic foot ulcers

The purpose of this study was to examine the validity of a new scoring system in predicting the outcome of diabetic foot ulcers. The scoring system (DEPA score) includes the depth of the ulcer (D), the extent of bacterial colonization (E), the phase of ulcer healing (P) and the associated underlying etiology (A). The scoring system was validated against the clinical outcome in terms of healing and lower-limb amputations. Eighty-four patients were included in the study: 32 patients had a DEPA score of < or =6, 34 patients had a DEPA score of 7 to 9, and 18 patients had a DEPA score of > or =10. Using the Spearman nonparametric correlation test, DEPA scoring system was accurate in predicting the outcome of management (correlation coefficient, 0.78; 95% confidence interval, 0.68 to 0.86; P <.0001) at a mean follow-up of 20 weeks. The correlation was further validated by using a linear regression model (r = 0.85; slope best-fit value, 0.51; 95% confidence interval, 0.41 to 0.59; P <.0001). All patients with DEPA scores < or =6 had excellent healing, whereas only 15% of those with a score of > or =10 had complete healing in <20 weeks. In conclusion, an increasing DEPA score is associated with increased risk of amputation and poor healing. Furthermore, inclusion of the phase of ulcer healing into the DEPA system increases the accuracy of predicting the outcome of diabetic foot ulcers.

Cost-effectiveness of prevention and treatment of the diabetic foot: a Markov analysis

OBJECTIVE

To estimate the lifetime health and economic effects of optimal prevention and treatment of the diabetic foot according to international standards and to determine the cost-effectiveness of these interventions in the Netherlands.

RESEARCH DESIGN AND METHODS

A risk-based Markov model was developed to simulate the onset and progression of diabetic foot disease in patients with newly diagnosed type 2 diabetes managed with care according to guidelines for their lifetime. Mean survival time, quality of life, foot complications, and costs were the outcome measures assessed. Current care was the reference comparison. Data from Dutch studies on the epidemiology of diabetic foot disease, health care use, and costs, complemented with information from international studies, were used to feed the model.

RESULTS

Compared with current care, guideline-based care resulted in improved life expectancy, gain of quality-adjusted life-years (QALYs), and reduced incidence of foot complications. The lifetime costs of management of the diabetic foot following guideline-based care resulted in a cost per QALY gained of < 25,000 US dollars, even for levels of preventive foot care as low as 10%. The cost-effectiveness varied sharply, depending on the level of foot ulcer reduction attained.

CONCLUSIONS

Management of the diabetic foot according to guideline-based care improves survival, reduces diabetic foot complications, and is cost-effective and even cost saving compared with standard care.

An evidence-based approach to diabetic foot infections

Foot infections are a major complication of diabetes mellitus and contribute to the development of gangrene and lower extremity amputation. Recent evidence indicates that persons with diabetes are at greater risk for infection because of underlying neuropathy, peripheral vascular disease, and impaired responses to infecting organisms. This article reviews the underlying pathophysiology, causes, microbiology, and current management concepts for this potentially limb-threatening complication. Multidisciplinary management consisting of teams of specialists with a focus on limb preservation can make significant improvements in outcomes, including a reduction in rates of lower extremity amputation.

Diabetic foot ulcerations: management and adjunctive therapy

Foot ulcerations, infections, gangrene, and lower extremity amputation are major causes of disability to the patient who has diabetes mellitus, often resulting in significant morbidity, extensive periods of hospitalization, and mortality. Although not all such lesions can be prevented, it is possible to dramatically reduce their incidence through appropriate management and prevention protocols incorporating a multidisciplinary team approach.

Infections in diabetic foot ulcerations

Diabetic foot complications are the largest nontraumatic cause of lower extremity amputations, accounting for almost 90,000 amputations per year. Most of these amputations are the result of infections caused by ulcerations of the foot that are not recognized or treated in an appropriate and timely fashion. Often, cultures are taken when not warranted and antibiotics are administered when no infection is present, causing significant increases in resistant organisms. Although there have been many attempts to classify diabetic foot lesions, none of these systems are specific for infectious complications. This paper presents a system for identifying the presence and severity of infection with suggestions for appropriate empiric antibiotic therapy.

Diabetic foot syndrome: evaluating the prevalence and incidence of foot pathology in Mexican Americans and non-Hispanic whites from a diabetes disease management cohort

OBJECTIVE

To report the incidence of diabetes-related lower-extremity complications in a cohort of patients enrolled in a diabetes disease management program.

RESEARCH DESIGN AND METHODS

We evaluated screening results and clinical outcomes for the first 1,666 patients enrolled in a disease management program for a period of 24 months (50.3% men, aged 69.1 +/- 11.1 years).

RESULTS

The incidence of ulceration, infection, amputation, and lower-extremity bypass was 68.4, 36.5, 5.9, and 7.7 per 1,000 persons with diabetes per year. Amputation incidence was higher in Mexican Americans than in non-Hispanic whites (7.4/1,000 vs. 4.1/1,000; P = 0.003, odds ratio [OR] 1.8, 95% CI 1.2-2.7). The amputation-to-ulcer ratio was 8.7%. The incidence of Charcot arthropathy was 8.5/1,000 per year. Charcot was more common in non-Hispanic whites than in Mexican Americans (11.7/1,000 vs. 6.4/1,000; P = 0.0001, 1.8, 1.3-2.5). The prevalence of peripheral vascular disease was 13.5%, with no significant difference based on ethnicity (P = 0.3). There was not a significant difference in incidence of foot infection (P = 0.9), lower-extremity bypass (P = 0.3), or ulceration (P = 0.1) based on ethnicity. However, there were more failed bypasses in Mexican Americans (33%) than in non-Hispanic whites (7.1%). Mexican Americans were 3.8 times more likely to have a failed bypass (leading to an amputation) or be diagnosed as "nonbypassable" than non-Hispanic whites (75.0 vs. 44.0%; P = 0.01, 3.8, 1.2-11.8).

CONCLUSIONS

The incidence of amputation is higher in Mexican Americans, despite rates of ulceration, infection, vascular disease, and lower-extremity bypass similar to those of non-Hispanic whites. There may be factors associated with failed or failure to bypass that mandate further investigation.

Classification of wounds of the diabetic foot

A classification system should be thought of as a diagnostic language. Ideally, this language should be used by a large, diverse population of clinicians to guide therapy and ultimately predict outcome. The diabetic foot ulcer is widely known to be the prime precipitant of lower extremity amputations. Its description and classification is the first step toward widespread standardization of treatment and prevention. This article chronologically describes the major diabetic foot wound classification systems devised over the previous generation, discussing each of their attributes and their shortcomings, with an emphasis on an evidence basis for care. It is our hope that discussions such as this one will ultimately lead to a diagnostic and therapeutic lingua franca for diabetic foot wounds and a commensurate reduction in the unconscionably high prevalence of amputations, which we now currently face.