Diagnosis and management of infection in the diabetic foot

Trends in the epidemiology of osteomyelitis: a population-based study, 1969 to 2009

BACKGROUND

The epidemiology of osteomyelitis in the United States is largely unknown. The purpose of this study was to determine long-term secular trends in the incidence of osteomyelitis in a population-based setting.

METHODS

The study population comprised 760 incident cases of osteomyelitis first diagnosed between January 1, 1969, and December 31, 2009, among residents of Olmsted County, Minnesota. The complete medical records for each potential subject were reviewed to confirm the osteomyelitis diagnosis and to extract details on anatomical sites, infecting organisms, etiological risk factors, and outcomes.

RESULTS

The overall age and sex-adjusted annual incidence of osteomyelitis was 21.8 cases per 100,000 person-years. The annual incidence was higher for men than for women and increased with age (p < 0.001). Rates increased with the calendar year (p < 0.001) from 11.4 cases per 100,000 person-years in the period from 1969 to 1979 to 24.4 per 100,000 person-years in the period from 2000 to 2009. The incidence remained relatively stable among children and young adults but almost tripled among individuals older than sixty years; this was partly driven by a significant increase in diabetes-related osteomyelitis from 2.3 cases per 100,000 person-years in the period from 1969 to 1979 to 7.6 cases per 100,000 person-years in the period from 2000 to 2009 (p < 0.001). Forty-four percent of cases involved Staphylococcus aureus infections.

CONCLUSIONS

The reasons for the increase in osteomyelitis between 1969 and 2009 are unclear but could comprise a variety of factors, including changes in diagnosing patterns or increases in the prevalence of risk factors (e.g., diabetes) in this population.

Predictors of lower-extremity amputation in patients with an infected diabetic foot ulcer

OBJECTIVE

Infection commonly complicates diabetic foot ulcers and is associated with a poor outcome. In a cohort of individuals with an infected diabetic foot ulcer, we aimed to determine independent predictors of lower-extremity amputation and the predictive value for amputation of the International Working Group on the Diabetic Foot (IWGDF) classification system and to develop a risk score for predicting amputation.

RESEARCH DESIGN AND METHODS

We prospectively studied 575 patients with an infected diabetic foot ulcer presenting to 1 of 14 diabetic foot clinics in 10 European countries.

RESULTS

Among these patients, 159 (28%) underwent an amputation. Independent risk factors for amputation were as follows: periwound edema, foul smell, (non)purulent exudate, deep ulcer, positive probe-to-bone test, pretibial edema, fever, and elevated C-reactive protein. Increasing IWGDF severity of infection also independently predicted amputation. We developed a risk score for any amputation and for amputations excluding the lesser toes (including the variables sex, pain on palpation, periwound edema, ulcer size, ulcer depth, and peripheral arterial disease) that predicted amputation better than the IWGDF system (area under the ROC curves 0.80, 0.78, and 0.67, respectively).

CONCLUSIONS

For individuals with an infected diabetic foot ulcer, we identified independent predictors of amputation, validated the prognostic value of the IWGDF classification system, and developed a new risk score for amputation that can be readily used in daily clinical practice. Our risk score may have better prognostic accuracy than the IWGDF system, the only currently available system, but our findings need to be validated in other cohorts.

Predictors of Lower-Extremity Amputation in Patients With an Infected Diabetic Foot Ulcer

OBJECTIVE

Infection commonly complicates diabetic foot ulcers and is associated with a poor outcome. In a cohort of individuals with an infected diabetic foot ulcer, we aimed to determine independent predictors of lower-extremity amputation and the predictive value for amputation of the International Working Group on the Diabetic Foot (IWGDF) classification system and to develop a risk score for predicting amputation.

RESEARCH DESIGN AND METHODS

We prospectively studied 575 patients with an infected diabetic foot ulcer presenting to 1 of 14 diabetic foot clinics in 10 European countries.

RESULTS

Among these patients, 159 (28%) underwent an amputation. Independent risk factors for amputation were as follows: periwound edema, foul smell, (non)purulent exudate, deep ulcer, positive probe-to-bone test, pretibial edema, fever, and elevated C-reactive protein. Increasing IWGDF severity of infection also independently predicted amputation. We developed a risk score for any amputation and for amputations excluding the lesser toes (including the variables sex, pain on palpation, periwound edema, ulcer size, ulcer depth, and peripheral arterial disease) that predicted amputation better than the IWGDF system (area under the ROC curves 0.80, 0.78, and 0.67, respectively).

CONCLUSIONS

For individuals with an infected diabetic foot ulcer, we identified independent predictors of amputation, validated the prognostic value of the IWGDF classification system, and developed a new risk score for amputation that can be readily used in daily clinical practice. Our risk score may have better prognostic accuracy than the IWGDF system, the only currently available system, but our findings need to be validated in other cohorts.

[Ethical decisions in surgery. Foundations for a principle-oriented case discussion]

BACKGROUND

Due to advanced medical interventions, the multitude of beliefs in our society, and increasing economic pressure, difficult ethical decisions are also part of the surgical care of patients.

QUESTION

How can health care personnel address the ethical challenges in a structured, well-founded ethical manner?

MATERIALS AND METHODS

Based on the four principles of biomedical ethics beneficence, nonmaleficence, respect for autonomy, and justice, we present a model for the step-wise ethical evaluation of difficult cases.

RESULTS

The principle-based model of ethical case discussions consists of five steps: 1) In the medical analysis of the case, the available management strategies are identified, including a detailed description of their benefits and risks. 2) The evaluation starts with the ethical obligations towards the patient: Which treatment strategy is in the patient's best interest? And: Which option does the patient prefer herself after appropriate disclosure? 3) Then it has to be examined whether obligations to third parties (family members, other patients, etc.) have to be taken into account. 4) In the synthesis, the individual evaluations are integrated into an overall assessment of the case; conflicting obligations have to be balanced based on good reasons. 5) A critical review of the case concludes the case discussion. The application of the model is exemplified based on a surgical case discussion.

CONCLUSION

Difficult ethical decisions can be supported by structured case discussions, in which all medical disciplines and professional groups involved in the care of the patient should participate.

Predictors for limb loss among patient with diabetic foot infections: an observational retrospective multicentric study in Turkey

We aimed to investigate the predictors for limb loss among patients with diabetes who have complicated skin/soft-tissue infections. In this observational study, consecutive patients with diabetic foot infection (DFI) from 17 centres in Turkey, between May 2011 and May 2013 were included. The Turkish DFI Working Group performed the study. Predictors of limb loss were investigated by multivariate analysis. In total, 455 patients with DFI were included. Median age was 61 years, 68% were male, 65% of the patients were hospitalized, 52% of the patients had used antibiotics within the last month, and 121 (27%) had osteomyelitis. Of the 208 microorganisms isolated, 92 (44.2%) were Gram-positive cocci and 114 (54.8%) were Gram-negative rods (GNR). The most common GNR was Pseudomonas; the second was Escherichia coli, with extended spectrum β-lactamase positivity of 33%. Methicillin-resistant Staphylococcus species were found in 14% (29/208). Amputations were performed in 126/455 (28%) patients, 44/126 (34%) of these were major amputations. In multivariate analysis, significant predictors for limb loss were, male gender (OR 1.75, 95% CI 1.04-2.96, p 0.034), duration of diabetes >20 years (OR 1.9, 95% CI 1.18-3.11, p 0.008), infected ulcer versus cellulitis (OR 1.9, 95% CI 1.11-3.18, p 0.019), history of peripheral vascular disease (OR 2, 95% CI 1.26-3.27, p 0.004), retinopathy (OR 2.25, 95% CI 1.19-4.25, p 0.012), erythrocyte sedimentation rate >70 mm/hr (OR 1.6, 95% CI 1.01-2.68, p 0.05), and infection with GNR (OR 1.8, 95% CI 1.08-3.02, p 0.02). Multivariate analysis revealed that, besides the known risk factors such as male gender, duration of diabetes >20 years, infected ulcers, history of peripheral vascular disease and retinopathy, detection of GNR was a significant predictor of limb loss.

Wound management of chronic diabetic foot ulcers: from the basics to regenerative medicine

BACKGROUND

Hospital-based studies have shown that mortality rates in individuals with diabetic foot ulcers are about twice those observed in individuals with diabetes without foot ulcers.

OBJECTIVE

To assess the etiology and management of chronic diabetic foot ulcers.

STUDY DESIGN

Literature review.

METHODS

Systematic review of the literature discussing management of diabetic foot ulcers. Since there were only a few randomized controlled trials on this topic, articles were selected to attempt to be comprehensive rather than a formal assessment of study quality.

RESULTS

Chronic nonhealing foot ulcers occur in approximately 15% of patients with diabetes. Many factors contribute to impaired diabetic wound healing. Risk factors include peripheral neuropathy, peripheral arterial disease, limited joint mobility, foot deformities, abnormal foot pressures, minor trauma, a history of ulceration or amputation, and impaired visual acuity. With the current treatment for nonhealing diabetic foot ulcers, a significant number of patients require amputation.

CONCLUSION

Diabetic foot ulcers are optimally managed by a multidisciplinary integrated team. Offloading and preventative management are important. Dressings play an adjunctive role. There is a critical need to develop novel treatments to improve healing of diabetic foot ulcers. The goal is to have wounds heal and remain healed.

CLINICAL RELEVANCE

Diabetic neuropathy and peripheral arterial disease are major factors involved in a diabetic foot ulcer. Despite current treatment modalities for nonhealing diabetic foot ulcers, there are a significant number of patients who require amputations. No known therapy will be effective without concomitant management of ischemia, infection, and adequate offloading.

Diagnosing diabetic foot osteomyelitis: narrative review and a suggested 2-step score-based diagnostic pathway for clinicians

The diabetic foot infection remains a major cause of morbidity and mortality in many patients and remains a challenging diagnosis for most clinicians. Diagnosis is largely based on clinical signs supplemented by various imaging tests. Magnetic resonance imaging (MRI) is not readily available to many clinicians, and bone biopsy, which is the accepted criterion standard for diagnosis, is rarely performed routinely. This evidence-based review and the proposed diagnostic scoring pathway substratifies the current International Working Group on the Diabetes Foot guidelines for diagnosing diabetic foot osteomyelitis into a convenient 2-step diagnostic pathway for clinicians. This proposed diagnostic approach will need further validation prospectively, but it can serve as a useful diagnostic tool during the initial assessment and management of diabetic foot infections. A MEDLINE search of English-language articles on diabetic foot osteomyelitis published between 1986 and March 2014 was conducted. Additional articles were also identified through a search of references from the retrieved articles, published guidelines, systematic reviews, and meta-analyses.

Osteomyelitis in the diabetic foot

Osteomyelitis (OM) is a common complication of diabetic foot ulcers and/or diabetic foot infections. This review article discusses the clinical presentation, diagnosis, and treatment of OM in the diabetic foot. Clinical features that point to the possibility of OM include the presence of exposed bone in the depth of a diabetic foot ulcer. Medical imaging studies include plain radiographs, magnetic resonance imaging, and bone scintigraphy. A high index of suspicion is also required to make the diagnosis of OM in the diabetic foot combined with clinical and radiological studies.

Inter-observer reproducibility of diagnosis of diabetic foot osteomyelitis based on a combination of probe-to-bone test and simple radiography

Probe-to-bone test and simple X-rays are both standard tests for the diagnosis of diabetic foot osteomyelitis. This study demonstrates the importance of considering jointly clinical information (probe-to-bone test) and diagnostic tests (simple radiography) to increase agreement among clinicians on diagnosis of diabetic foot osteomyelitis.

Evaluation of soluble CD200 levels in type 2 diabetic foot and nephropathic patients: association with disease activity

BACKGROUND

CD200 (OX-2) is a novel immune-effective molecule, existing in a cell membrane-bound form, as well as in a soluble form in serum (s OX-2), which acts to regulate inflammatory and acquired immune responses.

MATERIAL AND METHODS

We planned this study to evaluate the sOX-2 levels of type 2 diabetic foot (group B), and compare it with that of healthy controls (group A). The patient group had the following values: DM period: 27.9±10.3 year [mean ±SD], HbA1c: 9.52±2.44% [mean ±SD].

RESULTS

Blood samples for sCD200 measurement were always taken in the morning between 8 and 10 A.M.. The results were reported as means of duplicate measurements. Concentrations of sOX-2 in the serum samples were quantified using an ELISA kit. Serum hs-CRP levels were measured using an hs-CRP assay kit. The sOX-2 level in group B was 173.8±3.1 and in group A was 70.52±1.2 [p<0.0001). In subgroup analysis of T2DM-DFI patients, we noticed that sOX-2 levels were higher in WGS (Wagner grading system) I and II patients than in WGS III and IV patients. The HbA1c, BUN, creatinine, hs-CRP levels, and sedimentation rates were higher in the patient group (p<0.0001, p<0.001, p<0.001, p<0.005, and p<0.0001, respectively).

CONCLUSIONS

We suggest that there are vascular, immunologic, and neurologic components in DFI, whereas autoimmune diseases and inflammatory skin disorders have only an immunologic component. This is possibly evidence of a pro-inflammatory effect seen in DFI as a vascular complication.