Post-treatment leukocytosis predicts an unfavorable clinical response in patients with moderate to severe diabetic foot infections

Bacterial diversity and inflammatory response at first-time visit in younger and older individuals with diabetic foot infection (DFI)

AIM

Infection of a diabetic foot ulcer (DFU) is common. More than the half of DFUs become infected and 15-20% of them necessitate amputation in course of treatment. Diabetic foot infection (DFI) is therefore the major cause for non-traumatic lower limb amputation in Germany. Prompt and effective treatment of DFI is mandatory to safe limbs and lives. We investigated if there are relevant differences in evoked inflammatory response between different species and age-separated groups. We further investigated if there is an impact of ulcer localization on bacterial diversity.

METHODS

For a 12-month period, we investigated 353 individuals with infected DFU, their laboratory results and bacterial diversity at first-time visit in a Diabetic Foot Care Center in Southern Germany.

RESULTS

The ulcer microbiota was dominated by gram-positive species, primary Staphylococcus aureus. The gram-negative sector was mainly formed by Pseudomonas aeruginosa and Enterobacteriaceae (Proteus spp., Enterobacter spp., Escherichia coli and Klebsiella spp.). With increase in age, P. aeruginosa and S. aureus became more frequent, while Streptococci decreased. Ischemic and/or deep wounds were more likely to bear gram-negative species. Inflammatory response did not differ between gram-positive and gram-negative species, while Streptococci and Proteus spp. induced the highest serum inflammation reaction in their category. Streptococci, Enterobacter spp. and E. coli were more frequent in summer, while Enterococci spp., coagulase-negative Staphylococci and P. aeruginosa were more prevalent in winter half-year. DFIs of the forefoot and plantar side are mostly caused by gram-positive species, while Enterobacteriaceae were most frequent in plantar ulcerations.

CONCLUSION

Gram-positive species dominate bacterial spectrum in DFI. With increase in age, S. aureus, Streptococci and Pseudomonas aeruginosa became more frequent. The inflammatory response did not differ significantly between different species, but gram-negative species were slightly but not significant more frequent in ischemic wounds. Climatic distinction like summer or winter half-year as well as foot ulcer localization seems to influence bacterial diversity in DFUs.

Predictive Effect of Inflammatory Response and Foot Ulcer Localization on Outcome in Younger and Older Individuals with Infected Diabetic Foot Syndrome

The diabetic foot syndrome (DFS) is the most important cause for non-traumatic major amputation in adult individuals and actually one of the most frightening events in diabetics’ life. Despite the often protracted treatment of infected DFS at the end patients are often confronted with amputation. We investigated 352 individuals with infected DFS in two age separated-groups. Older individuals presented with significant worse renal function and lower HbA1c on day of admittance. Most detected ulcers involved the plantar sides of the metatarsal heads (MTH) and the toes. We saw an age-dependent translocation of foot ulcers from plantar and hindfoot to the forefoot and toes. In average every third wound provoked amputation, in the majority (94%) minor amputations, only 1.9% major amputations occurred. Lesions of the 5th toe or its MTH and interdigital or interphalangeal joint ulcers led to amputation in more than 60%. Worse renal function and WBC above 11 tsd/µl were linked with higher amputation risk. But in particular current scoring systems like SINBAD or Wagner-Armstrong scale and thus finally clinician’s assessment of the wound situation gave a substantial hint for subsequent amputation – regardless of age.

Risk factors affecting amputation in diabetic foot

Background

A diabetic foot is the most common cause of non-traumatic lower extremity amputations (LEA). The study seeks to assess the risk factors of amputation in patients with diabetic foot ulcers (DFU).

Methods

The study was conducted on 351 patients with DFUs from January 2010 to December 2018. Their demographic characteristics, disease history, laboratory data, ankle-brachial index, Wagner classification, osteomyelitis, sarcopenia index, and ulcer sizes were considered as variables to predict outcome. A chi-square test and multivariate logistic regression analysis were performed to test the relationship of the data gathered. Additionally, the subjects were divided into two groups based on their amputation surgery.

Results

Out of the 351 subjects, 170 required LEA. The mean age of the subjects was 61 years and the mean duration of diabetes was 15 years; there was no significant difference between the two groups in terms of these averages. Osteomyelitis (hazard ratio [HR], 6.164; 95% confidence interval [CI], 3.561−10.671), lesion on percutaneous transluminal angioplasty (HR, 2.494; 95% CI, 1.087−5.721), estimated glomerular filtration rate (eGFR; HR, 0.99; 95% CI, 0.981−0.999), ulcer size (HR, 1.247; 95% CI, 1.107−1.405), and forefoot ulcer location (HR, 2.475; 95% CI, 0.224−0.73) were associated with risk of amputation.

Conclusion

Osteomyelitis, peripheral artery disease, chronic kidney disease, ulcer size, and forefoot ulcer location were risk factors for amputation in diabetic foot patients. Further investigation would contribute to the establishment of a diabetic foot risk stratification system for Koreans, allowing for optimal individualized treatment.

Diagnostic Utility of Erythrocyte Sedimentation Rate and C-Reactive Protein in Osteomyelitis of the Foot in Persons Without Diabetes

The aim of the study was to assess the diagnostic value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels in differentiating foot osteomyelitis (OM) from soft tissue infection (STI) in persons without diabetes. We evaluated 102 patients in a retrospective cohort study of nondiabetic patients admitted to our institution with OM (n = 51) and with STI (n = 51). Patient diagnosis was determined through bone culture and/or histopathology for OM and magnetic resonance scan and/or single-photon emission computed tomography for STI. Cutoffs for ESR and CRP to predict OM as identified by receiver operating characteristic were 45.5 mm/h and 3.45 mg/dL, respectively. The ESR cutoff demonstrated a sensitivity and specificity of 49% and 79%, while the values for CRP were 45% and 71%, respectively. The combined sensitivity and specificity for ESR and CRP were 33% and 84%. The positive and negative predictive values were 68% and 60% for ESR and 61% and 56% for CRP, respectively. In conclusion, ESR and CRP demonstrate poor sensitivity and specificity for detecting OM in the nondiabetic foot. These markers have little diagnostic utility in the nondiabetic foot.

Risk factors for major amputation in hospitalised diabetic foot patients

Diabetic foot ulcers are the main cause of non-traumatic lower extremity amputation. The objective of this study was to evaluate the risk factors for major amputation in diabetic foot patients. Eight hundred and sixty diabetic patients were admitted to the diabetic wound centre of the Korea University Guro Hospital for foot ulcers between January 2010 and December 2013. Among them, 837 patients were successfully monitored until complete healing. Ulcers in 809 patients (96·7%) healed without major amputation and those in 28 patients (3·3%) healed with major amputation. Data of 88 potential risk factors including demographics, ulcer condition, vascularity, bioburden, neurology and serology were collected from patients in the two groups and compared. Among the 88 potential risk factors, statistically significant differences between the two groups were observed in 26 risk factors. In the univariate analysis, which was carried out for these 26 risk factors, statistically significant differences were observed in 22 risk factors. In a stepwise multiple logistic analysis, six of the 22 risk factors remained statistically significant. Multivariate-adjusted odds ratios were 11·673 for ulcers penetrating into the bone, 8·683 for dialysis, 6·740 for gastrointestinal (GI) disorders, 6·158 for hind foot ulcers, 0·641 for haemoglobin levels and 1·007 for fasting blood sugar levels. The risk factors for major amputation in diabetic foot patients were bony invasions, dialysis, GI disorders, hind foot locations, low levels of haemoglobin and elevated fasting blood sugar levels.

Revision Surgery for Diabetic Foot Infections

Revision surgery (RS) is frequently needed to control diabetic foot infections. It is the aim of this retrospective observational study to analyze the variables associated with undergoing RS and the variables associated with undergoing a major amputation when RS was required. We conducted a retrospective study of patients with diabetes treated in our department during 10 years (January 1, 2000 to January 1, 2010) who had foot infections identifying those who required RS. In all, 167 out of 417 patients (40%) with diabetes who underwent surgery for foot infections underwent RS for persistent infection. The predictive variables related to undergoing revision surgery were erythrocyte sedimentation rate >70 mm/h (odds ratio [OR] = 1.6, 95% confidence interval [CI] = 1.1-2.6), leukocytosis (OR = 1.6, 95% CI = 1.1-2.5), peripheral arterial disease (OR = 1.5, 95% CI = 1.0-2.4), and isolation of gram-negative rods from tissue biopsy (OR = 2.2, 95% CI = 1.5-3.4). Seventy-nine out of 167 patients (47.3) who underwent RS required a higher level of surgery achieving a limb salvage rate of 70.7%. Predictive variables related to undergoing a major amputation after RS were persistent infection located in the bone (OR = 0.08, 95% CI = 0.03-0.22), ischemic heart disease (OR = 3.4, 95% CI = 1.4-8.5), 2 or more reoperations (OR = 3.0, 95% CI = 1.2-7.1), isolation of gram-negative rods from tissue biopsy (OR = 3.3, 95% CI = 1.3-8.4), and peripheral arterial disease (OR = 6.5, 95% CI = 1.9-22.8). Despite the fact that 40% of patients underwent reoperations for diabetic foot infections and 47.3% of them required a higher level of surgery, a high rate of limb salvage could be achieved.

Diabetic foot infections: current concept review

The purpose of this manuscript is to provide a current concept review on the diagnosis and management of diabetic foot infections which are among the most serious and frequent complications encountered in patients with diabetes mellitus. A literature review on diabetic foot infections with emphasis on pathophysiology, identifiable risk factors, evaluation including physical examination, laboratory values, treatment strategies and assessing the severity of infection has been performed in detail. Diabetic foot infections are associated with high morbidity and risk factors for failure of treatment and classification systems are also described. Most diabetic foot infections begin with a wound and once an infection occurs, the risk of hospitalization and amputation increases dramatically. Early identification of infection and prompt treatment may optimize the patient's outcome and provide limb salvage.

Incidence, risk factors for amputation among patients with diabetic foot ulcer in a North Indian tertiary care hospital

OBJECTIVE

Aim of this study was to evaluate the incidence and risk factors for amputation among patients with diabetic foot ulcer (DFU).

RESEARCH DESIGN AND METHODS

We performed a prospective study of 162 DFU in patients treated in a multidisciplinary based diabetes and endocrinology centre of Jawaharlal Nehru Medical College of Aligarh Muslim University, Aligarh, India during the period of December 2008-March 2011. Detailed history and physical examination was carried out for every subject. Risk factors for amputation were determined by univariate analysis with 95% of CI.

RESULTS

The overall amputation rate was 28.4%. On univariate analysis, male sex [OR 2.8, RR 1.28], hypertension [OR 2.83, RR 1.31], neuropathy [OR 3.01, RR 1.35], nephropathy [OR 2.24, RR 1.26], LDL-C (>100mg/dl) [OR 2.53, RR 1.28], total cholesterol (>150mg/dl) [OR 3.74, RR 1.52],HDLC(<40mg/dl) [OR 1.19, RR 1.18], triglycerides (>200mg/dl) [OR 5.44, RR1.76], previous antibiotic use [OR 9.12, RR 1.92], osteomyelitis [OR 6.97, RR 2.43] and biofilm infection [OR 4.52, RR 1.41] were significant risk factors.

CONCLUSION

The risk factors for amputation were presence of PVD, leukocytosis, neuropathy, nephropathy, hypertension, dyslipidemia, over use of antibiotics, osteomyelitis, biofilm production and higher grade of ulcer.

Surgical treatment of limb- and life-threatening infections in the feet of patients with diabetes and at least one palpable pedal pulse: successes and lessons learnt

Outcomes of surgically treated limb- and life-threatening infections in patients with diabetes and a well-vascularized foot based only on the palpation of foot pulses are not well known. The authors retrospectively studied a series of 173 patients with diabetes and limb- (moderate) or life- (severe) threatening infections with at least one palpable pedal pulse who were admitted to their department for the treatment of infected diabetic foot from January 1, 1998, to December 31, 2009. A total of 141 patients (81.5%) presented with limb-threatening/moderate infections and 32 (18.5%) with life-threatening/severe infections. In all, 49 patients (28.3%) presented with soft tissue infections only, 90 (52%) with osteomyelitis and 34 (19.7%) with a combined infection. Amputation was needed in 74 patients (42.7%), of whom 6 needed a major amputation (3.5% of overall). A total of 99 (57.2%) patients were treated by conservative surgery. Four patients (2.3%) died during the postoperative period (30 days). Limb salvage was achieved in 167 (96.5%) of the patients who were followed up until healing. Healing of the wounds by secondary intention was achieved in a median of 72 days. Clinical results permit the observation that a high rate of limb salvage can be achieved after the surgical treatment of limb- and life-threatening infections in patients with at least one palpable pedal pulse.