Clinical, microbiological and inflammatory markers of severe diabetic foot infections

Significance of Neutrophil to Lymphocyte Ratio (NLR) and Platelet Lymphocyte Ratio (PLR) in Diabetic Foot Ulcer and Potential New Therapeutic Targets

Diabetic foot ulcer (DFU) is a well-known complication of diabetes and a significant burden on the national health systems. The neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio are inexpensive and easily accessible biomarkers that have proved to be useful in several inflammatory, infectious and cardiovascular diseases. We carried out a comprehensive review examining the association of NLR and PLR with the onset and progression of DFU. PLR and NLR were significantly increased in patients with DFU, compared with a control group of T2DM patients without DFU, and correlate well with DFU severity, evaluated by Wagner and IWGDF grading scales. In patients with diabetic foot infections (DFI), elevated NLR and PLR were correlated with osteomyelitis, increased risk of amputation, and septic complications. The significance of the elevated value of these biomarkers in DFU is related to chronic hyperglycemia and low-grade systemic inflammation, atherosclerotic and vascular complications, and also the associated septic factor. Serial, dynamic follow-up can provide useful information in planning and monitoring DFU treatment, as well as in risk stratification of these vulnerable patients. Further randomized studies are needed to set the cut-off values with clinical significance.

Risk factors for malnutrition in patients with diabetic foot ulcer and its association with prolonged length of hospitalization

PURPOSE

The study was designed to investigate the occurrence and risk factors of malnutrition in diabetic foot ulcers (DFU) patients and examine the association between malnutrition and length of stay (LOS).

METHODS

This observational study included DFU hospitalized patients in two campuses of a hospital from January 2021 to June 2023. The diagnosis standard of malnutrition was established by using the Global Leadership Initiative on Malnutrition (GLIM) criteria. Patients were followed up to ascertain the length of hospitalization, and hospital stays longer than 17 days were considered as prolonged LOS. To explore the risk factors of malnutrition and the association between malnutrition and LOS, univariate and multivariate logistic regression analyses were performed.

RESULTS

Overall 219 DFU patients were enrolled, malnutrition was identified in 38.36% of patients according to GLIM criteria, and 92 patients (42%) were recognized as prolonged LOS. Logistic regression analyses showed that BMI (P <0.001), Alb (P = 0.002), HbA1c (P <0.001), ulcer infection (P <0.001), LOS (P = 0.010), and ABI (P = 0.024) were independent risk factors for malnutrition. Besides, malnutrition by GLIM criteria was closely related to prolonged LOS and malnourished DFU patients were 2.857 times (95% CI, 1.497-5.450; P = 0.001) likely to present prolonged LOS than that of normal nutrition.

CONCLUSION

Malnutrition was considered to be extremely prevalent in DFU patients and was associated with approximately three times higher likelihood of prolonged LOS. Implementing and disseminating the diagnostic criteria during routine practice is crucial, given the predictive efficacy of GLIM criteria.

The Development and Evaluation of a Prediction Model for Kidney Transplant-Based Pneumocystis carinii Pneumonia Patients Based on Hematological Indicators

BACKGROUND

This study aimed to develop a simple predictive model for early identification of the risk of adverse outcomes in kidney transplant-associated Pneumocystis carinii pneumonia (PCP) patients.

METHODS

This study encompassed 103 patients diagnosed with PCP, who received treatment at our hospital between 2018 and 2023. Among these participants, 20 were categorized as suffering from severe PCP, and, regrettably, 13 among them succumbed. Through the application of machine learning techniques and multivariate logistic regression analysis, two pivotal variables were discerned and subsequently integrated into a nomogram. The efficacy of the model was assessed via receiver operating characteristic (ROC) curves and calibration curves. Additionally, decision curve analysis (DCA) and a clinical impact curve (CIC) were employed to evaluate the clinical utility of the model. The Kaplan-Meier (KM) survival curves were utilized to ascertain the model's aptitude for risk stratification.

RESULTS

Hematological markers, namely Procalcitonin (PCT) and C-reactive protein (CRP)-to-albumin ratio (CAR), were identified through machine learning and multivariate logistic regression. These variables were subsequently utilized to formulate a predictive model, presented in the form of a nomogram. The ROC curve exhibited commendable predictive accuracy in both internal validation (AUC = 0.861) and external validation (AUC = 0.896). Within a specific threshold probability range, both DCA and CIC demonstrated notable performance. Moreover, the KM survival curve further substantiated the nomogram's efficacy in risk stratification.

CONCLUSIONS

Based on hematological parameters, especially CAR and PCT, a simple nomogram was established to stratify prognostic risk in patients with renal transplant-related PCP.

Outpatient Foot-Sparing Surgery Is Safe in Selected Patients with Diabetic Foot Infections

OBJECTIVE

To determine if outpatient foot-sparing surgery for patients with diabetic foot infections (DFIs) is associated with a higher rate of treatment failure or longer healing time.

METHODS

In this prospective observational study, the authors consecutively recruited a cohort of 200 patients with moderate and severe DFIs from the Diabetic Foot Unit of Hospital San Juan de Dios, Caja Costarricense de Seguro Social, San José de Costa Rica, Costa Rica from October 15, 2020 to December 15, 2021. They compared outpatients with those admitted. Cox univariate analysis was performed, with time to treatment failure and time to healing as dependent variables and outpatient management as the independent variable.

RESULTS

Seventy-one patients underwent surgery on an outpatient basis (35.5%), and 129 (64.5%) were admitted. Sixty of 111 patients (54.1%) with moderate infections were treated as outpatients versus 11 of 89 (12.4%) of those with severe infections. Twelve (16.9%) of the outpatients and 26 (20.2%) of those admitted presented failure (P = .57). The Cox univariate analysis with time to failure of treatment associated with outpatient management reported a hazard ratio of 1.26 (95% CI, 0.64-2.50; P = .50), and the analysis regarding healing time reported a hazard ratio of 0.91 (95% CI, 0.66-1.25; P = .56).

CONCLUSIONS

Foot-sparing surgery on an outpatient basis was safe in more than half the cases of moderate DFIs, especially in patients with osteomyelitis. This approach is not associated with treatment failure or a longer healing time. Patients with severe infections, penetrating injuries, necrosis, or high inflammatory response and those with peripheral arterial disease who require revascularizations should be admitted to the hospital.

Evaluation of the healing potential of short-term ozone therapy for the treatment of diabetic foot ulcers

Background

The availability of research on short-term ozone therapy for diabetic foot ulcers (DFUs) is limited, and even when it is accessible, it mainly comprises of basic analysis conducted during long-term ozone therapy. This study was to evaluate the efficacy of short-term ozone therapy in promoting wound healing in DFUs.

Methods

A retrospective analysis was conducted on 89 patients with type 2 diabetes complicated by DFUs. The patients were divided into two groups: ozone therapy group (n=41) and control group (n=48). Wound condition, change of bacterial types, changes in inflammatory indicators (erythrocyte sedimentation rate [ESR], C-reactive protein [CRP], and procalcitonin [PCT]), vascular endothelial growth factor (VEGF), cytokines [Interleukin 6 (IL-6) and tumor necrosis factor-α(TNF-α)], and oxidative stress levels (superoxide dismutase [SOD], malondialdehyde [MDA], and total antioxidant capacity [T-AOC]) were observed pre-treatment and after 1 week. After a 12-week of follow-up, wound healing rate, amputation rate, inpatient day, duration of antibiotics, reinfection rate, incidence of new ulcers, readmission rate, and reoperation rate, and cumulative wound healing rate using Kaplan-Meier curves were assessed.

Results

After 1 week of treatment, the ozone therapy group showed higher VEGF, SOD, and T-AOC levels compared to the control group (P<0.05), while CRP, PCT, ESR, IL-6, TNF-α, MDA levels and bacterial types were lower (P<0.05). The ozone therapy group had a higher wound healing rate after a 12-week follow-up (P<0.05). Kaplan-Meier curves indicated a higher cumulative wound healing rate in the ozone therapy group (P<0.05). Additionally, the ozone therapy group had lower inpatient day, duration of antibiotics, reinfection rate, and readmission rate compared to the control group (P<0.05).

Conclusion

Short-term ozone therapy is effective in promoting wound healing in DFUs by reducing inflammation, increasing growth factor levels, improving oxidative stress status, shortening healing time, and improving long-term prognosis. These findings suggest the potential of short-term ozone therapy as a valuable treatment modality for DFUs.

Predictive Value of C-Reactive Protein to Albumin Ratio for Amputation Risk in Diabetic Foot Infection

Diabetic foot infections are one of the complications of diabetes mellitus resulting in extremity amputation and mortality. This study aimed to examine the predictive value of the C-reactive protein (CRP) to albumin ratio (CAR) for amputation risk in diabetic foot infection. Data from 178 patients were retrospectively examined. We found the cut point value of 15.45 according to the receiver operating characteristic (ROC) curve to show the predictive value of CAR for amputation risk in the overall population. We then divided the patients into two groups low (<15.45, n = 96) and high risk (≥15.45, n = 82) according to their CAR value. Matching based on propensity scores produced 64 patients in each group and showed that the amputation rate was high in the high-risk groups (50 vs 25%, P = .003). In the multivariate analysis in the matching group, previous amputation, antibiotic therapy in the last 3 months, and CAR (Odds ratio [OR]: 1.30, 95%Confidence interval [CI]: 1.01-1.45, P < .001) were independent predictors of amputation. These parameters may be useful to predict amputation risk in these patient groups.

The role of neutrophils in diabetic ulcers and targeting therapeutic strategies

Diabetic ulcers (DUs) are a common complication of diabetes with high morbidity, poor prognosis, and a high socio-economic burden. The main pathological manifestations of DUs are chronic inflammation, impaired re-epithelialization, and impaired angiogenesis. During the inflammatory phase, neutrophils are one of the main DU cell types and act by releasing neutrophil extracellular traps (NETs), leading to poor healing in DUs. This review summarizes the role of neutrophils in the pathology and treatment of DUs, with a view to potential novel therapies and therapeutic targets.

The infected diabetes-related foot: Comparison of erythrocyte sedementation rate/albumin and C-reactive protein/albumin ratios with erythrocyte sedimentation rate and C-reactive protein to differentiate bone and soft tissue infections

The objective of this study was to evaluate the effectiveness of C-reactive protein (CRP)/albumin, erythrocyte sedimentation rate (ESR)/albumin ratio, ESR, CRP and albumin to differentiate bone and soft tissue infection in persons with diabetes. We retrospectively evaluated 242 individuals admitted to hospital with diabetes-related foot infections (DFI). We categorised DFI cases as either bone (OM) or soft tissue infection based on bone culture and/or histology. We evaluated the diagnostic accuracy of CRP, ESR, albumin, CRP/albumin and ESR/albumin as biomarkers to diagnose OM in persons with diabetes. The median age was 53 years (74% male). There were 224 diabetes-related patients of which 125 had been diagnosed with osteomyelitis. The ESR/albumin and CRP/albumin ratios cut-points were >17.84 and >1.83, respectively. ESR/albumin and CRP/albumin ratios had similar diagnostic parameters: AUC (0.71, 0.71), sensitivity (70.0%, 57.0%), specificity (62.0%, 75.0%), positive predictive value (67.0%, 71.0%) and negative predictive value (66.0% and 71.0%). In contrast diagnostic efficiency of CRP and ESR were AUC 0.71 and 0.71, sensitivity (45.6%, 71.2%), specificity (85.5%, 60.7%), positive predictive value (70.0%, 65.9%) and negative predictive value (59.5%, 66.4%), respectively. When comparing area under the curves, the results showed that ESR/albumin was not significantly different to ESR alone (Delong test pvs ESR  >0.1). Similarly, CRP/albumin was not significantly different to CRP alone (Delong test pvs CRP  >0.1). In conclusion, ESR/albumin and CRP/albumin ratios provided comparable results as using ESR and CRP alone.

Risk factors for at-risk foot and peripheral artery disease among the population with diabetes: A multicommunity-based cross-sectional study

AIMS

This study aimed to investigate the prevalence, characteristics, and influence factors of the at-risk foot with diabetes mellitus (DM).

METHODS

This study included 3030 DM patients from the at-risk foot screening program of Shanghai in China between March 21 and April 30 in 2021. Data were collected from the questionnaire survey, physical examination, and fasting blood sample.

RESULTS

The prevalence of at-risk foot was 27.8% among DM patients. After adjusted, the risk of higher at-risk grade increased with age and urinary albumin creatinine ratio (OR = 1.04, 95%CI = 1.02-1.06; OR = 1.001, 95%CI = 1.000-1.002, respectively), whereas decreased with estimated glomerular filtration rate (eGFR) (OR = 0.991, 95%CI = 0.984-0.998). The incidence of peripheral artery disease (PAD) was 11.1% in all people with DM, and age, pulse rate, and low-density lipoprotein were independent risk factors for PAD. In contrast, high-density lipoprotein, eGFR, and lymphocyte-to-monocyte ratio were independent protective factors for PAD. Glycated hemoglobin HbA1c was not an independent risk factor for increased risk grade or more severe PAD.

CONCLUSIONS

The at-risk foot accounted for a high percentage among DM patients. Advanced age and renal dysfunction are independent risk factors for the at-risk foot. Glycemic control does not reduce the risk grade of at-risk foot and the incidence of PAD.

Clinical Features, Inflammatory Markers, and Limb Salvage in Older Adults with Diabetes-Related Foot Infections

Little information exists about diabetic foot infections (DFIs) in older patients. We hypothesize that older patients with DFIs have different clinical features and worse outcomes than younger patients. We conducted a prospective observational study consisting of a cohort of patients with diabetes and moderate to severe DFIs. Patients included in the cohort were dichotomized into two groups using percentile 75 (P75) of age as the cut-off value. Patients aged > P75 presented with more comorbidities and foot-related complications, a higher rate of peripheral arterial disease (PAD), worse renal function (higher values of blood urea nitrogen and creatinine, and lower values of estimated glomerular filtration rate), and lower values of HbA1c compared with younger patients. Infection severity, microbiological features, and inflammatory markers were similar in both groups. In the multivariate analysis, minor amputations were associated with age > P75 (OR = 2.8, 95% CI 1.3-5.9, p <0.01), necrosis (OR = 4.2, 95% CI 1.8-10.1, p < 0.01), and CRP values (OR = 1.045, 95% CI 1.018-1.073, p < 0.01). Major amputations were associated with a history of amputation (OR = 4.7, 95% CI 1.3-16.7, p = 0.01), PAD (OR = 4.3, 95% CI 1.2-14.6, p = 0.01), and albumin values (OR = 0.344, 95% CI 0.130-0.913, p = 0.03). In conclusion, limb salvage can be achieved in older patients with diabetes-related foot infections at the same rate as in younger patients, despite the fact that they have more comorbidities and foot-related complications, a higher rate of PAD, and worse renal function.

Classification Model for Diabetic Foot, Necrotizing Fasciitis, and Osteomyelitis

Simple Summary

Necrotizing fasciitis (NF) and osteomyelitis (OM) are severe complications in patients with diabetic foot ulcers (DFUs). Although NF and OM often cause results including limb amputation and death, definite diagnoses of these are challenging. To aid the prompt and proper diagnosis of NF and OM in patients with DFU, we developed and evaluated a novel prediction model based on machine learning technology. In summary, our prediction model appropriately discriminated the NF and OM from diabetic foot. Moreover, this prediction model has advantages in that it is based on the demographic data and routine laboratory results, which requires no additional examinations which are complicated or expensive.

Abstract

Diabetic foot ulcers (DFUs) and their life-threatening complications, such as necrotizing fasciitis (NF) and osteomyelitis (OM), increase the healthcare cost, morbidity and mortality in patients with diabetes mellitus. While the early recognition of these complications could improve the clinical outcome of diabetic patients, it is not straightforward to achieve in the usual clinical settings. In this study, we proposed a classification model for diabetic foot, NF and OM. To select features for the classification model, multidisciplinary teams were organized and data were collected based on a literature search and automatic platform. A dataset of 1581 patients (728 diabetic foot, 76 NF, and 777 OM) was divided into training and validation datasets at a ratio of 7:3 to be analyzed. The final prediction models based on training dataset exhibited areas under the receiver operating curve (AUC) of the 0.80 and 0.73 for NF model and OM model, respectively, in validation sets. In conclusion, our classification models for NF and OM showed remarkable discriminatory power and easy applicability in patients with DFU.

Limb Salvage in Severe Diabetic Foot Infection

Severe diabetic foot infections (DFI) are both limb threatening and life threatening and associated with negative impact on health-related quality of life. Most severe DFIs require surgical intervention, and the goal of treatment should be preservation of limb function in addition to eradication of infection. Minor amputations are required in approximately 40% and major amputations in approximately 20% of patients. Significant risk factors for lower extremity amputation included male gender, smoking, previous amputation, osteomyelitis, peripheral artery disease, retinopathy, severe infections, gangrene, neuroischemic diabetic foot infections, leukocytosis, positive wound cultures, and isolation of gram-negative bacteria.

Severe Diabetic Foot Infections without Systemic Inflammatory Response Syndrome. Prospective Validation of a New Category

We aimed to validate the prognostic value of subclassifying moderate diabetic foot infections into two categories: moderate and moderate/severe. We conducted a prospective study of a cohort of 200 patients with moderate and severe infections. Moderate infections were subclassified after applying a previously published score. Variables associated with prognosis were: need for any amputation, major amputation, need for hospitalization, length of hospitalization, length of antibiotic therapy, reinfection rate and infection-related mortality. Infections were moderate in 111 cases (55.5%) and severe in 89 (44.5%). Osteomyelitis was diagnosed in 114 cases (57%), 73 moderate (36.5%) and 41 severe (20.5%). Patients with severe OM had a higher rate of amputations, major amputations, hospitalizations and need for antibiotic therapy, and a longer duration of antibiotics when compared with moderate OM. After applying the score, moderate infections were subclassified into 73 moderate cases (65.7%) and 38 moderate/severe cases (34.3%). Moderate/severe had a higher rate of amputations, major amputations, hospitalizations and need for antibiotics than moderate ones. No differences regarding prognosis were found between moderate/severe and severe infections with systemic inflammatory response syndrome. Moderate/severe diabetic foot infections, which could also be known as severe infections without systemic inflammatory response syndrome, should be recognized as a new subgroup. We propose to merge severe diabetic foot infections with and without systemic inflammatory response syndrome into a unique category due to its prognostic value. Furthermore, osteomyelitis should be added to both moderate and severe new categories of diabetic foot infections. This article is protected by copyright. All rights reserved.