Factors associated with foot ulceration and amputation in adults on dialysis: a cross-sectional observational study

Foot and Ankle Care by Podiatrists and Amputations in Patients With Diabetes and Kidney Failure

Importance

Patients with kidney failure have an increased risk of diabetes-related foot complications. The benefit of regular foot and ankle care in this at-risk population is unknown.

Objective

To investigate foot and ankle care by podiatrists and the outcomes of diabetic foot ulcers (DFUs) in patients with kidney failure.

Design, Setting, and Participants

This retrospective cohort study included Medicare beneficiaries with type 2 diabetes receiving dialysis who had a new DFU diagnosis. The analysis of the calendar year 2016 to 2019 data from the United States Renal Data System was performed on June 15, 2023, with subsequent updates on December 11, 2023.

Exposures

Foot and ankle care by podiatrists during 3 months prior to DFU diagnosis.

Main Outcomes and Measures

The outcomes were a composite of death and/or major amputation, as well as major amputation alone. Kaplan-Meier analysis was used to estimate 2 to 3 years of amputation-free survival. Foot and ankle care by podiatrists and the composite outcome was examined using inverse probability-weighted Cox regression, while competing risk regression models were used for the analysis of amputation alone.

Results

Among the 14 935 adult patients with kidney failure and a new DFU (mean [SD] age, 59.3 [12.7] years; 35.4% aged ≥65 years; 8284 men [55.4%]; Asian, 2.7%; Black/African American, 35.0%; Hispanic, 17.7%; White, 58.5%), 18.4% (n = 2736) received care by podiatrists in the 3 months before index DFU diagnosis. These patients were older, more likely to be male, and have more comorbidities than those without prior podiatrist visits. Over a mean (SD) 13.5 (12.0)-month follow-up, 70% of those with podiatric care experienced death and/or major amputation, compared with 74% in the nonpodiatric group. Survival probabilities at 36 months were 26.3% vs 22.8% (P < .001, unadjusted Kaplan-Meier survival analysis). In multivariate regression analysis, foot and ankle care was associated with an 11% lower likelihood of death and/or amputation (hazard ratio [HR], 0.89 95% CI, 0.84-0.93) and a 9% lower likelihood of major amputation (above or below knee) (HR, 0.91; 95% CI, 0.84-0.99) than those who did not.

Conclusions and Relevance

The findings of this study suggest that patients with kidney failure at risk for DFUs who receive foot and ankle care from podiatrists may be associated with a reduced likelihood of diabetes-related amputations.

Risk factors of foot ulcers in patients with end-stage renal disease on dialysis: A meta-analysis

The present study aims to assess the risk factors for foot ulcers in patients undergoing dialysis for end-stage renal disease (ESRD) and to provide evidence-based guidance for prevention and treatment. A systematic search was conducted on PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, Chinese Biomedical Literature Database and Wanfang Data from the database inception until May 2023 to identify relevant studies investigating the risk factors for foot ulcers in dialysis patients with ESRD. Two independent researchers conducted the literature screening and data extraction. The meta-analysis was performed using STATA 17.0 software. Ultimately, six articles comprising 1620 patients were included for analysis. The meta-analysis revealed that male (OR, 1.464; 95% CI: 1.082-1.980, p = 0.013), hypertension (OR, 1.781; 95% CI: 1.293-2.4550, p < 0.001), peripheral artery disease (PAD) (OR, 5.014; 95% CI: 2.514-9.998, p < 0.001), type 1 diabetes mellitus (T1DM) (OR, 2.993; 95% CI: 1.477-6.065, p = 0.002) and type 2 diabetes mellitus (T2DM) (OR, 2.498; 95% CI:1.466-4.256, p = 0.001) were risk factors for foot ulcers in dialysis patients with ESRD. Conversely, the female sex (OR, 0.683; 95% CI: 0.505-0.924, p = 0.013) was a protective factor against foot ulcers. Our analysis revealed that male sex, hypertension, PAD, T1DM and T2DM were risk factors for foot ulcers in patients undergoing dialysis for ESRD. Conversely, the female sex was a protective factor against foot ulcers. Therefore, it is crucial to strengthen health education that targets patients with these risk factors and regularly screen high-risk individuals. Early detection and treatment can help delay disease progression.

Prevention and management of foot and lower limb health complications in adults undergoing dialysis: a scoping review

BACKGROUND

Foot and lower limb health complications are common among patients undergoing dialysis; but a summary of prevention and management evidence is not available. The aim of this scoping review was to summarise study characteristics and the nature of results regarding strategies to prevent and manage peripheral arterial disease (PAD), foot ulceration, amputation, associated infection and associated hospital admission in adults undergoing dialysis.

METHODS

MEDLINE, Embase, CINAHL and AMED databases were searched for longitudinal experimental and observational studies. Eligible studies included adults undergoing dialysis (≥10 dialysis patients, with separate results or ≥ 75% of the cohort). Any interventions relating to PAD, foot ulceration, amputation, associated infection, and associated hospital admission were included.

RESULTS

The review included 212 studies, of which 199 were observational (94%) and 13 were experimental (6%). Sixteen studies (8%) addressed the prevention of foot and lower limb health complications, 43 (20%) addressed management, and 153 (72%) addressed both. The main intervention type in each study was surgery (n = 159, 75%), care from one or more health professionals (n = 13, 6%), screening by a health professional (n = 10, 5%), medication (n = 9, 4%) and rehabilitation (n = 5, 2%). No studies were identified where exercise, offloading or education were the main intervention. Results for PAD were reported in 137 (65%) studies, foot ulceration in 54 (25%), amputation in 171 (81%), infection in 7 (3%), and admission in 26 studies (12%). Results for more than one foot or lower limb outcome were reported in 141 studies (67%), with each study reporting on average two outcomes. Results varied and spanned positive, negative, and neutral outcomes following intervention.

CONCLUSIONS

Identified studies frequently aimed to both prevent and manage foot and lower limb health complications. A variety of interventions were identified and studies often reported results for more than one foot or lower limb health outcome. Findings from this review can be used to guide future research, with a goal to support improved patient outcomes.

The Relationship Between Bone Metabolism and Peripheral Artery Disease in Patients on Hemodialysis: The Potential Role of Osteocalcin

Introduction

To examine the factors associated with PAD, with a specific focus on bone metabolism factors such as osteocalcin.

Methods

This cross-sectional study examined factors about demographic, clinical, and laboratory parameters including bone metabolism biomarkers in hemodialysis patients. The ankle-brachial index (ABI) was measured in all patients, with PAD diagnosed as an ABI <0.9.

Results

Out of the 71 patients, PAD was found in 23 individuals. These patients had an average age of 63.5±13.0 years, with 59.2% being male. Compared to non-PAD patients, those with PAD were older, had a lower proportion of males, and had a higher prevalence of diabetes and coronary artery disease. Among the factors related to bone metabolism, only osteocalcin exhibited a significant increase in the PAD group compared to the non-PAD group.

Conclusion

PAD in patients on hemodialysis was independently linked to high levels of osteocalcin in the bloodstream, indicating the presence of bone metabolism disorders.

Risk Factors for Lower Extremity Amputation in Patients with End-Stage Kidney Disease: A Nationwide Cohort Study

Individuals with end-stage kidney disease (ESKD) on dialysis are at a high risk of developing foot ulcerations and undergoing subsequent lower extremity amputation (LEA), which can exert significant impacts on their quality of life and contribute to rising healthcare costs. We aimed to identify risk factors associated with LEA in patients with ESKD to predict LEA progression and eventually prevent it. We used 18 years (2002-2019) of data from the Korean National Health Insurance Service (KNHIS). Data were collected from patients with ESKD who underwent renal replacement therapy (RRT) and had no history of amputation caused by trauma or toxins. The risk factors were compared between patients with or without LEA. We collected data from 220,838 patients newly diagnosed with ESKD, including 6348 in the LEA group and 214,490 in the non-LEA group. The total incidence of LEA was 2.9%. Older age, male gender, lower income, non-metropolitan residence, diabetes mellitus, dialysis treatment (compared to kidney transplantation), microvascular disease, peripheral vascular disease, endovascular procedure, and endovascular operation were associated with an increased risk of LEA. Thus, individuals with ESKD who are at a higher risk for LEA should be closely monitored, and kidney transplantation should be considered as a preventative measure.

Variability of toe pressures during haemodialysis: comparison of people with and without diabetes; a pilot study

BACKGROUND

Diabetes, end stage renal disease (ESRD), and peripheral arterial disease (PAD) are associated with a higher risk of diabetes-related lower limb amputation. Timely identification of PAD with toe systolic blood pressure (TSBP) and toe-brachial pressure index (TBPI) is critical in order to implement foot protection strategies to prevent foot complications in people with ESRD. There is limited evidence describing the effect of haemodialysis on TSBP and TBPI. This study aimed to determine the variability of TSBP and TBPI during haemodialysis in people with ESRD, and to determine whether any observed variability differed between people with and without diabetes.

METHODS

TSBP and TBPI were taken before dialysis (T1), one hour into dialysis (T2) and in the last 15 min of dialysis (T3) during a single dialysis session. Linear mixed effects models were undertaken to determine the variability in TSBP and TBPI across the three time points and to determine whether this variability differed between people with and without diabetes.

RESULTS

Thirty participants were recruited, including 17 (57%) with diabetes and 13 (43%) with no diabetes. A significant overall reduction in TSBP was observed across all participants (P < 0.001). There was a significant reduction in TSBP between T1 and T2 (P < 0.001) and between T1 and T3 (P < 0.001). There was no significant overall change in TBPI over time (P = 0.62). There was no significant overall difference in TSBP between people with diabetes and people with no diabetes (mean difference [95% CI]: -9.28 [-40.20, 21.64], P = 0.54). There was no significant overall difference in TBPI between people with diabetes and people with no diabetes (mean difference [95% CI]: -0.01 [-0.17, 03.16], P = 0.91).

CONCLUSION

TSBP and TBPI are an essential part of vascular assessment of the lower limb. TBPI remained stable and TSBP significantly reduced during dialysis. Given the frequency and duration of dialysis, clinicians taking toe pressures to screen for PAD should be aware of this reduction and consider how this may have an impact on wound healing capacity and the development of foot related complications.

Activation of the Aryl Hydrocarbon Receptor in Muscle Exacerbates Ischemic Pathology in Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) accelerates the development of atherosclerosis, decreases muscle function, and increases the risk of amputation or death in patients with peripheral artery disease (PAD). However, the mechanisms underlying this pathobiology are ill-defined. Recent work has indicated that tryptophan-derived uremic solutes, which are ligands for AHR (aryl hydrocarbon receptor), are associated with limb amputation in PAD. Herein, we examined the role of AHR activation in the myopathy of PAD and CKD.

METHODS

AHR-related gene expression was evaluated in skeletal muscle obtained from mice and human PAD patients with and without CKD. AHRmKO (skeletal muscle-specific AHR knockout) mice with and without CKD were subjected to femoral artery ligation, and a battery of assessments were performed to evaluate vascular, muscle, and mitochondrial health. Single-nuclei RNA sequencing was performed to explore intercellular communication. Expression of the constitutively active AHR was used to isolate the role of AHR in mice without CKD.

RESULTS

PAD patients and mice with CKD displayed significantly higher mRNA expression of classical AHR-dependent genes (Cyp1a1, Cyp1b1, and Aldh3a1) when compared with either muscle from the PAD condition with normal renal function (P<0.05 for all 3 genes) or nonischemic controls. AHRmKO significantly improved limb perfusion recovery and arteriogenesis, preserved vasculogenic paracrine signaling from myofibers, increased muscle mass and strength, as well as enhanced mitochondrial function in an experimental model of PAD/CKD. Moreover, viral-mediated skeletal muscle-specific expression of a constitutively active AHR in mice with normal kidney function exacerbated the ischemic myopathy evidenced by smaller muscle masses, reduced contractile function, histopathology, altered vasculogenic signaling, and lower mitochondrial respiratory function.

CONCLUSIONS

These findings establish AHR activation in muscle as a pivotal regulator of the ischemic limb pathology in CKD. Further, the totality of the results provides support for testing of clinical interventions that diminish AHR signaling in these conditions.

TFOS Lifestyle: Impact of nutrition on the ocular surface

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

Chronic activation of the aryl hydrocarbon receptor in muscle exacerbates ischemic pathology in chronic kidney disease

Chronic kidney disease (CKD) accelerates the development of atherosclerosis, decreases muscle function, and increases the risk of amputation or death in patients with peripheral artery disease (PAD). However, the cellular and physiological mechanisms underlying this pathobiology are ill-defined. Recent work has indicated that tryptophan-derived uremic toxins, many of which are ligands for the aryl hydrocarbon receptor (AHR), are associated with adverse limb outcomes in PAD. We hypothesized that chronic AHR activation, driven by the accumulation of tryptophan-derived uremic metabolites, may mediate the myopathic condition in the presence of CKD and PAD. Both PAD patients with CKD and mice with CKD subjected to femoral artery ligation (FAL) displayed significantly higher mRNA expression of classical AHR-dependent genes ( Cyp1a1 , Cyp1b1 , and Aldh3a1 ) when compared to either muscle from the PAD condition with normal renal function ( P <0.05 for all three genes) or non-ischemic controls. Skeletal-muscle-specific AHR deletion in mice (AHR mKO ) significantly improved limb muscle perfusion recovery and arteriogenesis, preserved vasculogenic paracrine signaling from myofibers, increased muscle mass and contractile function, as well as enhanced mitochondrial oxidative phosphorylation and respiratory capacity in an experimental model of PAD/CKD. Moreover, viral-mediated skeletal muscle-specific expression of a constitutively active AHR in mice with normal kidney function exacerbated the ischemic myopathy evidenced by smaller muscle masses, reduced contractile function, histopathology, altered vasculogenic signaling, and lower mitochondrial respiratory function. These findings establish chronic AHR activation in muscle as a pivotal regulator of the ischemic limb pathology in PAD. Further, the totality of the results provide support for testing of clinical interventions that diminish AHR signaling in these conditions.

[Clinical Characteristics and Prognosis of Diabetic Foot Ulcers Patients of Different Renal Function Statuses]

Objective

To explore the clinical characteristics and the prognosis of diabetic foot ulcers (DFU) inpatients of different renal function statuses.

Methods

A retrospective analysis of 962 inpatients with DFU was conducted. The patients were divided into three groups according to their renal function statuses, and the clinical characteristics of the three groups were compared to identify differences. In addition, the patients were followed up in outpatient clinics or by telephone and their prognostic status and risk factors for death were analyzed.

Results

Analysis of the clinical characteristics showed that, compared with diabetic patients with normal renal function or mild renal function impairment, diabetic patients with moderate and severe renal function impairment had a longer course of disease ( P<0.001). Patients with foot ulcers of Wagner grade 4 predominates the moderate and severe renal function impairment groups ( P<0.05). Patients in the moderate and severe renal function impairment groups had a relatively higher proportion of comorbidities, including hypertension, coronary heart disease, and peripheral arterial disease ( P<0.05). These patients had relatively lower levels of glycosylated hemoglobin and hemoglobin (all P<0.05) and relatively higher levels of neutrophil ratio and procalcitonin (all P<0.05). Of the two groups, patients in the moderate renal function impairment group were older ( P<0.001) and had lower ankle-brachial index ( P<0.001). The severe renal function impairment group had a higher proportion of patients with foot ulcers of Wagner grades 3 and 5 (all P<0.05). For the purpose of conducting prognostic analysis, 748 patients were followed up in outpatient clinics or by telephone for a median length of 41 months. Among them, 239 died. The all-cause mortality was 31.9%, and the mortality in the three groups was 25.8%, 46.2% ( P<0.001), and 59.4% ( P<0.001), respectively. The survival rate of patients in the moderate and severe renal function impairment groups was significantly lower than those in the normal renal function and mild renal function impairment groups ( P<0.001). Univariate Cox regression analysis showed that age, concomitant coronary heart disease and peripheral arterial disease, degree of renal function impairment, and foot ulcers of Wagner grade 4 and 5 were associated with all-cause deaths. Furthermore, multivariate Cox regression analysis showed that moderate and severe renal function impairment was an independent risk factor for all-cause deaths in DFU patients ( P<0.001).

Conclusions

As renal function impairment worsens, patients with DFU present clinical characteristics of greater complexity, higher risks of cardiovascular events, and higher mortality. It is essential to prevent kidney damage and foot ulcers, to pay attention to the cardiovascular risks of DFU patients with moderate and severe renal function impairment, and to reduce mortality.

Diabetic foot disease in subjects with End-stage renal Disease: A nationwide study over 14 years highlighting an emerging threat

AIMS

To disclose prevalence, demographic, foot characteristics as well as management and lower-extremity amputations (LEAs) of subjects with end-stage renal disease (ESRD) on diabetic foot diseases (DFDs).

METHODS

Data were derived from the Taiwan National Health Insurance Research Database between 2004 and 2017. DFDs were defined as ulcers, infections, or severe peripheral arterial diseases (PADs) in patients with type 2 diabetes. Clinical characteristics were analyzed between subjects with and without ESRD.

RESULTS

Subjects with ESRD have increased impacts on the DFD population either from annual prevalence (2.7 % to 10.42 %, P for trend < 0.001), or proportional representation in LEAs (7.91 % to 26.37 %, P < 0.001) over 14 years. The annual trends for major-LEAs rates have decreased in both subjects with and without ESRD (13.67 % to 5.82 % and 3.48 % to 1.47 %, both P < 0.001). Notably, the concomitant increase of endovascular treatments (EVTs) (7.09 % to 29.41 %, P < 0.001) was associated with the decrease of major-LEAs (P for interaction < 0.001) in subjects with ESRD.

CONCLUSIONS

As the annual prevalence of subjects with ESRD has increased 3.9-fold over years, they now account for more than 30% of annual major-LEA of the total DFD population. Interdisciplinary team approach and aggressive EVTs might reduce major-LEAs in these patients.

Renal hemodynamic dysfunction and neuropathy in longstanding type 1 diabetes: Results from the Canadian study of longevity in type 1 diabetes

AIMS

To determine the relationship between renal hemodynamic function and neuropathy in adults with ≥50-years of type 1 diabetes (T1D) compared to nondiabetic controls.

METHODS

Glomerular filtration rate (GFR, inulin), effective renal plasma flow (ERPF, p-aminohippurate), modified Toronto Clinical Neuropathy Score (mTCNS), corneal confocal microscopy, nerve conduction, and heart rate variability (autonomic function) were measured; afferent (RA) and efferent (RE) arteriolar resistances were estimated using the Gomez equations in 74 participants with T1D and in 75 controls. Diabetic kidney disease (DKD) non-resistors were defined by eGFRMDRD < 60 ml/min/1.73 m2 or 24-h urine albumin excretion >30 mg/day. Linear regression was applied to examine the relationships between renal function (dependent variable) and neuropathy measures (independent variable), adjusted for age, sex, HbA1c, systolic blood pressure, low density lipoprotein cholesterol, and 24-h urine albumin to creatinine ratio.

RESULTS

Higher mTCNS associated with lower renal blood flow (β ± SE:-9.29 ± 4.20, p = 0.03) and greater RE (β ± SE:32.97 ± 15.43, p = 0.04) in participants with T1D, but not in controls. DKD non-resistors had a higher mTCNS and worse measures of corneal nerve morphology compared to those without DKD. Renal hemodynamic parameters did not associate with autonomic nerve function.

CONCLUSIONS

Although neurological dysfunction in the presence of diabetes may contribute to impaired renal blood flow resulting in ischemic injury in patients with T1D, early autonomic dysfunction does not appear to be associated with kidney function changes.

The value of administering intravenous antibiotics during haemodialysis in the treatment of diabetic foot infections

OBJECTIVE

People with diabetes who are on haemodialysis (HD) are at a high risk of diabetic foot infections (DFI) and related complications. We explored the value of treating DFI with intravenous (IV) antibiotics during HD.

METHOD

This was an observational study of consecutively treated patients with DFIs with IV antibiotics during HD. Data collected included baseline characteristics, IV antibiotics used, details of multidisciplinary interventions and DFI treatment outcome.

RESULTS

A cohort of 11 patients, mean (±standard deviation) age 62.4±12.7 years, had 15 episodes of treatment with IV antibiotics during HD. Of the patients, six (54.5%) were male and nine (81.8%) had type 2 diabetes. The estimated mean glomerular filtration rate (eGFR) was 11.4±3.9ml/minute. All patients had infected foot ulceration, soft tissue infection, six (54.5%) patients had osteomyelitis, and two (18.2%) had wet gangrene. The commonest IV antibiotic used was vancomycin (10/15 episodes, 66.7%). Other IV antibiotics used were daptomycin and meropenem. In three episodes, oral ciprofloxacin was used with IV antibiotics. The mean duration of antibiotic treatment was 9.2±4.9 weeks. Of the episodes, 11 (73.3%) were treated successfully with IV antibiotics alone and two (13.3%) episodes required minor surgical debridement/amputation. Some 10 (90.9%) members of the cohort had peripheral arterial disease and of those, five (50%) underwent angioplasty during IV antibiotic treatment.

CONCLUSION

HD provides a good opportunity for treatment with IV antibiotics in DFI. This mode of administration of IV antibiotics, along with multidisciplinary intervention, is associated with ulcer healing and resolution of infection in over three-quarters of patients with DFI.

DECLARATION OF INTEREST

The authors have no conflicts of interest to declare.

Dialysis Treatment is an Independent Risk Factor for Foot Morbidity

Aim: To determine the prevalence of foot morbidity among patients with ESRD on dialysis. Methods: A prospective, non-experimental, quantitative time series design was employed. Forty-seven participants were recruited in the study. Medical records were reviewed followed by non-invasive foot assessments which included: Neurological, Arterial, Biomechanical, and Dermatological Assessment. Participants were assessed twice during the study. Results: Foot morbidity was found to be high among participants with ESRD on dialysis. 95.74% of participants presented with foot deformities, 76.60% had skin and nail conditions. 15% of participants had a history of ulceration and amputation. Moreover, active ulceration and history of revascularisation were also observed. Findings demonstrated overall poor foot health and footcare behavior within this population with 40.43% of participants having inappropriate footwear. The majority of participants did not check feet regularly, did not attend to podiatry appointments, and were unable to reach their feet for self-care. The Toe Brachial Pressure Index (TBPI), Spectral Doppler Waveform Analysis, and the Quantitative Sensory Testing (QST) were re-measured at each visit. Monophasic continuous doppler waveforms increased while triphasic waveforms decreased during the study period. Protective sensation did not decrease during the study period. The mean TBPI decreased during the study period. The relationship between the TBPI and duration of dialysis was found to be significant. Both DM and dialysis duration were identified as significant predictors of reduction in TBPI. Conclusion: This study demonstrates a high prevalence of foot morbidity among patients with ESRD on dialysis. This study highlighted the importance of expanding practice by introducing a podiatry service within the renal unit to provide foot screening, foot assessments, and foot care education, with the aim to reduce severe foot complications.

Micro‐ and macrovascular complications and risk factors for foot ulceration and amputation in individuals receiving dialysis with and without diabetes

Introduction

This study examined the prevalence of microvascular and macrovascular complications in people receiving dialysis with and without diabetes and investigated independent risk factors for foot ulcers and lower‐extremity amputations.

Methods

We performed a cross‐sectional study of 119 individuals with diabetes and 219 individuals without diabetes receiving chronic dialysis during June 2019 at the Department of Nephrology, Rigshospitalet, University of Copenhagen, Denmark. Effects of diabetes and other risk factors were assessed by log‐binomial regression. Prevalence data were compared with a historical control group of 38 individuals with diabetes receiving dialysis examined in 2004 in the same department.

Results

We found that persons with diabetes had a twofold higher risk ratio of current (unadjusted risk ratio 2.2 [95% CI 1.1, 4.7]) and previous foot ulcer (2.5 [1.7, 3.7]) and a fourfold higher risk ratio of lower‐extremity amputation (4.2 [2.1, 8.6]) in comparison with persons without diabetes (all p < .05). Furthermore, persons with diabetes had a 70% increased risk ratio of myocardial infarction (1.7 [1.0–2.8], p = .041). In multivariable‐adjusted analysis, current foot ulcer was independently associated with previous foot ulcer (adjusted risk ratio 4.0 [95% CI 1.8, 8.9]), while lower‐extremity amputation was independently associated with diabetes (3.8 [1.8, 8.2]) and male sex (4.1 [1.5, 11.3]) (all p < .01).

Conclusions

Individuals with diabetes receiving dialysis had a higher prevalence of foot ulcer, lower‐extremity amputation and myocardial infarction compared to individuals without diabetes. Previous foot ulcer was the most important risk factor for current foot ulcer, while diabetes and male sex were important risk factors for lower‐extremity amputation.

Narrative Review of the Relationship Between CKD and Diabetic Foot Ulcer

Diabetic foot ulcer (DFU) and chronic kidney disease (CKD) are 2 significant complications of diabetes mellitus (DM). Up to 40% of patients with DM are expected to also develop CKD, and 19% to 34% will suffer from DFU during their lifetimes. However, data on the link between podiatric risk and the extent of CKD are scarce. Neuropathy, a key element of the International Working Group on the Diabetic Foot (IWGDF) classification, nevertheless appears to be related to the CKD stage. The incidence of DFU and its poor evolution also appear to be linked to the stage of CKD, with mortality reaching its peak in patients with end-stage renal disease (ESRD). Whatever, the decrease in the rate of diabetic foot amputation observed worldwide, especially for major amputations, is also observed in patients with ESRD. Specific actions taken for patients undergoing dialysis seems to improve the DFU prognosis. CKD and DFU share a number of elements of pathophysiology, the first of which is peripheral arterial disease (PAD). Uremic neuropathy and nutritional status also seem to create a link between the development of the 2 complications. This literature review provides an update on the complex and dynamic relationship between DFU and CKD. It examines the epidemiologic link between CKD and diabetic foot risk, CKD and DFU occurrence, and CKD and DFU prognosis. It focuses on the pathophysiological links between these 2 complications. Finally, it highlights the actions taken to improve management in the ESRD population that have reduced the rate of major amputations in this population by more than half.

An explainable machine learning model for predicting in-hospital amputation rate of patients with diabetic foot ulcer

Diabetic foot ulcer (DFU) is one of the most serious and alarming diabetic complications, which often leads to high amputation rates in diabetic patients. Machine learning is a part of the field of artificial intelligence, which can automatically learn models from data and better inform clinical decision‐making. We aimed to develop an accurate and explainable prediction model to estimate the risk of in‐hospital amputation in patients with DFU. A total of 618 hospitalised patients with DFU were included in this study. The patients were divided into non‐amputation, minor amputation or major amputation group. Light Gradient Boosting Machine (LightGBM) and 5‐fold cross‐validation tools were used to construct a multi‐class classification model to predict the three outcomes of interest. In addition, we used the SHapley Additive exPlanations (SHAP) algorithm to interpret the predictions of the model. Our area under the receiver‐operating‐characteristic curve (AUC) demonstrated a 0.90, 0.85 and 0.86 predictive ability for non‐amputation, minor amputation and major amputation outcomes, respectively. Taken together, our data demonstrated that the developed explainable machine learning model provided accurate estimates of the amputation rate in patients with DFU during hospitalisation. Besides, the model could inform individualised analyses of the patients' risk factors.

Factores asociados a las úlceras en miembros inferiores del paciente con enfermedad renal crónica en un centro de diálisis

Introducción: las personas adultas con enfermedad renal crónica (ERC) tienen mayor riesgo de presentar úlceras, especialmente en las extremidades inferiores. Sin embargo, existen datos limitados sobre la prevalencia y los factores asociados. Objetivo: determinar la prevalencia de úlceras en miembros inferiores y sus factores asociados en pacientes con enfermedad renal crónica que asisten a una institución de IV nivel de complejidad. Método: estudio de tipo observacional, transversal y analítico, la muestra fue de 561 participantes. Los instrumentos fueron una cha de datos sociodemográcos y de antecedentes, y el índice tobillo brazo (ITB). Resultados: los participantes fueron en su mayoría hombres (67%), con promedio de edad de 62 años; se encontró signicancia estadística (p < 0,05) entre las variables antecedente de diabetes, ITB bajo, haber tenido úlcera previa y presencia de úlcera en miembros inferiores. Conclusiones: estudiar este tipo de fenómenos en unidades de cuidado renal se convierte en una necesidad debido a la alta prevalencia y a los factores de riesgo asociados. Esto permite la planicación de estrategias encaminadas a la prevención.  

Prevalence and risk factors of peripheral artery disease in a population with chronic kidney disease in Australia: A systematic review and meta-analysis

There is a lack of clarity and guidance for screening peripheral artery disease (PAD) in persons with chronic kidney disease (CKD) and end stage kidney disease (ESKD) despite this group being at excess risk of cardiovascular disease (CVD). In this current study, we performed a systematic review and meta-analysis to examine the prevalence and risk factors for PAD in persons with CKD in Australian cohorts. We used the inverse variance heterogeneity meta-analysis with double arcsine transformation to summarize the prevalence of PAD (with 95% CIs). Nine studies and 18 reports from the Australia and New Zealand dialysis and transplant registry with 36 cohorts were included in the review. We found a substantially higher PAD prevalence in cohorts based on an ankle-brachial index (ABI) or toe systolic pressure (TBI) than cohorts based on self-reported history. Higher PAD prevalence was observed in ESKD persons than CKD persons without dialysis (PAD diagnosis based on ABI or TBI: 31% in ESKD persons and 23% in CKD persons, PAD diagnosis based on self-reported history: 17% in ESKD persons and 10% in CKD persons). Older age, Caucasian race, cerebrovascular disease and haemodialysis were associated with the presence of PAD in ESKD persons. Our findings indicated a considerable proportion of PAD in CKD and ESKD persons particularly in those with ESKD. To develop and provide an adequate plan to clinically manage CKD patients with PAD, evidence of cost-effectiveness and clinical benefit of early detection of PAD in persons with CKD in Australia is recommended for future studies.

The association of estimated glomerular filtration rate with outcomes following infrainguinal bypass for peripheral arterial disease

OBJECTIVE

Chronic kidney disease (CKD) is a recognized predictor of long-term survival, frequently coexisting with peripheral arterial disease (PAD). Estimated glomerular filtration rate (eGFR) is a more accurate marker of renal function than creatinine. This study sought to determine the graded impact of CKD, defined by eGFR, on infrainguinal lower extremity bypass (LEB) outcomes.

METHODS

This retrospective study examined 44,332 patients from the Vascular Quality Initiative database who underwent LEB between January 2003 and November 2019. The GFR was estimated using the Modification of Diet in Renal Disease equation. Multivariable logistic regression was used to study perioperative mortality and Kaplan-Meier survival estimation and multivariable Cox regression were used to evaluate 5-year mortality, 1-year major amputation, and major amputation/death.

RESULTS

The 30-day mortality odds was increased for CKD 3 (odds ratio [OR], 1.58; 95% confidence interval [CI], 1.32-1.91; P < .001) and CKD 5 (OR, 3.08; 95% CI, 2.45-3.87; P < .001) relative to CKD 1 to 2. Comparing CKD stages 3, 4, and 5 with CKD 1 and 2, there was a stepwise increase in the adjusted hazard of 5-year mortality (hazard ratio [HR], 1.18; 95% CI, 1.09-1.27; P < .001), (HR, 1.73; 95% CI; 1.47-2.03; P < .001) and (HR, 2.58; 95% CI, 2.33-3.84; P < .001), respectively. Although the risk of 1-year death or major amputation did not differ for CKD 3 compared with CKD 1, this was 50% higher for CKD 4 (HR, 1.50; 95% CI, 1.26-1.78; P < .001) and doubled for CKD 5 (HR, 2.07; 95% CI, 1.87-2.29; P < .001) compared with CKD 1 and 2. The adjusted HR for major amputation in 1 year was 0.81 (95% CI, 0.71-0.92; P = .002), 1.14 (95% CI, 0.84-1.54; P = .396) and 1.56 (95% CI,1.31-1.84; P < .001) for CKD 3, 4, and 5, respectively, compared with CKD 1 and 2.

CONCLUSIONS

The estimated GFR is a useful predictor of postoperative mortality, overall survival, and/or amputation after LEB in patients with PAD. It should be considered in the preoperative risk-benefit analysis process to guide patient selection in the population with concomitant PAD and CKD being considered for LEB.

Lower Limb Ulcer Associated with Peritonitis in Patients Undergoing Peritoneal Dialysis

Purpose

Peritoneal dialysis (PD)-related peritonitis and lower limb ulcer are the important complications in patients undergoing PD. Although the association between lower limb ulcer and peritonitis in patients undergoing PD is unclear, based on our clinical experience and the clinical importance of the complications in patients undergoing PD, we hypothesized that lower limb ulcer is associated with peritonitis in patients on PD.

Patients and Methods

In this single center, retrospective cohort study, we studied 87 patients who started undergoing PD at our hospital from April 2015 to March 2020. We compared these 8 patients with lower limb ulcer with the other 79 patients without lower limb ulcer. We compared between the patients in the objection period of this study about peritonitis using Log rank test, and used the unpaired t-test and Fisher’s exact test to compare the clinical factors between the two groups. Moreover, we used univariate and multivariate logistic regression analyses to study the association of PD-related peritonitis with the clinical factors.

Results

The period developed first peritonitis of the patients on PD with lower limb ulcer was significant shorter than those without lower limb ulcer in Log rank test (P = 0.011). The Fisher’s exact test and unpaired t-test showed that the difference in the prevalence of PD-related peritonitis (P = 0.009), peritonitis/patient years (P = 0.036), the BMI (P = 0.007) and icodextrin (P = 0.001) were significant. Lower limb ulcer had significant associations with peritonitis in patients on PD in both univariate [odds ratio (OR) 8.461, 95% confidence interval (CI) 1.854–45.60, P = 0.006] and multivariate [OR 7.169, 95% CI 1.519–39.480, P = 0.013] logistic regression analysis.

Conclusion

In conclusion, lower limb ulcer may be associated with peritonitis in patients undergoing PD. Further large-scale, prospective studies are required to confirm these results.

Indoxyl sulfate impairs angiogenesis via chronic aryl hydrocarbon receptor activation

Chronic kidney disease (CKD) is associated with a substantial increased risk of cardiovascular disease. There is growing evidence that uremic metabolites, which accumulate in the blood with CKD, have detrimental impacts on endothelial cell health and function. However, the molecular mechanisms by which uremic metabolites negatively impact endothelial cell biology are not fully understood. In this study, activation of the aryl hydrocarbon receptor (AHR) via indoxyl sulfate, a known uremic metabolite, was found to impair endothelial cell tube formation and proliferation but not migratory function. Moreover, aortic ring cultures treated with indoxyl sulfate also exhibited decreased sprouting and high AHR activation. Next, genetic knockdown of the AHR using shRNA was found to rescue endothelial cell tube formation, proliferation, and aortic ring sprouting. Similarly, pharmacological AHR antagonism using resveratrol and CH223191 were also found to rescue angiogenesis in cell and aortic ring cultures. Finally, a constitutively active AHR (CAAHR) vector was generated and used to confirm AHR-specific effects. Expression of the CAAHR recapitulated the impaired tube formation and proliferation in cultured endothelial cells and decreased sprouting in aortic ring cultures. Taken together, these data define the impact of AHR activation on angiogenesis and highlight the potential for therapeutic AHR antagonists, which may improve angiogenesis in the context of CKD and cardiovascular disease.

Intradialytic Hypotension and Newly Recognized Peripheral Artery Disease in Patients Receiving Hemodialysis

RATIONALE & OBJECTIVE

Intradialytic hypotension (IDH) may decrease systemic circulation to the legs, exacerbating symptoms of peripheral artery disease (PAD). We sought to evaluate the relationship between IDH and newly recognized lower extremity PAD among hemodialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Linking data from the US Renal Data System to the electronic health records of a large dialysis provider, we identified adult patients (≥18 years of age) with Medicare Parts A and B who initiated dialysis (2006-2011) without previously recognized PAD.

EXPOSURE

The time-varying proportion of hemodialysis sessions with IDH defined as the nadir intradialytic systolic blood pressure <90 mm Hg. We categorized the proportion of sessions with IDH within serial 30-day intervals as 0%, >0% to <15%, 15% to <30%, and ≥30%.

OUTCOMES

Newly recognized PAD was ascertained using PAD diagnostic and procedure codes for amputation or revascularization, in serial 30-day intervals subsequent to each 30-day exposure interval.

ANALYTICAL APPROACH

To account for the competing risks of death and kidney transplantation, we estimated unadjusted and adjusted subdistribution hazard ratios using the Kaplan-Meier multiple imputation method in combination with the extended Cox model to account for IDH as a time-varying exposure.

RESULTS

Among 45,591 patients, those with more frequent baseline IDH had a higher prevalence of cardiovascular diseases. During 61,725 person-years of follow-up, 7,886 patients had newly recognized PAD. We found a graded, direct association between IDH and newly recognized PAD. For example, having IDH in ≥30% of dialysis sessions during a given 30-day interval (vs 0%) was associated with a 24% (95% CI, 17%-32%) higher hazard than having newly recognized PAD in the subsequent 30 days.

LIMITATIONS

Unmeasured confounding; ascertainment of PAD from claims.

CONCLUSIONS

Patients receiving hemodialysis who had more frequent IDH had higher rates of newly recognized PAD. Patients with frequent IDH may warrant careful examination for PAD.

Infrared dermal thermometry is highly reliable in the assessment of patients with Charcot neuroarthropathy

BACKGROUND

Charcot neuroarthropathy (Charcot foot) is a serious limb-threatening complication most commonly seen in individuals with diabetic peripheral neuropathy. Although dermal thermometry is widely used by clinicians to assist in the diagnosis, monitoring, and management of the disease, there is limited high-quality evidence to support its reliability. Therefore, this study investigated the intra-rater and inter-rater reliability of infrared dermal thermometry in patients with Charcot neuroarthropathy.

METHODS

We collected clinical, demographic, health status, and foot examination information on 32 adults with Charcot neuroarthropathy from a metropolitan high-risk foot service in Melbourne, Australia. Infrared dermal thermometry assessments were conducted by two independent raters at 10 anatomical sites of the Charcot foot using both a (i) touch and (ii) non-touch technique. Intra-rater and inter-rater reliability of the two assessment techniques were evaluated using intra-class correlation coefficients (ICCs), limits of agreement, standard error of measurement, and minimal detectable change statistics.

RESULTS

Mean age was 59.9 (standard deviation [SD], 10.5) years, 68.8% were male, average duration of diabetes was 20.6 (SD, 15.1) years, 71.9% had type 2 diabetes, 93.8% had peripheral neuropathy, 43.8% had peripheral arterial disease, and 50% had previous foot ulceration. Charcot foot most commonly affected the tarsometatarsal joints (38.9%), had a median duration of 2.8 (interquartile range [IQR], 1.3 to 5.9) months, and a large proportion were being treated with total contact casting (69.4%). Overall, there was good to excellent intra-rater and inter-rater relative reliability for the 'touch' technique (ICC, 0.87 to 0.99; ICC, 0.83 to 0.98, respectively), and excellent intra-rater and inter-rater relative reliability for the 'non-touch' technique (ICC, 0.93 to 0.99; ICC, 0.91 to 0.99, respectively). In addition, measurement error was found to be relatively low across the 10 anatomical sites.

CONCLUSIONS

Infrared dermal thermometry can now be used with confidence in clinical and research settings to provide a reliable assessment of skin temperature in patients with Charcot neuroarthropathy, using either a touch or non-touch technique at 10 commonly used testing sites. A non-touch technique, however, was observed to have slightly higher reliability indicating it may be associated with less measurement error than the touch technique.

How ESKD complicates the management of diabetic foot ulcers: The vital role of the dialysis team in prevention, early detection, and support of multidisciplinary treatment to reduce lower extremity amputations

Diabetic foot ulcers do not heal as well in ESKD as in the absence of kidney failure, and rates of recurrent foot ulcers, as well as lower extremity amputation, are higher. This review of the literature highlights the vital role of the dialysis team in prevention, early detection, and support of treatment of diabetic foot ulcers. Our review has five goals-(a) increase nephrologists' understanding of the high morbidity and mortality associated with chronic foot ulcers and (lower extrimity) LE amputations in ESKD; (b) promote nephrologists' understanding of grading systems for diabetic foot ulcer severity, in order to expedite communication with local diabetic foot experts; (c) promote collaboration between nephrologists and infectious disease specialists regarding the dose, route, and delivery logistics of intravenous antibiotics for infected chronic foot ulcers, in particular in the presence of osteomyelitis and other deep-seated infections; (d) increase the awareness of dialysis nurses, technicians, dietitians, social workers and administrators regarding evidence-based and multidisciplinary approaches to patients' diabetic foot ulcers; (e) encourage the application of published works integrating patient-centered diabetic foot education into the dialysis setting to reduce lower extremity amputations.

Prevention of foot ulcers in the at-risk patient with diabetes: a systematic review

Prevention of foot ulcers in patients with diabetes is important to help reduce the substantial burden on both patient and health resources. A comprehensive analysis of reported interventions is needed to better inform healthcare professionals about effective prevention. The aim of this systematic review is to investigate the effectiveness of interventions to help prevent both first and recurrent foot ulcers in persons with diabetes who are at risk for this complication. We searched the available medical scientific literature in PubMed, EMBASE, CINAHL, and the Cochrane databases for original research studies on preventative interventions. We screened trial registries for additional studies not found in our search and unpublished trials. Two independent reviewers assessed data from controlled studies for methodological quality, and extracted and presented this in evidence and risk of bias tables. From the 13,490 records screened, 35 controlled studies and 46 non-controlled studies were included. Few controlled studies, which were of generally low to moderate quality, were identified on the prevention of a first foot ulcer. For the prevention of recurrent plantar foot ulcers, there is benefit for the use of daily foot skin temperature measurements, and for therapeutic footwear with demonstrated plantar pressure relief, provided it is consistently worn by the patient. For prevention of ulcer recurrence, there is some evidence for providing integrated foot care, and no evidence for a single session of education.Surgical interventions have been shown effective in selected patients, but the evidence base is small. Foot-related exercises do not appear to prevent a first foot ulcer. A small increase in the level of weight-bearing daily activities does not seem to increase the risk for foot ulceration. The evidence base to support the use of specific self-management and footwear interventions for the prevention of recurrent plantar foot ulcers is quite strong. The evidence is weak for the use of other, sometimes widely applied, interventions, and is practically non-existent for the prevention of a first foot ulcer and non-plantar foot ulcer.

Corneal nerve fiber loss in diabetes with chronic kidney disease

AIMS

Patients with chronic kidney disease (CKD) in type 2 diabetes typically manifest with severe peripheral neuropathy. Corneal confocal microscopy is a novel technique that may serve as a marker of nerve injury in peripheral neuropathy. This study examines the changes that occur in corneal nerve morphology as a result of peripheral neuropathy due to renal dysfunction in people with type 2 diabetes.

METHODS

Sixty-two participants (mean age, 62 ± 12 years) with type 2 diabetes and 25 age-matched healthy controls underwent a comprehensive assessment of neuropathy using the total neuropathy score (TNS). The corneal sub-basal nerve plexus was imaged using corneal confocal microscopy. Corneal nerve fiber length, fiber density, branch density, total branch density, nerve fractal dimension, inferior whorl length and inferior whorl nerve fractal dimension were quantified. Based on the eGFR, participants were classified into those with diabetic CKD (eGFR < 60; n = 22) and those without CKD (eGFR ≥ 60; n = 40).

RESULTS

Participants with diabetic CKD had significantly lower corneal nerve fiber density (P = 0.037), length (P = 0.036) and nerve fractal dimension (P = 0.036) compared to those without CKD. Multiple linear regression analysis revealed that reduced corneal nerve fiber density (ß coefficient = 0.098, P = 0.017), length (ß coefficient = 0.006, P = 0.008) and nerve fractal dimension (ß coefficient = 0.001, P = 0.007) was associated with low eGFR levels when adjusted for age, duration of diabetes and severity of neuropathy.

CONCLUSION

Corneal confocal microscopy detects corneal nerve loss in patients with diabetic CKD and reduction in corneal nerve parameters is associated with the decline of kidney function.

Risk factors for foot ulceration in adults with end-stage renal disease on dialysis: a prospective observational cohort study

Background

Dialysis patients experience high rates of foot ulceration. Although risk factors for ulceration have been extensively studied in patients with diabetes, there is limited high-quality, longitudinal evidence in the dialysis population. Therefore, this study investigated risk factors for foot ulceration in a stable dialysis cohort.

Methods

We prospectively collected clinical, demographic, health status, and foot examination information on 450 adults with end-stage renal disease from satellite and home-therapy dialysis units in Melbourne, Australia over 12 months. The primary outcome was foot ulceration. Cox proportional hazard modelling and multinomial regression were used to investigate risk factors.

Results

Among 450 dialysis patients (mean age, 67.5 years; 64.7% male; 94% hemodialysis; 50.2% diabetes), new cases of foot ulceration were identified in 81 (18%) participants. Overall, risk factors for foot ulceration were neuropathy (HR 3.02; 95% CI 1.48 to 6.15) and previous ulceration (HR 2.86; CI 1.53 to 5.34). In those without history of ulceration, nail pathology (RR 3.85; CI 1.08 to 13.75) and neuropathy (RR 2.66; CI 1.04 to 6.82) were risk factors. In those with history of ulceration, neuropathy (RR 11.23; CI 3.16 to 39.87), peripheral arterial disease (RR 7.15; CI 2.24 to 22.82) and cerebrovascular disease (RR 2.08; CI 1.04 to 4.16) were risk factors. There were 12 (2.7%) new amputations, 96 (21.3%) infections, 24 (5.3%) revascularizations, 42 (9.3%) foot-related hospitalizations, and 52 (11.6%) deaths.

Conclusions

Neuropathy and previous ulceration are major risk factors for foot ulceration in dialysis patients. Risk factors differ between those with and without prior ulceration. The risk factors identified will help to reduce the incidence of ulceration and its associated complications.

Chronic kidney disease exacerbates ischemic limb myopathy in mice via altered mitochondrial energetics

Chronic kidney disease (CKD) substantially increases the severity of peripheral arterial disease (PAD) symptomology, however, the biological mechanisms remain unclear. The objective herein was to determine the impact of CKD on PAD pathology in mice. C57BL6/J mice were subjected to a diet-induced model of CKD by delivery of adenine for six weeks. CKD was confirmed by measurements of glomerular filtration rate, blood urea nitrogen, and kidney histopathology. Mice with CKD displayed lower muscle force production and greater ischemic lesions in the tibialis anterior muscle (78.1 ± 14.5% vs. 2.5 ± 0.5% in control mice, P < 0.0001, N = 5-10/group) and decreased myofiber size (1661 ± 134 μm2 vs. 2221 ± 100 μm2 in control mice, P < 0.01, N = 5-10/group). This skeletal myopathy occurred despite normal capillary density (516 ± 59 vs. 466 ± 45 capillaries/20x field of view) and limb perfusion. CKD mice displayed a ~50-65% reduction in muscle mitochondrial respiratory capacity in ischemic muscle, whereas control mice had normal mitochondrial function. Hydrogen peroxide emission was modestly higher in the ischemic muscle of CKD mice, which coincided with decreased oxidant buffering. Exposure of cultured myotubes to CKD serum resulted in myotube atrophy and elevated oxidative stress, which were attenuated by mitochondrial-targeted therapies. Taken together, these findings suggest that mitochondrial impairments caused by CKD contribute to the exacerbation of ischemic pathology.

Excess risk of lower extremity amputations in people with type 1 diabetes compared with the general population: amputations and type 1 diabetes

OBJECTIVE

This study investigates how the excess risk of lower extremity amputations (amputations) in people with type 1 diabetes mellitus (DM) differs from the general population by diabetes duration, glycemic control, and renal complications.

RESEARCH DESIGN AND METHODS

We analyzed data from people with type 1 DM from the Swedish National Diabetes Register without prior amputation from January 1998 to December 2013. Each person (n=36 872) was randomly matched with five controls by sex, age, and county (n=184 360) from the population without diabetes. All were followed until first amputation, death or end of follow-up.

RESULTS

The overall adjusted HR for all amputation was 40.1 (95% CI 32.8 to 49.1) for type 1 DM versus controls. HR increased with longer diabetes duration. The incidence of amputation/1000 patient-years was 3.18 (95% CI 2.99 to 3.38) for type 1 DM and 0.07 (95% CI 0.05 to 0.08) for controls. The incidence decreased from 1998-2001 (3.09, 95% CI 2.56 to 3.62) to 2011-2013 (2.64, 95% CI 2.31 to 2.98). The HR for major amputations was lower than for minor amputations and decreased over the time period (p=0.0045). Worsening in glycemic control among patients with diabetes led to increased risk for amputation with an HR of 1.80 (95% CI 1.72 to 1.88) per 10 mmol/mol (1%) increase in hemoglobin A1c.

CONCLUSIONS

Although the absolute risk of amputation is relatively low, the overall excess risk was 40 times that of controls. Excess risk was substantially lower for those with good glycemic control and without renal complications, but excess risk still existed and is greatest for minor amputations.

Trends in Rates of Lower Extremity Amputation Among Patients With End-stage Renal Disease Who Receive Dialysis

IMPORTANCE

Patients with end-stage renal disease (ESRD) who receive dialysis are at high risk of lower extremity amputation. Recent studies indicate decreasing rates of lower extremity amputation in non-ESRD populations, but contemporary data for patients with ESRD who receive dialysis are lacking.

OBJECTIVES

To assess rates of lower extremity amputation among patients with ESRD who receive dialysis during a recent 15-year period; to analyze whether those rates differed by age, sex, diabetes, or geographic region; and to determine 1-year mortality rates in this population after lower extremity amputation.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective study of 3 700 902 records obtained from a US national registry of patients with ESRD who receive dialysis assessed cross-sectional cohorts for each calendar year from 2000 through 2014. Adult patients with prevalent ESRD treated with hemodialysis or peritoneal dialysis covered by Medicare Part A and B on January 1 of each cohort year were included. Data analysis was conducted from August 2017 to April 2018.

EXPOSURES

Age, sex, diabetes, and hospital referral region.

MAIN OUTCOMES AND MEASURES

Annual rates per 100 person-years of nontraumatic major (above- or below-knee) and minor (below-ankle) amputations.

RESULTS

For each annual cohort, there were fewer women (47.5% in 2000, 46.2% in 2005, 44.9% in 2010, and 44.0% in 2014) than men, more than half the patients were white individuals (58.1% in 2000, 56.9% in 2005, 56.9% in 2010, and 56.7% in 2014), and a small proportion were employed (13.9% in 2000, 15.1% in 2005, 16.1% in 2010, and 16.5% in 2014). The rate of lower extremity amputations for patients with ESRD who receive dialysis decreased by 51.0% from 2000 to 2014, driven primarily by a decrease in the rate of major amputations (5.42 [95% CI, 5.28-5.56] in 2000 vs 2.66 [95% CI, 2.59-2.72] per 100 person-years in 2014). Patients with diabetes had amputation rates more than 5 times as high as patients without diabetes. Patients younger than 65 years had higher adjusted amputation rates than older patients, and men had consistently higher adjusted amputation rates than women. Adjusted 1-year mortality rates after lower extremity amputation for patients with ESRD who receive dialysis decreased from 52.2% (95% CI, 50.9%-53.4%) in 2000 to 43.6% (95% CI, 42.5%-44.8%) in 2013. In general, amputation rates decreased among all regions from 2000 to 2014, but regional variability persisted across time despite adjustment for differences in patient demographics and comorbid conditions.

CONCLUSIONS AND RELEVANCE

Although rates of lower extremity amputations among US patients with ESRD who receive dialysis decreased by 51% during a recent 15-year period, mortality rates remained high, with nearly half of patients dying within a year after lower extremity amputation. Our results highlight the need for more research on ways to prevent lower extremity amputation in this extremely high-risk population.

Topical epidermal growth factor spray for the treatment of chronic diabetic foot ulcers: A phase III multicenter, double-blind, randomized, placebo-controlled trial

AIMS

This study was conducted to evaluate the efficacy and safety of a novel spray-applied growth factor therapy containing recombinant human epidermal growth factor (rhEGF) for the treatment of chronic diabetic foot ulcers (DFU).

METHODS

This study was a phase III double-blind, randomized, placebo-controlled trial. 167 adult patients at six medical centers were randomized to receive routine wound care plus either topical spray treatment with 0.005% rhEGF (n = 82) or an equivalent volume of saline spray (n = 85) twice a day until ulcer healing or for up to 12 weeks.

RESULTS

Demographics, medical status, and wound characteristics were comparable between rhEGF and placebo groups. More patients in the rhEGF group significantly had complete wound healing compared to placebo (73.2% versus 50.6%, respectively; P = .001). Wound healing velocity was faster in the rhEGF group (P = .029) regardless of HbA1c levels. The rhEGF group had a shorter median time to 50% ulcer size reduction (21 versus 35 days; hazard ratio = 3.13, P < .001) and shorter time to complete ulcer healing (56 versus 84 days; hazard ratio = 2.13, P < .001).

CONCLUSIONS

This study confirms that application of spray-applied rhEGF in DFU patients results in faster healing velocity and higher complete healing rate regardless of HbA1c levels.

Influence of micro- and macro-vascular disease and Tumor Necrosis Factor Receptor 1 on the level of lower-extremity amputation in patients with type 2 diabetes

BACKGROUND

Patients with type 2 diabetes (T2D) face a high amputation rate. We investigated the relationship between the level of amputation and the presence of micro or macro-vascular disease and related circulating biomarkers, Tumor Necrosis Factor Receptor 1 (TNFR1) and Angiopoietin like-2 protein (ANGPTL2).

METHODS

We have analyzed data from 1468 T2D participants in a single center prospective cohort (the SURDIAGENE cohort). Our outcome was the occurrence of lower limb amputation categorized in minor (below-ankle) or major (above ankle) amputation. Microvascular disease was defined as a history of albuminuria [microalbuminuria: uACR (urinary albumine-to-creatinine ratio) 30-299 mg/g or macroalbuminuria: uACR ≥ 300 mg/g] and/or severe diabetic retinopathy or macular edema. Macrovascular disease at baseline was divided into peripheral arterial disease (PAD): peripheral artery revascularization and/or major amputation and in non-peripheral macrovascular disease: coronary artery revascularization, myocardial infarction, carotid artery revascularization, stroke. We used a proportional hazard model considering survival without minor or major amputation.

RESULTS

During a median follow-up period of 7 (0.5) years, 79 patients (5.5%) underwent amputation including 29 minor and 50 major amputations. History of PAD (HR 4.37 95% CI [2.11-9.07]; p < 0.001), severe diabetic retinopathy (2.69 [1.31-5.57]; p = 0.0073), male gender (10.12 [2.41-42.56]; p = 0.0016) and serum ANGPTL2 concentrations (1.25 [1.08-1.45]; p = 0.0025) were associated with minor amputation outcome. History of PAD (6.91 [3.75-12.72]; p < 0.0001), systolic blood pressure (1.02 [1.00-1.03]; p = 0.004), male gender (3.81 [1.67-8.71]; p = 0.002), and serum TNFR1 concentrations (HR 13.68 [5.57-33.59]; p < 0.0001) were associated with major amputation outcome. Urinary albumin excretion was not significantly associated with the risk of minor and major amputation.

CONCLUSIONS

This study suggests that the risk factors associated with the minor vs. major amputation including biomarkers such as TNFR1 should be considered differently in patients with T2D.