Prevalence of polyneuropathy in pre-diabetes and diabetes is associated with abdominal obesity and macroangiopathy: the MONICA/KORA Augsburg Surveys S2 and S3

Obesity-related neuropathy: the new epidemic

PURPOSE OF REVIEW

To examine the evidence evaluating the association between obesity and neuropathy as well as potential interventions.

RECENT FINDINGS

Although diabetes has long been associated with neuropathy, additional metabolic syndrome components, including obesity, are increasingly linked to neuropathy development, regardless of glycemic status. Preclinical rodent models as well as clinical studies are shedding light on the mechanisms of obesity-related neuropathy as well as challenges associated with slowing progression. Dietary and surgical weight loss and exercise interventions are promising, but more data is needed.

SUMMARY

High-fat-diet rodent models have shown that obesity-related neuropathy is a product of excess glucose and lipid accumulation leading to inflammation and cell death. Clinical studies consistently demonstrate obesity is independently associated with neuropathy; therefore, likely a causal risk factor. Dietary weight loss improves neuropathy symptoms but not examination scores. Bariatric surgery and exercise are promising interventions, but larger, more rigorous studies are needed. Further research is also needed to determine the utility of weight loss medications and ideal timing for obesity interventions to prevent neuropathy.

Sheffield One-Stop Service: A potential model to improve the screening uptake of diabetic peripheral neuropathy and other microvascular complications of diabetes

The world is experiencing an enormous rise in the prevalence of diabetes, which is associated with massive healthcare costs that threaten to overwhelm many healthcare systems. Most of the diabetes expenditure is attributed to the management of chronic diabetes complications, including diabetic peripheral neuropathy (DPN)/diabetic foot complications, chronic kidney disease, sight-threatening retinopathy and cardiovascular diseases. Of these complications, the most overlooked is DPN. Most consultations around the world do not even involve taking off shoes and socks to carry out a foot examination, and even when carried out, the peripheral neurological examination using the 10-g monofilament diagnoses DPN when it is already at an advanced stage. Thus, all too often diabetes complications are diagnosed late, resulting in devastating outcomes, particularly in low- to middle-income countries. There is, therefore, an urgent need to instigate new strategies to improve microvascular screening uptake using a holistic protocol for annual diabetes health checks outside the busy diabetes clinic. One such approach, the Sheffield One-Stop Microvascular Screening Service, which involves modern point of care devices to diagnose DPN, has been shown to be feasible and effective, resulting in high uptake and early management of diabetes complications. This article outlines the advantages of this One-Stop Microvascular Screening Service and a plan to trial an adapted version of this service to a resource-limited country, the Philippines. If successful, this model has the potential for implementation in other countries around the world.

Correlations between distal sensorimotor polyneuropathy and cardiovascular complications in diabetic patients in the North-Eastern region of Hungary

Distal sensorimotor polyneuropathy (DSPN) is the earliest detectable and the most frequent microvascular complication in diabetes mellitus. Several studies have previously demonstrated correlations between cardiovascular risk factors in diabetic patients and independent risk factors for diabetic neuropathy. Our objective was to retrospectively analyze data from diabetic patients in the North-East region of Hungary who underwent neuropathy screening at the Diabetic Neuropathy Center, University of Debrecen, between 2017 and 2021. We aimed to investigate the correlations between cardiovascular risk factors and microvascular complications among patients with DSPN. The median age of the patients was 67 years, 59,6% were female, and 91,1% had type 2 diabetes. The prevalence of DSPN among the study subjects was 71.7%. A significantly longer duration of diabetes (p<0.01) was noted in patients with DSPN. Those with DSPN demonstrated a significantly higher HbA1c level (p<0.001) and a greater frequency of insulin use (p = 0.001). We observed a significantly elevated albumin/creatinine ratio (p<0.001) and a significantly lower eGFR (p<0.001) in patients with DSPN. Diabetic retinopathy exhibited a significantly higher prevalence in patients with DSPN (p<0.001). A higher prevalence of myocardial infarction (p<0.05), ischemic heart disease (p<0.001), peripheral arterial disease (p<0.05) and a history of atherosclerosis (p<0.05) was observed in patients with DSPN. In a multivariate logistic regression analysis, the following factors were independently associated with the presence of DSPN: higher HbA1c (OR:2.58, 95% CI:1.89-3.52, p<0.001), age (OR:1.03, 95% CI:1.01-1.05, p = 0.006), albumin/creatinine ratio above 3 mg/mmol (OR:1.23, 95% CI:1.06-1.45, p = 0.008), retinopathy (OR:6.06, 95% CI:1.33-27.53, p = 0.02), and composite cardiovascular endpoint (OR:1.95, 95% CI:1.19-3.19, p = 0.008). Our study revealed that age, elevated HbA1c levels, significant albuminuria, retinopathy, and cardiovascular complications may increase the risk of DSPN. Further investigation of these associations is necessary to understand the impact of patient characteristics during the treatment of diabetic neuropathy.

Prediabetes: A Benign Intermediate Stage or a Risk Factor in Itself?

Prediabetes is a condition when the blood glucose levels are above the normal range but below the threshold for defining diabetes. Previously considered benign, it is now recognized to be associated with various macrovascular and microvascular complications, with increases in the risk of cardiovascular events, nephropathy neuropathy, and retinopathy. Early identification of prediabetics may help detect the risk for these future complications at an earlier stage. Moreover, therapeutic options for prediabetes are available, which can retard its progression to diabetes and the subsequent development of complications. Hence, we make a case for the early identification of prediabetes through screening methods and appropriate institution of management strategies.

Contemporary prevalence of diabetic neuropathies in individuals with type 1 and type 2 diabetes in a Danish tertiary outpatient clinic

BACKGROUND

Population-based prevalence estimates of distal symmetric polyneuropathy (DPN) and diabetic autonomic neuropathy (DAN) are scares. Here we present neuropathy estimates and describe their overlap in a large cohort of people with type 1 and type 2 diabetes.

METHODS

In a large population of outpatient participants, DPN was assessed using vibration perception threshold, sural nerve function, touch, pain and thermal sensation. Definite DPN was defined by the Toronto Consensus Criteria. Painful DPN was defined by Douleur Neuropathique 4 Questions. DAN measures were: cardiovascular reflex tests, electrochemical skin conductance, and gastroparesis cardinal symptom index.

RESULTS

We included 822 individuals with type 1 (mean age (±SD) 54 ± 16 years, median [IQR] diabetes duration 26 [15-40] years) and 899 with type 2 diabetes (mean age 67 ± 11 years, median diabetes duration 16 [11-22] years). Definite DPN was prevalent in 54 % and 68 %, and painful DPN was in 5 % and 15 % of type 1 and type 2 participants, respectively. The prevalence of DAN varied between 6 and 39 % for type 1 and 9-49 % for type 2 diabetes. DPN without other neuropathy was present in 45 % with T1D and 50 % with T2D.

CONCLUSION

The prevalence of DPN and DAN was high. DPN and DAN co-existed in only 50 % of cases.

Evidence mapping of traditional Chinese medicine in diabetic peripheral neuropathy treatment

Objective: Diabetic peripheral neuropathy (DPN) stands as a crucial complication of diabetes, significantly affecting patients' quality of life. This study aims to elucidate the evidence distribution from clinical randomized controlled trials (RCTs) on DPN treatment with traditional Chinese medicine (TCM) through evidence mapping. Methods: A comprehensive search was conducted from January 2017 to October 2022 in databases such as Wanfang (China Online Journals), CNKI (China National Knowledge Infrastructure), VIP (China Science and Technology Journal Database), SinoMed (Chinese Biomedical Literature Database), PubMed, Web of Science, and Cochrane Library. Literature related to the treatment of DPN with TCM was selected. From the 1,229 RCTs identified over the past 6 years, relevant data were extracted. The evidence mapping approach was utilized, and trends in publications, study scales, intervention types, and evaluation indicators were analyzed using descriptive text combined with tables and bubble charts. Results: Research on the treatment of DPN with TCM is extensive. The publication trend remains relatively stable with predominantly smaller sample sizes. The main treatments encompass oral Chinese medicine and traditional external treatments. The most common evaluation indicators are neurophysiological, efficiency rate, symptom signs, neuropathy scores, and traditional Chinese symptoms, with less focus on psychological status and the ankle-brachial index (ABI). Conclusion: Shedding light on contemporary research, this study explores the current RCTs evaluating TCM's efficacy in treating DPN. The findings not only highlight the potential role of TCM in addressing diabetic complications but also underscore areas that could benefit from refined research approaches, expanded intervention methods, and broader assessment criteria. Our observations aim to inform and inspire future research directions and clinical practices concerning TCM's role in managing diabetes-associated complications.

Distinguish different sensorimotor performance of the hand between the individuals with diabetes mellitus and chronic kidney disease through deep learning models

Diabetes mellitus and chronic kidney disease represent escalating global epidemics with comorbidities akin to neuropathies, resulting in various neuromuscular symptoms that impede daily performance. Interestingly, previous studies indicated differing sensorimotor functions within these conditions. If assessing sensorimotor features can effectively distinguish between diabetes mellitus and chronic kidney disease, it could serve as a valuable and non-invasive indicator for early detection, swift screening, and ongoing monitoring, aiding in the differentiation between these diseases. This study classified diverse diagnoses based on motor performance using a novel pinch-holding-up-activity test and machine learning models based on deep learning. Dataset from 271 participants, encompassing 3263 hand samples across three cohorts (healthy adults, diabetes mellitus, and chronic kidney disease), formed the basis of analysis. Leveraging convolutional neural networks, three deep learning models were employed to classify healthy adults, diabetes mellitus, and chronic kidney disease based on pinch-holding-up-activity data. Notably, the testing set displayed accuracies of 95.3% and 89.8% for the intra- and inter-participant comparisons, respectively. The weighted F1 scores for these conditions reached 0.897 and 0.953, respectively. The study findings underscore the adeptness of the dilation convolutional neural networks model in distinguishing sensorimotor performance among individuals with diabetes mellitus, chronic kidney disease, and healthy adults. These outcomes suggest discernible differences in sensorimotor performance across the diabetes mellitus, chronic kidney disease, and healthy cohorts, pointing towards the potential of rapid screening based on these parameters as an innovative clinical approach.

Spectrum of Diabetic Neuropathy: New Insights in Diagnosis and Treatment

Diabetic neuropathy is a highly prevalent complication of diabetes. It consists of a broad range of neuropathic conditions, such as distal symmetric polyneuropathy and various forms of autonomic neuropathies involving the cardiovascular, gastrointestinal, and urogenital systems. Prevention or diagnosis in early stages of disease is crucial to prevent symptomatic onset and progression, particularly in the absence of current disease-modifying therapies. In this review, we describe the four main types of diabetic neuropathy. We review current understanding with respect to diagnosis and treatment while highlighting knowledge gaps and future directions.

In vivo corneal confocal microscopy as a non-invasive test to assess obesity induced small fibre nerve damage and inflammation

PURPOSE

To investigate small nerve fibre damage and inflammation at the level of the sub-basal nerve plexus (SNP) of severe obese patients and compare the results with those of healthy subjects.

METHODS

This cross-sectional, observational study investigated the data of 28 patients (14 out of 28 prediabetic or diabetic) with severe obesity (Body Mass Index; BMI ≥ 40) and 20 healthy subjects. Corneal nerve fibre density (CNFD), branch density (CNBD), fibre length (CNFL), nerve fibre area (CNFA), nerve fibre width (CNFW), and nerve fractal dimension (CNFrD) and dendritic cell (DC) density were evaluated using in vivo confocal microscopy (IVCM, Heidelberg Retinal Tomograph III Rostock Cornea Module). Automatic CCMetrics software (University of Manchester, UK) was used for quantitative analysis of SNP.

RESULTS

Mean age was 48.4±7.4 and 45.1 ± 5.8 in the control and obese group, respectively (p = 0.09). Mean BMI were 49.1 ± 7.8 vs. 23.3 ± 1.4 in obese vs. control group, respectively (p < 0.001). Mean CNFD, CNBD, CNFL, CNFA, CNFW were significantly reduced in obese group compared with those in the control group (always p < 0.05, respectively). There were no significant differences in any ACCMetrics parameters between prediabetic/diabetic and non-diabetic obese patients. Increased DC densities were detected in obese group compared with those in control group (p < 0.0001). There were significant correlations between BMI scores and SNP parameters.

CONCLUSION

Imaging with IVCM is a feasible, non-invasive method to detect and quantify occult corneal nerve damage and increased inflammation in patients with obesity. This study suggests that obesity may be a separate risk factor for peripheral neuropathy regardless of DM.

Prediabetes is associated with a higher serum neurofilament light chain level in adolescents

Objective

Serum neurofilament light chain (sNfL) level, which is a biomarker indicative of neuroaxonal damage and cognitive impairment, has been reported in several neurological diseases. There has been a lack of studies on the association between sNfL levels and prediabetes in adolescents. This study investigated whether sNfL levels were higher in adolescents with prediabetes undergoing elective orthopedic surgery.

Methods

The sNfL level was measured in 149 adolescents aged from 12 to 18 years who underwent elective orthopedic surgery at the Hunan Children's Hospital (18 with and 131 without prediabetes). We evaluated the association between prediabetes and sNfL level after adjusting for age, sex, and triglycerides using a multivariable linear regression model.

Results

The prevalence of prediabetes in adolescents was 12.08%. Univariate logistic regression analysis showed that prediabetes was related to sNfL. In multivariate logistic regression analysis, the association between prediabetes with sNfL levels remained significant after adjustment for age, sex, and triglyceride. The relationship between the two was further visualized by a smoothed curve.

Conclusions

Prediabetes is associated with a higher sNfL. Further large-scale and prospective studies are needed to verify the clinical application of sNfL as a monitoring biomarker for adolescent prediabetes in adolescents and to evaluate the performance of sNfL in predicting the incidence of neuropathy and cognitive dysfunction in adolescents with prediabetes.

The Association of Inflammatory Factors With Peripheral Neuropathy: The Study of Women's Health Across the Nation

PURPOSE

Previous work has focused on the role of diabetes in peripheral neuropathy (PN), but PN often occurs before, and independently from, diabetes. This study measures the association of cardiometabolic and inflammatory factor with PN, independent of diabetes.

METHODS

Study of Women's Health Across the Nation participants (n = 1910), ages 60 to 73 (mean 65.6) were assessed for PN by symptom questionnaire and monofilament testing at the 15th follow-up visit (V15). Anthropometric measures and biomarkers were measured at study baseline approximately 20 years prior, and C-reactive protein (CRP) and fibrinogen were measured longitudinally. Log-binomial regression was used to model the association between metabolic syndrome (MetS), obesity (≥35 body mass index), CRP, and fibrinogen with PN, adjusting for sociodemographic and health behavior measures.

RESULTS

Baseline MetS [prevalence ratio (PR) 1.79, 95% CI (1.45, 2.20)], obesity [PR 2.08 (1.65, 2.61)], median CRP [PR 1.32 per log(mg/dL), (1.20, 1.45)], and mean fibrinogen (PR 1.28 per 100 mg/dL, (1.09, 1.50)] were associated with PN symptoms at V15. After excluding participants with baseline diabetes or obesity, MetS [PR 1.59 (1.17, 2.14)] and CRP [PR 1.19 per log(mg/dL), (1.06, 1.35)] remained statistically significantly associated with PN. There was a negative interaction between MetS and obesity, and the association between these conditions and PN was mediated by CRP.

CONCLUSIONS

Cardiometabolic factors and inflammation are significantly associated with PN, independent of diabetes and obesity. CRP mediates the relationship of both obesity and MetS with PN, suggesting an etiological role of inflammation in PN in this sample.

Association between sarcopenia and prediabetes among non-elderly US adults

AIM

To explore the specific association between sarcopenia and prediabetes based on large population samples.

METHODS

A total of 16,116 U.S. adults aged 20-59 with dual energy X-ray absorptiometry (DXA) was identified from the National Health and Nutrition Examination Surveys (NHANES). Sarcopenia was defined according to appendicular skeletal muscle mass (ASM) adjusted for body mass index (BMI). Multivariable binary logistic regression models were used to ascertain odds ratios (ORs) for developing prediabetes. Stratified analyses were also performed.

RESULTS

Prevalence of prediabetes was higher in the sarcopenia group (n = 1055) compared with the non-sarcopenia group (n = 15,061) (45.50% vs 28.74%, P < 0.001). Sarcopenia was strongly associated with an increased risk of prediabetes after full adjustment (OR = 1.21, 95CI%: 1.05, 1.39, P = 0.009). In the stratified analysis, this association remained significant independent of obesity, triglycerides, and low-density lipoprotein cholesterol levels. When sarcopenia subjects combined with obesity especially central obesity, the risk of prediabetes was the highest (OR = 2.63, 95CI%: 2.22, 3.11, P < 0.001). Furthermore, a greater proportion of any of impaired glucose tolerance (IGT) individuals was observed in the sarcopenia group compared to the non-sarcopenia group among prediabetes population (41.72% vs 24.06%, P < 0.001).

CONCLUSIONS

Sarcopenia was positively associated with prevalent prediabetes especially IGT in the non-elderly. Moreover, synergistic interactions between the sarcopenia and obesity could greatly increase the risk of prediabetes.

Environmental risk factors of incident distal sensorimotor polyneuropathy: Results from the prospective population-based KORA F4/FF4 study

Distal sensorimotor polyneuropathy (DSPN) is a common condition in older populations with high prevalence of obesity and type 2 diabetes. We hypothesised that the risk of DSPN is increased by multiple ubiquitous environmental risk factors, particularly in people with obesity. This study was based on 423 individuals aged 62-81 years without DSPN who participated in the population-based Cooperative Health Research in the Region of Augsburg (KORA) F4 survey (2006-2008) in Southern Germany. During 6.5 years of follow-up, 188 participants developed clinical DSPN as assessed by the Michigan Neuropathy Screening Instrument. Environmental exposures, including air temperature, surrounding greenness (assessed with the normalized difference vegetation index [NDVI]), long-term road traffic noise and air pollution, were assessed at participants' residences. The cumulative risk index (CRI) evaluated the joint effects of co-occurring exposures on DSPN risk based on effect estimates from multi-exposure Poisson regression models. The models were adjusted for age, sex, height, waist circumference, smoking, alcohol consumption, physical activity, education and neighbourhood socioeconomic status. In the entire cohort, the co-occurrence of an interquartile range (IQR) decrease in temperature of the warm season and NDVI in a 100-m buffer and of an IQR increase in night-time average traffic noise and in annual average particle number concentration (PNC) was positively associated with incident DSPN (CRI [95 % CI] 1.39 [1.02, 1.91]). Effect estimates for exposure combinations were generally higher in individuals with obesity (CRI 1.34-2.01) than in those without obesity (CRI 0.90-1.33). The four-exposure model showed a twofold increased risk of DSPN among obese (CRI [95 % CI] 2.01 [1.10, 3.67]), but not among non-obese individuals (CRI [95 % CI] 1.18 [0.83, 1.67]). Thus, ubiquitous environmental exposures jointly augment the risk of DSPN in the older population. Lower air temperature in the warm season, less greenness, and higher noise levels and ultrafine particle concentrations identified people with obesity as a particularly vulnerable subgroup.

Lower Limb Arterial Ischemia: An Independent Risk Factor of Sudomotor Dysfunction in Type 2 Diabetes

BACKGROUND

As an early manifestation of diabetic peripheral neuropathy (DPN), sudomotor dysfunction significantly increases the risk of diabetic foot ulcer. The pathogenesis of sudomotor dysfunction is still unclear. Lower limb ischemia may be related to sudomotor dysfunction, but few studies have explored it. The purpose of this study is to explore the relationship between sudomotor function and comprehensive lower limb arterial ischemia including large arteries, small arteries and microvascular in type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

511 T2DM patients were enrolled in this cross-sectional study. Sudomotor function was assessed qualitatively and quantitatively by Neuropad. Lower limb arterial ischemia was defined as any abnormality of the ankle brachial index (ABI), toe brachial index (TBI) or transcutaneous oxygen tension (TcPO2).

RESULTS

In this study, 75.1% of patients had sudomotor dysfunction. Compared with normal sudomotor function, patients with sudomotor dysfunction had a higher incidence of lower limb arterial ischemia (51.2% vs 36.2%, p = 0.004). Similarly, compared with the non-arterial ischemia group, the proportion of sudomotor disorders was higher in the arterial ischemia group (p = 0.004). Low TBI and low TcPO2 groups also had a higher proportion of sudomotor disorders (all p < 0.05).Compare with normal groups, low ABI, low TBI, and low TcPO2 groups had lower Slop4 which quantitatively reflecting Neuropad discoloration. Arterial ischemia was an independent risk factor for sudomotor dysfunction [OR = 1.754, p = 0.024]. Low TcPO2 also independently increased the risk of sudomotor disorders [OR = 2.231, p = 0.026].

CONCLUSION

Lower limb arterial ischemia is an independent risk factor of sudomotor dysfunction. Especially below the ankle (BTA) small arteries and microvascular ischemia may also be involved in the occurrence of sudomotor disorders.

The conundrum of diabetic neuropathies-Past, present, and future

Diabetic neuropathy (DN) remains arguably the most prevalent chronic complication in people with both type 1 and type 2 diabetes, including in youth, despite changes in the current standards of clinical care. Additionally, emerging evidence demonstrates that neuropathy affects a large proportion of people with undiagnosed diabetes and/or prediabetes, as well as those with obesity. Here we summarize the latest epidemiology of DN, recent findings regarding the pathophysiology of the disease, as well as current outcome measures for screening and diagnosis, in research and clinical settings. The authors discuss novel perspectives on the impact of social determinants of health in DN development and management, and the latest evidence on effective therapies, including pharmacological and nonpharmacological therapies for neuropathic pain. Throughout the publication, we identify knowledge gaps and the need for future funding to address these gaps, as well as needs to advocate for a personalized care approach to reduce the burden of DN and optimize quality of life for all affected individuals.

The Peripheral Neuropathy Prevalence and Characteristics Are Comparable in People with Obesity and Long-Duration Type 1 Diabetes

INTRODUCTION

Peripheral neuropathy is reported in obesity even in the absence of hyperglycaemia.

OBJECTIVE

To compare the prevalence and characterise the phenotype of peripheral neuropathy in people living with obesity (OB) and long-duration type 1 diabetes (T1D).

PATIENTS AND METHODS

We performed a prospective cross-sectional study of 130 participants including healthy volunteers (HV) (n = 28), people with T1D (n = 51), and OB (BMI 30-50 kg/m2) (n = 51). Participants underwent assessment of neuropathic symptoms (Neuropathy Symptom Profile, NSP), neurological deficits (Neuropathy Disability Score, NDS), vibration perception threshold (VPT) and evaluation of sural nerve conduction velocity and amplitude.

RESULTS

Peripheral neuropathy was present in 43.1% of people with T1D (age 49.9 ± 12.9 years; duration of diabetes 23.4 ± 13.5 years) and 33.3% of OB (age 48.2 ± 10.8 years). VPT for high risk of neuropathic foot ulceration (VPT ≥ 25 V) was present in 31.4% of T1D and 19.6% of OB. Participants living with OB were heavier (BMI 42.9 ± 3.5 kg/m2) and had greater centripetal adiposity with an increased body fat percentage (FM%) (P < 0.001) and waist circumference (WC) (P < 0.001) compared to T1D. The OB group had a higher NDS (P < 0.001), VAS for pain (P < 0.001), NSP (P < 0.001), VPT (P < 0.001) and reduced sural nerve conduction velocity (P < 0.001) and amplitude (P < 0.001) compared to HV, but these parameters were comparable in T1D. VPT was positively associated with increased WC (P = 0.011), FM% (P = 0.001) and HbA1c (P < 0.001) after adjusting for age (R2 = 0.547). Subgroup analysis of respiratory quotient (RQ) measured in the OB group did not correlate with VPT (P = 0.788), nerve conduction velocity (P = 0.743) or amplitude (P = 0.677).

CONCLUSION

The characteristics of peripheral neuropathy were comparable between normoglycaemic people living with obesity and people with long-duration T1D, suggesting that metabolic factors linked to obesity play a pivotal role in the development of peripheral neuropathy. Further studies are needed to investigate the mechanistic link between visceral adiposity and neuropathy.

Association Between HbA1c Levels and Diabetic Peripheral Neuropathy: A Case-Control Study of Patients with Type 2 Diabetes Using Claims Data

BACKGROUND

Evidence on the efficacy of glycemic control for diabetic peripheral neuropathy (DPN) is limited in patients with type 2 diabetes mellitus. Despite the known relationship between hemoglobin A1c (HbA1c) and DPN, the parameters (e.g., mean values or variability) that play an important role have not been elucidated.

OBJECTIVE

The objective of this study was to explore factors associated with DPN, including long-term HbA1c parameters, among patients with type 2 diabetes, in a large-scale longitudinal study.

METHODS

We conducted a case-control study using a medical claims database. We extracted data of patients with type 2 diabetes and disease records of DPN (indicating that they received treatment for DPN) and those without DPN records (controls), and matched for age, sex, index year, and duration since the first type 2 diabetes record. A logistic regression analysis was performed to explore factors associated with DPN, and a receiver-operating characteristic analysis to estimate the optimal mean HbA1c target.

RESULTS

Of 1,792,037 patients with type 2 diabetes, data from 1632 patients (816 per group) were analyzed. The mean HbA1c levels in the 3-year observation period were 7.2 ± 1.0% in the DPN group and 6.9 ± 1.1% in the control group. Elevated 3-year mean HbA1c levels were significantly associated with DPN records (adjusted odds ratio: 1.23, 95% confidence interval 1.06-1.42), while HbA1c variability was not significantly associated. The mean HbA1c levels that discriminated between patients with and without DPN records were 6.5% (unadjusted) and 7.1% (adjusted).

CONCLUSIONS

The development or progression of DPN in patients with type 2 diabetes was associated with the 3-year mean HbA1c level in real-world data.

Chemometric exploratory data analysis for patients with diabetes type 2 and diabetic complications

The present study deals with the interpretation and modeling of clinical data for patients with diabetes mellitus type 2 (DMT2) additionally diagnosed with complications of the disease by the use of multivariate statistical methods. The major goal is to determine some specific clinical descriptors characterizing each health problem by applying the options of the exploratory data analysis. The results from the statistical analysis are commented in details by medical reasons for each of the complications. It was found that each of the complications is characterized by specific medical descriptors linked into each one of the five latent factors identified by factor and principal components analysis. Such an approach to interpret concomitant to DMT2 complications is original and allows a better understanding of the role of clinical parameters for diagnostic and prevention goals.

Progressive, Qualitative, and Quantitative Alterations in HDL Lipidome from Healthy Subjects to Patients with Prediabetes and Type 2 Diabetes

Prediabetes is a clinically silent, insulin-resistant state with increased risk for the development of type 2 diabetes (T2D) and cardiovascular disease (CVD). Since glucose homeostasis and lipid metabolism are highly intersected and interrelated, an in-depth characterization of qualitative and quantitative abnormalities in lipoproteins could unravel the metabolic pathways underlying the progression of prediabetes to T2D and also the proneness of these patients to developing premature atherosclerosis. We investigated the HDL lipidome in 40 patients with prediabetes and compared it to that of 40 normoglycemic individuals and 40 patients with established T2D using Nuclear Magnetic Resonance (NMR) spectroscopy. Patients with prediabetes presented significant qualitative and quantitative alterations, potentially atherogenic, in HDL lipidome compared to normoglycemic characterized by higher percentages of free cholesterol and triglycerides, whereas phospholipids were lower. Glycerophospholipids and ether glycerolipids were significantly lower in prediabetic compared to normoglycemic individuals, whereas sphingolipids were significantly higher. In prediabetes, lipids were esterified with saturated rather than unsaturated fatty acids. These changes are qualitatively similar, but quantitatively milder, than those found in patients with T2D. We conclude that the detailed characterization of the HDL lipid profile bears a potential to identify patients with subtle (but still proatherogenic) abnormalities who are at high risk for development of T2D and CVD.

Changes in salivary biomarkers associated with periodontitis and diabetic neuropathy in individuals with type 1 diabetes

The objective of this pilot clinical study was to identify salivary biomarkers that are associated with periodontal disease and measures of diabetic autonomic dysfunction. Saliva samples from 32 participants were obtained from 3 groups: healthy (H), type 1 diabetes mellitus (DM), and type 1 diabetes mellitus with neuropathy (DMN). Based on the periodontal examination, individuals’ mean Periodontal Screening and Recording scores were categorized into two groups (periodontally healthy and gingivitis), and correlated to specific salivary inflammatory biomarkers assessed by a customized protein array and enzyme assay. The mean salivary IgA level in DM was 9211.5 ± 4776.4 pg/ml, which was significantly lower than H (17,182.2 ± 8899.3 pg/ml). IgA in DMN with healthy periodontium was significantly lower (5905.5 ± 3124.8 pg/ml) compared to H, although IgA levels in DMN patients with gingivitis (16,894. 6 ± 7084.3) were not. According to the result of a logistic regression model, IgA and periodontal condition were the indicators of the binary response given by H versus DM, and H versus DMN, respectively. These data suggest that selected salivary biomarkers, such as IgA, combined with a periodontal examination prior to obtaining salivary samples can offer a non-invasive method to assess risk for developing diabetic neuropathy.

Painful Diabetic Neuropathy as a Cause for Refractory Ear Pain in Type 2 Diabetic Patients

OBJECTIVE

To assess painful diabetic neuropathy (PDN) as a cause for refractory ear pain in type 2 diabetics.

DESIGN

An observational prospective case series study.

SETTING

Otolaryngology departments of tertiary referral hospitals from November 2019 to January 2021.

PATIENTS

Sixty-eight patients with type 2 diabetes with refractory ear pain of more than 1-month duration not responding to the routine analgesics.

INTERVENTION

Diagnostic intervention.

MAIN OUTCOME MEASURE

The primary outcome measure was the prevalence of painful diabetic neuropathy among different causes of ear pain in the study sample of type II diabetics with refractory ear pain with an assessment of the response of these cases to routine neuropathic pain treatment with pregabalin.

RESULTS

Fifteen out of 68 (22.1%) were diagnosed as having painful diabetic neuropathy based on the "Douleur Neuropathique en 4 Questions" (DN4) questionnaire with its mean value being 6.47±1.19. There was a highly significant improvement of the 10 items of painful diabetic neuropathy scales after 1 month of treatment ( p < 0.001 for all). There was a significant positive correlation between the Hemoglobin A1c level and duration of diabetes at one hand and intensity of pain derived from the painful diabetic neuropathy scale at the other hand ( p = 0.0002, and p = 0.032 respectively).

CONCLUSION

Painful diabetic neuropathy showed a potential correlation with refractory ear pain in type II diabetic patients with significant improvement after painful diabetic neuropathy treatment. Further studies are needed to confirm these findings.

Cardiac Autonomic Neuropathy in Patients with Newly Diagnosed Carbohydrate Disturbances

Cardiac autonomic neuropathy (CAN) is a serious complication of diabetes mellitus that can predispose patients to higher risk for cardiovascular death. The aim of the present study was to evaluate the presence of cardiac autonomic neuropathy and sudomotor dysfunction in patients with newly diagnosed carbohydrate disturbances (prediabetes or diabetes) and to assess their relationship to metabolic disturbances and cardiovascular risk. In the present study, we included 160 patients -78 with obesity without carbohydrate disturbances, 52 with prediabetes, and 30 with newly diagnosed diabetes. CAN was diagnosed using cardiovascular reflex tests and sudomotor function was evaluated by SUDOSCAN. Cardiovascular risk was calculated using SCORE and FRMINGHAM risk scores. The prevalence of cardiac autonomic neuropathy was significantly higher in patients with newly diagnosed diabetes. Independently of their glycemic status, the patients who had blood glucose on the 60th-minute of OGTT>8.5 mmol/l had significantly higher prevalence of cardiac autonomic neuropathy (30.2% vs 15.6%, р=0.044). Patients with high cardiovascular risk according to FRAMINGHAM and SCORE had worse heart rate variability scores. Autonomic neuropathy risk assessed by SUDOSCAN was a good predictor for the presence of CAN. In conclusion, CAN has a higher prevalence on patients with newly diagnosed diabetes compared to prediabetic and normoglycemic subjects, while the patients with blood glucose>8.5 mmol/l on the 60th-minute of OGTT have higher prevalence of CAN independently of their glycemic status. SUDOSCAN testing can be used to assess the risk of CAN and to select patients that should undergo further testing.

Relation of Glycemic Status with Unrecognized MI and the Subsequent Risk of Mortality: The Jackson Heart Study

Background

Almost 1/3 to 1/2 of initial myocardial infarctions (MI) may be silent or unrecognized (UMI), which forecasts future clinical events. Further, limited data exist to describe the potential risk for UMI in African-Americans. The relationship of glucose status with UMI was examined in the Jackson Heart Study: a cohort of African-American individuals.

Methods and results

At baseline, there were 5,073 participants with an initial 12-lead electrocardiogram (ECG) and fasting glucose measured. Of these participants, 106(2.1%) had a UMI, and 268(4.2%) had a recognized MI. This population consisted of 3,233 (63.7%) participants with normal fasting glucose (NFG), 533 (10.5%) with IFG, and 1,039 (20.4%) with DM. Logistic regression investigated the relationship between glucose status and UMI. Cox proportional hazard models determined the significance of all-cause mortality during follow-up by MI status. The sample was 65% female with a mean age of 55.3 ± 12.9 years. Over a mean follow-up of 10.4 years, there were 795 deaths. Relative to NFG, the crude odds ratio (OR) estimates for UMI at baseline with IFG and DM were 1.00(95% CI:0.48–2.14) and 3.22(2.15–4.81), respectively. With adjustment, DM continued to be significantly associated with UMI [2.30 (1.42–3.71)]. Overall, participants with a baseline UMI had an adjusted Hazard ratio (HR) of 2.00(1.39–2.78) of death compared to no prior MI. Compared to those with no MI, those with a recognizedMI had an adjusted HR of 1.70(1.31–2.17) for mortality.

Conclusions

DM is associated with UMI in African-Americans. Further, a UMI carried similar risk of death compared to those with a recognized MI.

Plasma C1q/tumor necrosis factor-related protein-3 concentrations are associated with diabetic peripheral neuropathy

INTRODUCTION

To analyze the associations of circulating C1q/tumor necrosis factor-related protein-3 (CTRP3) concentrations with several metabolic parameters and to investigate the possible role of CTRP3 in subjects with diabetic peripheral neuropathy (DPN).

RESEARCH DESIGN AND METHODS

A total of 347 participants were recruited in this study, and plasma CTRP3 concentrations were analyzed in subjects with DPN (n=172) and without DPN (non-DPN, n=175). The nerve conduction test and oral glucose tolerance test were performed, and Neuropathy Symptom Score (NSS)/Neuropathy Disability Score (NDS) and biochemical parameters were measured in all participants.

RESULTS

Plasma CTRP3 concentrations were significantly lower in patients with DPN compared with those in patients with diabetes without DPN (p<0.01), despite the comparable glucose and lipid metabolism levels in both groups. Groups with a higher plasma CTRP3 level had a faster nerve conduction velocity. In addition, plasma CTRP3 concentrations were negatively correlated with hemoglobin A1c (HbA1c), urea acid (UA), triglyceride, NSS and NDS (p<0.05) after being adjusted for age and sex. Multivariate logistic regression analysis revealed that plasma CTRP3 concentrations were significantly correlated with DPN after being controlled for age, sex, body mass index, HbA1c, blood pressure, lipid profiles, and renal function.

CONCLUSIONS

Plasma CTRP3 concentrations were significantly lower in patients with DPM and positively correlated with nerve conduction velocity. The relationship between CTRP3 levels and DPN is independent of the glucose and lipid status. Therefore, circulating CTRP3 might serve as a predictor of impairment of nerve conduction in patients with DPN.

Screening, diagnosis and management of diabetic sensorimotor polyneuropathy in clinical practice: International expert consensus recommendations

Diabetic sensorimotor polyneuropathy (DSPN) affects around one third of people with diabetes and accounts for considerable morbidity, increased risk of mortality, reduced quality of life, and increased health care costs resulting particularly from neuropathic pain and foot ulcers. Painful DSPN is encountered in 13-26% of diabetes patients, while up to 50% of patients with DSPN may be asymptomatic. Unfortunately, DSPN still remains inadequately diagnosed and treated. Herein we provide international expert consensus recommendations and algorithms for screening, diagnosis, and treatment of DSPN in clinical practice derived from a Delphi process. Typical neuropathic symptoms include pain, paresthesias, and numbness particularly in the feet and calves. Clinical diagnosis of DSPN is based on neuropathic symptoms and signs (deficits). Management of DSPN includes three cornerstones: (1) lifestyle modification, optimal diabetes treatment aimed at near-normoglycemia, and multifactorial cardiovascular risk intervention, (2) pathogenetically oriented pharmacotherapy (e.g. α-lipoic acid and benfotiamine), and (3) symptomatic treatment of neuropathic pain including analgesic pharmacotherapy (antidepressants, anticonvulsants, opioids, capsaicin 8% patch and combinations, if required) and non-pharmacological options. Considering the individual risk profile, pain management should not only aim at pain relief, but also allow for improvement in quality of sleep, functionality, and general quality of life.

Plasma Metabolomics and Lipidomics Differentiate Obese Individuals by Peripheral Neuropathy Status

CONTEXT

Peripheral neuropathy (PN) is a frequent prediabetes and type 2 diabetes (T2D) complication. Multiple clinical studies reveal that obesity and dyslipidemia can also drive PN progression, independent of glycemia, suggesting a complex interplay of specific metabolite and/or lipid species may underlie PN.

OBJECTIVE

This work aimed to identify the plasma metabolomics and lipidomics signature that underlies PN in an observational study of a sample of individuals with average class 3 obesity.

METHODS

We performed plasma global metabolomics and targeted lipidomics on obese participants with (n = 44) and without PN (n = 44), matched for glycemic status, vs lean nonneuropathic controls (n = 43). We analyzed data by Wilcoxon, logistic regression, partial least squares-discriminant analysis, and group-lasso to identify differential metabolites and lipids by obesity and PN status. We also conducted subanalysis by prediabetes and T2D status.

RESULTS

Lean vs obese comparisons, regardless of PN status, identified the most significant differences in gamma-glutamyl and branched-chain amino acid metabolism from metabolomics analysis and triacylglycerols from lipidomics. Stratification by PN status within obese individuals identified differences in polyamine, purine biosynthesis, and benzoate metabolism. Lipidomics found diacylglycerols as the most significant subpathway distinguishing obese individuals by PN status, with additional contributions from phosphatidylcholines, sphingomyelins, ceramides, and dihydroceramides. Stratifying the obese group by glycemic status did not affect discrimination by PN status.

CONCLUSION

Obesity may be as strong a PN driver as prediabetes or T2D in a sample of individuals with average class 3 obesity, at least by plasma metabolomics and lipidomics profile. Metabolic and complex lipid pathways can differentiate obese individuals with and without PN, independent of glycemic status.

SUDOSCAN in Combination with the Michigan Neuropathy Screening Instrument Is an Effective Tool for Screening Diabetic Peripheral Neuropathy

BACKGROUND

Screening for diabetic peripheral neuropathy (DPN) is important to prevent severe foot complication, but the detection rate of DPN is unsatisfactory. We investigated whether SUDOSCAN combined with Michigan Neuropathy Screening Instrument (MNSI) could be an effective tool for screening for DPN in people with type 2 diabetes mellitus (T2DM) in clinical practice.

METHODS

We analysed the data for 144 people with T2DM without other cause of neuropathy. The presence of DPN was confirmed according to the Toronto Consensus criteria. Electrochemical skin conductance (ESC) of the feet was assessed using SUDOSCAN. We compared the discrimination power of following methods, MNSI only vs. SUDOSCAN only vs. MNSI plus SUDOSCAN vs. MNSI plus 10-g monofilament test.

RESULTS

Confirmed DPN was detected in 27.8% of the participants. The optimal cut-off value of feet ESC to distinguish DPN was 56 μS. We made the DPN screening scores using the corresponding odds ratios for MNSI-Questionnaire, MNSI-Physical Examination, SUDOSCAN, and 10-g monofilament test. For distinguishing the presence of DPN, the MNSI plus SUDOSCAN model showed higher areas under the receiver operating characteristic curve (AUC) than MNSI only model (0.717 vs. 0.638, P=0.011), and SUDOSCAN only model or MNSI plus 10-g monofilament test showed comparable AUC with MNSI only model.

CONCLUSION

The screening model for DPN that includes both MNSI and SUDOSCAN can detect DPN with acceptable discrimination power and it may be useful in Korean patients with T2DM.

Diagnostic Tools, Biomarkers, and Treatments in Diabetic polyneuropathy and Cardiovascular Autonomic Neuropathy

The various manifestations of diabetic neuropathy, including distal symmetric sensorimotor polyneuropathy (DSPN) and cardiovascular autonomic neuropathy (CAN), are among the most prevalent chronic complications of diabetes. Major clinical complications of diabetic neuropathies, such as neuropathic pain, chronic foot ulcers, and orthostatic hypotension, are associated with considerable morbidity, increased mortality, and diminished quality of life. Despite the substantial individual and socioeconomic burden, the strategies to diagnose and treat diabetic neuropathies remain insufficient. This review provides an overview of the current clinical aspects and recent advances in exploring local and systemic biomarkers of both DSPN and CAN assessed in human studies (such as biomarkers of inflammation and oxidative stress) for better understanding of the underlying pathophysiology and for improving early detection. Current therapeutic options for DSPN are (I) causal treatment, including lifestyle modification, optimal glycemic control, and multifactorial risk intervention, (II) pharmacotherapy derived from pathogenetic concepts, and (III) analgesic treatment against neuropathic pain. Recent advances in each category are discussed, including non-pharmacological approaches, such as electrical stimulation. Finally, the current therapeutic options for cardiovascular autonomic complications are provided. These insights should contribute to a broader understanding of the various manifestations of diabetic neuropathies from both the research and clinical perspectives.

Systems Biology to Address Unmet Medical Needs in Neurological Disorders

Neurological diseases are highly prevalent and constitute a significant cause of mortality and disability. Neurological disorders encompass a heterogeneous group of neurodegenerative conditions, broadly characterized by injury to the peripheral and/or central nervous system. Although the etiology of neurological diseases varies greatly, they share several characteristics, such as heterogeneity of clinical presentation, non-cell autonomous nature, and diversity of cellular, subcellular, and molecular pathways. Systems biology has emerged as a valuable platform for addressing the challenges of studying heterogeneous neurological diseases. Systems biology has manifold applications to address unmet medical needs for neurological illness, including integrating and correlating different large datasets covering the transcriptome, epigenome, proteome, and metabolome associated with a specific condition. This is particularly useful for disentangling the heterogeneity and complexity of neurological conditions. Hence, systems biology can help in uncovering pathophysiology to develop novel therapeutic targets and assessing the impact of known treatments on disease progression. Additionally, systems biology can identify early diagnostic biomarkers, to help diagnose neurological disease preceded by a long subclinical phase, as well as define the exposome, the collection of environmental toxicants that increase risk of certain neurological diseases. In addition to these current applications, there are numerous potential emergent uses, such as precision medicine.

The Effects of Diabetic Polyneuropathy and Autonomic Neuropathy on Bone Turnover

Background: The effect of diabetic polyneuropathy (DPN) and autonomic neuropathy (AN) on bone turnover in type 2 diabetes mellitus (DM) is uncertain due to the lack of data. In this study, we tried to determine the effect of DPN and AN on bone metabolism. Materials and Methods: The study included patients with type 2 DM (aged 18-80 years) and age-matched healthy individuals who presented to the Departments of Metabolism and Diabetes, Geriatrics, and General Internal Medicine, Cerrahpaşa Medical School, Istanbul University. The patients were examined to find out whether they had AN, and neuropathy scores were recorded by exploring peripheral neuropathy. Bone mineral density was measured by dual-energy X-ray (DXA). Demographic characteristics, the presence of microvascular complications, and biochemical data were obtained from patients' files. Serum cross-linked C-telopeptide (Ctx), osteocalcin, and bone-specific alkaline phosphatase (B-ALP) were analyzed. Results: The study comprised a total of 64 patients: 23 had type 2 DM and osteoporosis (OP) (duration of diabetes 10.1 ± 7 years; mean age 63 ± 9.1 years; female/male 18/5; Group 1), 41 had type 2 DM and non-OP (duration of diabetes 10.3 ± 7.6 years; mean age 58 ± 7.4 years; female/male 30/11; Group 2), and 26 healthy volunteers made up the control group (mean age 62 ± 11.9 years; female/male 14/12; Group 3). The bone turnover parameters were lower in type 2 DM individuals. The levels of osteocalcin (13.3 ± 5.2 ng/mL) and B-ALP (44.7 ± 10.9 IU/L) in patients with type 2 DM were lower than those of healthy subjects: osteocalcin (20.6 ± 10 ng/mL) and B-ALP (111 ± 31.4 IU/L; P = 0.001 and P = 0.000, respectively). Ctx levels (193.5 ± 49.3; 207.6 ± 40 ng/mL) were recorded to be similar (P = 0.2). AN was also noted as a risk factor for OP. For patients without AN, the likelihood of developing OP (odds ratio) was 0.7. The corresponding ratio for patients with AN was 9.3. Conclusions: Among the independent variables, the neuropathy score was determined to have an impact on bone turnover. AN was identified to be a significant risk factor for OP.

Triglyceride glucose-body mass index in identifying high-risk groups of pre-diabetes

Background

Triglyceride glucose-body mass index (TyG-BMI) has been recommended as an alternative indicator of insulin resistance. However, the association between TyG-BMI and pre-diabetes remains to be elucidated.

Methods

More than 100,000 subjects with normal glucose at baseline received follow-up. The main outcome event of concern was pre-diabetes defined according to the diagnostic criteria recommended by the American Diabetes Association (ADA) in 2018 and the World Health Organization (WHO) in 1999. A Cox proportional hazard regression model was used to evaluate the role of TyG-BMI in identifying people at high risk of pre-diabetes.

Results

At a mean observation period of 3.1 years, the incidence of pre-diabetes in the cohort was 3.70 and 12.31% according to the WHO and ADA diagnostic criteria for pre-diabetes, respectively. The multivariate Cox regression analysis demonstrated that TyG-BMI was independently positively correlated with pre-diabetes, and there was a special population dependence phenomenon. Among them, non-obese people, women and people under 50 years old had a significantly higher risk of TyG-BMI-related pre-diabetes (P-interaction< 0.05).

Conclusions

These findings suggest that a higher TyG-BMI significantly increases an individual’s risk of pre-diabetes, and this risk is significantly higher in women, non-obese individuals, and individuals younger than 50 years of age.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01594-7.

Pathophysiological Mechanisms That Alter the Autonomic Brain-Liver Communication in Metabolic Diseases

The brain influences liver metabolism through many neuroendocrine and autonomic mechanisms that have evolved to protect the organism against starvation and hypoglycemia. Unfortunately, this effective way of preventing death has become dysregulated in modern obesogenic environments, although the pathophysiological mechanisms behind metabolic dyshomeostasis are still unclear. In this Mini-Review, we provide our thoughts regarding obesity and type 2 diabetes as diseases of the autonomic nervous system. We discuss the pathophysiological mechanisms that alter the autonomic brain-liver communication in these diseases, and how they could represent important targets to prevent or treat metabolic dysfunctions. We discuss how sympathetic hyperactivity to the liver may represent an early event in the progression of metabolic diseases and could progressively lead to hepatic neuropathy. We hope that this discussion will inspire and help to frame a model based on better understanding of the chronology of autonomic dysfunctions in the liver, enabling the application of the right strategy at the right time.

Evaluation and treatment of peripheral nervous system dysfunction in patients with prediabetes

The worldwide prevalence of prediabetes is steadily increasing, with up to a third of patients already showing signs of diabetic neuropathy (DN). Prediabetes includes impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or a combination of both.

Recent diagnostic criteria of prediabetes according to Russian, European, and American clinical guidelines are presented. The review covers the most common forms of DN in patients with prediabetes (distal symmetric sensory polyneuropathy, painful DN, cardiovascular autonomic neuropathy) and their prevalence. Recommended methods of DN screening are discussed: diagnostic scales, sensory testing, nerve conduction study, autonomic testing, corneal confocal microscopy. The results of studies evaluating instrumental methods for diagnosing peripheral nervous system (PNS) dysfunction in prediabetes are discussed. Management tactics in patients with prediabetes and PNS dysfunction should include non-pharmacological and pharmacological interventions. Combining a low-calorie diet and regular physical activity can delay the development of diabetes mellitus and reduce the severity of neuropathic pain. In patients with painful DN, the first-line therapy includes pregabalin, gabapentin, and duloxetine. Since there is no current data on the effect of hypoglycemic therapy on the risks of development and/or progression of DN in patients with prediabetes, antioxidants are considered pathogenetic therapy. Alpha-lipoic acid (Berlition®) in the management of patients with prediabetes is discussed.

Progression and regression of nerve fibre pathology and dysfunction early in diabetes over 5 years

It has been traditionally suggested that the early development of diabetic sensorimotor polyneuropathy (DSPN) is characterized by a predominant and progressive injury to small nerve fibres followed by large fibre impairment. We alternatively hypothesized that small and large fibre damage due to DSPN in type 1 and type 2 diabetes could develop in parallel and may not only be progressive but also reversible. Participants from the German Diabetes Study baseline cohort with recent-onset type 1/type 2 diabetes (n = 350/570) and age-matched glucose-tolerant control individuals (Control 1/Control 2: n = 114/190) were assessed by nerve conduction studies (NCS), thermal detection thresholds (TDT), vibration perception threshold (VPT), Neuropathy Symptom Score (NSS), Neuropathy Disability Score (NDS), and intraepidermal nerve fibre density (IENFD) in skin biopsies (type 1/type 2 diabetes: n = 102/226; Control 1/Control 2: n = 109/208). Subsets of participants with type 1/type 2 diabetes were followed for 5 years (n = 184/307; IENFD subset: n = 18/69). DSPN was defined by the Toronto Consensus criteria. At baseline, DSPN was present in 8.1 and 13.3% of the type 1 and type 2 diabetes groups, respectively. The most frequently abnormal tests in the lower limbs below or above the 2.5th and 97.5th centile of the controls were IENFD (13.7%) and individual NCS (up to 9.4%) in type 1 diabetes participants and IENFD (21.8%), malleolar VPT (17.5%), and individual NCS (up to 11.8%) in those with type 2 diabetes, whereas TDT abnormalities did not differ between the control and diabetes groups. After 5 years in type 2 diabetes participants, the highest progression rates from the normal to the abnormal range were found for IENFD (18.8%) by -4.1 ± 2.8 fibres/mm, malleolar VPT (18.6%) by 9.1 ± 20.2 µm, and NDS (15.0%) by 3.7 ± 1.5 points, while vice versa the highest regression rates were observed for NDS (11.2%) by -3.1 ± 1.3 points, sural nerve amplitude (9.1%) by 4.7 ± 3.0 µV, IENFD (8.7%) by 1.4 ± 1.3 fibres/mm, and NSS (8.2%) by -5.8 ± 1.6 points. In type 1 diabetes participants, no major progression was seen after 5 years, but subclinical DSPN regressed in 10.3%. These findings point to an early parallel damage to both small and large nerve fibres in well-controlled recent-onset type 2 and, to a lesser extent, type 1 diabetes. After 5 years peripheral nerve morphology and function and clinical measures progress to the abnormal range in type 2 diabetes, but initial nerve alterations are also reversible to a meaningful degree.

Prevalence of diabetes related vascular complications in subjects with normal glucose tolerance, prediabetes, newly detected diabetes and known diabetes

AIMS

Varying prevalence of individual diabetes related vascular complications in prediabetes has been reported. However, very few studies have looked at both macrovascular and microvascular complications in prediabetes.

METHODS

Study subjects without any history of diabetes underwent oral glucose tolerance test (OGTT) and were classified as either normal glucose tolerance (NGT), prediabetes (PD), newly detected diabetes mellitus (NDDM) on the basis of American Diabetes Association (ADA) criteria. Age and sex matched known diabetes mellitus (KDM) patients were also recruited. All the participants were subsequently screened for both macrovascular (CAD, CVA,PVD) and microvascular (retinopathy, nephropathy and neuropathy)complications of diabetes.

RESULTS

Prevalence of vascular complications among prediabetes subjects was 11.1% as compared to 1.4% among NGT subjects, 13.9% among NDDM subjects and 23.8% among KDM subjects. There was no significant between complication rates in prediabetes and NDDM group (p = 0.060). The prevalence of macrovascular and microvascular complications among prediabetes subjects was 4.2% and 6.9% while the same in NDDM was 4.2% and 9.7%.

CONCLUSIONS

The proportion of subjects with prediabetes and vascular complications was about half of those with known diabetes and almost similar to those with newly detected diabetes mellitus.

Effect of sensorimotor training on spatiotemporal parameters of gait among middle and older age adults with diabetic peripheral neuropathy

PURPOSE

The study aimed to evaluate the effect of sensorimotor training on spatiotemporal parameters of gait among middle-aged and older adults with diabetic peripheral neuropathy (DPN).

METHODS

A randomised controlled study with four parallel arms (two intervention groups and two control groups) was conducted. Thirty-seven DPN patients were selected on the basis of inclusion and exclusion criteria. Of these, 16 middle-aged and 21 older adults were randomly allocated to the intervention and control groups. Participants in the intervention group were administered eight weeks (three days/week) of sensorimotor training along with diabetes and foot care education whereas participants in the control group received only diabetes and foot care education. Outcome measures involved spatiotemporal parameters of gait at self-paced and maximal-paced, measured before and after eight weeks.

RESULTS

Age difference was found to be significant in velocity (p ≤ 0.013) and stride length (p ≤ 0.017) at self-paced and maximal-paced walking. After the intervention, velocity was found to be a significant group effect and time × group interaction at self-paced (p = 0.003) and maximal-paced (p = 0.003) walking. Stride length (p = 0.006) was found to be a significant group effect and time × group interaction at self-paced only. Cadence (p = 0.041) and gait cycle (p = 0.05) were found to be significant time × group interaction only at maximal-paced walking. Stance (p ≤ 0.047) and double limb support (p ≤ 0.02) were found to be significant group effect and time × group interaction at self-paced and maximal-paced walking.

CONCLUSION

Sensorimotor training improves spatiotemporal parameters of gait after eight weeks in similar fashion in middle-aged and older age DPN patients, regardless of age.

Lipids and peripheral neuropathy

PURPOSE OF REVIEW

Hyperlipidaemia is associated with the development of neuropathy. Indeed, a mechanistic link between altered lipid metabolism and peripheral nerve dysfunction has been demonstrated in a number of experimental and clinical studies. Furthermore, post hoc analyses of clinical trials of cholesterol and triglyceride-lowering pharmacotherapy have shown reduced rates of progression of diabetic neuropathy. Given, there are currently no FDA approved disease-modifying therapies for diabetic neuropathy, modulation of lipids may represent a key therapeutic target for the treatment of diabetic nerve damage. This review summarizes the current evidence base on the role of hyperlipidaemia and lipid lowering therapy on the development and progression of peripheral neuropathy.

RECENT FINDINGS

A body of literature supports a detrimental effect of dyslipidaemia on nerve fibres resulting in somatic and autonomic neuropathy. The case for an important modulating role of hypertriglyceridemia is stronger than for low-density lipoprotein cholesterol (LDL-C) in relation to peripheral neuropathy. This is reflected in the outcomes of clinical trials with the different therapeutic agents targeting hyperlipidaemia reporting beneficial or neutral effects with statins and fibrates. The potential concern with the association between proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor therapy and cognitive decline raised the possibility that extreme LDL-C lowering may result in neurodegeneration. However, studies in murine models and data from small observational studies indicate an association between increased circulating PCSK9 levels and small nerve fibre damage with a protective effect of PCSK9i therapy against small fibre neuropathy. Additionally, weight loss with bariatric surgery leads to an improvement in peripheral neuropathy and regeneration of small nerve fibres measured with corneal confocal microscopy in people with obesity with or without type 2 diabetes. These improvements correlate inversely with changes in triglyceride levels.

SUMMARY

Hyperlipidaemia, particularly hypertriglyceridemia, is associated with the development and progression of neuropathy. Lipid modifying agents may represent a potential therapeutic option for peripheral neuropathy. Post hoc analyses indicate that lipid-lowering therapies may halt the progression of neuropathy or even lead to regeneration of nerve fibres. Well designed randomized controlled trials are needed to establish if intensive targeted lipid lowering therapy as a part of holistic metabolic control leads to nerve fibre regeneration and improvement in neuropathy symptoms.

[The role of glycation end products in the development and progression of diabetic neuroarthropathy]

Diabetic neuroarthropathy (DNOAP, Charcot's foot) is a serious complication of diabetes mellitus, the genesis of which is not fully understood. In most cases, this pathology is diagnosed late, which leads to the development of severe deformities of the foot, up to the loss of support ability of the limb. There is no single hypothesis for the formation of Charcot's foot, but there are factors predisposing to its development, as well as a few likely provoking events. Excessive formation and accumulation of end products of glycation may play an important role in the pathogenesis of this complication of diabetes. End products of glycation (AGE) are a variety of compounds formed as a result of a non-enzymatic reaction between carbohydrates and free amino groups of proteins, lipids and nucleic acids. There are various factors that lead to the accumulation of AGE in the human body. Allocate endogenous and exogenous factors. The former include certain diseases, such as diabetes mellitus, renal failure, which accelerate glycation processes. Exogenous factors leading to the formation of lipo-oxidation and glyco-oxidation products include tobacco smoke and prolonged heat treatment of food.This review provides information on the role of glycation end products in the development and progression of complications in patients with diabetes mellitus.

Pathogenesis, diagnosis and clinical management of diabetic sensorimotor peripheral neuropathy

Diabetic sensorimotor peripheral neuropathy (DSPN) is a serious complication of diabetes mellitus and is associated with increased mortality, lower-limb amputations and distressing painful neuropathic symptoms (painful DSPN). Our understanding of the pathophysiology of the disease has largely been derived from animal models, which have identified key potential mechanisms. However, effective therapies in preclinical models have not translated into clinical trials and we have no universally accepted disease-modifying treatments. Moreover, the condition is generally diagnosed late when irreversible nerve damage has already taken place. Innovative point-of-care devices have great potential to enable the early diagnosis of DSPN when the condition might be more amenable to treatment. The management of painful DSPN remains less than optimal; however, studies suggest that a mechanism-based approach might offer an enhanced benefit in certain pain phenotypes. The management of patients with DSPN involves the control of individualized cardiometabolic targets, a multidisciplinary approach aimed at the prevention and management of foot complications, and the timely diagnosis and management of neuropathic pain. Here, we discuss the latest advances in the mechanisms of DSPN and painful DSPN, originating both from the periphery and the central nervous system, as well as the emerging diagnostics and treatments.

Long-Term Use of a Sensory Prosthesis Improves Function in a Patient With Peripheral Neuropathy: A Case Report

Background: Peripheral neuropathy (PN) can result in either partial or complete loss of distal sensation resulting in an increased fall risk. Walkasins® uses a shoe insert to detect the magnitude and direction of sway and sends signals to a leg unit that provides sensory balance cues. The objective of this case report is to describe the long-term influence of the Walkasins® lower limb sensory neuroprosthesis on balance and gait for an individual with diabetic PN. Case Description: A 51-year-old male with a 3-year history of PN and a 10-year history of type II diabetes mellitus was fitted bilaterally with Walkasins® and utilized them 8-10 hours/day for more than 2 years. Although, vibration and tactile sensation thresholds were severely impaired at his 1st metatarsophalangeal joint and the lateral malleolus bilaterally he could perceive tactile stimuli from the Walkasins® above the ankles. Outcomes: Following Walkasins® use, his Activities-specific Balance Confidence Scale (ABC) scores improved from 33 to 80%. His mean Vestibular Activities of Daily Living (VADL) scores decreased from 3.54 to 1. His Functional Gait Assessment (FGA) scores increased from 13/30 to 28/30 and his miniBESTest scores improved from 15/28 to 26/28. Gait speed increased from 0.23 to 1.5 m/s. The patient described a decrease in pain and cramping throughout his lower extremities and an increase in function. Discussion: Gait and balance improved with the use of the Walkasins® and participation in a wellness program. This improvement suggests that the use of sensory substitution devices, such as the Walkasins®, may replace sensory deficits related to gait and balance dysfunction experienced by patients with PN. Further research is needed to determine if other patients will have a similar response and what the necessary threshold of sensory function is to benefit from use of the Walkasins®.

The role of abnormalities of lipoproteins and HDL functionality in small fibre dysfunction in people with severe obesity

Obesity and associated dyslipidemia may contribute to increased cardiovascular disease. Obesity has also been associated with neuropathy. We have investigated presence of peripheral nerve damage in patients with severe obesity without type 2 diabetes and the status of metabolic syndrome and lipoprotein abnormalities. 47participants with severe obesity and 30 age-matched healthy controls underwent detailed phenotyping of neuropathy and an assessment of lipoproteins and HDL-functionality. Participants with severe obesity had a higher neuropathy symptom profile, lower sural and peroneal nerve amplitudes, abnormal thermal thresholds, heart rate variability with deep breathing and corneal nerve parameters compared to healthy controls. Circulating apolipoprotein A1 (P = 0.009), HDL cholesterol (HDL-C) (P < 0.0001), cholesterol efflux (P = 0.002) and paroxonase-1 (PON-1) activity (P < 0.0001) were lower, and serum amyloid A (SAA) (P < 0.0001) was higher in participants with obesity compared to controls. Obese participants with small nerve fibre damage had higher serum triglycerides (P = 0.02), lower PON-1 activity (P = 0.002) and higher prevalence of metabolic syndrome (58% vs. 23%, P = 0.02) compared to those without. However, HDL-C (P = 0.8), cholesterol efflux (P = 0.08), apoA1 (P = 0.8) and SAA (P = 0.8) did not differ significantly between obese participants with and without small nerve fibre damage. Small nerve fibre damage occurs in people with severe obesity. Patients with obesity have deranged lipoproteins and compromised HDL functionality compared to controls. Obese patients with evidence of small nerve fibre damage, compared to those without, had significantly higher serum triglycerides, lower PON-1 activity and a higher prevalence of metabolic syndrome.

Whole plantar nerve conduction study: A new tool for early diagnosis of peripheral diabetic neuropathy

AIMS

Peripheral neuropathy (PN) affects two-thirds of type 2 diabetes patients (T2DM). According to diabetic PN length-dependent pattern, neurophysiological evaluation of foot-sole nerves might increase NCS diagnostic sensitivity, hence allowing early diagnosis of PN. Thus, we aim to assess the ability of whole plantar nerve (WPN) conduction in diabetic PN early diagnosis.

METHODS

This is a single center prospective observational cohort study on 70 T2DM patients referred to Internal Medicine Unit of A.O.U. "Luigi Vanvitelli" between October 2019/October 2020. Primary endpoint was WPN efficacy assessment in PN early detection. As secondary, we evaluated (i) a potential cut-off of SNAPs amplitude by WPN and (ii) WPN diagnostic accuracy vs. gold-standard distal sural nerve conduction.

RESULTS

ROC curve analysis allowed to establish two potential cut-offs for people aged ≤60 years (AUROC: 0.83, 95%CI: 0.69-0.96, p < 0.001) and ≤60 years (AUROC: 0.76, 95%CI: 0.59-0.93, p = 0.017). In depth, we fixed a cut-off of WPN-SNAP amplitude of 4.55 μV and 2.65 μV, respectively, with subsequent 48 patients classified as PN-T2DM.

CONCLUSIONS

Our data support WPN conduction study reliability in characterizing the most distal sensory nerve fibers at lower limbs. Thus, WPN may represent an extremely useful diagnostic tool for diabetic PN early detection.

The determinants of complication trajectories in American Indians with type 2 diabetes

BACKGROUNDWe aimed to determine whether metabolic syndrome (MetS) affects longitudinal trajectories of diabetic complications, including neuropathy, cardiovascular autonomic neuropathy (CAN), and kidney disease in American Indians with type 2 diabetes.METHODSWe performed a prospective study where participants underwent annual metabolic phenotyping and outcome measurements. The updated National Cholesterol Education Program criteria were used to define MetS and its individual components, using BMI instead of waist circumference. Neuropathy was defined using the Michigan Neuropathy Screening Instrument index, CAN with the expiration/inspiration ratio, and kidney disease with glomerular filtration rate. Mixed-effects models were used to evaluate associations between MetS and these outcomes.RESULTSWe enrolled 141 participants: 73.1% female, a mean (±SD) age of 49.8 (12.3), and a diabetes duration of 19.6 years (9.7 years) who were followed for a mean of 3.1 years (1.7 years). MetS components were stable during follow-up except for declining obesity and cholesterol. Neuropathy (point estimate [PE]: 0.30, 95% CI: 0.24, 0.35) and kidney disease (PE: -14.2, 95% CI: -16.8, -11.4) worsened over time, but CAN did not (PE: -0.002, 95% CI: -0.006, 0.002). We found a significant interaction between the number of MetS components and time for neuropathy (PE: 0.05, 95% CI: 0.01-0.10) but not CAN (PE: -0.003, 95% CI: -0.007, 0.001) or kidney disease (PE: -0.69, 95% CI: -3.16, 1.76). Systolic blood pressure (SBP, unit = 10 mmHg) was associated with each complication: neuropathy (PE: 0.23, 95% CI: 0.07, 0.39), CAN (PE: -0.02, 95% CI: -0.03, -0.02), and kidney disease (PE: -10.2, 95% CI: -15.4, -5.1).CONCLUSIONIn participants with longstanding diabetes, neuropathy and kidney disease worsened during follow-up, despite stable to improving MetS components, suggesting that early metabolic intervention is necessary to prevent complications in such patients. Additionally, the number of MetS components was associated with an increased rate of neuropathy progression, and SBP was associated with each complication.FUNDINGThe following are funding sources: NIH T32NS0007222, NIH R24DK082841, NIH R21NS102924, NIH R01DK115687, the Intramural Program of the NIDDK, the NeuroNetwork for Emerging Therapies, the Robert and Katherine Jacobs Environmental Health Initiative, the Robert E. Nederlander Sr. Program for Alzheimer's Research, and the Sinai Medical Staff Foundation.TRIAL REGISTRATIONClinicalTrials.gov, NCT00340678.

Prevalence of peripheral neuropathy in pre-diabetes: a systematic review

There is growing evidence of excess peripheral neuropathy in pre-diabetes. We aimed to determine its prevalence, including the impact of diagnostic methodology on prevalence rates, through a systematic review conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive electronic bibliographic search was performed in MEDLINE, EMBASE, PubMed, Web of Science and the Cochrane Central Register of Controlled Trials from inception to June 1, 2020. Two reviewers independently selected studies, extracted data and assessed risk of bias. An evaluation was undertaken by method of neuropathy assessment. After screening 1784 abstracts and reviewing 84 full-text records, 29 studies (9351 participants) were included. There was a wide range of prevalence estimates (2%-77%, IQR: 6%-34%), but the majority of studies (n=21, 72%) reported a prevalence ≥10%. The three highest prevalence estimates of 77% (95% CI: 54% to 100%), 71% (95% CI: 55% to 88%) and 66% (95% CI: 53% to 78%) were reported using plantar thermography, multimodal quantitative sensory testing and nerve conduction tests, respectively. In general, studies evaluating small nerve fiber parameters yielded a higher prevalence of peripheral neuropathy. Due to a variety of study populations and methods of assessing neuropathy, there was marked heterogeneity in the prevalence estimates. Most studies reported a higher prevalence of peripheral neuropathy in pre-diabetes, primarily of a small nerve fiber origin, than would be expected in the background population. Given the marked rise in pre-diabetes, further consideration of targeting screening in this population is required. Development of risk-stratification tools may facilitate earlier interventions.

Sex differences in insulin resistance, but not peripheral neuropathy, in a diet-induced prediabetes mouse model

Peripheral neuropathy (PN) is a common complication of prediabetes and diabetes and is an increasing problem worldwide. Existing PN treatments rely solely on glycemic control, which is effective in type 1 but not type 2 diabetes. Sex differences in response to anti-diabetic drugs further complicate the identification of effective PN therapies. Preclinical research has been primarily carried out in males, highlighting the need for increased sex consideration in PN models. We previously reported PN sex dimorphism in obese leptin-deficient ob/ob mice. This genetic model is inherently limited, however, owing to leptin's role in metabolism. Therefore, the current study goal was to examine PN and insulin resistance in male and female C57BL6/J mice fed a high-fat diet (HFD), an established murine model of human prediabetes lacking genetic mutations. HFD mice of both sexes underwent longitudinal phenotyping and exhibited expected metabolic and PN dysfunction compared to standard diet (SD)-fed animals. Hindpaw thermal latencies to heat were shorter in HFD females versus HFD males, as well as SD females versus males. Compared to HFD males, female HFD mice exhibited delayed insulin resistance, yet still developed the same trajectory of nerve conduction deficits and intraepidermal nerve fiber density loss. Subtle differences in adipokine levels were also noted by sex and obesity status. Collectively, our results indicate that although females retain early insulin sensitivity upon HFD challenge, this does not protect them from developing the same degree of PN as their male counterparts. This article has an associated First Person interview with the first author of the paper.

Reversion From Pre-Diabetes Mellitus to Normoglycemia and Risk of Cardiovascular Disease and All-Cause Mortality in a Chinese Population: A Prospective Cohort Study

Background

It is unclear whether reversion from pre–diabetes mellitus to normoglycemia reduces cardiovascular disease (CVD) and all‐cause mortality risk in a Chinese population. We aimed to fill this research gap.

Methods and Results

The current study included 14 231 Chinese participants (mean age, 58.08 years) who were free from myocardial infarction and stroke at the time of survey participation (2006–2007 and 2008–2009). Participants were divided into 3 categories according to the 2‐year changes in pre–diabetes mellitus, defined by fasting plasma glucose: those with progression to diabetes mellitus, those with reversion from pre–diabetes mellitus to normoglycemia, and those with persistent pre–diabetes mellitus. Cox proportional hazards models were used to calculate hazard ratios (HRs) and their 95% CIs for CVD and all‐cause mortality. After a median follow‐up period of 8.75 years, a total of 879 CVD events (including 180 myocardial infarction events and 713 stroke events) and 941 all‐cause mortality events were recorded. After adjustment for confounding factors, reversion from pre–diabetes mellitus to normoglycemia was associated with decreased risks of CVD (HR, 0.78; 95% CI, 0.64–0.96), myocardial infarction (HR, 0.62; 95% CI, 0.40–0.97), stroke (HR, 0.79; 95% CI, 0.63–0.98), and all‐cause mortality (HR, 0.82; 95% CI, 0.68–0.99) compared with progression to diabetes mellitus.

Conclusions

Reversion from fasting plasma glucose–defined pre–diabetes mellitus to normoglycemia was associated with a reduction in the future risk of CVD and all‐cause mortality in a Chinese population.

Registration

URL: https://www.chictr.org; Unique identifier: ChiCTRTNC‐11001489.

A systematic review and meta-analysis of the serum lipid profile in prediction of diabetic neuropathy

Whether the lipid profile in diabetic patients is associated with diabetic neuropathy (DN) development remains ambiguous, as does the predictive value of serum lipid levels in the risk of DN. Here, we performed the first meta-analysis designed to investigate the relationship between DN and the serum levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL). Candidate studies were comprehensively identified by searching PubMed, Embase, Cochrane Library and Web of Science databases up to May 2020. Observational methodological meta-analysis was conducted to assess the relationships of TG, TC, HDL, and LDL levels with DN. Changes in blood lipids were used to estimate the effect size. The results were pooled using a random-effects or fixed-effects model. Potential sources of heterogeneity were explored by subgroup analysis. Various outcomes were included, and statistical analyses were performed using STATA (Version 12.0). Mean differences (MDs) and odds ratios (ORs) with 95% confidence intervals (CIs) were estimated. The Newcastle–Ottawa Scale (NOS) was applied to assess the methodological quality. I2 statistics were calculated to evaluate statistical heterogeneity. Funnel plots were utilized to test for publication bias. A sensitivity analysis was performed by omitting each study one by one. Thirty-nine clinical trials containing 32,668 patients were included in the meta-analysis. The results demonstrated that DN patients showed higher TG and lower HDL levels (MD = 0.34, 95% CI: 0.20–0.48 for TG; MD = -0.05, 95% CI: -0.08–-0.02, I² = 81.3% for HDL) than controls. Subgroup analysis showed that patients with type 1 diabetes mellitus (T1DM) neuropathy had elevated TG levels in their serum (MD = 0.25, 95% CI: 0.16–0.35,I² = 64.4% for T1DM). However, only patients with T1DM neuropathy had reduced serum HDL levels, and there was no significant difference in serum HDL levels between patients with T2DM neuropathy and controls (MD = -0.07, 95% CI: -0.10–-0.03, I² = 12.4% for T1DM; MD = -0.02, 95% CI: -0.07–0.03, I² = 80.2% for T2DM). TC and LDL levels were not significantly different between DN patients and controls (MD = -0.03, 95% CI: -0.14–0.09, I² = 82.9% for TC; MD = -0.00, 95% CI: -0.08–0.08, I² = 78.9% for LDL). In addition, compared with mild or painless DN patients, those with moderate or severe pain DN pain had significantly reduced serum TC and LDL levels (MD = -0.31, 95% CI: -0.49–-0.13, I² = 0% for TC; MD = -0.19, 95% CI: -0.32–-0.08, I² = 0% for LDL). TG levels and HDL levels did not vary considerably between patients with mild or painless DN and those with moderate or severe DN pain patients (MD = 0.12, 95% CI: -0.28–0.51, I² = 83.2% for TG; MD = -0.07, 95% CI:-0.14–0.01, I² = 58.8% for HDL). Furthermore, people with higher TG and LDL levels had higher risk of DN (OR = 1.36, 95% CI: 1.20–1.54, I² = 86.1% for TG and OR = 1.10, 95% CI: 1.02–1.19, I² = 17.8% for LDL). Conversely, high serum HDL levels reduced the risk of DN (OR = 0.85, 95% CI: 0.75–0.96, I² = 72.6%), while TC levels made no significant difference with the risk of DN (OR = 1.02, 95% CI: 1.00–1.04, I² = 84.7%). This meta-analysis indicated that serum lipid profile changes are among the biological characteristics of DN. Lipid levels should be explored as routine laboratory markers for predicting the risk of DN, as they will help clinicians choose appropriate therapies, and thus optimize the use of available resources.

Association Between Obesity and Microvascular Diseases in Patients With Type 2 Diabetes Mellitus

This study aimed to evaluate the association between obesity, evaluated by fat mass index (FMI) with the risk of microvascular diseases in patients with type 2 diabetes mellitus (T2DM) and compare the magnitude of associations of FMI, body mass index (BMI), and waist circumference (WC) with the risk of microvascular diseases. We performed a post-hoc analysis of the Action to Control Cardiovascular Risk in Diabetes study. The primary microvascular outcomes of the present study included chronic kidney disease (CKD) progression, retinopathy, and neuropathy. Cox proportional-hazards models were performed to evaluate the association of FMI with microvascular diseases. A discordant analysis was performed to compare the magnitude of associations of FMI, BMI, and WC with the risk of microvascular diseases. Our study included 10,251 T2DM participants with a median of 5 years (interquartile range, 4.2-5.7) of follow-up. A total of 6,184 participants developed CKD progression, 896 participants had retinopathy, and 3,213 participants developed neuropathy (Michigan Neuropathy Screening Instrument, >2.0). After the confounding factors were adjusted for, patients in the highest FMI quartile had a higher risk of CKD progression (HR: 1.26, 95%CI: 1.16-1.36) and neuropathy (HR: 1.93, 95% CI: 1.74-2.15), except for retinopathy (HR: 1.17, 95% CI: 0.96-1.43), than those in the lowest quartile. Discordant analyses found that FMI and WC are better in identifying individuals with obesity-related risk of neuropathy, compared with BMI; neither is better in identifying individuals with obesity-related risk of CKD progression and retinopathy. Obesity is associated with CKD progression and neuropathy in T2DM participants. Further randomized trials are needed to test whether obesity control can improve the outcomes of T2DM participants with CKD or neuropathy. FMI and WC are more useful in identifying obesity-related risk of neuropathy compared with BMI in T2DM patients.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov, NCT00000620.