The prevalence of cardiac autonomic neuropathy in prediabetes: a systematic review

Electrodiagnostic assessment of autonomic nervous system in diabetic autonomic neuropathy: Case series in 72 diabetes patients

Diabetic autonomic neuropathy is one of the most common complications of diabetes which is asymptomatic in early stage. Hence HRV and AFT are performed to detect and prevent its progression to advanced stages. To discuss the HRV and AFT findings in diabetic patients. An observational study was conducted in Physiology department of AIIMS, Bhopal in collaboration with the Medicine department of the institute. Seventy-two diagnosed Type-2 Diabetes mellitus patients were examined using POWER LAB AND LAB CHART 8 BY AD INSTRUMENT: For recording heart rate variability (HRV) and Ewing's battery of tests: For Autonomic function testing. Microsoft Excel was utilized for data compilation and for result analysis. In the present study, based on HRV parameters sympathetic involvement was seen in 39% while parasympathetic involvement was seen in 15% of patients. Balanced state was observed in 46% of the patients. Based on AFT battery, normal early involvement was observed in 62% of the patients while definite and severe involvement was observed in 14 and 24%, respectively. Diabetic autonomic neuropathy was observed in 72% of the patients based on HRV and AFT testing. In severe involvement, orthostatic hypotension was seen. Severe involvement was observed in 24% of the patients in present study. Involvement of the vagal parasympathetic component of ANS was obvious evidenced by increase in resting heart rate, decrease in Valsalva ratio, E/I index, and standing ratio. Diabetic autonomic neuropathy was observed in majority of patients with normal early involvement seen predominantly and though majority of them were in balanced state, sympathetic involvement was also seen at large. HRV studies depicted a decrease of total power, decreased low frequency (LF) and high frequency (HF) with LF/HF and SD1/SD2 ratios depicting sympathetic involvement.

Heart Rate Variability in Relation to Cardiovascular Autonomic Neuropathy Among Patients at an Urban Hospital in Kazakhstan

In clinical practice, heart rate variability (HRV) has not been considered an indicator for the preventive assessment of cardiovascular autonomic neuropathy (CAN). The paper studies HRV in a large, randomly selected group. A cross-sectional study included a representative sample of 5707 Kazakhs aged 20 years and older from a total population of 25,454 attached to an urban clinic in the capital of Kazakhstan. The sample was drawn from individuals who visited the clinic for a preventive examination. CAN diagnosis was confirmed using data from questionnaires, electronic medical records, HRV, and heart rate measurements. Mean values of the standard deviation of normal sinus RR intervals (SDNN) and the root mean square of successive RR interval differences (RMSSDs) from a 24 h electrocardiogram recording were assessed. CAN was identified in 17.19% of the study participants, with a ratio of the subclinical to clinical phase of 1:0.24. Diabetes mellitus was present in 30.99% of patients with CAN. The prevalence of CAN varied by sex and age, aligning with the prevalence trajectory of diabetes. It was concluded that the SDNN and RMSSD parameters in electrocardiographic studies can be used for preventive measures in the context of limited healthcare resources.

Cardiovascular autonomic neuropathy in diabetes: an update with a focus on management

Cardiovascular autonomic neuropathy (CAN) is an under-recognised yet highly prevalent microvascular complication of diabetes. CAN affects approximately 20% of people with diabetes, with recent studies highlighting the presence of CAN in prediabetes (impaired glucose tolerance and/or impaired fasting glucose), indicating early involvement of the autonomic nervous system. Understanding of the pathophysiology of CAN continues to evolve, with emerging evidence supporting a potential link between lipid metabolites, mitochondrial dysfunction and genetics. Recent advancements, such as streamlining CAN detection through wearable devices and monitoring of heart rate variability, present simplified and cost-effective approaches for early CAN detection. Further research on the optimal use of the extensive data provided by such devices is required. Despite the lack of specific pharmacological interventions targeting the underlying pathophysiology of autonomic neuropathy, several studies have suggested a favourable impact of newer glucose-lowering agents, such as sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide-1 receptor agonists, where there is a wealth of clinical trial data on the prevention of cardiovascular events. This review delves into recent developments in the area of CAN, with emphasis on practical guidance to recognise and manage this underdiagnosed condition, which significantly increases the risk of cardiovascular events and mortality in diabetes.

Compromised cardiac autonomic function in non-diabetic subjects with 1 h post-load hyperglycemia: a cross-sectional study

BACKGROUND

A compromised cardiac autonomic function has been found in subjects with insulin resistance related disorders such as obesity, impaired glucose tolerance (IGT) and type 2 diabetes and confers an increased risk of adverse cardiovascular outcomes. Growing evidence indicate that 1 h plasma glucose levels (1hPG) during an oral glucose tolerance test (OGTT) ≥ 155 mg/dl identify amongst subjects with normal glucose tolerance (NGT) a new category of prediabetes (NGT 1 h-high), harboring an increased risk of cardiovascular organ damage. In this study we explored the relationship between 1 h post-load hyperglycemia and cardiac autonomic dysfunction.

METHODS

Presence of cardiac autonomic neuropathy (CAN) defined by cardiovascular autonomic reflex tests (CARTs) and heart rate variability (HRV), assessed by 24-h electrocardiography were evaluated in 88 non-diabetic subjects subdivided on the basis of OGTT data in: NGT with 1 h PG < 155 mg/dl (NGT 1 h-low), NGT 1 h-high and IGT.

RESULTS

As compared to subjects with NGT 1 h-low, those with NGT 1 h-high and IGT were more likely to have CARTs defined CAN and reduced values of the 24 h time domain HVR parameters including standard deviation of all normal heart cycles (SDNN), standard deviation of the average RR interval for each 5 min segment (SDANN), square root of the differences between adjacent RR intervals (RMSSD), percentage of beats with a consecutive RR interval difference > 50 ms (PNN50) and Triangular index. Univariate analyses showed that 1hPG, but not fasting and 2hPG, was inversely associated with all the explored HVR parameters and positively with CARTs determined presence of CAN. In multivariate regression analysis models including several confounders we found that 1hPG was an independent contributor of HRV and presence of CAN.

CONCLUSION

Subjects with 1hPG ≥ 155 mg/dl have an impaired cardiac autonomic function.

Association of high-sensitivity troponin T with left ventricular dysfunction in prediabetes

BACKGROUND

Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are an increasingly serious problem worldwide. Tissue Doppler imaging (TDI), a non-invasive technique, may evaluate both systolic and diastolic function during the first phases of cardiovascular disease (CVD). High-sensitivity cardiac troponin T (hs-cTnT) can detect subclinical myocardial injury in asymptomatic prediabetic patients.

AIM

We aimed to investigate the relationship between left ventricular (LV) function and hs-cTnT in prediabetic patients.

METHODS

Between 1 October 2021 and 1 October 2022, we recruited 96 prediabetic and an equal number of age- and gender-matched healthy volunteers prospectively. TDI was used to evaluate both systolic and diastolic functions. Hs-cTnT levels were obtained and compared between groups.

RESULTS

It was found that the values for mitral annular plane systolic excursion (MAPSE), E, the rapid filling wave, E/Em, and the peak annular velocities of systolic excursion in the ejection period (Sm) were all significantly higher in these patients compared to healthy individuals (p < .001). Hs-cTnT was an independent predictor of left ventricular diastolic dysfunction (LVDD) and left ventricular systolic dysfunction (LVSD) (odds ratio [OR] = 2.625, 95% confidence interval [CI] = 1.324-4.308, p < .001, and OR = 1.922, 95% CI = 0.454-3.206, p = .004).

CONCLUSIONS

Prediabetics had higher hs-cTnT levels than controls. We showed that LVSD and LVDD functions were negatively affected in prediabetic patients. Our results proved that hs-cTnT levels may be associated with subclinical LV dysfunction in prediabetes.

The Relationship between the Ewing Test, Sudoscan Cardiovascular Autonomic Neuropathy Score and Cardiovascular Risk Score Calculated with SCORE2-Diabetes

Background and Objectives: Cardiac autonomic neuropathy (CAN) is a severe complication of diabetes mellitus (DM) strongly linked to a nearly five-fold higher risk of cardiovascular mortality. Patients with Type 2 Diabetes Mellitus (T2DM) are a significant cohort in which these assessments have particular relevance to the increased cardiovascular risk inherent in the condition. Materials and Methods: This study aimed to explore the subtle correlation between the Ewing test, Sudoscan-cardiovascular autonomic neuropathy score, and cardiovascular risk calculated using SCORE 2 Diabetes in individuals with T2DM. The methodology involved detailed assessments including Sudoscan tests to evaluate sudomotor function and various cardiovascular reflex tests (CART). The cohort consisted of 211 patients diagnosed with T2DM with overweight or obesity without established ASCVD, aged between 40 to 69 years. Results: The prevalence of CAN in our group was 67.2%. In the study group, according SCORE2-Diabetes, four patients (1.9%) were classified with moderate cardiovascular risk, thirty-five (16.6%) with high risk, and one hundred seventy-two (81.5%) with very high cardiovascular risk. Conclusions: On multiple linear regression, the SCORE2-Diabetes algorithm remained significantly associated with Sudoscan CAN-score and Sudoscan Nephro-score and Ewing test score. Testing for the diagnosis of CAN in very high-risk patients should be performed because approximately 70% of them associate CAN. Increased cardiovascular risk is associated with sudomotor damage and that Sudoscan is an effective and non-invasive measure of identifying such risk.

Genetic markers of cardiac autonomic neuropathy in the Kazakh population

BACKGROUND

Cardiac autonomic neuropathy (CAN) is a complication of diabetes mellitus (DM) that increases the risk of morbidity and mortality by disrupting cardiac innervation. Recent evidence suggests that CAN may manifest even before the onset of DM, with prediabetes and metabolic syndrome potentially serving as precursors. This study aims to identify genetic markers associated with CAN development in the Kazakh population by investigating the SNPs of specific genes.

MATERIALS AND METHODS

A case-control study involved 82 patients with CAN (cases) and 100 patients without CAN (controls). A total of 182 individuals of Kazakh nationality were enrolled from a hospital affiliated with the RSE "Medical Center Hospital of the President's Affairs Administration of the Republic of Kazakhstan". 7 SNPs of genes FTO, PPARG, SNCA, XRCC1, FLACC1/CASP8 were studied. Statistical analysis was performed using Chi-square methods, calculation of odds ratios (OR) with 95% confidence intervals (CI), and logistic regression in SPSS 26.0.

RESULTS

Among the SNCA gene polymorphisms, rs2737029 was significantly associated with CAN, almost doubling the risk of CAN (OR 2.03(1.09-3.77), p = 0.03). However, no statistically significant association with CAN was detected with the rs2736990 of the SNCA gene (OR 1.00 CI (0.63-1.59), p = 0.99). rs12149832 of the FTO gene increased the risk of CAN threefold (OR 3.22(1.04-9.95), p = 0.04), while rs1801282 of the PPARG gene and rs13016963 of the FLACC1 gene increased the risk twofold (OR 2.56(1.19-5.49), p = 0.02) and (OR 2.34(1.00-5.46), p = 0.05) respectively. rs1108775 and rs1799782 of the XRCC1 gene were associated with reduced chances of developing CAN both before and after adjustment (OR 0.24, CI (0.09-0.68), p = 0.007, and OR 0.43, CI (0.22-0.84), p = 0.02, respectively).

CONCLUSION

The study suggests that rs2737029 (SNCA gene), rs12149832 (FTO gene), rs1801282 (PPARG gene), and rs13016963 (FLACC1 gene) may be predisposing factors for CAN development. Additionally, SNPs rs1108775 and rs1799782 (XRCC1 gene) may confer resistance to CAN. Only one polymorphism rs2736990 of the SNCA gene was not associated with CAN.

MORTALITY AND CARDIOVASCULAR RISK REDUCTION AFTER REVERSION OF PREDIABETES TO NORMOGLYCEMIA: A SYSTEMATIC REVIEW

Introduction

It is unclear whether reversion to normoglycemia decreases overall cardiovascular events and all-cause mortality risk in the long term. We aim to investigate the magnitude of change in cardiovascular risk and mortality in patients who reverted from a prediabetes state.

Methods

Three electronic databases, including PubMed, Proquest, and EBSCOHost databases, were utilized. A manual hand search of articles was also done. We selected studies that measure cardiovascular risk and all-cause mortality risk after reversion from prediabetes to normoglycemia. The following terms and its variant were used in the search strategy: 'reversion,' 'prediabetes,' 'normoglycemia,' cardiovascular risk,' and 'mortality.'

Results

Seven studies with a total of 73,845 participants were obtained. Most studies suggest that reversion of prediabetes reduced the cardiovascular and all-cause mortality risk (RR: 0.50 - 0.78) compared to persistent prediabetes state or progression to diabetes with long-term follow-up ranging from 5 to 12 years, while two studies did not show significant association in CVD and all-cause morality risk.

Conclusion

Although there were mixed results regarding if prediabetes poses a higher risk than normoglycemia for cardiovascular events and all-cause mortality, measures to normalize blood glucose for prediabetes should still be advocated.

Modifications of long-term heart rate variability produced in an experimental model of diet-induced metabolic syndrome

Metabolic syndrome (MetS) has been linked to a higher prevalence of cardiac arrhythmias, the most frequent being atrial fibrillation, but the mechanisms are not well understood. One possible underlying mechanism may be an abnormal modulation of autonomic nervous system activity, which can be quantified by analysing heart rate variability (HRV). Our aim was to investigate the modifications of long-term HRV in an experimental model of diet-induced MetS to identify the early changes in HRV and the link between autonomic dysregulation and MetS components. NZW rabbits were randomly assigned to control (n = 10) or MetS (n = 10) groups, fed 28 weeks with high-fat, high-sucrose diet. 24-hour recordings were used to analyse HRV at week 28 using time-domain, frequency-domain and nonlinear analyses. Time-domain analysis showed a decrease in RR interval and triangular index (Ti). In the frequency domain, we found a decrease in the low frequency band. Nonlinear analyses showed a decrease in DFA-α1 and DFA-α2 (detrended fluctuations analysis) and maximum multiscale entropy. The strongest association between HRV parameters and markers of MetS was found between Ti and mean arterial pressure, and Ti and left atrial diameter, which could point towards the initial changes induced by the autonomic imbalance in MetS.

Epidemiology and Functional Impact of Early Peripheral Neuropathy Signs in Older Adults from a General Population

INTRODUCTION

Peripheral neuropathy (PN) becomes more common with increasing life expectancy, but general population prevalence estimates are lacking. We investigated an epidemiological distribution of signs of PN among 2,996 community-dwelling participants in Good Aging in Skåne Study, age 60-97, and their impact on physical and autonomic function.

METHODS

Signs of PN were measured with Utah Early Neuropathy Scale (UENS). Associations between UENS and physical tests, pain, and dysautonomic phenomena were calculated for each sex, adjusted for age, with estimated marginal means (EMM) and odds ratios (ORs) in four UENS quantiles (Q1-Q4).

RESULTS

Participants in Q4 had worse EMM for: time to complete Timed Up and Go test (Q4-Q1: male 10.8-9.6 s; female 11.7-10.2 s), 15 m Walk test (Q4-Q1: male 11.1-9.9 s; female 11.2-10.4 s), and fewer repetitions in Step test (Q4-Q1: male 15.2-17.0 steps; female 14.5-15.8 steps). Higher OR of failing one-leg balance 60 s test {male 2.5 (confidence interval [CI] 95%: 1.7-3.8); female 2.1 (1.1-3.2)}, Foam Pad Balance test (male 4.6 [CI 95%: 3.2-6.7]; female 1.8 [1.3-2.6]), and lower physical quality of life were seen in Q4 compared to Q1. Participants in Q4 had higher OR for walking aid usage, falls, fear of falling, pain, and urinary incontinence, while in males, higher OR for orthostatic intolerance, fecal incontinence, and constipation.

CONCLUSIONS

In a general population, 20-25% of older adults who have highest UENS scores, a sensitive measure of early PN, express slower gait, worse balance, lower quality of life, pain, falls and fear of falling, and autonomic symptoms.

Prediabetes is an incremental risk factor for adverse cardiac events: A nationwide analysis

Background and aims

Prediabetes is defined as a state of impaired glucose metabolism with hemoglobin A1c (HbA1c) levels that precede those of a diabetic state. There is increasing evidence that suggests that hyperglycemic derangement in prediabetes leads to microvascular and macrovascular complications even before progression to overt diabetes mellitus. We aim to identify the association of prediabetes with acute cardiovascular events.

Methods

We utilized the National inpatient sample 2018-2020 to identify adult hospitalizations with prediabetes after excluding all hospitalizations with diabetes. Demographics and prevalence of other cardiovascular risk factors were compared in hospitalizations with and without prediabetes using the chi-square test for categorical variables and the t-test for continuous variables. Multivariate regression analysis was further performed to study the impact of prediabetes on acute coronary syndrome, acute ischemic stroke, intracranial hemorrhage, and acute heart failure.

Results

Hospitalizations with prediabetes had a higher prevalence of cardiovascular risk factors like hypertension, hyperlipidemia, obesity, and tobacco abuse. In addition, the adjusted analysis revealed that hospitalizations with prediabetes were associated with higher odds of developing acute coronary syndrome (OR-2.01; C.I:1.94-2.08; P<0.001), acute ischemic stroke (OR-2.21; 2.11-2.31; p<0.001), and acute heart failure (OR-1.41; C.I.: 1.29-1.55; p<0.001) as compared to hospitalizations without prediabetes.

Conclusions

Our study suggests that prediabetes is associated with a higher odds of major cardiovascular events. Further prospective studies should be conducted to identify prediabetes as an independent causative factor for these events. In addition, screening and lifestyle modifications for prediabetics should be encouraged to improve patient outcomes.

Diabetic Neuropathies

OBJECTIVE

This article provides an up-to-date review of the diagnosis and management of the most common neuropathies that occur in patients with diabetes.

LATEST DEVELOPMENTS

The prevalence of diabetes continues to grow worldwide and, as a result, the burden of diabetic neuropathies is also increasing. Most diabetic neuropathies are caused by hyperglycemic effects on small and large fiber nerves, and glycemic control in individuals with type 1 diabetes reduces neuropathy prevalence. However, among people with type 2 diabetes, additional factors, particularly metabolic syndrome components, play a role and should be addressed. Although length-dependent distal symmetric polyneuropathy is the most common form of neuropathy, autonomic syndromes, particularly cardiovascular autonomic neuropathy, are associated with increased mortality, whereas lumbosacral radiculoplexus neuropathy and treatment-induced neuropathy cause substantial morbidity. Recent evidence-based guidelines have updated the recommended treatment options to manage pain associated with distal symmetric polyneuropathy of diabetes.

ESSENTIAL POINTS

Identifying and appropriately diagnosing the neuropathies of diabetes is key to preventing progression. Until better disease-modifying therapies are identified, management remains focused on diabetes and metabolic risk factor control and pain management.

Cardiovascular autonomic neuropathy is associated with increased glycemic variability driven by hyperglycemia rather than hypoglycemia in patients with diabetes

AIM

Cardiac autonomic neuropathy (CAN) has been suggested to be associated with hypoglycemia and impaired hypoglycemia unawareness. We have assessed the relationship between CAN and extensive measures of glucose variability (GV) in patients with type 1 and type 2 diabetes.

METHODS

Participants with diabetes underwent continuous glucose monitoring (CGM) to obtain measures of GV and the extent of hyperglycemia and hypoglycemia and cardiovascular autonomic reflex testing.

RESULTS

Of the 40 participants (20 T1DM and 20 T2DM) (aged 40.70±13.73 years, diabetes duration 14.43±7.35 years, HbA1c 8.85±1.70%), 23 (57.5%) had CAN. Despite a lower coefficient of variation (CV) (31.26±11.87 vs. 40.33±11.03, P=0.018), they had a higher CONGA (8.42±2.58 vs. 6.68±1.88, P=0.024) with a lower median LBGI (1.60 (range: 0.20-3.50) vs. 4.90 (range: 3.20-7.40), P=0.010) and percentage median time spent in hypoglycemia (4 (range:4-13) vs. 1 (range:0-5), P=0.008), compared to those without CAN. The percentage GRADE_Euglycemia (3.30±2.78 vs. 5.69±3.09, P=0.017) and GRADE_Hypoglycemia (0.3 (range: 0 - 3.80) vs. 1.8 (range: 0.9-6.5), P=0.036) were significantly lower, while the percentage median GRADE_{Hyperglycemia} (95.45 (range:93-98) vs. 91.6 (82.8-95.1), P=0.013) was significantly higher in participants with CAN compared to those without CAN.

CONCLUSION

CAN was associated with increased glycemic variability with less time in euglycemia attributed to a greater time in hyperglycemia but not hypoglycemia.

A Comparative Cross-Sectional Study of Cardiac Autonomic Status by Five Minute Heart Rate Variability among Type 2 Diabetics, Hypertensives and Normotensive-Nondiabetics

Background

Diabetes and hypertension are known to co-exist frequently as adverse cardiovascular risk factors. Both can produce cardiac autonomic neuropathythat can be measured by ECG RR interval-based heart rate variability (HRV). We compared 5 minutes HRV in four groups based on diabetes and hypertension.

Methodology

A cross sectional study was done on 203 participants divided into four groups- diabetics, hypertensives, diabetic-hypertensives and normotensive-nondiabetics. They were evaluated for current disease control and five minutes HRV was done in supine condition following standard protocols by Variowin HR Software. HRV parameters of time domain, frequency domain and Poincare plot were compared between groups and associated with gender, glycaemic control and blood pressure control. Statistical significance was set at p<0.05.

Results

Three diseasedgroups had mean age in mid-fifties, mean duration of disease > 6 years, comparable BMI, poor glycaemic and blood pressure control. As compared to normal groups, three diseased groups exhibit reduced HRV with respect to all three domains of HRV with varying statistical significance. Among diseased groups, HRV was associated with blood pressure control better than glycaemic control but not with gender. LF /HF ratio was the most consistent HRV parameter showing statistical significance in tests.

Conclusion

HRV is reduced in both diabetics more than hypertensives; related to blood pressure control more than glycaemic control. It points altered cardiac autonomic balance, and possibility of cardiovascular risk and early detection of it with timely intervention. It also calls for investigation of same for reinforcement of our observations and further exploration.

Effects of Therapeutic Calf Massage on Cardiac Autonomic Function in Healthy Volunteers-a Pilot Study

Background

Calf massage is a therapeutic intervention that improves circulation and relieves us from pain & tightness. The calf massage also improves autonomic performance by modulating the vagal tone of the cardiovascular system. Therefore, the current study was intended to determine therapeutic calf massage on cardio autonomic activity in healthy subjects.

Objective

To assess the immediate effect of a single 20-min session of calf massage on cardiac autonomic modulation through heart rate variability (HRV) measurement.

Materials & Methods

In this study, 26 apparent healthy female participants aged between 18 and 25 years participated. Massage over the calf muscles on both legs for 20 min was performed, and resting cardiovascular parameters and HRV parameters were measured at baseline, immediately after the massage, and during the recovery periods (10 and 30 min after the massage). Data were analyzed using one-way ANOVA followed with post hoc analysis.

Results

Immediately after the massage intervention, heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressure were decreased (p < .01), and the reduction was persisted at 10 min and 30 min of the recovery period (p < .01). In HRV parameters, the root mean square of successive differences (RMSSD) and high-frequency normalized unit (HF n.u.) increased, and low frequency (LF n.u.) decreased after the massage, and at the 10 and 30 min of the recovery period.

Conclusion

The present study reports suggest a significant reduction in heart rate and blood pressure after the massage therapy. A drop in sympathetic tone and raise in parasympathetic tone can also attribute to the therapeutic effect.

Parasympathetic tonus in type 2 diabetes and pre-diabetes and its clinical implications

Autonomic imbalance reflected by higher resting heart rate and reduced parasympathetic tone may be driven by low-grade inflammation (LGI) and impaired glycemic control in type 2 diabetes mellitus (T2DM) and pre-diabetes. We examined the interaction of parasympathetic components of heart rate variability (HRV), variables of LGI, and glucose metabolism in people with T2DM, pre-diabetes, and normal glucose metabolism (NGM). We recorded HRV by Holter (48 h) in 633 community-dwelling people of whom T2DM n = 131, pre-diabetes n = 372, and NGM n = 130 and mean HbA1c of 7.2, 6.0 and 5.3%, respectively. Age was 55-75 years and all were without known cardiovascular disease except from hypertension. Fasting plasma glucose, fasting insulin, HOMA-IR, HbA1c and LGI (CRP, Interleukin-18 (IL-18), and white blood cells) were measured. Root-mean-square-of-normal-to-normal-beats (RMSSD), and proportion of normal-to-normal complexes differing by more than 50 ms (pNN50) are accepted measures of parasympathetic activity. In univariate analyses, RMSSD and pNN50 were significantly inversely correlated with level of HbA1c and CRP among people with T2DM and pre-diabetes, but not among NGM. RMSSD and pNN50 remained significantly inversely associated with level of HbA1c after adjusting for age, sex, smoking, and BMI among people with T2DM (β = - 0.22) and pre-diabetes (β = - 0.11); adjustment for LGI, HOMA-IR, and FPG did not attenuate these associations. In backward elimination models, age and level of HbA1c remained associated with RMSSD and pNN50. In people with well controlled diabetes and pre-diabetes, a lower parasympathetic activity was more related to age and HbA1c than to markers of LGI. Thus, this study shows that the driver of parasympathetic tonus may be more the level of glycemic control than inflammation in people with prediabetes and well controlled diabetes.

Identification of a Multi-Messenger RNA Signature as Type 2 Diabetes Mellitus Candidate Genes Involved in Crosstalk between Inflammation and Insulin Resistance

Type 2 Diabetes Mellitus (T2DM) is a metabolic disease associated with inflammation widening the scope of immune-metabolism, linking the inflammation to insulin resistance and beta cell dysfunction. New potential and prognostic biomarkers are urgently required to identify individuals at high risk of β-cell dysfunction and pre-DM. The DNA-sensing stimulator of interferon genes (STING) is an important component of innate immune signaling that governs inflammation-mediated T2DM. NOD-like receptor (NLR) reduces STING-dependent innate immune activation in response to cyclic di-GMP and DNA viruses by impeding STING-TBK1 interaction. We proposed exploring novel blood-based mRNA signatures that are selective for components related to inflammatory, immune, and metabolic stress which may reveal the landscape of T2DM progression for diagnosing or treating patients in the pre-DM state. In this study, we used microarray data set to identify a group of differentially expressed mRNAs related to the cGAS/STING, NODlike receptor pathways (NLR) and T2DM. Then, we comparatively analyzed six mRNAs expression levels in healthy individuals, prediabetes (pre-DM) and T2DM patients by real-time PCR. The expressions of ZBP1, DDX58, NFKB1 and CHUK were significantly higher in the pre-DM group compared to either healthy control or T2DM patients. The expression of ZBP1 and NFKB1 mRNA could discriminate between good versus poor glycemic control groups. HSPA1B mRNA showed a significant difference in its expression regarding the insulin resistance. Linear regression analysis revealed that LDLc, HSPA1B and NFKB1 were significant variables for the prediction of pre-DM from the healthy control. Our study shed light on a new finding that addresses the role of ZBP1 and HSPA1B in the early prediction and progression of T2DM.

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.

Associations between objectively measured physical activity, sedentary time, and cardiorespiratory fitness with inflammatory and oxidative stress markers and heart rate variability

Background

To assess the associations between physical activity (PA) and sedentary time (SEDT) with inflammatory and oxidative stress markers, heart rate variability (HRV) and post-exercise recovery (HRR) controlling for cardiorespiratory fitness (CRF) and potential confounders.

Design and methods

The following data was collected from 44 participants during 2019 (age = 49.5 ± 6.4 years, 66% women): Plasma levels of C-reactive protein (CRP) and cytokines (IL-1β, INF-γ, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL-18, IL-23); catalase (CAT) and glutathione peroxidase (GPX) activities; resting heart (HR) rate for HRV analysis, anthropometric measures, a submaximal cycling test to evaluate CRF with active recovery to assess and HRR (absolute and ΔHR), and 7-day accelerometry.

Results

Women spent significantly more SEDT (p = 0.035), had higher inflammatory markers (IL-6 and TNF) and lower HRV indices [SDNN, LF/HF, SD2 (p > 0.05)]. Significant associations were found between SEDT and markers of inflammation [CRP, B = 0.006, p = 0.001; MCP-1, B = 0.003, p = 0.038]. HRV indices were significantly associated with inflammatory/oxidative stress markers [IL-10 (p = 0.04), GPX (p = 0.014), ln-IL 23 (p = 0.036), CAT (p = 0.026)] while HRR was positively associated with light PA [Δ3 (B = 0.051, p = 0.043), Δ4 (B = 0.062, p = 0.021)] and inversely related to catalase [Δ3 (B = -54.7, p = 0.042), Δ4 (B = -54.1, p = 0.021] and CRP [Δ5 (B = -19.8, p = 0.033)]. Higher CRF showed lower values for TNF-α (p = 0.02) and IL-10 (p = 0.003) and better HRV/HRR indices [RMSSD, PNS, SampEn, SD1 (p < 0.05)].

Conclusions

SEDT had a higher impact on inflammation and autonomic balance, independently of PA levels with differences by sex and CRF. PA appears to be more important for a better HRR. Lower HRV and HRR could be indicative of inflammatory status.

Prediabetes and risk of mortality, diabetes-related complications and comorbidities: umbrella review of meta-analyses of prospective studies

AIMS/HYPOTHESIS

The term prediabetes is used for individuals who have impaired glucose metabolism whose glucose or HbA_1c levels are not yet high enough to be diagnosed as diabetes. Prediabetes may already be associated with an increased risk of chronic 'diabetes-related' complications. This umbrella review aimed to provide a systematic overview of the available evidence from meta-analyses of prospective observational studies on the associations between prediabetes and incident diabetes-related complications in adults and to evaluate their strength and certainty.

METHODS

For this umbrella review, systematic reviews with meta-analyses reporting summary risk estimates for the associations between prediabetes (based on fasting or 2 h postload glucose or on HbA_1c) and incidence of diabetes-related complications, comorbidities and mortality risk were included. PubMed, Web of Science, the Cochrane Library and Epistemonikos were searched up to 17 June 2021. Summary risk estimates were recalculated using a random effects model. The certainty of evidence was evaluated by applying the GRADE tool. This study is registered with PROSPERO, CRD42020153227.

RESULTS

Ninety-five meta-analyses from 16 publications were identified. In the general population, prediabetes was associated with a 6-101% increased risk for all-cause mortality and the incidence of cardiovascular outcomes, CHD, stroke, heart failure, atrial fibrillation and chronic kidney disease, as well as total cancer, total liver cancer, hepatocellular carcinoma, breast cancer and all-cause dementia with moderate certainty of evidence. No associations between prediabetes and incident depressive symptoms and cognitive impairment were observed (with low or very low certainty of evidence). The association with all-cause mortality was stronger for prediabetes defined by impaired glucose tolerance than for prediabetes defined by HbA_1c.

CONCLUSIONS/INTERPRETATION

Prediabetes was positively associated with risk of all-cause mortality and the incidence of cardiovascular outcomes, CHD, stroke, chronic kidney disease, cancer and dementia. Further high-quality studies, particularly on HbA_1c-defined prediabetes and other relevant health outcomes (e. g. neuropathy) are required to support the evidence.

Exercise as Treatment for Neuropathy in the Setting of Diabetes and Prediabetic Metabolic Syndrome: A Review of Animal Models and Human Trials

BACKGROUND

Peripheral neuropathy is among the most common complications of diabetes, but a phenotypically identical distal sensory predominant, painful axonopathy afflicts patients with prediabetic metabolic syndrome, exemplifying a spectrum of risk and continuity of pathogenesis. No pharmacological treatment convincingly improves neuropathy in the setting of metabolic syndrome, but evolving data suggest that exercise may be a promising alternative.

OBJECTIVE

The aim of the study was to review in depth the current literature regarding exercise treatment of metabolic syndrome neuropathy in humans and animal models, highlight the diverse mechanisms by which exercise exerts beneficial effects, and examine adherence limitations, safety aspects, modes and dose of exercise.

RESULTS

Rodent models that recapitulate the organismal milieu of prediabetic metabolic syndrome and the phenotype of its neuropathy provide a strong platform to dissect exercise effects on neuropathy pathogenesis. In these models, exercise reverses hyperglycemia and consequent oxidative and nitrosative stress, improves microvascular vasoreactivity, enhances axonal transport, ameliorates the lipotoxicity and inflammatory effects of hyperlipidemia and obesity, supports neuronal survival and regeneration following injury, and enhances mitochondrial bioenergetics at the distal axon. Prospective human studies are limited in scale but suggest exercise to improve cutaneous nerve regenerative capacity, neuropathic pain, and task-specific functional performance measures of gait and balance. Like other heath behavioral interventions, the benefits of exercise are limited by patient adherence.

CONCLUSION

Exercise is an integrative therapy that potently reduces cellular inflammatory state and improves distal axonal oxidative metabolism to ameliorate features of neuropathy in metabolic syndrome. The intensity of exercise need not improve cardinal features of metabolic syndrome, including weight, glucose control, to exert beneficial effects.

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.

Angiotensin converting enzyme inhibitors versus angiotensin II type 1 receptor blockers in patients with acute myocardial infarction and prediabetes after successful implantation of newer-generation drug-eluting stents

BACKGROUND

Because limited data are available, the present study investigated 2-year major clinical outcomes after angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs) therapy in patients with acute myocardial infarction (AMI) and prediabetes after successful implantation of newer-generation drug-eluting stents (DESs).

METHODS

Overall, 2932 patients with AMI and prediabetes were classified into two groups - the ACEIs group (n = 2059) and the ARBs group (n = 873). The primary endpoint was the occurrence of patient- -oriented composite outcome (POCO), defined as all-cause death, recurrent myocardial infarction (Re-MI), or any repeat revascularization. The secondary endpoint was definite or probable stent thrombosis (ST).

RESULTS

The cumulative incidences of POCO (adjusted hazard ratio [aHR]: 1.020; 95% confidence interval [CI]: 0.740-1.404; p = 0.906), all-cause death (aHR: 1.394; 95% CI: 0.803-2.419; p = 0.238), Re-MI (aHR: 1.210; 95% CI: 0.626-2.340; p = 0.570), any repeat revascularization (aHR: 1.150; 95% CI: 0.713-1.855; p = 0.568), and ST (aHR: 1.736; 95% CI: 0.445-6.766; p = 0.427) were similar between the groups. These results were confirmed after propensity score-adjusted analysis.

CONCLUSIONS

In this study, patients with AMI and prediabetes who received ACEIs or ARBs showed comparable clinical outcomes during the 2-year follow-up period.

Dependence of Heart Rate Variability Indices on the Mean Heart Rate in Women with Well-Controlled Type 2 Diabetes

Heart rate variability (HRV) is a method used to evaluate the presence of cardiac autonomic neuropathy (CAN) because it is usually attributed to oscillations in cardiac autonomic nerve activity. Recent studies in other pathologies suggest that HRV indices are strongly related to mean heart rate, and this does not depend on autonomic activity only. This study aimed to evaluate the correlation between the mean heart rate and the HRV indices in women patients with well-controlled T2DM and a control group. HRV was evaluated in 19 T2DM women and 44 healthy women during basal supine position and two maneuvers: active standing and rhythmic breathing. Time-domain (SDNN, RMSSD, pNN20) and frequency-domain (LF, HF, LF/HF) indices were obtained. Our results show that meanNN, age, and the maneuvers are the main predictors of most HRV indices, while the diabetic condition was a predictor only for pNN20. Given the known reduced HRV in patients with T2DM, it is clinically important that much of the HRV indices are dependent on heart rate irrespective of the presence of T2DM. Moreover, the multiple regression analyses evidenced the multifactorial etiology of HRV.

Cardiovascular autonomic neuropathy in diabetes: Pathophysiology, clinical assessment and implications

Cardiovascular autonomic neuropathy (CAN) is a debilitating condition that mainly occurs in long-standing type 2 diabetes patients but can manifest earlier, even before diabetes is diagnosed. CAN is a microvascular complication that results from lesions of the sympathetic and parasympathetic nerve fibers, which innervate the heart and blood vessels and promote alterations in cardiovascular autonomic control. The entire mechanism is still not elucidated, but several aspects of the pathophysiology of CAN have already been described, such as the production of advanced glycation end products, reactive oxygen species, nuclear factor kappa B, and pro-inflammatory cytokines. This microvascular complication is an important risk factor for silent myocardial ischemia, chronic kidney disease, myocardial dysfunction, major cardiovascular events, cardiac arrhythmias, and sudden death. It has also been suggested that, compared to other traditional cardiovascular risk factors, CAN progression may have a greater impact on cardiovascular disease development. However, CAN might be subclinical for several years, and a late diagnosis increases the mortality risk. The duration of the transition period from the subclinical to clinical stage remains unknown, but the progression of CAN is associated with a poor prognosis. Several tests can be used for CAN diagnosis, such as heart rate variability (HRV), cardiovascular autonomic reflex tests, and myocardial scintigraphy. Currently, it has already been described that CAN could be detected even during the subclinical stage through a reduction in HRV, which is a non-invasive test with a lower operating cost. Therefore, considering that diabetes mellitus is a global epidemic and that diabetic neuropathy is the most common chronic complication of diabetes, the early identification and treatment of CAN could be a key point to mitigate the morbidity and mortality associated with this long-lasting condition.

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.

Prediabetes screening: Questionable benefits in the golden years

Irrespective of the definition and diagnostic criteria used, the term prediabetes denotes a state of dysmetabolism with a high risk of progression to diabetes mellitus. Although diabetes-related complications may already be evident among individuals with prediabetes, interventions at this stage primarily aim to hinder the development of overt hyperglycemia rather than to prevent complications. Current recommendations for prediabetes testing are common across all adult age categories. Recent evidence arising from the prospective investigation of the natural course of prediabetes among elderly individuals pose questions regarding the benefits of meticulous prediabetes screening in this age group. In view of this and due to the lack of sufficient data to concretely support a positive impact of further preventive strategies among older individuals, screening recommendations should be reevaluated to target selected elderly individuals who are most likely to benefit in terms of quality of life and prognosis. Further therapeutic measures should be tailored to the inherent features of this frail age group, in order to exert a meaningful effect on overall health status.

Gender differences in screening for glucose perturbations, cardiovascular risk factor management and prognosis in patients with dysglycaemia and coronary artery disease: results from the ESC-EORP EUROASPIRE surveys

Background

Gender disparities in the management of dysglycaemia, defined as either impaired glucose tolerance (IGT) or type 2 diabetes (T2DM), in coronary artery disease (CAD) patients are a medical challenge. Recent data from two nationwide cohorts of patients suggested no gender difference as regards the risk for diabetes-related CV complications but indicated the presence of a gender disparity in risk factor management. The aim of this study was to investigate gender differences in screening for dysglycaemia, cardiovascular risk factor management and prognosis in dysglycemic CAD patients.

Methods

The study population (n = 16,259; 4077 women) included 7998 patients from the ESC-EORP EUROASPIRE IV (EAIV: 2012–2013, 79 centres in 24 countries) and 8261 patients from the ESC-EORP EUROASPIRE V (EAV: 2016–2017, 131 centres in 27 countries) cross-sectional surveys. In each centre, patients were investigated with standardised methods by centrally trained staff and those without known diabetes were offered an oral glucose tolerance test (OGTT). The first of CV death or hospitalisation for non-fatal myocardial infarction, stroke, heart failure or revascularization served as endpoint. Median follow-up time was 1.7 years. The association between gender and time to the occurrence of the endpoint was evaluated using Cox survival modelling, adjusting for age.

Results

Known diabetes was more common among women (32.9%) than men (28.4%, p < 0.0001). OGTT (n = 8655) disclosed IGT in 17.2% of women vs. 15.1% of men (p = 0.004) and diabetes in 13.4% of women vs. 14.6% of men (p = 0.078). In both known diabetes and newly detected dysglycaemia groups, women were older, with higher proportions of hypertension, dyslipidaemia and obesity. HbA1c was higher in women with known diabetes. Recommended targets of physical activity, blood pressure and cholesterol were achieved by significantly lower proportions of women than men. Women with known diabetes had higher risk for the endpoint than men (age-adjusted HR 1.22; 95% CI 1.04–1.43).

Conclusions

Guideline-recommended risk factor control is poorer in dysglycemic women than men. This may contribute to the worse prognosis in CAD women with known diabetes.