Prevalence and pattern of cardiac autonomic dysfunction in newly detected type 2 diabetes mellitus

Effects of Revascularization on Cardiac Autonomic Neuropathy in Type 2 Diabetes Mellitus Patients With Chronic Stable Angina

BACKGROUND

Type 2 diabetes mellitus (T2DM) leads to cardiac autonomic neuropathy (CAN), affecting blood flow and heart rate regulation eventually causing chronic stable angina (CSA). Percutaneous coronary intervention (PCI) can correct autonomic dysfunctions and improve myocardial perfusion. This study aimed to assess CAN using heart rate variability (HRV) and cardiovascular reflex tests in T2DM patients with CSA before and after PCI.

MATERIAL AND METHODS

From cardiology outpatient clinics, 30 patients with T2DM with CSA were recruited. Before and after PCI, the following HRV parameters like low frequency (LF), high frequency (HF), LF:HF ratio, total power (TP), square root of mean square differences of successive R-R intervals (RMSSD), standard deviation of normal R-R intervals (SDNN), and percentage of adjacent NN intervals that differ from each other by more than 50 seconds (pNN50) were measured for every patient. Cardiovascular reflex tests, including the deep breathing test, the isometric handgrip test, the 30:15 ratio, the Valsalva ratio, and the lying-to-standing test (LST), were performed on the patients both before and after PCI. SPSS version 21.0 (IBM Corp., Armonk, NY), a licensed statistical program, was used to compile and analyze the data.

RESULTS

When compared to the pre-PCI group, 30 patients with T2DM with CSA, age range between 45 and 70 years, both genders demonstrated a significant increase in post-PCI HRV frequency domain parameters, such as LF (239.52±67.21ms2 vs. 307.62±74.17 ms2) and HF (249±25.21 ms2 vs. 379.67±76.55 ms2). The time domain parameters showed a significant increase in post-PCI values compared to pre-PCI values. These included RMSSD (33.97±3.96 ms vs. 8.005±3.25 ms), SDNN (41.4±9.78 vs. 31.74±7.04ms), NN50 (13.241±3.07 vs. 5.20±6.63), and TP (1130.08±320.10 ms2 vs. 754.54±96.93 ms2). In cardiovascular reflex tests, pre-PCI groups had significantly lower delta HR (DBT) (10.47±1.76 bpm vs. 14.20±2.09), E:I ratio (DBT) (1.14±0.042 vs. 1.20±0.026), and Valsalva ratio (1.10±0.071 vs. 1.22±0.084) than post-PCI groups. The pre-PCI group showed a substantial decrease in both the systolic blood pressure (LST) (-6.13±4.85 mmHg vs. -1.01±3.63 mmHg) and the 30:15 ratio (1.13±0.074 vs. 1.09±0.067) when compared to the post-PCI group. The handgrip test (18.73±4.31 mmHg vs. 15.31±4.27 mmHg) did not yield statistically significant results.

CONCLUSIONS

Before PCI, T2DM patients with CSA experienced autonomic dysfunction, but after revascularization, their functions improved by reestablishing basal cardiac autonomic tone and autonomic reactivity. HRV and cardiovascular reflex tests are useful noninvasive tools for assessing CAN and stratifying a prospective risk factor for estimating the morbidity and death from cardiovascular illnesses in T2DM with CSA.

Cardiac Autonomic Neuropathy in Newly Diagnosed Patients With Type 2 Diabetes Mellitus

INTRODUCTION

Cardiac autonomic neuropathy (CAN) is a debilitating complication in diabetes mellitus, leading to life-threatening arrhythmias and various impairments. Its prevalence varies widely, and early detection and management are crucial. This study investigates the prevalence of CAN in newly diagnosed type 2 diabetes mellitus patients in Central India, comparing them to a control group.

METHODOLOGY

This case-control study included 35 newly diagnosed type 2 diabetes mellitus patients and 35 age-matched healthy controls from the general population. Cardiac autonomic function testing (AFT) was done by heart rate variability (HRV), the deep breathing test (DBT), the cold pressor test (CPT), and the lying-to-standing test (LST). Parameters were recorded and analyzed using statistical tests.

RESULTS

Patients with type 2 diabetes mellitus had significantly higher weight, BMI, fasting blood sugar, post-prandial blood sugar, urine albumin-creatinine ratios, and systolic and diastolic blood pressure than controls. Abnormalities in HRV and E: I ratio during the DBT and CPT were more prevalent in these patients. Parasympathetic dysfunction (delta HR) and a lower E: I ratio were also significantly high in this group. Also, LST results suggested a greater likelihood of orthostatic symptoms in the patients' group.

CONCLUSION

This study highlights the importance of AFT in diagnosing early CAN in newly diagnosed patients. Early diagnosis and management of diabetic CAN are essential to prevent complications.

Sympathectomy Effects on Intra-Abdominal Organ Catecholamine Levels in a Streptozotocin-Induced Diabetic Rat Model

Diabetes mellitus (DM) is a metabolic disorder whose prevalence has continuously increased worldwide and is associated with dysfunction of the autonomic nervous system and, in particular, that of the sympathetic nervous system (SNS). The objective of this study was to analyze the interaction of DM and the SNS, building a model of sympathectomized diabetic rats to determine alterations in the content of CA (catecholamines) in different intra-abdominal organs. Sympathectomy was conducted with guanethidine (GNT). Additionally, DM was induced with STZ (Streptozotocin). Treatment with GNT decreased norepinephrine (NE) content in all analyzed tissues, with significant differences found in the paraganglia, liver, pancreas, duodenum, and heart compared to the control group. With respect to epinephrine (E), which was only found in the liver, pancreas, and heart, presenting significant differences (p < 0.05) in the heart, a decrease in its concentration was observed for all of the experimental groups with respect to the control. The decrease in dopamine (DA) content due to the GNT−STZ treatment was 30.1% in the heart with respect to the diabetic (STZ) group. The amount of CA in the adrenal medulla indicates the effect of sympathectomy on the GNT group where there was a significant reduction (p < 0.05) of DA. These findings suggest that the elimination of the sympathetic nervous system in diabetic organisms contributed to a decrease in blood glucose; likewise, an alteration in the levels of CA was observed in the different selected organs, possibly attributed to the severity, duration, and pathogenesis of the complications of acute and chronic DM.

Post-Acute Effect of SARS-CoV-2 Infection on the Cardiac Autonomic Function

Background

Methods

Results

Conclusion

Heart Rate Variability for the Early Detection of Cardiac Autonomic Dysfunction in Type 1 Diabetes

Type 1 diabetes mellitus (T1DM) has an important impact on morbidity and mortality because it may start early in life. Therefore, the early detection of cardiovascular autonomic neuropathy (DCAN) in T1DM patients is important to intervene quickly and prevent further deterioration. Traditional autonomic function tests detect abnormalities in severely symptomatic patients but they are difficult to be standardized, require the patient’s active participation and their sensitivity to the early disease is limited. In comparison, heart rate variability (HRV) is easier to be measured and standardized. Therefore, we aim to find the HRV indexes that better identify DCAN at an early stage in T1DM patients, and evaluate if HRV is a valid alternative to traditional tests. For this aim, we administered the SCOPA-AUT questionnaire on symptoms of autonomic dysfunction as well as deep breathing, Valsalva, handgrip, head-up tilt (HUT), and cold-pressor tests, to 52 T1DM patients and 27 controls. We calculated HRV indexes during supine rest (SUP) and HUT, assessing differences between groups and postures by a linear mixed-effect model for repeated measures. Receiver Operating Characteristic (ROC) analysis quantified how each HRV index and autonomic test distinguishes between patients and controls. We found that the SCOPA-AUT score was slightly but significantly (p < 0.05) greater in patients, indicating an early DCAN. T1DM patients preserved the HRV response to changing posture but in SUP they showed significantly lower standard deviation and vagal indexes of HRV than controls. The area under the ROC curve of these HRV indexes was not lower than 0.68. By contrast, traditional autonomic tests did not differ between groups. Therefore, early DCAN initially causes an impairment of the cardiac vagal control manifest in conditions of elevated vagal tone, as in SUP. Compensatory adjustments of the sympathetic control might explain the unaltered response to traditional autonomic tests. In conclusion, vagal HRV indexes in SUP help to identify early DCAN better than traditional tests, potentially allowing rapid interventions.

Berberine restored nitrergic and adrenergic function in mesenteric and iliac arteries from streptozotocin-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Perivascular neuropathy was reported to involve in the vascular disorders associated with diabetes. The dried rhizomes of Coptis chinensis Franch. (Latin name: Coptidis Rhizoma; common name: Huang Lian in China), used frequently in Traditional Chinese medicine to treat diabetes (Xiaoke), have been confirmed to possess beneficial effects on diabetic peripheral neuropathy by modern clinical and pharmacological studies. Berberine (BBR), the main effective component of Huang Lian in the treatment of diabetes, is reported to ameliorate diabetic central and peripheral neuropathy. However, the effects of BBR on nerve function of mesenteric and iliac arteries are unclear.

AIM OF THE STUDY

To investigate the effects of BBR on the diabetes-induced changes in nitrergic and adrenergic function in mesenteric and iliac arteries.

MATERIALS AND METHODS

In this study, the animals were randomized into three groups: control rats, diabetic rats, and diabetic rats gavaged with BBR. We established diabetic rat model using intraperitoneal injection of streptozotocin (STZ, 55 mg kg^-1). Two weeks after model establishment, those in the BBR-treated groups were gavaged with berberine chloride (Sichuan Xieli Fharmaceutical. Co., Ltd; 200 mg·kg^-1·day^-1) diluted in distilled water for another 2 weeks. The superior mesenteric artery and iliac artery were excised. Electric field stimulation (EFS) was used to induce arterial vasoconstriction and explore (1) the diabetes-induced changes in neurogenic function of the superior mesenteric artery and iliac artery; (2) the effects of BBR on neurovascular dysfunction in the early stage of STZ-induced diabetic rats. Nitric oxide (NO) and noradrenaline (NA) released from the nitrergic and adrenergic nerves were quantified using fluorescence assays and ELISA, respectively.

RESULTS

EFS induced frequency-dependent vasoconstrictions in both superior mesenteric and iliac artery, and the contractile responses of arteries were abolished by 0.1 μmol·L^-1 tetrodotoxin (TTX), or inhibited by 1 μmol·L^-1 phentolamine or increased by 0.1 mmol·L^-1 N^ω-Nitro-L-arginine methyl ester hydrochloride (L-NAME). In superior mesenteric artery, but not in iliac artery, the changes of contractile responses with L-NAME were significantly decreased in diabetic rats, and NO release was less also. In contrast, in iliac artery of diabetic rats, but not in superior mesenteric artery, the changes of contractile responses with phentolamine were increased, and NA release was increased significantly. All these changes in diabetic rats on both superior mesenteric artery and iliac artery were reversed by treated with BBR.

CONCLUSIONS

In the STZ-induced early diabetic rats, neural control of mesenteric and iliac vasomotor tone are altered differently. The diminished nitrergic nerve in superior mesenteric artery and enhanced adrenergic nerve in iliac artery both contributed to increased vasocontrictor responses. All these changes in diabetic rats were reversed by BBR, suggesting a novel mechanism of BBR in balance of neural regulation of vascular tone.

The Effectiveness of a Brief Psychological Intervention for Patients with Diabetes-Related Distress

BACKGROUND

Diabetes-related distress (DRD) is the negative emotional and psychological reaction to living with diabetes mellitus (DM). DRD has been reported to affect glycemic control and self-management practices adversely. Limited research is available on the effectiveness of psychological interventions for DRD. We aimed to study the effectiveness of a brief psychological intervention for patients with DRD.

METHODS

The findings of a targeted brief psychological intervention conducted for patients with DRD, as a part of psycho-endocrinology liaison services in a general hospital, are reported. Details regarding the assessment and intervention given were collected from the patients' records. Forty-one patients with DRD diagnosed using Diabetes Distress Scale (DDS) were given the single session intervention consisting of brief diabetes education focusing on physical activity and medication adherence, relaxation techniques, and illness-specific problem-solving strategies. Effectiveness was assessed using change in Clinical Global Impression-Severity (CGI-S), patient-rated visual analog scale, brief physical activity questionnaire, and medication adherence at baseline and 2-month follow-up.

RESULTS

Analysis using Wilcoxon signed rank test found a significant change in the follow-up scores on all the assessment scales.

CONCLUSIONS

The study highlights the benefits of brief intervention for reducing DRD, thus reducing the emotional burden of living with DM.

Predisposing factors to heart failure in diabetic nephropathy: a look at the sympathetic nervous system hyperactivity

Diabetes mellitus (DM) and heart failure (HF) are frequent comorbidities among elderly patients. HF, a leading cause of mortality and morbidity worldwide, is characterized by sympathetic nervous system hyperactivity. The prevalence of diabetes mellitus (DM) is rapidly growing and the risk of developing HF is higher among DM patients. DM is responsible for several macro- and micro-angiopathies that contribute to the development of coronary artery disease (CAD), peripheral artery disease, retinopathy, neuropathy and diabetic nephropathy (DN) as well. Independently of CAD, chronic kidney disease (CKD) and DM increase the risk of HF. Individuals with diabetic nephropathy are likely to present a distinct pathological condition, defined as diabetic cardiomyopathy, even in the absence of hypertension or CAD, whose pathogenesis is only partially known. However, several hypotheses have been proposed to explain the mechanism of diabetic cardiomyopathy: increased oxidative stress, altered substrate metabolism, mitochondrial dysfunction, activation of renin-angiotensin-aldosterone system (RAAS), insulin resistance, and autonomic dysfunction. In this review, we will focus on the involvement of sympathetic system hyperactivity in the diabetic nephropathy.

Diagnostic accuracy of composite autonomic symptom scale 31 (COMPASS-31) in early detection of autonomic dysfunction in type 2 diabetes mellitus

PURPOSE

Diabetic autonomic neuropathy (DAN) is a common and disabling complication of diabetes, with cardiac autonomic neuropathy (CAN) being a major cause of mortality and morbidity. Standard autonomic function tests (AFT) are cumbersome and time consuming to conduct in OPD setting.

OBJECTIVE

To evaluate the diagnostic accuracy of composite autonomic symptom scale 31 (COMPASS-31) as a screening test for DAN.

PATIENTS AND METHODS

A cross-sectional study which enrolled 60 type 2 diabetes individuals was conducted at a tertiary care center. Autonomic functions were evaluated by COMPASS-31 questionnaire as well as by standard Ewing's battery of tests; short-term heart rate variability; sympathetic skin response along with nerve conduction studies.

RESULTS

Thirty males and 24 females completed the study. Forty-nine (89%) participants had CAN, of which, 9 (17%) had definite CAN. Peripheral neuropathy was present in 20 (37%). COMPASS-31 scores showed no difference between "No CAN" and "Early CAN". "Definite CAN" individuals differed significantly from "No and Early CAN" on COMPASS-31 scores and its gastrointestinal sub-domain. Receiver operating characteristic between "Definite CAN" and "No and Early CAN" showed fair accuracy with AUC of 0.731 (95% CI 0.561-0.901), sensitivity 77.8%, specificity 71.7% at a cut-off of 28.67 of COMPASS-31 score. Gastrointestinal sub-domain, at a cut-off score of 5.8, had 77.8% sensitivity, 60% specificity, and AUC was 0.748 (95% CI 0.603-0.894).

CONCLUSION

COMPASS-31, a self-administered tool, requiring less time, qualifies as an acceptable screening tool, especially for definite CAN. However, individuals scoring low on COMPASS-31 are still required to be evaluated by Ewing's battery to differentiate between "Early CAN" and "No CAN".

Decreased β-Cell Function is Associated with Cardiovascular Autonomic Neuropathy in Chinese Patients Newly Diagnosed with Type 2 Diabetes

The influence of β-cell function on cardiovascular autonomic neuropathy (CAN), an important diabetes-related complication, is still unclear. In this study, we aimed to investigate the association between residual β-cell function and CAN in patients newly diagnosed with type 2 diabetes. We enrolled 90 newly-diagnosed type 2 diabetic patients and 37 participants with normal glucose tolerance as controls. The patients were divided into a CAN+ group (diabetic patients with CAN, n = 20) and a CAN− group (diabetic patients without CAN, n = 70) according to the standard Ewing battery of tests. Fasting and postprandial plasma glucose, insulin, and C-peptide were measured. Homeostasis model assessment-beta cells (HOMA-B) and HOMA-insulin resistance (IR) were calculated. The prevalence of CAN in this population was 22.2%. Compared with the CAN− group, the CAN+ group had significantly lower fasting plasma insulin (6.60 ± 4.39 vs 10.45 ± 7.82 μ/L, P = 0.029), fasting C-peptide (0.51 ± 0.20 vs 0.82 ± 0.51 nmol/L, P = 0.004), and HOMA-B (21.44 ± 17.06 vs 44.17 ± 38.49, P = 0.002). Fasting C-peptide was correlated with the Valsalva ratio (r = 0.24, P = 0.043) and the 30:15 test (r = 0.26, P = 0.023). Further analysis showed that fasting C-peptide (OR: 0.041, 95% CI 0.003–0.501, P = 0.012) and HOMA-B (OR: 0.965, 95% CI 0.934–0.996, P = 0.028) were independently associated with cardiovascular autonomic nerve function in this population. The patients with fasting C-peptide values < 0.67 nmol/L were more likely to have CAN than those with C-peptide levels ≥0.67 nmol/L (OR: 6.00, 95% CI 1.815–19.830, P = 0.003). A high prevalence of CAN was found in patients with newly-diagnosed type 2 diabetes. Decreased β-cell function was closely associated with CAN in this population.

Independent and cumulative effects of resting heart rate and pulse pressure with type 2 diabetes mellitus in Chinese rural population

The purpose was to explore the effects of resting heart rate (RHR) and pulse pressure (PP) independently as well as their cumulative effects on the risk of type 2 diabetes mellitus (T2DM) through cross-sectional study plus meta-analysis. A total of 8276 subjects aged 35–74 years from the Rural Diabetes, Obesity and Lifestyle (RuralDiab) study were included in the study. Meanwhile, two meta-analyses were conducted to validate the results of the epidemiological research. The results showed that RHR and PP were associated with higher risk of T2DM, and the corresponding adjusted OR(95%CI) for each quartiles were 1.00, 0.99(0.68–1.42), 1.58(1.13–2.20), 2.93(2.15–3.98) and 1.00, 1.06(0.75–1.48), 1.11(0.79–1.56), 1.45(1.03–2.03), respectively. The cumulative effect analysis indicated that the adjusted OR(95%CI) in the fast RHR-high PP were 3.36(2.26–4.99), 2.60(1.47–4.59), and 3.60(2.09–6.20) compared with the slow RHR-low PP for total population, male and female, respectively. Meta-analysis showed that the pooled effect values for RHR and PP were 1.94(1.64–2.31) and 1.25(1.04–1.51), respectively. This study demonstrated that elevated RHR and PP are independently associated with the risk of T2DM as well as the influences of conventional confounders, and fast RHR with high PP might cumulatively increase the risk of T2DM. However, the potential clinical application remains to be determined.

Cardio-metabolic profile of subjects with early stages of glucose intolerance and cardiovascular autonomic dysfunction

AIMS

The present study evaluates the cardio-metabolic profile of subjects with early stages of glucose intolerance and presence of cardiovascular autonomic dysfunction (CAD).

MATERIALS AND METHODS

478 subjects, of mean age 49.3±13.7years and mean BMI 31.0±6.2kg/m², divided according to glucose tolerance: 130 with normal glucose tolerance, 227 with prediabetes, and 121 with newly-diagnosed type 2 diabetes, were enrolled. Glucose tolerance was studied during OGTT applying 2006 WHO criteria. Anthropometric indices, blood pressure, HbA1c, serum lipids, hsCRP, and albumin-to-creatinine ratio (ACR) were measured. Body fat distribution was estimated by a bioimpedance method (InBody720, BioSpace). Tissue AGEs accumulation was assessed by skin autofluorescence (AGE-Reader-DiagnOptics™). CAD was assessed by ANX-3.0 method.

RESULTS

CAD was found in 24.1% of subjects with any disorder of glucose tolerance in comparison to 12.3% in NGT, OR 2.0 (95% CI: 1.2-3.2), p=0.005. Sympathetic and parasympathetic tone declined with the progression of glucose intolerance. Age, waist circumference, visceral fat area, fasting and 120-min plasma glucose, HbA1c, AGEs, ACR and QTc interval were higher in subjects with CAD, p<0.05. In a logistic regression analysis the panel of age >53years (76% sensitivity, 61% specificity), HbA1c >6.0% (66% sensitivity, 60% specificity), QTc interval >423ms (65% sensitivity, 61% specificity) and presence of arterial hypertension (83% sensitivity, 55% specificity) was related to the presence of CAD - AUC 0.778 (95% CI: 0.73-0.83), p<0.001.

CONCLUSION

Our results demonstrate a high prevalence of CAD in early stages of glucose dysmetabolism. Age, HbA1c, QTc interval and presence of arterial hypertension are related to the presence of CAD in this population.

Ambulatory 24-h ECG monitoring and cardiovascular autonomic assessment for the screening of silent myocardial ischemia in elderly type 2 diabetic hypertensive patients

The aim of the study was to evaluate the usefulness of Holter monitoring for the detection of silent myocardial ischemia (SMI) in elderly type 2 diabetic patients with hypertension and the possible relationship between SMI and cardiovascular autonomic neuropathy (CAN). Two hundred and forty-three asymptomatic outpatients, aged 65-75 years, with type 2 diabetes and essential hypertension underwent 24-h ECG monitoring and 5 tests for the evaluation of both parasympathetic (heart rate variability, response to breath deeping, and Valsalva manoeuvre) and sympathetic (cold pressor test and orthostatic hypotension test) autonomic function. A total of 518 asymptomatic episodes of ST depression during Holter monitoring indicative of SMI were detected in 51 of the 243 studied patients (20.9 %). None of the patients with ST depression episodes exhibited a normal response to at least one of the evaluated autonomic function tests, whereas 22 of the 192 patients without ST changes (11.4 %) exhibited a normal response to all tests. Abnormality in both parasympathetic and sympathetic function test responses was found in 94.1 % of patients with ST depression episodes vs 26.1 % of those without ST changes (P < 0.001). Statistical evaluation of the relationship between the abnormal response to single autonomic function test and episodes of ST depression was highly significant for all the 5 tests (P < 0.001). These results indicate that: (a) Holter monitoring enables to detect ST segment changes indicative of SMI in 20.9 % of elderly diabetic patients with hypertension; (b) the presence of autonomic cardiac dysfunction in these patients suggests a role of diabetic neuropathy in the pathogenesis of SMI; and

Epidemiology of microvascular complications of diabetes in South Asians and comparison with other ethnicities

Type 2 diabetes mellitus is widely prevalent in South Asians, and has a significant effect on health, as well as the economies of South Asian countries, particularly when the disease is associated with complications. There are certain characteristics associated with the South Asian phenotype that make South Asians especially prone to diabetes, as well as its complications. Microvascular complications cause considerable morbidity and mortality. There are significant differences in the epidemiology of microvascular complications between South Asians and people of other races. There is evidence of higher prevalence of nephropathy and retinopathy in South Asians compared with Caucasians; however, recent studies indicate that this trend seems to be leveling off. Importantly, diabetic neuropathy occurs less frequently in South Asians compared with Caucasians. These observations have important implications in managing South Asian patients with diabetes and microvascular complications.

Cardiovascular Autonomic Neuropathy and Early Atherosclerosis in Adolescent Type 1 Diabetic Patient

AIM:

To evaluate cardiovascular autonomic neuropathy (CAN) in type 1 Diabetics and to detect its relation to coronary artery calcification.

PATIENTS AND METHODS:

It is a cross sectional study included 62 diabetics and 30 controls. Clinical, laboratory assessment and 24 Hr holter were done for all patients and controls and coronary artery calcium (CAC) scoring by multisclice CT was done for all patients only. T-test, Mann Whitney U test, and stepwise multiple regression were used for statistical analyses.

RESULTS:

CAC score was positive in 8.1 % of patients. Heart rate variability (HRV) was significantly lower in diabetics. All parameters of HRV were insignificantly lower in diabetics with positive CAC score. Patients with microalbuminuria had a significantly lower HRV. HRV had a significant correlation with age of patients, duration of disease, HbA1, and Qtc in diabetics.

CONCLUSION:

Percentage of arrhythmia and early atherosclerosis is high in adolescent type 1 diabetic patients. CAN is associated with early atherosclerosis. Cardiac autonomic neuropathy is associated with older age, longer duration, and poor glycemic control and microalbuminuria.

Prevalence of Cardiovascular Autonomic Neuropathy in a Cohort of Patients With Newly Diagnosed Type 2 Diabetes: The Verona Newly Diagnosed Type 2 Diabetes Study (VNDS)

OBJECTIVE

Cardiovascular autonomic diabetic neuropathy (CAN) is a serious complication of diabetes. No reliable data on the prevalence of CAN among patients with newly diagnosed type 2 diabetes are available. Therefore, the aim of this study was to estimate the prevalence of CAN among patients with newly diagnosed type 2 diabetes.

RESEARCH DESIGN AND METHODS

A cohort of 557 patients with newly diagnosed type 2 diabetes with cardiovascular autonomic test results available was selected. Early and confirmed neuropathy were assessed using a standardized methodology and their prevalences determined. A multivariate logistic regression analysis was modeled to study the factors associated with CAN.

RESULTS

In the entire cohort, the prevalence of confirmed CAN was 1.8%, whereas that of early CAN was 15.3%. Prevalence did not differ between men and women. In the multivariate analyses BMI results were independently and significantly associated with CAN after adjusting for age, sex, hemoglobin A1c, pulse pressure, triglyceride-to-HDL cholesterol ratio, kidney function parameters, and antihypertensive treatment.

CONCLUSIONS

CAN could be detected very early in type 2 diabetes. This study may suggest the importance of performing standardized cardiovascular autonomic tests after diagnosis of type 2 diabetes.

Heart rate and systolic blood pressure variability on recently diagnosed diabetics

Background

Diabetes affects approximately 250 million people in the world. Cardiovascular autonomic neuropathy is a common complication of diabetes that leads to severe postural hypotension, exercise intolerance, and increased incidence of silent myocardial infarction.

Objective

To determine the variability of heart rate (HR) and systolic blood pressure (SBP) in recently diagnosed diabetic patients.

Methods

The study included 30 patients with a diagnosis of type 2 diabetes of less than 2 years and 30 healthy controls. We used a Finapres® device to measure during five minutes beat-to-beat HR and blood pressure in three experimental conditions: supine position, standing position, and rhythmic breathing at 0.1 Hz. The results were analyzed in the time and frequency domains.

Results

In the HR analysis, statistically significant differences were found in the time domain, specifically on short-term values such as standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD), and number of pairs of successive NNs that differ by more than 50 ms (pNN50). In the BP analysis, there were no significant differences, but there was a sympathetic dominance in all three conditions. The baroreflex sensitivity (BRS) decreased in patients with early diabetes compared with healthy subjects during the standing maneuver.

Conclusions

There is a decrease in HR variability in patients with early type 2 diabetes. No changes were observed in the BP analysis in the supine position, but there were changes in BRS with the standing maneuver, probably due to sympathetic hyperactivity.

Impaired mitochondrial energy supply coupled to increased H2O2 emission under energy/redox stress leads to myocardial dysfunction during Type I diabetes

In Type I diabetic (T1DM) patients, both peaks of hyperglycaemia and increased sympathetic tone probably contribute to impair systolic and diastolic function. However, how these stressors eventually alter cardiac function during T1DM is not fully understood. In the present study, we hypothesized that impaired mitochondrial energy supply and excess reactive oxygen species (ROS) emission is centrally involved in T1DM cardiac dysfunction due to metabolic/redox stress and aimed to determine the mitochondrial sites implicated in these alterations. To this end, we used isolated myocytes and mitochondria from Sham and streptozotocin (STZ)-induced T1DM guinea pigs (GPs), untreated or treated with insulin. Relative to controls, T1DM myocytes exhibited higher oxidative stress when challenged with high glucose (HG) combined with β-adrenergic stimulation [via isoprenaline (isoproterenol) (ISO)], leading to contraction/relaxation deficits. T1DM mitochondria had decreased respiration with complex II and IV substrates and markedly lower ADP phosphorylation rates and higher H2O2 emission when challenged with oxidants to mimic the more oxidized redox milieu present in HG + ISO-treated cardiomyocytes. Since in T1DM hearts insulin-sensitivity is preserved and a glucose-to-fatty acid (FA) shift occurs, we next tested whether insulin therapy or acute palmitate (Palm) infusion prevents HG + ISO-induced cardiac dysfunction. We found that insulin rescued proper cardiac redox balance, but not mitochondrial respiration or contractile performance. Conversely, Palm restored redox balance and preserved myocyte function. Thus, stressors such as peaks of HG and adrenergic hyperactivity impair mitochondrial respiration, hampering energy supply while exacerbating ROS emission. Our study suggests that an ideal therapeutic measure to treat metabolically/redox-challenged T1DM hearts should concomitantly correct energetic and redox abnormalities to fully maintain cardiac function.

Independent predictor factors of supine tachycardia in patients with type 2 diabetes mellitus

INTRODUCTION

Supine tachycardia, frequently encountered in diabetic patients, is usually considered as an isolated diabetic complication in cardiac autonomic neuropathy. The objective of this study was to determine independent predictor factors of supine tachycardia among the clinical characteristics of type 2 diabetes mellitus.

METHODS

This prospective study included type 2 diabetic patients. Supine tachycardia was considered as 10 minutes resting heart rate equal or higher than 80 beats/minutes. According to presence or not of supine tachycardia, two groups were identified: tachycardia diabetic patients and none tachycardia diabetic patients. Cardiovascular autonomic tests: deep breathing, hand-grip, and mental stress tests and blood tests were performed in all patients. Statistical analysis was done using the Student's t-test, and univariate and multivariate logistic regression analysis.

RESULTS

We included 91 patients. The vagal response measured by the deep breathing test was 24.5 ± 5.7% in tachycardia diabetic patients vs 35.6 ± 6.8% in none tachycardia diabetic patients (P=0.007). The odds of supine tachycardia increased with serum creatinine (OR=1.350, 95% CI: 1.065-1.712, P=0.013) and serum uric acid levels (OR=1.034, 95% CI: 1.005-1.064, P=0.02) respectively, in diabetic patients. The prevalence of moderate renal failure was 45.5% in tachycardia diabetic patients vs. 21.6% in none tachycardia diabetic patients (P=0.034).

CONCLUSION

A high frequency of supine tachycardia in type 2 diabetic patients was significantly related with an impairment of the parasympathetic nervous system but other independent predictor factors were associated to the occurrence of this supine tachycardia, such as higher levels of serum creatinine and uric acid and moderate renal failure.

Positive psychological characteristics in diabetes: a review

Positive psychological characteristics, such as optimism, self-efficacy, and resilience, have been increasingly associated with improved outcomes in medically ill individuals. However, there has been minimal systematic review of these characteristics and their associations with outcomes in people with diabetes. We aim to review these associations, their potential mediating mechanisms, and the evidence supporting interventions targeting these qualities. In people with diabetes, positive psychological characteristics are significantly associated with improved glycemic control, fewer complications, and reduced rates of mortality. Potential mechanisms mediating these associations include behavioral factors (e.g., improved treatment adherence), reduced inflammation, and improved neuroendocrine and autonomic functioning. Most psychosocial treatments in this population have focused on improving self-efficacy and resilience; such interventions may improve quality of life, well-being, and diabetes self-care. While untested in diabetes, interventions to boost other positive characteristics have been effective in other medically ill patients and may warrant further study in this cohort.

Cardiac autonomic function in patients with diabetes improves with practice of comprehensive yogic breathing program

BACKGROUND

The aim of this study was to observe the effect comprehensive yogic breathing (Sudarshan Kriya Yoga [SKY] and Pranayam) had on cardiac autonomic functions in patients with diabetes.

MATERIALS AND METHODS

This is a prospective randomized controlled intervention trial. Cardiac autonomic functions were assessed in 64 diabetics. Patients were randomized into two groups, one group receiving standard therapy for diabetes and the other group receiving standard therapy for diabetes and comprehensive yogic breathing program. Standard therapy included dietary advice, brisk walking for 45 min daily, and administration of oral antidiabetic drugs. Comprehensive yogic breathing program was introduced to the participants through a course of 12 h spread over 3 days. It was an interactive session in which SKY, a rhythmic cyclical breathing, preceded by Pranayam is taught under the guidance of a certified teacher. Cardiac autonomic function tests were done before and after 6 months of intervention.

RESULTS

In the intervention group, after practicing the breathing techniques for 6 months, the improvement in sympathetic functions was statistically significant (P 0.04). The change in sympathetic functions in the standard therapy group was not significant (P 0.75). Parasympathetic functions did not show any significant change in either group. When both parasympathetic and sympathetic cardiac autonomic functions were considered, there was a trend toward improvement in patients following comprehensive yogic breathing program (P 0.06). In the standard therapy group, no change in cardiac autonomic functions was noted (P 0.99).

CONCLUSION

Cardiac autonomic functions improved in patients with diabetes on standard treatment who followed the comprehensive yogic breathing program compared to patients who were on standard therapy alone.

Cardiovascular implications of antihyperglycemic therapies for type 2 diabetes

BACKGROUND

Several risk factors for cardiovascular disease (CVD), including insulin resistance/hyperinsulinemia, hyperglycemia, overweight/obesity, dyslipidemia, and hypertension, are often present in varying combinations in patients with type 2 diabetes mellitus (DM). Patients with a clustering of these risk factors, termed the metabolic syndrome, are at greater risk for CVD than are patients with only a single risk factor. Although glycemic control is the central feature of type 2 DM management, patients require an individualized approach to therapy that takes their other CVD risk factors into account.

OBJECTIVE

This review examined the effects of antidiabetes therapy on glycemic control, as well as its potential to affect body weight, serum lipids, and blood pressure (BP), and thus CVD risk.

METHODS

Information was obtained by searching the MEDLINE and EMBASE databases from 1995 through March 2010. The search terms included type 2 DM, metabolic syndrome, CV complications of type 2 DM, and therapy for type 2 DM. Articles that described relevant details of the metabolic syndrome, CV complications of type 2 DM, and effects of antidiabetes therapy on glycosylated hemoglobin, body weight, serum lipids, and BP were selected for in-depth review. Only English language publications were reviewed. Clinical trials, meta-analyses, and review articles on the key words were preferentially selected for review and analysis. Non-English language publications, case reports, letters to the editor, and similar types of publications were excluded.

RESULTS

Although all approved antidiabetes agents lowered glucose, their effect on other CV risk factors, such as BP, lipids, and weight, differed significantly. Therapy with insulin, the sulfonylureas, and the thiazolidinediones was associated with weight gain. Metformin and the dipeptidyl-peptidase-4 inhibitors were generally considered weight neutral, whereas the glucagon-like peptide-1 receptor agonists and amylin agonists were associated with weight loss. Metformin, sulfonylureas, thiazolidinedioness, and dipeptidyl-peptidase-4 inhibitors had modest effects on serum lipid levels and BP. The glucagon-like peptide-1 receptor agonists generally had beneficial effects on serum lipid levels and systolic and diastolic BP.

CONCLUSION

A wide variety of agents were available to aid glycemic control in patients with type 2 DM. These agents had variable effects on known CV risk factors that might be present in this patient population, including excess body weight, elevated BP, and increased serum lipids. Some of the newer agents improved glycemic control while also having potentially favorable effects on these CV risk factors. The impact of various agents on known CV risk factors should be considered when selecting a therapeutic regimen.