The Diabetes Control and Complications Trial Research Group. The effect of intensive diabetes therapy on measures of autonomic nervous system function in the Diabetes Control and Complications Trial (DCCT)

Physical activity and dietary interventions in diabetic neuropathy: a systematic review

PURPOSE

Diabetic neuropathy is a common and disabling disorder, and there are currently no proven effective disease-modifying treatments. Physical activity and dietary interventions in patients with diabetes and diabetic neuropathy have multiple beneficial effects and are generally low risk, which makes lifestyle interventions an attractive treatment option. We reviewed the literature on the effects of physical activity and dietary interventions on length-dependent peripheral neuropathy and cardiac autonomic neuropathy in diabetes.

METHODS

The electronic database PubMed was systematically searched for original human and mouse model studies examining the effect of either dietary or physical activity interventions in subjects with diabetes, prediabetes, or metabolic syndrome.

RESULTS

Twenty studies are included in this review. Fourteen studies were human studies and six were in mice. Studies were generally small with few controlled trials, and there are no widely agreed upon outcome measures.

CONCLUSIONS

Recent research indicates that dietary interventions are effective in modifying diabetic neuropathy in animal models, and there are promising data that they may also ameliorate diabetic neuropathy in humans. It has been known for some time that lifestyle interventions can prevent the development of diabetic neuropathy in type 2 diabetes mellitus subjects. However, there is emerging evidence that lifestyle interventions are effective in individuals with established diabetic neuropathy. In addition to the observed clinical value of lifestyle interventions, there is emerging evidence of effects on biochemical pathways that improve muscle function and affect other organ systems, including the peripheral nerve. However, data from randomized controlled trials are needed.

Genetic variants in DNMT1 and the risk of cardiac autonomic neuropathy in women with type 1 diabetes

AIMS/INTRODUCTION

Epigenetics participate in the pathogenesis of metabolic memory, a situation in which hyperglycemia exerts prolonged deleterious effects even after its normalization. We tested the hypothesis that genetic variants in an epigenetic gene could predispose to diabetes complications.

MATERIAL AND METHODS

We assessed the frequency of five single-nucleotide polymorphisms in the gene encoding deoxyribonucleic acid methytransferase 1 (DNMT1; rs8112895, rs7254567, rs11085721, rs17291414 and rs10854076), and their associations with diabetic kidney disease, retinopathy, distal polyneuropathy and autonomic cardiovascular neuropathy in 359 individuals with long-term type 1 diabetes.

RESULTS

None of the single-nucleotide polymorphisms studied was significantly associated with the presence of chronic complications in the overall population. However, after sex stratification, the minor allele C of rs11085721 conferred risk for cardiovascular neuropathy in women after adjustment for confounding variables (odds ratio 2.32; 95% confidence interval 1.26-4.33; P = 0.006).

CONCLUSIONS

The fact that heterozygous mutations in DNMT1 are associated with hereditary sensory autonomic neuropathy provides plausibility to the present finding. If confirmed in independent samples, it suggests that genetic variants in epigenetic genes might predispose to more or fewer epigenetic changes in the face of similar metabolic derangements triggered by hyperglycemia, constituting the "genetics of epigenetics" for microvascular diabetes complications.

HbA1C Variability Is Strongly Associated With the Severity of Cardiovascular Autonomic Neuropathy in Patients With Type 2 Diabetes After Longer Diabetes Duration

Background

Variability in the glycated hemoglobin (HbA1c) level is associated with a higher risk of microvascular complications in patients with type 2 diabetes. We tested the hypothesis that HbA1c variability is not only strongly associated with the presence but also the degree of severity of cardiovascular autonomic neuropathy (CAN) in patients with long diabetes durations (more than 10 years).

Methods

For each patient, the intrapersonal mean, standard deviation (SD), and coefficient of variation (CV) for HbA1c were calculated using all measurements obtained 3 years before the study. We constructed the composite autonomic scoring scale (CASS) as a measure of the severity of cardiovascular autonomic functions. Stepwise logistic regression and linear regression analyses were performed to evaluate the presence of CAN and the influence of independent variables on the mean CASS, respectively.

Results

Those with CAN had a higher mean age, a higher low-density lipoprotein cholesterol (LDL-C), HbA1c-SD, HbA1c-CV, mean HbA1c, and index HbA1c, higher prevalence of retinopathy as the underlying disease, and lower high-density lipoprotein (HDL) levels. Stepwise logistic regression showed that HbA1c-SD and retinopathy were risk factors that were independently associated with the presence of CAN. Mean HbA1c, HbA1c-CV, HbA1c-SD, and index HbA1c were positively correlated with mean CASS, and a multiple linear regression analysis revealed that HbA1c-SD was independently associated with the mean CASS.

Conclusion

HbA1c variability is strongly associated with not only the presence but also the degree of severity of CAN. A longitudinal study is required to confirm whether controlling blood glucose level is effective in reducing CAN progression.

Cardiovascular disease in type 1 diabetes

Cardiovascular disease (CVD) is a well-recognized complication of diabetes. Although the association of type 2 diabetes with CVD has been well described, the mechanisms, risk stratification and screening strategies of CVD in type 1 diabetes (T1D) are less understood. This review aims to evaluate recent literature and guidelines regarding CVD in T1D. At the cellular level, the early stage of CVD is characterized by endothelial dysfunction. Recent studies have shown that endothelial function is unaffected in younger T1D patients but there is a significant degree of endothelial dysfunction in the older T1D population compared with healthy age-matched controls, highlighting the importance of the endothelial dysfunction in T1D as a major age-dependent cardiovascular risk factor. T1D risk assessment tools have been developed similar to those seen in type 2 diabetes. Foremost among these are the Danish Steno Type 1 risk engine, the Swedish T1D risk score, the Scottish T1D risk score and the QRISK risk calculator. The latter risk prediction tool is used for all patients but contains T1D as an independent risk variable and has the advantage of being derived from, and validated in, a large and diverse population. The latest version (QRISK3) is likely to be recommended for routine use in T1D patients in upcoming guidelines by the National Institute of Clinical Excellence. Mortality in adults with T1D is increasingly due to CVD. This is driven by hyperglycaemia-mediated oxidative stress and vascular inflammation, resulting in atherosclerosis and cardiac autonomic neuropathy. Coronary artery disease is the most significant contributor to CVD and in T1D, has a propensity towards a more silent and severe form. Routine screening of coronary artery disease does not alter outcomes and is therefore not recommended; however, risk prediction tools are being developed to aid identification of high-risk individuals for aggressive risk factor modification strategies.

11. Microvascular Complications and Foot Care: Standards of Medical Care in Diabetes-2019

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Prevalence of Diabetic Neuropathy in Young Adults with Type 1 Diabetes and the Association with Insulin Pump Therapy

AIMS

The aim was to investigate the prevalence of diabetic sensorimotor polyneuropathy (DSPN) and cardiovascular autonomic neuropathy (CAN) in a Danish population of young adults with type 1 diabetes (T1D) using both established and novel measuring modalities. Furthermore, to investigate the association between continuous subcutaneous insulin infusion (CSII) treatment and these complications.

MATERIALS AND METHODS

CAN was assessed by cardiovascular autonomic reflex tests. DSPN was assessed not only by perception of light touch and pain, vibration perception threshold (VPT), Brief Pain Inventory (BPI), and Michigan Neuropathy Screening Instrument questionnaires but also by novel modalities: electrochemical skin conductance (ESC), sural nerve conduction velocity (SNCV), and sural nerve amplitude potential (SNAP).

RESULTS

The study comprised 156 young adults with a mean age of 22 years (standard deviation 1.6). The prevalence of CAN and early CAN was 9% and 28.1%, respectively. Subclinical DSPN was 55.1% and confirmed DSPN was 2.6%. Prevalence of abnormal SNAP was 23.8%, SNCV was 37.1%, ESC on the hands and feet was 4% and 8%, respectively, VPT was 1.3%, and BPI questionnaire was 1.9%. No association was found between CSII treatment and the measures of DSPN and CAN.

CONCLUSION

DSPN and CAN are prevalent in young adults with T1D with no association found with CSII treatment. The use of novel measuring modalities identified a higher number of subjects with DSPN compared with established measures. Screening for diabetic neuropathy in young adults may be beneficial to detect and prevent nerve damages at early stages.

Cardiac Autonomic Neuropathy in Diabetes Mellitus

Cardiovascular autonomic neuropathy (CAN) is a severely debilitating yet underdiagnosed condition in patients with diabetes. The prevalence can range from 2.5% (based on the primary prevention cohort in the Diabetes Control and Complications Trial) to as high as 90% of patients with type 1 diabetes. Clinical manifestations range from orthostasis to myocardial infarction. The diagnosis is made using multiple autonomic function tests to assess both sympathetic and parasympathetic function. The pathophysiology of CAN is complex, likely multifactorial, and not completely understood. Treatment is limited to symptomatic control of orthostatic hypotension, which is a late complication, and current strategies to reverse CAN are limited. This review explores the epidemiology, pathophysiology, clinical manifestations, diagnosis, and complications of CAN as well as current treatment options.

Cardiac autonomic neuropathy in type 1 and type 2 diabetes patients

Background

Cardiac autonomic neuropathy (CAN) in diabetes is among the strongest risk markers for future global and cardiovascular mortality. The aim of this study was to analyse CAN prevalence and to compare the associations between CAN, the glycaemic control, cardiovascular risk factors, peripheral neuropathy, retinopathy and macroangiopathy in patients with type 1 (T1DM) and type 2 diabetes mellitus (T2DM).

Methods

One hundred ninety-five diabetic patients were included in this study. All patients were evaluated for detection of CAN (with standardised cardiovascular reflex tests), diabetes-related microvascular complications (polyneuropathy, retinopathy), common carotid artery intima-media thickness (IMT) and ankle-brachial index (ABI).

Results

The prevalence of CAN was 39.1% in T2DM and 61.8% in T1DM patients. Multivariate logistic regression analysis demonstrated that in T2DM, the odds [OR (95% confidence intervals)] of CAN increased with diabetes duration [1.67(1.42–1.92)], HbA1c [1.74(1.34–2.27)], cholesterol [1.01(1.00–1.01)], triglycerides [1.01(0.99–1.00)], smoking [2.35(1.23–4.49)], systolic blood pressure [1.01(1.00–1.03)], BMI [1.16(1.08–1.24)], glomerular filtration rate [0.91(0.88–0.93)], peripheral neuropathy [25.94(11.04–44.25)], retinopathy [13.13(3.03–84.73)] and IMT [10.12 (7.21–15.32)]. In T1DM, the odds of CAN increased with diabetes duration [1.62(1.13–2.31)], HbA1c [4.49(1.27–15.9)], age of patients [1.14(1.03–1.27)], glomerular filtration rate [0.94(0.89–0.99)], peripheral neuropathy [31.6(4.5–45.8)] and IMT [5.5(2.3–8.3)].

Conclusion

This study indicated that CAN is a more frequent complication in T1DM. Apart from glycaemic control, the existence of CAN is associated with potentially modifiable cardiovascular risk only in T2DM patients. The presence of other micro- and macrovascular complications increases the probability of having CAN in both types of DM (but more pronounced in T2DM).

Update on the Management of Diabetic Neuropathy

IN BRIEF Distal symmetric polyneuropathy (DSPN) and diabetic autonomic neuropathies, particularly cardiovascular autonomic neuropathy (CAN), are prevalent diabetes complications with high morbidity, mortality, and amputation risks. The diagnosis of DSPN is principally a clinical one based on the presence of typical symptoms combined with symmetrical, distal-to-proximal stocking-glove sensory loss. CAN is an independent risk factor for cardiovascular mortality, arrhythmia, silent ischemia, major cardiovascular events, and myocardial dysfunction. Screening for CAN in high-risk patients is recommended. Symptoms of gastroparesis are nonspecific and do not correspond with its severity. Diagnosis of gastroparesis should exclude other factors well documented to affect gastric emptying such as hyperglycemia, hypoglycemia, and certain medications. There is a lack of treatment options targeting the neuropathic disease state. Managing neuropathic pain also remains a challenge. Given the high risk of addiction, abuse, psychosocial issues, and mortality, opioids are not recommended as first-, second-, or third-line agents for treating painful DSPN.

Diabetic Gastroparesis: Principles and Current Trends in Management

This article is a comprehensive review of diabetic gastroparesis, defined as delayed or disordered gastric emptying, including basic principles and current trends in management. This review includes sections on anatomy and physiology, diagnosis and differential diagnosis as well as management and current guidelines for treatment of diabetic gastroparesis. Diabetic gastroparesis (DGp) is a component of autonomic neuropathy resulting from long-standing poorly controlled type 1 and type 2 diabetes. The diagnostic workup of DGp first excludes obstruction and other causes including medications that may mimic delayed/disordered gastric emptying. Targeting nutrition, hydration, symptomatic relief and glycemic control are mainstays of treatment for DGp. Additionally, optimal treatment of DGp includes good glycemic management, often involving customizing insulin delivery using basal-bolus insulin and technology, including sensor-augmented pumps and continuous glucose monitoring systems. Prokinetic medications may be helpful in DGp symptoms, although only limited number of medications is currently available in the USA. Selected medication-refractory patients with DGp may benefit from gastric neuromodulation, and some from surgical interventions including pyloric therapies that can also be done endoscopically. As is true of any of the diabetic complications, prevention of DGp by early and optimal glycemic control is more cost-effective.Funding: Hansa Medcell, India.

Higher body mass index predicts cardiac autonomic dysfunction: A longitudinal study in adolescent type 1 diabetes

BACKGROUND

Obesity is associated with an increased risk of cardiovascular morbidity in adults with diabetes.

OBJECTIVE

To examine the predictive role of body mass index (BMI) and adiposity on cardiac autonomic function in childhood onset type 1 diabetes.

SUBJECTS

Two hundred and fifty-three participants with type 1 diabetes (aged 8-30 years) were assessed for diabetes complications at a tertiary hospital, and followed over 7 years (total 922 visits).

METHODS

Heart rate variability (HRV) measures assessed by 10-minute electrocardiography recording using LabChart Pro were standard deviation of RR intervals, time between consecutive QRS complexes, [SDNN], root mean squared difference of successive RR intervals (RMSSD), triangular index (TI), and low to high frequency ratio [LF:HF]. Multivariable generalized estimating equations were used to model the longitudinal associations between HRV measures and clinical variables (BMI standard deviation scores [SDS], waist:height ratio, total daily insulin dose/kg (TDD) and hemoglobin A1c [HbA1c]).

RESULTS

At baseline, mean age was 14.4 ± 2.7 years, diabetes duration 7.1 ± 3.7 years, HbA1c 8.3% ± 1.5% (67 ± 16 mmol/mol), and 33% were overweight/obese (BMI ≥85th percentile). At final visit, mean age was 18.5 ± 2.7 years, duration 11.3 ± 3.9 years, HbA1c 9.0% ± 1.8% (75 ± 20 mmol/mol), and 40% were overweight/obese. Adiposity (higher BMI SDS or waist: height ratio) was a significant predictor of worse HRV (lower SDNN, RMSSD; P < .05), while higher HbA1c and TDD predicted all adverse HRV measures (lower SDNN, RMSSD, TI; P < .05) and abnormal sympathovagal balance (higher LF:HF ratio; P < .05).

CONCLUSIONS

Higher BMI and central adiposity are associated with cardiac autonomic dysfunction in childhood onset type 1 diabetes, after adjusting for HbA1c. Interventions targeting overweight/obesity during adolescence may optimize long-term vascular health in type 1 diabetes.

Orthostatic hypotension: A review

Orthostatic hypotension, defined by a drop in blood pressure of at least 20mmHg for systolic blood pressure and at least 10mmHg for diastolic blood pressure within 3minutes of standing up, is a frequent finding, particularly in elderly patients. It is associated with a significant increase in morbidity and mortality. Although it is often multifactorial, the first favoring factor is medications. Other etiologies are divided in neurogenic orthostatic hypotension, characterized by autonomic failure due to central or peripheral nervous system disorders, and non-neurogenic orthostatic hypotension, mainly favoured by hypovolemia. Treatment always requires education of the patient regarding triggering situations and physiological countermanoeuvers. Pharmacological treatment may sometimes be necessary and mainly relies on volume expansion by fludrocortisone and/or a vasopressor agents such as midodrine. There is no predefined blood pressure target, the goal of therapy being the relief of symptoms and fall prevention.

Cardiovascular autonomic dysfunction predicts increasing albumin excretion in type 1 diabetes

OBJECTIVE

To determine the potential role of cardiovascular autonomic dysfunction in the development of renal complications in young people with type 1 diabetes (T1D).

METHODS

In this prospective study, 199 children and adolescents recruited to the Oxford Regional Prospective Study underwent assessment of autonomic function ~5 years after diagnosis, and were subsequently followed with longitudinal assessments of HbA_1c and urine albumin-creatinine ratio (ACR) over 8.6 ± 3.4 years. Autonomic function was assessed with 4 standardized tests of cardiovascular reflexes: heart rate (HR) response to (1) Valsalva Maneuver, (2) deep breathing, (3) standing, and (4) blood pressure (BP) response to standing. Linear mixed models were used to assess the association between autonomic parameters and future changes in ACR.

RESULTS

Independent of HbA_1c , each SD increase in HR response to Valsalva Maneuver predicted an ACR increase of 2.16% [95% CI: 0.08; 4.28] per year (P = .04), while each SD increase in diastolic BP response to standing predicted an ACR increase of 2.55% [95% CI: 0.37; 4.77] per year (P = .02). The effect of HR response to standing on ACR reached borderline significance (-2.07% [95% CI: -4.11; 0.01] per year per SD increase, P = .051).

CONCLUSIONS

In this cohort of young people with T1D, enhanced cardiovascular reflexes at baseline predicted future increases in ACR. These results support a potential role for autonomic dysfunction in the pathogenesis of diabetic nephropathy.

Autonomic Neuropathy-a Prospective Cohort Study of Symptoms and E/I Ratio in Normal Glucose Tolerance, Impaired Glucose Tolerance, and Type 2 Diabetes

Background

Autonomic neuropathy in diabetes, in addition to causing a range of symptoms originating from the autonomic nervous system, may increase cardiovascular morbidity. Our aim was to study the progression of autonomic neuropathy, based on symptom score and evaluation of an autonomic test, in persons with normal and impaired glucose tolerance and in patients with type 2 diabetes (T2D).

Methods

Participants were recruited in 2003/2004 with a follow-up in 2014. The participants’ glucose tolerance was categorized using oral glucose tolerance tests. Symptoms were evaluated using an autonomic symptom score (ASS), ECG was used to test cardiac autonomic function based on the expiration/inspiration ratio (E/I ratio), and blood samples were taken on both occasions.

Results

ASSs were higher at follow-up in the T2D patients than in the normal glucose tolerance group (mean 1.21 ± 1.30 vs. 0.79 ± 0.7; p < 0.05). E/I ratio did not deteriorate more than could be expected as an aging effect in well-controlled T2D. No relationship was found between E/I ratio and HbA1c or ASS.

Conclusion

The presence of autonomic symptoms increased over time in T2D patients, but the symptoms did not correlate with the E/I ratio in this metabolically well-controlled cohort. ASSs can be a useful clinical tool when assessing the progression of autonomic dysfunction in patients with abnormal glucose metabolism.

Cardiac Autonomic Neuropathy as a Result of Mild Hypercaloric Challenge in Absence of Signs of Diabetes: Modulation by Antidiabetic Drugs

Cardiac autonomic neuropathy (CAN) is an early cardiovascular complication of diabetes occurring before metabolic derangement is evident. The cause of CAN remains elusive and cannot be directly linked to hyperglycemia. Recent clinical data report cardioprotective effects of some antidiabetic drugs independent of their hypoglycemic action. Here, we used a rat model receiving limited daily increase in calories from fat (HC diet) to assess whether mild metabolic challenge led to CAN in absence of interfering effects of hyperglycemia, glucose intolerance, or obesity. Rats receiving HC diet for 12 weeks showed reduction in baroreceptor sensitivity and heart rate variability despite lack of change in baseline hemodynamic and cardiovascular structural parameters. Impairment of cardiac autonomic control was accompanied with perivascular adipose inflammation observed as an increased inflammatory cytokine expression, together with increased cardiac oxidative stress, and signaling derangement characteristic of diabetic cardiomyopathy. Two-week treatment with metformin or pioglitazone rectified the autonomic derangement and corrected the molecular changes. Switching rats to normal chow but not to isocaloric amounts of HC for two weeks reversed CAN. As such, we conclude that adipose inflammation due to increased fat intake might underlie development of CAN and, hence, the beneficial effects of metformin and pioglitazone.

Cardiac autonomic neuropathy: Risk factors, diagnosis and treatment

Cardiac autonomic neuropathy (CAN) is a serious complication of diabetes mellitus (DM) that is strongly associated with approximately five-fold increased risk of cardiovascular mortality. CAN manifests in a spectrum of things, ranging from resting tachycardia and fixed heart rate (HR) to development of "silent" myocardial infarction. Clinical correlates or risk markers for CAN are age, DM duration, glycemic control, hypertension, and dyslipidemia (DLP), development of other microvascular complications. Established risk factors for CAN are poor glycemic control in type 1 DM and a combination of hypertension, DLP, obesity, and unsatisfactory glycemic control in type 2 DM. Symptomatic manifestations of CAN include sinus tachycardia, exercise intolerance, orthostatic hypotension (OH), abnormal blood pressure (BP) regulation, dizziness, presyncope and syncope, intraoperative cardiovascular instability, asymptomatic myocardial ischemia and infarction. Methods of CAN assessment in clinical practice include assessment of symptoms and signs, cardiovascular reflex tests based on HR and BP, short-term electrocardiography (ECG), QT interval prolongation, HR variability (24 h, classic 24 h Holter ECG), ambulatory BP monitoring, HR turbulence, baroreflex sensitivity, muscle sympathetic nerve activity, catecholamine assessment and cardiovascular sympathetic tests, heart sympathetic imaging. Although it is common complication, the significance of CAN has not been fully appreciated and there are no unified treatment algorithms for today. Treatment is based on early diagnosis, life style changes, optimization of glycemic control and management of cardiovascular risk factors. Pathogenetic treatment of CAN includes: Balanced diet and physical activity; optimization of glycemic control; treatment of DLP; antioxidants, first of all α-lipoic acid (ALA), aldose reductase inhibitors, acetyl-L-carnitine; vitamins, first of all fat-soluble vitamin B1; correction of vascular endothelial dysfunction; prevention and treatment of thrombosis; in severe cases-treatment of OH. The promising methods include prescription of prostacyclin analogues, thromboxane A2 blockers and drugs that contribute into strengthening and/or normalization of Na+, K+-ATPase (phosphodiesterase inhibitor), ALA, dihomo-γ-linolenic acid (DGLA), ω-3 polyunsaturated fatty acids (ω-3 PUFAs), and the simultaneous prescription of ALA, ω-3 PUFAs and DGLA, but the future investigations are needed. Development of OH is associated with severe or advanced CAN and prescription of nonpharmacological and pharmacological, in the foreground midodrine and fludrocortisone acetate, treatment methods are necessary.

A Comparative Assessment of Cardiovascular Autonomic Reflex Testing and Cardiac 123I-Metaiodobenzylguanidine Imaging in Patients with Type 1 Diabetes Mellitus without Complications or Cardiovascular Risk Factors

AIM

To compare the cardiovascular autonomic reflex tests (CARTs) with cardiac sympathetic innervation imaging with ¹²³I-metaiodobenzylguanidine (MIBG) in patients with type 1 diabetes mellitus (T1DM).

PATIENTS AND METHODS

Forty-nine patients (29 males, mean age 36 ± 10 years, mean T1DM duration 19 ± 6 years) without cardiovascular risk factors were prospectively enrolled. Participants were evaluated for autonomic dysfunction by assessing the mean circular resultant (MCR), Valsalva maneuver (Vals), postural index (PI), and orthostatic hypotension (OH). Within one month from the performance of these tests, patients underwent cardiac MIBG imaging and the ratio of the heart to upper mediastinum count density (H/M) at 4 hours postinjection was calculated (abnormal values, H/M < 1.80).

RESULTS

Twenty-nine patients (59%) had abnormal CARTs, and 37 (76%) patients had an H/M_4 < 1.80 (p = 0.456). MCR, PI, Vals, and OH were abnormal in 29 (59%), 8 (16%), 5 (10%), and 11 (22%) patients, respectively. When using H/M_4 < 1.80 as the reference standard, a cutoff point of ≥2 abnormal CARTs had a sensitivity of 100% but a specificity of only 33% for determining CAN.

CONCLUSIONS

CARTs are not closely associated with ¹²³I-MIBG measurements, which can detect autonomic dysfunction more efficiently than the former. In comparison to semiquantitative cardiac MIBG assessment, the recommended threshold of ≥2 abnormal CARTs to define cardiovascular autonomic dysfunction is highly sensitive but of limited specificity and is independently determined by the duration of T1DM.

10. Microvascular Complications and Foot Care: Standards of Medical Care in Diabetes-2018

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Combination of Ewing test, heart rate variability, and heart rate turbulence analysis for early diagnosis of diabetic cardiac autonomic neuropathy

The aim of this study was to compare and analyze Ewing test, heart rate variability (HRV), and heart rate turbulence (HRT) in the diagnosis of cardiac autonomic neuropathy (CAN) in diabetic patients.Ninety diabetic patients (age 18-78) and 20 nondiabetic control subjects were studied. Standard Ewing test and 24-hour Holter was performed in all participants to evaluate CAN. Patients with Ewing score ≥2 were classified as CAN+.The rate of CAN+ in diabetic patients [44.4% (40/90)] was higher than that in the controls [5% (1/20)] (P < .05). Using the HRV analysis and HRT analysis, rates of CAN+ in diabetic patients were 56.67% (51/90) and 52.22% (47/90), respectively. SD of all normal-to-normal (NN) intervals (SDNN), SD of the average NN intervals calculated over 5-minute periods of the entire recording (SDANN), low frequency power (LF), and turbulence slope (TS) were significantly correlated negatively with Ewing scores. TS (r = -0.68, P < .05) and SDNN (r = -0.58, P < .05) had the strongest correlation with Ewing scores among relevant factors. Combining TS with SDNN as diagnostic criteria for CAN, the diagnostic sensitivity can be increased to 98%.Parameters used for evaluating parasympathetic functions in Ewing test, HR variability, and HR turbulence were found to significantly decrease in CAN+ group. The combination of SDNN and TS showed greater diagnostic value than Ewing test, HRV analysis, or HRT analysis alone.

Diagnostic Accuracy of Random ECG in Primary Care for Early, Asymptomatic Cardiac Autonomic Neuropathy

AIMS

Cardiac autonomic reflex tests (CARTs) are time consuming and require patient cooperation for detecting cardiac autonomic neuropathy (CAN). Heart rate variability (HRV) analysis requires less patient cooperation and is quicker to complete. However the reliability of HRV results as a clinical tool, with respect to length of recording and accuracy of diagnosis is inconclusive. The current study investigated the reproducibility associated with varying length of recording for early CAN (eCAN) assessment.

METHODS

Participants were 68 males, 72 females with average age of 55 for controls and 63 for early CAN. Inclusion criteria were that participants were medication free and presented with no comorbidities. ECGs of control and eCAN were recorded and heart rate changes analyzed with the fast Fourier transform (FFT) and Lomb-Scargle periodogram (LSP). Ten-second to 5-minute recordings were extracted from a 15-minute lead-II ECG and accuracy in assessment of eCAN determined.

RESULTS

The eCAN group was older ( P < .001) and systolic blood pressure was higher ( P < .01). HDL-cholesterol was also higher in the eCAN group ( P < .05). HRV analysis showed that both FFT and LSP results were significantly different between eCAN and control down to a 10-second ECG length for low frequency (LSP: P = .013, FFT: P = .024) and high frequency (HF-LSP: P = .002, FFT: P = .002) power. eCAN assessment was optimal down to 90-second recordings with a sensitivity of 100% and specificity of 29.49%.

CONCLUSION

HRV is suitable for clinical practice from ECG recordings of more than 90 seconds with high accuracy and repeatability within a session for each participant.

Cardiac vagal tone, a non-invasive measure of parasympathetic tone, is a clinically relevant tool in Type 1 diabetes mellitus

AIMS

To compare a novel index of parasympathetic tone, cardiac vagal tone, with established autonomic variables and to test the hypotheses that (1) cardiac vagal tone would be associated with established time and frequency domain measures of heart rate and (2) cardiac vagal tone would be lower in people with Type 1 diabetes than in a matched healthy cohort and lower still in people with established neuropathy.

METHODS

Cardiac vagal tone is a validated cardiometrically derived index of parasympathetic tone. It is measured using a standard three-lead electrocardiogram which connects, via Bluetooth, to a smartphone application. A 5-min resting recording of cardiac vagal tone was undertaken and observational comparisons were made between 42 people with Type 1 diabetes and peripheral neuropathy and 23 without peripheral neuropathy and 65 healthy people. In those with neuropathy, 24-h heart rate variability values were compared with cardiac vagal tone. Correlations between cardiac vagal tone and clinical variables were also made.

RESULTS

Cardiac vagal tone was lower in people with established neuropathy and Type 1 diabetes in comparison with healthy participants [median (interquartile range) linear vagal scale 3.4 (1.6-5.5 vs 7.0 (5.5-9.6); P < 0.0001]. Cardiac vagal tone was positively associated with time (r = 0.8, P < 0.0001) and frequency domain markers of heart rate variability (r = 0.75, P < 0.0001), representing established measures of parasympathetic function. Cardiac vagal tone was negatively associated with age (r=-0.32, P = 0.003), disease duration (r=-0.43, P < 0.0001) and cardiovascular risk score (r=-0.32, P = 0.006).

CONCLUSIONS

Cardiac vagal tone represents a convenient, clinically relevant method of assessing parasympathetic nervous system tone, potentially facilitating the earlier identification of people with Type 1 diabetes who should undergo formal autonomic function testing.

Microvascular Complications Associated With Rapid Improvements in Glycemic Control in Diabetes

PURPOSE OF REVIEW

Aggressive glycemic control has become the standard clinical approach to diabetes care. Unintended consequences have included the development of microvascular complications that are related to the rapidity of glycemic improvement.

RECENT FINDINGS

Diabetic neuropathy may develop in up to 10% of individuals secondary to aggressive glycemic control. The neuropathy is predominantly small fiber sensory and autonomic, and the severity of the neuropathy is tied to the change in the glycosylated hemoglobin A1C. Other microvascular complications such as retinopathy and nephropathy are common and may occur in parallel with the neuropathy. Eating disorders are a common comorbid risk factor. Individuals with uncontrolled diabetes for prolonged periods, particularly those with a history of eating disorders involving insulin restriction for calorie purging, are at high risk for developing treatment-induced microvascular complications. Gradual glycemic improvements should be encouraged but future research is needed to optimize treatment and prevention strategies.

Potential Association of Triglyceride Glucose Index with Cardiac Autonomic Neuropathy in Type 2 Diabetes Mellitus Patients

Cardiac autonomic neuropathy (CAN) is a common and most neglected complication of diabetes, estimated to be roughly 8% in recently diagnosed patients and greater than 50% in patients with chronic disease history. The insulin resistance (IR) itself is bidirectionally associated with increased risk of type 2 diabetes mellitus (T2DM) and CAN is a predisposing factor. The primary objective of the present study was aimed to find a correlation of triglyceride glucose index (TyG index) in CAN patients along with the prevalence of CAN in T2DM patients as a secondary objective. This prevalence study was conducted on 202 patients visiting the diabetic clinic of Hamdard Institute of Medical Sciences and Research, Jamia Hamdard (HIMSR) teaching hospital in New Delhi, India who fulfilled the inclusion criteria. The Ewings autonomic function test was used for diagnosis of CAN. TyG index was calculated for patients based on fasting levels of glucose and triglyceride. The CAN was diagnosed in 62 participants out of 202 T2DM patients (overall prevalence 30.7%). The mean ± standard deviation (SD) for TyG index was 10.3 ± 0.2 and 9.5 ± 0.2 in CAN positive, T2DM patients, respectively. The difference of TyG index, in CAN positive and T2DM patients, was highly significant (P < 0.001). Further correlation analysis was performed to find an association of TyG index, duration, and age with patient groups. TyG index showed a positive correlation with heart rate during deep breathing (HRD), heart rate variation during standing (HRS), blood pressure (BP) response to handgrip and BP response to standing. Our finding highlights the TyG index, low-cost IR index, might be useful as an alternative tool for the early screening of patients at a high risk of diabetic neuropathy.

Association of Glycemic Variability in Type 1 Diabetes With Progression of Microvascular Outcomes in the Diabetes Control and Complications Trial

OBJECTIVE

The Diabetes Control and Complications Trial (DCCT) demonstrated the beneficial effects of intensive versus conventional therapy on the development and progression of microvascular complications of type 1 diabetes. These beneficial effects were almost completely explained by the difference between groups in the levels of HbA_1c, which in turn were associated with the risk of these complications. We assessed the association of glucose variability within and between quarterly 7-point glucose profiles with the development and progression of retinopathy, nephropathy, and cardiovascular autonomic neuropathy during the DCCT.

RESEARCH DESIGN AND METHODS

Measures of variability included the within-day and updated mean (over time) of the SD, mean amplitude of glycemic excursions (MAGE), and M-value, and the longitudinal within-day, between-day, and total variances. Imputation methods filled in the 16.3% of expected glucose values that were missing.

RESULTS

Cox proportional hazards models assessed the association of each measure of glycemic variation, as a time-dependent covariate, with the risk of retinopathy and nephropathy, and a longitudinal logistic regression model did likewise for cardiovascular autonomic neuropathy. Adjusted for mean blood glucose, no measure of within-day variability was associated with any outcome. Only the longitudinal mean M-value (over time) was significantly associated with microalbuminuria when adjusted for the longitudinal mean blood glucose and corrected for multiple tests using the Holm procedure.

CONCLUSIONS

Overall, within-day glycemic variability, as determined from quarterly glucose profiles, does not play an apparent role in the development of microvascular complications beyond the influence of the mean glucose.

Cardiac autonomic neuropathy in patients with diabetes mellitus: current perspectives

Cardiac autonomic neuropathy (CAN) is a common and often-underdiagnosed complication of diabetes mellitus (DM). CAN is associated with increased mortality, cardiovascular disease, chronic kidney disease, and morbidity in patients with DM, but despite these significant consequences CAN often remains undiagnosed for a prolonged period. This is commonly due to the disease being asymptomatic until the later stages, as well as a lack of easily available screening strategies. In this article, we review the latest developments in the epidemiology, pathogenesis, diagnosis, consequences, and treatments of CAN in patients with DM.

Cardiac Autonomic Neuropathy: Why Should Cardiologists Care about That?

BACKGROUND

Cardiac autonomic neuropathy (CAN) is a frequent but underdiagnosed complication of diabetes mellitus. It has a strong influence on various cardiac disorders including myocardial ischemia and infarction, hypertension, orthostatic hypotonia, heart failure, and arrhythmias. CAN can lead to severe morbidity and mortality and increase the risk of sudden cardiac death.

METHODS

This review article summarizes the latest evidence regarding the epidemiology, pathogenesis, influence on the cardiovascular system, and diagnostic methods for CAN. The methodology of this review involved analyzing available data from recent papers relevant to the topic of diabetic autonomic neuropathy and cardiac disorders.

CONCLUSIONS

The early diagnosis of CAN can improve the prognosis and reduce adverse cardiac events. Methods based on heart rate variability enable the diagnosis of CAN even at a preclinical stage. These methods are simple and widely available for use in everyday clinical practice. According to the recently published Toronto Consensus Panel on Diabetic Neuropathy, all diabetic patients should be screened for CAN. Because diabetes mellitus often coexists with heart diseases and the most common methods used for diagnosis of CAN are based on ECG, not only diabetologists but also cardiologists should be responsible for diagnosis of CAN.

Cardiovascular Autonomic Neuropathy and Cardiovascular Outcomes in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study

OBJECTIVE

To examine whether cardiovascular autonomic neuropathy (CAN) is an independent risk factor of cardiovascular disease (CVD) events during DCCT/EDIC.

RESEARCH DESIGN AND METHODS

Standardized cardiovascular autonomic reflex tests (R-R response to paced breathing, Valsalva maneuver, postural changes in blood pressure) were performed at DCCT baseline, every 2 years throughout DCCT, and at two time points in EDIC. CVD events were ascertained throughout the study and adjudicated by a review committee. Cox proportional hazards models were used to estimate the effect of CAN at DCCT closeout on subsequent CVD risk.

RESULTS

There were 299 adjudicated CVD events in 165 participants following the DCCT closeout assessment: 132 of 1,262 subjects (10%) without CAN at DCCT closeout who experienced 244 CVD events versus 33 of 131 subjects (25%) with CAN at DCCT closeout who experienced 55 events (hazard ratio 2.79, 95% CI 1.91-4.09 for time to first CVD event). The cumulative incidence of the first occurrence of any CVD event during EDIC was significantly higher in participants with CAN at DCCT closeout compared with those without CAN. The association remained marginally significant after adjustment for multiple risk factors, including the EDIC updated mean HbA1c. When analyzed as a continuous variable, R-R variation was significantly lower at DCCT closeout in participants who experienced a CVD event compared with those who did not (P = 0.0012).

CONCLUSIONS

In the DCCT/EDIC cohort, individuals diagnosed with CAN at DCCT closeout experienced a higher long-term risk of CVD events during follow-up in EDIC. This association was not independent of historic glycemic exposure and its metabolic memory effect, the principal determinant of both long-term CVD risk and CAN in type 1 diabetes.

Urogenital Autonomic Dysfunction in Diabetes

This review details the epidemiology, possible mechanisms, and risk factors associated with urogenital autonomic dysfunction in diabetes. Autonomic neuropathy in diabetes is associated with various urological complications including bladder and sexual dysfunction. Several studies have reported the high prevalence of bladder and sexual dysfunction in both men and women. The DCCT/EDIC UroEDIC study examined the association between cardiovascular autonomic neuropathy and bladder and sexual dysfunction in a large cohort of participants with type 1 diabetes and was the first to report significant associations. Future studies are needed to further evaluate the association of urogenital complications and autonomic dysfunction in diabetes.

Cardiovascular Autonomic Neuropathy, Sexual Dysfunction, and Urinary Incontinence in Women With Type 1 Diabetes

OBJECTIVE

This study evaluated associations among cardiovascular autonomic neuropathy (CAN), female sexual dysfunction (FSD), and urinary incontinence (UI) in women with type I diabetes mellitus (T1DM).

RESEARCH DESIGN AND METHODS

We studied 580 women with T1DM in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study (DCCT/EDIC). CAN was defined as: 1) R-R variation <15 with deep breathing or 2) R-R variation of 15-19.9 plus Valsalva ratio ≤1.5 or a supine-to-standing drop of 10 mmHg in diastolic blood pressure. A Sandvik Severity Index of 3-12 defined UI, and a Female Sexual Function Index (FSFI-R) score ≥22.75 defined FSD. Multivariable models estimated associations among CAN, FSD, and UI.

RESULTS

At EDIC year 17, FSD was observed in 41% of women and UI in 30%. No statistically significant associations were observed between measures of CAN at DCCT closeout and subsequent report of FSD or UI. At EDIC year 16/17, there was a 53% increased odds of having UI with a Valsalva ratio ≤1.5. At both EDIC year 13/14 and EDIC year 16/17, a 5-unit increase in R-R variation was associated with a 1.11 greater odds of having FSD.

CONCLUSIONS

In women with T1DM in the DCCT/EDIC, we found significant increased odds of FSD and UI with specific measures of CAN. In long-standing T1DM, CAN may predict development of FSD and may be a useful surrogate for generalized diabetic autonomic neuropathy.

Cardiovascular autonomic neuropathy in patients with diabetes mellitus

Cardiovascular autonomic neuropathy associated with diabetes mellitus is caused by an impairment of the autonomic system. The prevalence of this condition ranges from 20% to 65%, depending on the duration of the diabetes mellitus. Clinically, the autonomic function disorder is associated with resting tachycardia, exercise intolerance, orthostatic hypotension, intraoperative cardiovascular instability, silent myocardial ischemia and increased mortality. For the diagnosis, the integrity of the parasympathetic and sympathetic nervous system is assessed. Parasympathetic activity is examined by measuring heart rate variability in response to deep breathing, standing and the Valsalva manoeuvre. Sympathetic integrity is examined by measuring blood pressure in response to standing and isometric exercise. The treatment includes the metabolic control of diabetes mellitus and of the cardiovascular risk factors. Treating symptoms such as orthostatic hypotension requires special attention.

Review: Autonomic neuropathy: a marker of cardiovascular risk

Cardiac autonomic neuropathy (CAN) represents a serious complication as it carries an approximately five-fold risk of mortality in patients with diabetes just as in those with chronic liver diseases. The high mortality rate may be related to silent myocardial infarction, cardiac arrhythmias, cardiovascular and cardiorespiratory instability and to other causes not yet explained. Resting tachycardia due to parasympathetic damage may represent one of the earliest signs. Typical findings referring to autonomic dysfunction may include exercise intolerance, orthostatic hypotension and cardiac dysfunction to rest or exercise. Severe autonomic neuropathy may be responsible for spontaneous respiratory arrest and unexplained sudden death. A relationship between the presence and/or severity of CAN and corrected QT interval prolongation is well documented. Better understanding of the prognostic importance of autonomic neuropathy followed the use of simple non-invasive cardiovascular reflex tests. These most commonly include heart rate variation in response to deep breathing, standing, the Valsalva maneouvre and blood pressure response to standing and sustained handgrip. Near normoglycaemia is now generally accepted as the primary approach to the prevention of diabetic neuropathy, but is not achievable in most patients. Our experience of the use of the antioxidant alpha-lipoic acid in the treatment of cardiac autonomic neuropathy is described.

Sensor and software use for the glycaemic management of insulin-treated type 1 and type 2 diabetes patients

Lowering glucose levels, while avoiding hypoglycaemia, can be challenging in insulin-treated patients with diabetes. We evaluated the role of ambulatory glucose profile in optimising glycaemic control in this population. Insulin-treated patients with type 1 and type 2 diabetes were recruited into a prospective, multicentre, 100-day study and randomised to control (n = 28) or intervention (n = 59) groups. The intervention group used ambulatory glucose profile, generated by continuous glucose monitoring, to assess daily glucose levels, whereas the controls relied on capillary glucose testing. Patients were reviewed at days 30 and 45 by the health care professional to adjust insulin therapy. Comparing first and last 2 weeks of the study, ambulatory glucose profile-monitored type 2 diabetes patients (n = 28) showed increased time in euglycaemia (mean ± standard deviation) by 1.4 ± 3.5 h/day (p = 0.0427) associated with reduction in HbA1c from 77 ± 15 to 67 ± 13 mmol/mol (p = 0.0002) without increased hypoglycaemia. Type 1 diabetes patients (n = 25) showed reduction in hypoglycaemia from 1.4 ± 1.7 to 0.8 ± 0.8 h/day (p = 0.0472) associated with a marginal HbA1c decrease from 75 ± 10 to 72 ± 8 mmol/mol (p = 0.0508). Largely similar findings were observed comparing intervention and control groups at end of study. In conclusion, ambulatory glucose profile helps glycaemic management in insulin-treated diabetes patients by increasing time spent in euglycaemia and decreasing HbA1c in type 2 diabetes patients, while reducing hypoglycaemia in type 1 diabetes patients.

Alternative Quantitative Tools in the Assessment of Diabetic Peripheral and Autonomic Neuropathy

Here we review some seldom-discussed presentations of diabetic neuropathy, including large fiber dysfunction and peripheral autonomic dysfunction, emphasizing the impact of sympathetic/parasympathetic imbalance. Diabetic neuropathy is the most common complication of diabetes and contributes additional risks in the aging adult. Loss of sensory perception, loss of muscle strength, and ataxia or incoordination lead to a risk of falling that is 17-fold greater in the older diabetic compared to their young nondiabetic counterparts. A fall is accompanied by lacerations, tears, fractures, and worst of all, traumatic brain injury, from which more than 60% do not recover. Autonomic neuropathy has been hailed as the "Prophet of Doom" for good reason. It is conducive to increased risk of myocardial infarction and sudden death. An imbalance in the autonomic nervous system occurs early in the evolution of diabetes, at a stage when active intervention can abrogate the otherwise relentless progression. In addition to hypotension, many newly recognized syndromes can be attributed to cardiac autonomic neuropathy such as orthostatic tachycardia and bradycardia. Ultimately, this constellation of features of neuropathy conspire to impede activities of daily living, especially in the patient with pain, anxiety, depression, and sleep disorders. The resulting reduction in quality of life may worsen prognosis and should be routinely evaluated and addressed. Early neuropathy detection can only be achieved by assessment of both large and small- nerve fibers. New noninvasive sudomotor function technologies may play an increasing role in identifying early peripheral and autonomic neuropathy, allowing rapid intervention and potentially reversal of small-fiber loss.

Neuropathy in the DCCT/EDIC-What Was Done Then and What We Would Do Better Now

The Diabetes Control and Complications Trial (DCCT) and its epidemiological follow-up, the Epidemiology of Diabetes Interventions and Complications (EDIC) provide important insight on the natural history of distal symmetrical polyneuropathy and cardiovascular autonomic neuropathy in patients with type 1 diabetes and on the impact of intensive treatment of hyperglycemia on disease progression. This chapter summarizes the design and methods used for neuropathy evaluations both in the DCCT and in EDIC, the characteristics of the DCCT/EDIC patient population, and summarizes the findings of the DCCT/EDIC relative to neuropathic complications of type 1 diabetes. Lessons learned from the DCCT and EDIC experiences of longitudinal assessments of neuropathic complications are also reviewed.

Obese Patients with Type 2 Diabetes on Conventional Versus Intensive Insulin Therapy: Efficacy of Low-Calorie Dietary Intervention

INTRODUCTION

The aim of this prospective study was to assess the results of a standard low-calorie dietary intervention (7.5 MJ/day) on body weight (BW) and the metabolic profile of obese patients with type 2 diabetes mellitus (T2DM) on intensive insulin therapy (IIT: 4 insulin injections/day) versus conventional insulin therapy (CIT: 2/3 insulin injections/day).

METHODS

A total of 60 patients (n = 60, 23 males and 37 postmenopausal females) were recruited and categorized into two groups according to the scheme of insulin treatment. Thirty were on IIT (13 males and 17 females) and an equal number on CIT (10 males and 20 females). BW, body mass index (BMI), HbA1c, and metabolic parameters were compared at 6 and 12 months after baseline.

RESULTS

Significant reductions were observed in the BW, BMI, HbA1c (p ≤ 0.001 for all) and cholesterol (p ≤ 0.05) at 6 months post-intervention. At 1 year, median BW reduction was 4.5 kg (3.3, 5.8) for patients on IIT and 4.8 kg (3.6, 7.0) for those on CIT. The 12-month dietary intervention increased prevalence of normoglycemia in the IIT group and reduced the prevalence of obesity prevalence among the CIT participants (all p < 0.001). CIT patients with BW reduction ≥5.0% demonstrated 11-fold greater chances of being normoglycemic (odds ratio 11.3, 95% CI 1.1-110.5). BW reduction ≥7.0% was associated with CIT, being overweight, and having normal HDLc, LDLc, and cholesterol levels. A reduction in BW between 5.0% and 6.9% was associated with IIT, normoglycemia, and obesity.

CONCLUSION

A 12-month 1800-kcal dietary intervention achieved significant BW and HbA1c reductions irrespectively of insulin regimen. CIT was associated with BW reduction greater than 8.0%, whereas IIT was associated with higher rates of normoglycemia.

A study for association and interaction analysis to metabolic syndrome and the ESR1 gene on cardiovascular autonomic neuropathy in a Chinese Han population

BACKGROUND

The aim of this study was to investigate the association and interaction of metabolic syndrome (MetS) and estrogen receptor alpha 1 (ESR1) gene polymorphisms on cardiovascular autonomic neuropathy (CAN).

METHODS

A large-scale, population-based study was conducted to analyze the interaction of MetS and ESR1 gene polymorphisms to CAN, including a total of 1977 Chinese subjects. The most common studied single nucleotide polymorphism of ESR1 gene-rs9340799, was genotyped. Multiple logistic regression (MLR) was performed to evaluate the interaction effect of environmental variables and gene polymorphisms. Interaction on an additive scale can be calculated by using the relative excess risk due to interaction (RERI), the proportion attributable to interaction (AP), and the synergy index (S).

RESULTS

After controlling potential confounders, MLR showed that significant association between MetS and CAN (p < 0.001). Interestingly, we found that the participants with MetS bearing the minor allele G had an increased CAN prevalence comparing those with allele A (p = 0.045), and a positive interaction was estimated by using RETI = 0.396 (95 % CI 0.262 to 0.598), AP = 0.216 (95 % CI -0.784 to 1.216) and S = 1.906 (95 % CI 0.905 to 4.015).

CONCLUSION

The present findings suggest that MetS is significantly associated with CAN and provide evidence for the hypothesis that MetS and ESR1 gene polymorphism (rs9340799) have interactive effects on CAN. ClinicalTrials gov Identifier NCT02461342.

Orthostatic hypotension in diabetic patients-10-year follow-up study

INTRODUCTION

Cardiovascular autonomic neuropathy in diabetics is a common but often underestimated and underdiagnosed complication of diabetes mellitus. One of the most clinical apparent forms of cardiovascular autonomic neuropathy is orthostatic hypotension.

OBJECTIVES

To retrospectively assess the association of the orthostatic hypotension (OH) with macrovascular and microvascular complications of diabetes mellitus and to determine its effect on mortality.

DESIGN AND METHODS

We retrospectively analyzed 187 patients with diabetes mellitus (60 patients with diabetes type 1 and 127 patients with diabetes type 2). Patients were divided into groups according to presence or absence of OH and type of diabetes. Association of OH with macrovascular and microvascular complications was evaluated and the effect of OH on 10-year all-cause mortality was also assessed.

RESULTS

OH was present in 31.7% of patients with diabetes type 1 (DM1) and in 32.3% of patients with diabetes type 2 (DM2). OH was positively associated with the prevalence of myocardial infarction in DM1 (OR=10.67) and with prevalence of stroke in DM2 (OR=3.33). There was also a strong association of OH and the prevalence of peripheral artery disease in both DM1 (OR=14.18) and DM2 (OR=3.26). Patients with both types of diabetes and OH had significantly higher prevalence of nephropathy (DM1 OR=8.68, DM2 OR=3.24), retinopathy (DM1 OR=8.09, DM2 OR=4.08) and peripheral neuropathy (DM1 OR=17.14, DM2 OR=7.51) Overall 10year mortality rate was higher in diabetic patients with OH.

CONCLUSIONS

Presence of OH in diabetics is associated with higher prevalence of macrovascular and microvascular complications of diabetes mellitus and also with higher 10-year mortality.

Effects of exenatide on measures of diabetic neuropathy in subjects with type 2 diabetes: results from an 18-month proof-of-concept open-label randomized study

OBJECTIVE

Experimental studies have reported potential benefit of glucagon-like peptide-1(GLP-1) receptor agonists in preventing diabetic peripheral neuropathy (DPN). We therefore performed a proof-of-concept pilot study to evaluate the effect of exenatide, a GLP-1 agonist, on measures of DPN and cardiovascular autonomic neuropathy (CAN) in patients with type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

Forty-six T2D subjects (age 54±10years, diabetes duration 8±5years, HbA1c 8.2±1.3%) with mild to moderate DPN at baseline were randomized to receive either twice daily exenatide (n=22) or daily insulin glargine (n=24). The subjects, with similar HbA1c levels, were followed for 18months. The primary end point was the prevalence of confirmed clinical neuropathy (CCN). Changes in measures of CAN, other measures of small fiber neuropathy such as intra-epidermal nerve fiber density (IENFD), and quality of life were also analyzed.

RESULTS

Glucose control was similar in both groups during the study. There were no statistically significant treatment group differences in the prevalence of CCN, IENFD, measures of CAN, nerve conductions studies, or quality of life indices.

CONCLUSIONS

In this pilot study of patients with T2D and mild to moderate DPN, 18months of exenatide treatment had no significant effect on measures of neuropathy compared with glargine treatment.

Diabetes and cardiovascular disease: Epidemiology, biological mechanisms, treatment recommendations and future research

The incidence of diabetes mellitus (DM) continues to rise and has quickly become one of the most prevalent and costly chronic diseases worldwide. A close link exists between DM and cardiovascular disease (CVD), which is the most prevalent cause of morbidity and mortality in diabetic patients. Cardiovascular (CV) risk factors such as obesity, hypertension and dyslipidemia are common in patients with DM, placing them at increased risk for cardiac events. In addition, many studies have found biological mechanisms associated with DM that independently increase the risk of CVD in diabetic patients. Therefore, targeting CV risk factors in patients with DM is critical to minimize the long-term CV complications of the disease. This paper summarizes the relationship between diabetes and CVD, examines possible mechanisms of disease progression, discusses current treatment recommendations, and outlines future research directions.

Short-term diabetic hyperglycemia suppresses celiac ganglia neurotransmission, thereby impairing sympathetically mediated glucagon responses

Short-term hyperglycemia suppresses superior cervical ganglia neurotransmission. If this ganglionic dysfunction also occurs in the islet sympathetic pathway, sympathetically mediated glucagon responses could be impaired. Our objectives were 1) to test for a suppressive effect of 7 days of streptozotocin (STZ) diabetes on celiac ganglia (CG) activation and on neurotransmitter and glucagon responses to preganglionic nerve stimulation, 2) to isolate the defect in the islet sympathetic pathway to the CG itself, and 3) to test for a protective effect of the WLD(S) mutation. We injected saline or nicotine in nondiabetic and STZ-diabetic rats and measured fos mRNA levels in whole CG. We electrically stimulated the preganglionic or postganglionic nerve trunk of the CG in nondiabetic and STZ-diabetic rats and measured portal venous norepinephrine and glucagon responses. We repeated the nicotine and preganglionic nerve stimulation studies in nondiabetic and STZ-diabetic WLD(S) rats. In STZ-diabetic rats, the CG fos response to nicotine was suppressed, and the norepinephrine and glucagon responses to preganglionic nerve stimulation were impaired. In contrast, the norepinephrine and glucagon responses to postganglionic nerve stimulation were normal. The CG fos response to nicotine, and the norepinephrine and glucagon responses to preganglionic nerve stimulation, were normal in STZ-diabetic WLD(S) rats. In conclusion, short-term hyperglycemia's suppressive effect on nicotinic acetylcholine receptors of the CG impairs sympathetically mediated glucagon responses. WLD(S) rats are protected from this dysfunction. The implication is that this CG dysfunction may contribute to the impaired glucagon response to insulin-induced hypoglycemia seen early in type 1 diabetes.