Coexistence of impaired indices of autonomic neuropathy and diabetic nephropathy in a cohort of children with type 1 diabetes mellitus

25-hydroxyvitamin D as a predictor of reduced heart rate variability in elderly patients with diabetes mellitus

Objective

To analyze the risk factors for decreased heart rate variability (HRV) in elderly diabetic patients and evaluate the predictive value of 25-hydroxyvitamin D [25-(OH)D].

Methods

A retrospective study was conducted, enrolling 101 elderly diabetic patients admitted to the Department of Geriatric Endocrinology at the First Affiliated Hospital of Anhui Medical University from 2023 to 2024. Patients were divided into two groups based on the standard deviation of all normal RR intervals (SDNN) from 24-hour Holter monitoring: the normal HRV group (180 ms ≥ SDNN ≥ 100 ms) and the decreased HRV group (SDNN < 100 ms). Clinical data collected included age, sex, body mass index (BMI), Diabetic peripheral neuropathy (DPN), Diabetic peripheral vascular disease (DPVD), Diabetic nephropathy (DN), Diabetic retinopathy (DR), as well as laboratory parameters such as fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), creatinine (Cr), glomerular filtration rate (GFR), uric acid (UA), cystatin C (CysC), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol (VLDL-C), non-HDL-C, 25-(OH)D, 24-hour urinary total protein (24hUTP), 24-hour urinary uric acid (24hUA), microalbuminuria (MAlb), urinary albumin-to-creatinine ratio (UACR), and calculated ratios including TG/HDL-C, UA/HDL-C, and non-HDL-C/HDL-C. Statistical analyses included χ² test, independent t-test, Mann-Whitney U test, and multivariate logistic regression to identify risk factors for HRV reduction. Receiver operating characteristic (ROC) curve analysis was performed to assess the predictive value of these factors.

Results

Compared with the normal HRV group, the decreased HRV group had significantly lower HDL-C and 25-(OH)D levels but higher prevalence of DN, along with elevated 24hUTP, MAlb, UACR, TG/HDL-C, and UA/HDL-C (all P < 0.05). These factors were identified as independent risk factors for HRV reduction in elderly diabetic patients.

Conclusion

This study identified key risk factors for HRV reduction in elderly diabetic patients. Furthermore, 25-(OH)D levels may serve as an early predictive marker for decreased HRV in this population.

Evaluation of cardiac autonomic dysfunctions in children with type 1 diabetes mellitus

BACKGROUND

Cardiovascular autonomic neuropathy (CAN) is a serious complication of diabetes, impacting the autonomic nerves that regulate the heart and blood vessels. Timely recognition and treatment of CAN are crucial in averting the onset of cardiovascular complications. Both clinically apparent autonomic neuropathy and subclinical autonomic neuropathy, particularly CAN pose a significant risk of morbidity and mortality in children with type 1 diabetes mellitus (T1DM). Notably, CAN can progress silently before manifesting clinically. In our study, we assessed patients with poor metabolic control, without symptoms, following the ISPAD 2022 guideline. The objective is is to determine which parameters we can use to diagnose CAN in the subclinical period.

METHODS

Our study is a cross-sectional case-control study that includes 30 children diagnosed with T1DM exhibiting poor metabolic control (average HbA1c > 8.5% for at least 1 year) according to the ISPAD 2022 Consensus Guide. These patients, who are under the care of the pediatric diabetes clinic, underwent evaluation through four noninvasive autonomic tests: echocardiography, 24-h Holter ECG for heart rate variability (HRV), cardiopulmonary exercise test, and tilt table test.

RESULTS

The average age of the patients was 13.73 ± 1.96 years, the average diabetes duration was 8 ± 3.66 years, and the 1-year average HbA1c value was 11.34 ± 21%. In our asymptomatic and poorly metabolically controlled patient group, we found a decrease in HRV values, the presence of postural hypotension with the tilt table test, and a decrease in ventricular diastolic functions that are consistent with the presence of CAN. Despite CAN, the systolic functions of the ventricles were preserved, and the dimensions of the cardiac chambers and cardiopulmonary exercise test were normal.

CONCLUSIONS

CAN is a common complication of T1DM, often associated with the patient's age and poor glycemic control. HRV, active orthostatic tests, and the evaluation of diastolic dysfunctions play significant roles in the comprehensive assessment of CAN. These diagnostic measures are valuable tools in identifying autonomic dysfunction at an early stage, allowing for timely intervention and management to mitigate the impact of cardiovascular complications associated with T1DM.

Homozygosity of the Z-2 polymorphic variant in the aldose reductase gene promoter confers increased risk for neuropathy in children and adolescents with Type 1 diabetes

BACKGROUND

Diabetic neuropathy (DN) is the least recognized complication of diabetes mellitus and may start early in the course of the disease. Aldose reductase (AKR1B1) gene promoter Z-2/Z-2 polymorphism increases the expression of AKR1B1 enzyme and may contribute to DN.

SUBJECTS

We evaluated 108 Type 1 diabetes (T1D) children and adolescents (mean ± SD age: 13.5 ± 3.46 years, disease duration: 5.3 ± 3.4 years) and 150 healthy controls (age: 11.9 ± 2.7 years).

METHODS

In both groups, pupillary dilation (PD) in darkness, postural blood pressure test (PBPT), and vibration sensation thresholds (VST) in upper and lower limbs were estimated as indices of autonomic and peripheral neuropathy, respectively. Nerve conduction studies (NCS) were performed in patients as peripheral neuropathy index. The polymorphisms of AKR1B1 gene were evaluated using microsatellite (AC)n sequence Z.

RESULTS

PBPT, PD, and VST impairments were more frequent in patient group compared with controls, while 38.6% of patients exhibited NCS abnormality. Gender, age, pubertal status, height, body mass index, diabetes duration, HbA1c, and anti-GAD titers were associated with neuropathy indices in patients. There was a strong correlation between PD and NCS in patients, while homozygous patients for Z-2 AKR1B1 gene polymorphism had higher prevalence of abnormal NCS (83.3% vs. 34.6%), PD (62.5% vs. 31.5%), and PBPT values compared with heterozygous or negative patients. Homozygous AKR1B1 status predicted PD, NCS, and PBPT variance, while PD, VST, NCS, and PBPT parameters accurately discriminated homozygous AKR1B1 patients.

CONCLUSIONS

Impaired indices of peripheral and autonomic DN were present in a significant proportion of young T1D patients. PD, VST, NCS, and PBPT parameters were simultaneously associated with homozygous state of AKR1B1 Z-2 gene polymorphism, implicating polyol metabolism with both autonomic and peripheral neuropathies.

A Comprehensive Review of Neuronal Changes in Diabetics

There has been an exponential rise in diabetes mellitus (DM) cases on a global scale. Diabetes affects almost every system of the body, and the nervous system is no exception. Although the brain is dependent on glucose, providing it with the energy required for optimal functionality, glucose also plays a key role in the regulation of oxidative stress, cell death, among others, which furthermore contribute to the pathophysiology of neurological disorders. The variety of biochemical processes engaged in this process is only matched by the multitude of clinical consequences resulting from it. The wide-ranging effects on the central and peripheral nervous system include, but are not limited to axonopathies, neurodegenerative diseases, neurovascular diseases, and general cognitive impairment. All language search was conducted on MEDLINE, COCHRANE, EMBASE, and GOOGLE SCHOLAR till September 2021. The following search strings and Medical Subject Headings (MeSH terms) were used: "Diabetes Mellitus," "CNS," "Diabetic Neuropathy," and "Insulin." We explored the literature on diabetic neuropathy, covering its epidemiology, pathophysiology with the respective molecular pathways, clinical consequences with a special focus on the central nervous system and finally, measures to prevent and treat neuronal changes. Diabetes is slowly becoming an epidemic, rapidly increasing the clinical burden on account of its wide-ranging complications. This review focuses on the neuronal changes occurring in diabetes such as the impact of hyperglycemia on brain function and structure, its association with various neurological disorders, and a few diabetes-induced peripheral neuropathic changes. It is an attempt to summarize the relevant literature about neuronal consequences of DM as treatment options available today are mostly focused on achieving better glycemic control; further research on novel treatment options to prevent or delay the progression of neuronal changes is still needed.

Diabetic neuropathy in children and youth: New and emerging risk factors

Pediatric neuropathy attributed to metabolic dysfunction is a well-known complication in children and youth with type 1 diabetes. Moreover, the rise of obesity and in particular of type 2 diabetes may cause an uptick in pediatric neuropathy incidence. However, despite the anticipated increase in neuropathy incidence, pathogenic insights and strategies to prevent or manage neuropathy in the setting of diabetes and obesity in children and youth remain unknown. Data from adult studies and available youth cohort studies are providing an initial understanding of potential diagnostic, management, and preventative measures in early life. This review discusses the current state of knowledge emanating from these efforts, with particular emphasis on the prevalence, clinical presentation, diagnostic approaches and considerations, and risk factors of neuropathy in type 1 and type 2 diabetes in children and youth. Also highlighted are current management strategies and recommendations for neuropathy in children and youth with diabetes. This knowledge, along with continued and sustained emphasis on identifying and eliminating modifiable risk factors, completing randomized controlled trials to assess effectiveness of strategies like weight loss and exercise, and enhancing awareness to support early detection and prevention, are pertinent to addressing the rising incidence of neuropathy associated with diabetes and obesity in children and youth.

Cardiac autonomic function in children with type 1 diabetes

Cardiovascular autonomic neuropathy (CAN) is a major complication of type 1 diabetes (T1D). This study aimed to evaluate cardiac autonomic nervous system (ANS) function in children with T1D and its relation to different demographic, clinical and laboratory variable. This cross-sectional study included 60 children with T1D (mean age = 15.1 ± 3.3 years; duration of diabetes = 7.95 ± 3.83 years). The following 8 non-invasive autonomic testing were used for evaluation: heart rate at rest and in response to active standing (30:15 ratio), deep breathing and Valsalva maneuver (indicating parasympathetic function); blood pressure response to standing (orthostatic hypotension or OH), sustained handgrip and cold; and heart rate response to standing or positional orthostatic tachycardia syndrome or POTs (indicating sympathetic function). None had clinically manifest CAN. Compared to healthy children (5%), 36.67% of children with T1D had ≥ 2 abnormal tests (i.e., CAN) (P = 0.0001) which included significantly abnormal heart rate response to standing (POTs) (P = 0.052), active standing (30:15 ratio) (P = 0.0001) and Valsalva maneuver (P = 0.0001), indicating parasympathetic autonomic dysfunction, and blood pressure response to cold (P = 0.01), indicating sympathetic autonomic dysfunction. 54.55, 27.27 and 18.18% had early, definite and severe dysfunction of ANS. All patients had sensorimotor peripheral neuropathy. The longer duration of diabetes (> 5 years), presence of diabetic complications and worse glycemic control were significantly associated with CAN.

CONCLUSIONS

The study concluded that both parasympathetic and sympathetic autonomic dysfunctions are common in children with T1D particularly with longer duration of diabetes and presence of microvascular complications. What is Known: • Cardiovascular autonomic neuropathy (CAN) is a major complication of type 1 diabetes (T1D). • Limited studies evaluated CAN in children with T1D. What is New: • CAN is common in children with T1D. • Cardiac autonomic functions should be assessed in children with T1D particularly in presence of microvascular complications.

Unusual Structural Autonomic Disorders Presenting in Pediatrics: Disorders Associated with Hypoventilation and Autonomic Neuropathies

Structural autonomic disorders (producing structural damage to the autonomic nervous system or autonomic centers) are far less common than functional autonomic disorders (reflected in abnormal function of a fundamentally normal autonomic nervous system) in children and teenagers. This article focuses on this uncommon first group in the pediatric clinic. These disorders are grouped into 2 main categories: those characterized by hypoventilation and those that feature an autonomic neuropathy.

Autonomic neuropathy in diabetes mellitus

Diabetic autonomic neuropathy (DAN) is a serious and common complication of diabetes, often overlooked and misdiagnosed. It is a systemic-wide disorder that may be asymptomatic in the early stages. The most studied and clinically important form of DAN is cardiovascular autonomic neuropathy defined as the impairment of autonomic control of the cardiovascular system in patients with diabetes after exclusion of other causes. The reported prevalence of DAN varies widely depending on inconsistent definition, different diagnostic method, different patient cohorts studied. The pathogenesis is still unclear and probably multifactorial. Once DAN becomes clinically evident, no form of therapy has been identified, which can effectively stop or reverse it. Prevention strategies are based on strict glycemic control with intensive insulin treatment, multifactorial intervention, and lifestyle modification including control of hypertension, dyslipidemia, stop smoking, weight loss, and adequate physical exercise. The present review summarizes the latest knowledge regarding clinical presentation, epidemiology, pathogenesis, and management of DAN, with some mention to childhood and adolescent population.

Autonomic neuropathy in young people with type 1 diabetes: a systematic review

Autonomic neuropathy is an under-recognized complication of diabetes, although it affects multiple organ systems and has widespread clinical manifestations including orthostatic hypotension, exercise intolerance, gastroparesis, diarrhea, constipation, and urinary incontinence. The most severe consequences include hypoglycemia unawareness and cardiovascular dysfunction. Autonomic neuropathy is also implicated in sudden unexplained deaths in otherwise healthy young people--the ‘dead in bed syndrome’. In adults, cardiovascular autonomic neuropathy is an independent predictor of mortality, predominantly due to cardiovascular disease, nephropathy, and hypoglycemia. While overt autonomic neuropathy is rare in childhood and adolescence, subclinical signs of autonomic dysfunction are common, and can be found soon after diabetes diagnosis. Risk factors for autonomic neuropathy in young people include diabetes duration, poor glycemic control, and presence of aldose reductase gene (AKR1B1) polymorphisms, specifically the Z-2/Z-2 genotype. Autonomic dysfunction is accelerated by puberty.

Autonomic function testing in children and adolescents with diabetes mellitus

Cardiac autonomic neuropathy (CAN) is a common complication in type 1 diabetes mellitus (T1DM) and associated with an increased mortality. Early detection of CAN would be desirable for a better individual risk stratification. The aim of this study was to determine whether autonomic dysfunction can be diagnosed in young patients with a recent history of T1DM. Autonomic function was assessed in 20 pediatric patients with T1DM, aged 10-19 yr, and a control group of 136 non-diabetic patients using four cardiorespiratory reflexes: heart rate and blood pressure response in standing position, deep breathing, and Valsalva maneuver. Furthermore, power spectral analyses of the low- and high-frequency band of heart rate variability (HRV) and baroreflex sensitivity (BRS) were tested with the non-invasive Task force monitor (CNSystems, Graz, Austria). Cardiorespiratory reflexes were pathologic for at least one item in 75% of the diabetic and 60% in the healthy control group. A reduced BRS was always combined with abnormal HRV. We found this pattern in 30% of diabetic patients and never in the control group. In patients with impaired BRS, mean hemoglobin A1c (HbA1c) was 7.7% and duration of diabetes 6.5 yr. This did not differ from the overall value of the diabetic group: HbA1c level 8.4% and diabetes duration 7.3 yr. In conclusion, signs of autonomic dysfunction are not uncommon in an early stage of diabetes in young patients. Classical cardiorespiratory reflexes seem to be less specific than HRV and BRS as testing methods.

Glycaemic control and hypoglycaemia in children, adolescents and young adults with unstable type 1 diabetes mellitus treated with insulin glargine or intermediate-acting insulin

In this open study of clinical practice, 142 paediatric patients with type 1 diabetes mellitus (>1 year duration), stratified by age, received prandial insulin (regular or lispro) and either once daily insulin glargine (GLAR; n=74), titrated to target fasting blood glucose (FBG) levels 4.4-7.8 mmol/l, or NPH/semilente insulin (NPH insulin, administered once, twice or three times daily; n=68), titrated to target FBG 4.4-8.9 mmol/l. Both groups were treated for 20 +/- 10 months. HbA(1c) significantly increased in GLAR (7.3 +/- 1.0% to 7.6 +/- 1.1%; p = 0.003) and NPH/semilente insulin (7.7 +/- 1.6% to 8.3 +/- 1.5%; p = 0.0001) treated patients. The incidence of symptomatic hypoglycaemia was comparable between GLAR versus NPH/semilente insulin at endpoint (2.19 vs. 1.94 episodes/week); however, the overall incidence of severe hypoglycaemia was significantly lower with GLAR versus NPH/semilente insulin (0.14 vs. 0.73 events/patient-year; p = 0.002). The daily insulin dose was similar between the treatment groups; however, perceived quality of life (QoL) was better with GLAR. GLAR is associated with equivalent glycaemic control, less severe hypoglycaemia and improved QoL compared with NPH/semilente insulin.

Early Diabetes-Related Complications in Adolescents

Micro- and macrovascular complications account for the major part of the morbidity and mortality associated with diabetes developing in childhood. Although advanced complications are exceptionally rare in the adolescent age group, it is during this phase that the progression of risk may accelerate. A number of potentially important factors have been identified which might contribute to risk of complication development: some provide insights into the genetics of these complications, while others are potentially modifiable, such as metabolic control, hypertension, smoking, obesity and hyperlipidemia. Recently, both consensus and evidence-based guidelines have been developed to guide those involved in the care of adolescents with diabetes in the prevention, screening and management of early diabetes-related complications in this vulnerable population. This article reviews the literature that underpins the available guidelines and stresses the pivotal role of excellent metabolic control in complication prevention.

Left ventricular dysfunction in normotensive Type 1 diabetic patients: the impact of autonomic neuropathy

AIMS

The pathophysiological mechanisms responsible for increased cardiovascular mortality in diabetic autonomic neuropathy (AN) are largely unknown. The aim was to determine the relative role of AN in the pathogenesis of cardiac diastolic dysfunction and left ventricular hypertrophy in Type 1 diabetes.

METHODS

Ten Type 1 diabetic patients with AN, defined by cardiovascular tests (AN+) and 10 age- and sex-matched patients without neuropathy (AN-) as well as 10 healthy subjects (C) participated in the study. Left ventricular diastolic function was assessed by Doppler echocardiography, whilst systolic function was evaluated by cine magnetic resonance (MR) imaging.

RESULTS

Doppler echocardiography showed a significant decrease in E/A ratio, i.e. the ratio between peak Early transmitral filling velocity during early diastole (E-wave) and peak transmitral Atrial filling velocity during late diastole (A-wave), in AN+ compared with C (P < 0.01) [0.95 +/- 0.08 (mean +/- sem) (AN+); 1.19 +/- 0.09 (AN-); 1.33 +/- 0.10 (C)]. The E-wave deceleration time was significantly shorter in AN+ compared with AN- and C (P < 0.02) [178 +/- 7 ms (AN+); 203 +/- 9 ms (AN-); 205 +/- 9 ms (C)]. Cine MR imaging showed a significantly greater left ventricular mass index in AN+ compared with C [103 +/- 4 g/m(2) (AN+) vs. 98 +/- 7 (AN-) and 92 +/- 4 g/m(2) (C), P < 0.05].

CONCLUSION

Autonomic neuropathy is associated with left ventricular hypertrophy and diastolic dysfunction in Type 1 diabetic patients.