Diabetes and cardiac autonomic neuropathy: Clinical manifestations, cardiovascular consequences, diagnosis and treatment

Autonomic Nervous System Dysfunction: JACC Focus Seminar

Autonomic nervous system control of the heart is a dynamic process in both health and disease. A multilevel neural network is responsible for control of chronotropy, lusitropy, dromotropy, and inotropy. Intrinsic autonomic dysfunction arises from diseases that directly affect the autonomic nerves, such as diabetes mellitus and the syndromes of primary autonomic failure. Extrinsic autonomic dysfunction reflects the changes in autonomic function that are secondarily induced by cardiac or other disease. An array of tests interrogate various aspects of cardiac autonomic control in either resting conditions or with physiological perturbations from resting conditions. The prognostic significance of these assessments have been well established. Clinical usefulness has not been established, and the precise mechanistic link to mortality is less well established. Further efforts are required to develop optimal approaches to delineate cardiac autonomic dysfunction and its adverse effects to develop tools that can be used to guide clinical decision-making.

Simultaneous Pancreas Kidney Transplantation Improves Cardiovascular Autonomic Neuropathy with Improved Valsalva Ratio as the Most Precocious Test

BACKGROUND

Simultaneous pancreas-kidney (SPK) transplantation is a proven option of treatment for patients with type 1 diabetes mellitus (T1DM) and related end-stage renal disease. There is discrepancy between the results of different studies about the impact of prolonged normalization of glucose metabolism achieved by SPK on the course of diabetic complications including severe forms of diabetic neuropathy. The objective of the study was to evaluate the prevalence of cardiovascular autonomic neuropathy (CAN) in patients undergoing SPK transplantation and its evolution 10 years after transplantation.

METHODS

Prospective study of 81 patients transplanted in a single center from year 2002 to 2015. Autonomic function was assessed using cardiovascular autonomic reflex tests (CARTs). CARTs were made before SPK transplantation and during the follow-up. Evolution of tests after SPK transplantation was evaluated by contrasting hypotheses (paired tests). Multiple testing was adjusted with the Benjamini-Hochberg procedure with a false discovery rate of 10%.

RESULTS

48 males and 33 females, mean age 37.4 ± 5.7 years, mean BMI 24.0 ± 3.4 kg/m², and mean duration of diabetes 25.5 ± 6.5 years, received SPK transplantation. Ten years after SPK transplantation, 56 patients re tained the pancreatic graft (42 of them with normofunctioning pancreas and 14 with low doses of insulin therapy). These 42 patients were selected for the autonomic study. Before transplant procedure, all CART results were abnormal. After SPK transplantation, paired test analysis showed an improvement of systolic blood pressure (SBP) response to orthostasis at the 5^th year after SPK (p = 0.03), as well as improvement of the Valsalva ratio at the 3^rd (p < 0.001) and 5^th (p = 0.001) year after SPK. After correcting for the false discovery rate, all the variables of autonomic study reached significance at different time points.

CONCLUSIONS

Prevalence of CAN in patients who are candidates for SPK transplantation is high and is generally advanced. SPK transplantation improves CAN with improved Valsalva ratio as the most precocious test.

Cardiac Autonomic Neuropathy in Obesity, the Metabolic Syndrome and Prediabetes: A Narrative Review

Cardiac autonomic neuropathy (CAN) is a major complication of type 1 and type 2 diabetes mellitus (T1DM and T2DM). The increased morbidity, cardiovascular and all-cause mortality associated with CAN is established from numerous epidemiological studies. However, CAN is increasingly recognised in people with prediabetes (pre-DM) and the metabolic syndrome (MetS) with a reported prevalence up to 11% and 24% respectively. CAN is associated with components of MetS including hypertension and obesity, predating hyperglycaemia. The aetiology of CAN is multifactorial and there is a reciprocal relationship with insulin resistance and MetS. Obstructive sleep apnoea (OSA) is also associated with CAN possibly through MetS and an independent mechanism. An estimated global prevalence of the impaired glucose tolerance (IGT) form of pre-DM of 587 million people by 2045 means CAN will become a major clinical problem. CAN is independently associated with silent myocardial ischaemia, major cardiovascular events, myocardial dysfunction and cardiovascular mortality. Screening for CAN in pre-DM using risk scores with analysis of heart rate variability (HRV) or Sudoscan is important to allow earlier treatment at a reversible stage. The link between obesity and CAN highlights the therapeutic potential of lifestyle interventions including diet and physical activity to reverse MetS and prevent CAN. Weight loss achieved using these dietary and exercise lifestyle interventions improves the sympathetic and parasympathetic HRV indices of cardiac autonomic function. Further research is needed to identify high-risk populations of people with pre-DM or obesity that might benefit from targeted pharmacotherapy including metformin, sodium/glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide 1 (GLP-1) analogues. Bariatric surgery also improves HRV through weight loss which might also prevent CAN in severe obesity. This article reviews the literature on CAN in obesity, pre-DM and MetS, to help determine a rationale for screening, early intervention treatment and formulate future research questions in this highly prevalent condition.

Lifestyle Modification for Enhancing Autonomic Cardiac Regulation in Children: The Role of Exercise

Decreased physical activity (PA) is a global concern contributing to the rise in cardiometabolic diseases. One potential mechanism linking insufficient PA and poor health is dysregulated autonomic nervous system (ANS) activity. This relationship is established in adults and PA recommendations, with specific exercise prescription guidelines, have been proposed to overcome this societal health burden. However, research on the benefits and underlying mechanisms of exercise on ANS activity in children <18 years old is limited. This review aimed to describe the optimal exercise “dose” and potential mechanisms of action that exercise may pose on enhancing child ANS activity, represented by heart rate variability (HRV). PubMed, Web of Science and Google Scholar were searched for articles examining the influence of exercise on child HRV. Various exercise duration and frequency combinations appear to improve HRV indices, primarily those representing parasympathetic influence. Furthermore, both aerobic and resistance training benefit HRV through potentially different mechanisms with intensity proposed to be important for exercise prescription. Findings indicate that exercise is a crucial lifestyle modification with protective and therapeutic effects on cardiometabolic health associated with improvements in child ANS activity. Exercise programming must consider the various components including mode, intensity and population characteristics to optimize ANS health.

Short term optimization of glycaemic control using insulin improves sympatho-vagal tone activities in patients with type 2 diabetes

INTRODUCTION

Diabetic cardiac autonomic neuropathy (CAN) is potentially life threatening and its severity might further be aggravated by poor glycaemic control. A decrease in Heart rate variability (HRV) is the earliest finding of CAN even at the sub clinical stage. While intensive glycaemic control prevents the development of CAN in patients with type 1 diabetes, it is not known whether the intensification of glycaemic control using insulin would improve cardiovascular autonomic functions in type 2 diabetes patients. This study aimed to determine the short term effects of optimizing glycaemic control using insulin on the HRV in type 2 diabetes patients.

METHODS

We conducted a single arm open label clinical trial. Participants were poorly controlled non-insulin treated type 2 diabetes mellitus patients (HbA1c ≥ 7%). The intervention lasted 60 days and consisted in the intensification of glycaemic control through the initiation of a basal plus insulin regimen with titration of insulin to protocol defined glycaemic targets which were; fasting glycaemia: 0.70-1.30 g/L and post prandial glycaemia <1.80 g/L. Long term HRV measurement was done using a 24-h ambulatory electrocardiographic (ECG) recording on day 0 and day 60. Wilcoxon signed rank test was used to compare differences in HRV parameters before and after the intervention.

RESULTS

A total of 29 (14 males and 15 females) consenting type 2 diabetes mellitus patients without clinical signs of CAN were enrolled and allocated to intervention (14 males and 15 females). The median age was 52 [43-59] years, and duration of diabetes 3.0 [0.6-6.7] years. The intervention induced a reduction in HbA1c from 10.1 [9.1-11.9]% to 6.7 [5.9-6.9]% (p < 0.001) without severe hypoglycaemic events. Concerning HRV parameters, there was a significant improvement in markers of the parasympathetic tone (PNN50: 5.7 [3.6-10.3]% to 8.1 [3.1-16.9]%, p = 0.008) and sympathetic tone (SDNN: 102.01 [90.45-111.05] ms to 122.40 [91.70-135.95] ms, p = 0.01).

CONCLUSION

The optimization of glycaemic control using a basal plus insulin regimen while inducing a significant reduction in glycated hemoglobin, significantly improves 24-h ambulatory ECG derived sympathetic and parasympathetic activities. This suggests that tight glycaemic control using insulin may revert cardiac autonomic neuropathy in type 2 diabetes mellitus patients.

(r)Alpha Lipoic Acid Is a Safe, Effective Pharmacologic Therapy of Chronic Orthostatic Hypotension Associated with Low Sympathetic Tone

Chronic orthostatic hypotension (OH), affecting 10 to 30% of the elderly, is associated with falls, and increased morbidity and mortality. Current pharmacologic therapy can cause or worsen hypertension and fluid retention. (r)α lipoic acid (ALA), a powerful natural antioxidant, avoids those complications and may assist management of chronic neurogenic orthostatic hypotension (NOH). The purpose of this study is to demonstrate improvement in the symptoms of orthostatic dysfunction with r-ALA, including improved sympathetic (S) and blood pressure (BP) responses to head-up postural change (standing). A cohort of 109 patients with low S tone upon standing was detected using the ANX -3.0, Autonomic Monitor, ANSAR Medical Technologies, Inc., Philadelphia, PA. From the cohort, 29 patients demonstrated NOH (change in (∆) standing BP ≥ -20/-10 mm Hg); 60 patients demonstrated orthostatic intolerance (OI, ∆ standing systolic BP between -6 and -19 mm Hg). These 89 were given ALA orally: either 590 to 788 mg (r)ALA or 867 to 1,500 mg of the less expensive 50 to 50% mixture (r)ALA and inactive (s)ALA. Changes in their S and parasympathetic (P) tone, and BPs, were compared with 20 control patients during mean follow-up of 2.28 years. Nineteen of 29 (66%) NOH patients responded with a ∆ standing BP from -28/-6 mm Hg to 0/+2 mm Hg. Forty of 60 (67%) of patients with OI responded with a ∆ standing BP of -9/+1 mm Hg to +6/+2 mm Hg. Although all patients treated with ALA increased S tone, the ∆ BP depended upon the pretreatment of S tone. Those with the lowest S tone responded the least well. The only treatment side effects were nausea, intolerable in only 5%. Nausea improved with routine gastrointestinal medications. Glucose levels improved in the 28% of patients who were diabetic. Also, resting hypertension improved. Control patients had no ∆ BP and no increase in S tone. (r)ALA improves S-, and BP, responses to head-up postural change, and thereby NOH/OI, in a majority of patients without causing harmful side effects.

Impaired heart rate variability, Valsalva and 30:15 ratio indexes are associated with reduced submaximal exercise capacity in subjects with diabetes mellitus

AIMS

To assess cardiac autonomic control and its association with submaximal exercise measured using the 6-minute walk test (6MWT) in subjects with type-2 diabetes mellitus (DM2).

METHODS

Cardiac autonomic control was assessed using Ewing's tests and heart rate variability (HRV) in DM2 volunteers (DG, n = 22) and sex-, age- and body mass index-matched non-diabetic controls (CG, n = 22) before, during and after 6MWT.

RESULTS

Before the 6MWT, DG presented lower HRV represented by reduced SDNN [median 28.9 ms² (IQR:18.6-35.4) vs. 45.1 (IQR:39.2-62.67), p < 0.001] and Total Power [median 785 ms² (IQR:256-1264) vs. 1757 ms² (IQR:1006-2912), p = 0.004]. Exercise capacity was reduced in DG [maximal predicted distance (%) = 88.4 ± 6.4 vs. 95.2 ± 11.0%, p = 0.018]. DG demonstrated lower global HRV during recovery and lower parasympathetic drive, represented by reduced RMSSD, during all phases of the 6MWT. Moreover, supine HR (r = -0.32), HR orthostatism (ρ = -0.40), SDNN pre-6MWT (ρ = 0.39), TP pre-6MWT (ρ = 0.38), Valsalva ratio (ρ = 0.39) and 30:15 ratio (ρ = 0.38) were all correlated with maximal walked distance.

CONCLUSIONS

DM2 subjects presented abnormal HRV during and after submaximal exercise. Furthermore, autonomic control impairment in orthostatism, represented by lower global HRV (SDNN, Total power) and lower Ewing's indexes (Valsalva and 30:15 ratios), was associated with lower exercise capacity.

Clinical factors associated with the recovery of cardiovascular autonomic neuropathy in patients with type 2 diabetes mellitus

Background

Cardiovascular autonomic neuropathy (CAN) is a major cause of morbidity and mortality in diabetes patients. Although several risk factors for CAN progression have been established, whether CAN is reversible remains unclear and the clinical factors associated with CAN recovery have not been identified. This study aimed to determine clinical factors related to CAN recovery.

Methods

Type 2 diabetes patients with CAN but free of cardiovascular disease at baseline were enrolled and followed for 2–3 years in this retrospective longitudinal study. CAN was classified as early (one abnormal parasympathetic test), definite (two or more abnormal parasympathetic tests), severe (definite plus orthostatic hypotension), or atypical (early plus orthostatic hypotension or orthostatic hypotension alone) based on Ewing’s method. CAN recovery was classified as partial or complete: Partial recovery was defined as one-step improvement in CAN stage (early to normal, definite to early, or severe to definite), including the disappearance of only one abnormal result in any stage. Complete recovery was defined as normalization from definite or severe CAN.

Results

Among 759 subjects with CAN, 29.9% (n = 227) experienced CAN recovery, and 1.2% (n = 9) recovered completely. In a multivariate model, younger age (odds ratio [OR] per 5-year decrease 1.49; 95% confidence interval [CI] 1.25–1.78, P < 0.001), shorter duration of diabetes (OR per 5-year decrease 1.33; 95% CI 1.05–1.67, P = 0.016), presence of micro/macroalbuminuria (OR 0.34; 95% CI 0.15–0.78, P = 0.011), body weight reduction (OR per 1-kg decrease 1.11; 95% CI 1.02–1.21, P = 0.016), and HbA1c reduction (OR per 1% decrease 1.32; 95% CI 1.05–1.67, P = 0.019) were significantly associated with composite events of partial and complete CAN recovery. Age had the highest relative significance among the associated clinical factors. In addition, younger age was the only significant factor in complete CAN recovery.

Conclusions

Younger age was the most important factor in CAN recovery in subjects with type 2 diabetes, including recovery from the definite or severe stage. HbA1c reduction, body weight reduction, no concurrent micro/macroalbuminuria, and shorter duration of diabetes were also significantly associated with CAN recovery.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0830-4) contains supplementary material, which is available to authorized users.

Continuous glucose monitoring defined glucose variability is associated with cardiovascular autonomic neuropathy in type 1 diabetes

BACKGROUND

The purpose of this study was to establish the association between continuous glucose monitoring (CGM)-defined glycaemic variability (GV) and cardiovascular autonomic neuropathy (CAN) in type 1 diabetes independent of mean glucose and to examine the relative contribution of each internationally standardized CGM parameter to this association.

MATERIALS AND METHODS

This study included 80 adults with type 1 diabetes who underwent 3-day CGM and autonomic function tests within 3 months. The degree of association between internationally standardized CGM parameters and CAN, defined as at least two abnormal parasympathetic tests or the presence of orthostatic hypotension, were analysed by logistic regression, receiver operating characteristics (ROC), and dominance analysis.

RESULTS

A total of 36 subjects (45.0%) were diagnosed with CAN. When adjusted with mean glucose and clinical risk factors of CAN, standard deviation, coefficient of variation, mean amplitude of glycaemic excursion, percent time in level 1 (glucose 54-69 mg/dL) and level 2 (glucose < 54 mg/dL) hypoglycaemia, area under the curve in level 2 hypoglycaemia, low blood glucose index, high blood glucose index, and percent time in glucose 70 to 180 mg/dL were independently associated with CAN. Multivariable ROC analysis and dominance analysis revealed the highest relative contribution of percent time in level 2 hypoglycaemia to the independent associations between CGM parameters and presence of CAN.

CONCLUSIONS

CGM-defined GV was associated with CAN independent of mean glucose in adults with type 1 diabetes. Among internationally standardized CGM parameters, those describing the degree of level 2 hypoglycaemia were the most significant contributors to this association.

Omega-3 Polyunsaturated Fatty Acids Improved Arterial Stiffness Parameters in Type 2 Diabetic Patients with Cardiac Autonomic Neuropathy

Background and Aims: Diabetic cardiac autonomic neuropathy (DCAN) in type 2 diabetes (T2D) is among the strongest and independent risk markers for future global and cardiac mortality. Material and Methods: Thirty-six patients suffering from T2D and confirmed DCAN were enrolled in this investigation. Depending on the prescribed therapy, patients were allocated into two groups: group 1 was comprised of 15 patients to whom standard hypoglycemic treatment was prescribed (control group), the second received standard hypoglycemic treatment and omega-3 polyunsaturated fatty acids (ω-3 PUFAs, n = 21). The duration of the study was three month. Results: In subjects with T2D and DСAN prescription of ω-3 PUFAs was associated with a significant decrease of aorta augmentation index (AIxao), pulse wave velocity (PWV) during the active period of the day and decrease of AIxao, brachial augmentation index and PWV during the passive period of the day compared with the control group. Therefore, three month of ω-3 PUFAs supplementation to patients with confirmed DCAN and T2D promotes to improvement of arterial stiffness indices. Conclusions: In patients with T2D and СAN treatment with ω-3 PUFAs improved arterial stiffness parameters. The effectiveness of ω-3 PUFAs is not connected with optimization of glycemic control, but is rather the result of a direct drug action on the studied parameters.

ANSiscope™: Can it be the crystal ball of cardiac anesthesia?

Background

: Autonomic dysfunction (AD) is infrequently evaluated preoperatively despite having profound perioperative implications. The ANSiscope™ is a monitoring device that quantifies AD. This study aims to determine the potential of the device to predict hypotension following anesthetic induction, occurrence of arrhythmias, and inotrope requirement for patients undergoing off-pump coronary artery bypass surgery (OPCAB).

Study Design

: Prospective observational double-blinded study.

Materials and Methodology

Seventy-five patients undergoing OPCAB had their autonomic function assessed by ANSiscope™. They were classified into four groups based on their AD and compared to perioperative adverse events.

Results

Patients with diabetes had a higher ANSindex (P = 0.0263). They had a greater decrease in systolic blood pressure (P = 0.001) and mean arterial pressure (P = 0.004) postinduction, had an increased incidence of arrhythmias (P = 0.009), required higher inotropic support immediately (P = 0.010) and at 24 h after surgery (P = 0.018), and longer duration of postoperative ventilation (P < 0.001). They also had a higher incidence of emergency conversion of OPCAB to on-pump surgery (P = 0.009).

Conclusions

An increased association between AD as quantified by the ANSiscope™ and perioperative adverse outcomes was observed. An increased rate of emergency conversion of OPCAB to on-pump surgery with higher dysfunction was noted. The authors opine that the threshold for conversion must be lower in patients deemed to be at a higher risk. Proper evaluation of the autonomic nervous system empowers the anesthesiologist to anticipate and adequately prepare for complications.

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".

A cardiac risk score based on sudomotor function to evaluate cardiovascular autonomic neuropathy in asymptomatic Chinese patients with diabetes mellitus

Backgrounds

Cardiac autonomic neuropathy is a common but always overlooked. More convenient diagnostic methods are needed.

Hypothesis

Cardiac autonomic neuropathy risk score evaluated by SUDOSCAN has a fine diagnostic efficacy detecting cardiac autonomic neuropathy.

Methods

This is a cross-sectional study among patients with diabetes mellitus. Subjects undertook SUDOSCAN tests and cardiac autonomic reflex tests, including heart rate variability due to Valsalva maneuver, heart rate response due to deep breathing and heart rate response due to standing up. Presenting 2 abnormal results was defined as cardiac autonomic neuropathy.

Results

Subjects with cardiac autonomic neuropathy has significantly higher cardiac autonomic neuropathy risk score (32.88±1.60 vs 27.64±1.24,P = 0.010). Cardiac autonomic neuropathy risk score was correlated significantly with the heart rate response due to deep breathing(P = 0.004). Multiple regression analysis including significant variables showed an independent association of cardiac autonomic neuropathy risk score and heart rate response due to deep breathing (P = 0.031) and age (P = 0.000). In receiver operating characteristic curve analysis evaluating the relationship between cardiac autonomic neuropathy risk score and cardiac autonomic neuropathy, The cut-off value was 20.5, with the sensitivity of 90.48%, the specificity of 29.5%, and the positive predictive value of 46.9%. In two-step diagnostic methods, Setting 20.5 as the cut-off value of cardiac autonomic neuropathy risk score and abnormal heart rate response due to standing up as the second diagnostic step’s positive result, and setting 16.5 as the cut-off value of cardiac autonomic neuropathy risk score and abnormal heart rate response due to deep breathing as the second diagnostic step’s positive result, both achieved good diagnostic efficacy.

Conclusion

Cardiac autonomic neuropathy risk score evaluated by SUDOSCAN is a good screening test for cardiac autonomic neuropathy. The two-step diagnostic methods could be considered as surrogate diagnostic methods.

Metabolic Effects of Metformin in the Failing Heart

Accumulating evidence shows that metformin is an insulin-sensitizing antidiabetic drug widely used in the treatment of type 2 diabetes mellitus (T2DM), which can exert favorable effects on cardiovascular risk and may be safely used in patients with heart failure (HF), and even able to reduce the incidence of HF and to reduce HF mortality. In failing hearts, metformin improves myocardial energy metabolic status through the activation of AMP (adenosine monophosphate)-activated protein kinase (AMPK) and the regulation of lipid and glucose metabolism. By increasing nitric oxide (NO) bioavailability, limiting interstitial fibrosis, reducing the deposition of advanced glycation end-products (AGEs), and inhibiting myocardial cell apoptosis metformin reduces cardiac remodeling and hypertrophy, and thereby preserves left ventricular systolic and diastolic functions. While a lot of preclinical and clinical studies showed the cardiovascular safety of metformin therapy in diabetic patients and HF, to confirm observed benefits, the specific large-scale trials configured for HF development in diabetic patients as a primary endpoints are necessary.

Knockdown the P2X3 receptor in the stellate ganglia of rats relieved the diabetic cardiac autonomic neuropathy

Diabetic cardiac autonomic neuropathy (DCAN) is a common and serious complication of diabetes mellitus (DM), is manifested by nerve fiber injury in the sympathetic and parasympathetic nerve of the autonomic nervous system, and causes hypertension, cardiac arrhythmias, silent myocardial infarction, and sudden death. Our previous study observed that P2X3 receptor in superior cervical ganglia in rat was associated with sympathetic neuropathy caused by myocardial ischemia. However, whether the P2X3 receptor is involved in the diabetic cardiac autonomic neuropathy and the underlying mechanisms remain unclear. The aim of this research was explored the effect of P2X3 short hairpin RNA (shRNA) on information transmission of sympathetic nerve induced by DCAN. Sprague-Dawley (SD) male rats were randomly divided into four groups: Control, DM, DM treated with P2X3 shRNA and DM treated with scramble shRNA. Blood pressure, heart rate and heart rate variability were measured in each group. The expression of P2X3 in stellate ganglion (SG) was detected by immunohistochemistry, western blotting and QPCR. Results showed that P2X3 shRNA alleviated blood pressure and heart rate, improved heart rate variability, decreased the up-regulated expression levels of P2X3, interleukin-1beta and tumor necrosis factor alpha in stellate ganglion (SG) of diabetic rats. P2X3 shRNA also reduced the incremental concentration of serum epinephrine and the phosphorylation level of extracellular regulated protein kinases1/2 in diabetic rats. These results indicated that P2X3 shRNA could decrease sympathetic activity via inhibiting P2X3 receptor in the SG to alleviate DCAN.

Cardiovascular reflex tests in patients with systemic lupus erythematosus: clinical performance and utility

Background

This review summarizes current knowledge about cardiovascular reflex tests (CVRTs) and other selected autonomic nervous system (ANS) assessment tests in systemic lupus erythematosus (SLE) patients and assesses their clinical utility in this group of patients.

Methods

The PubMed database was searched for terms associated with CVRTs and SLE. Only papers available in full text and published in English were considered. Ultimately, 13 were selected and analyzed.

Results

In most of the studies CVRTs results were reported more likely to be abnormal in patients with SLE when compared with controls. The reported prevalence of ANS dysfunction in SLE, diagnosed using CVRTs, ranged from 23.5% to 82.7% of patients, likely because of different definitions of ANS dysfunction, variability in methods of performing CVRTs, and potential confounding factors. In general CVRTs results did not correlate with SLE activity or disease duration, but some CVRTs results correlated with some peptides associated with ANS function, including neuropeptide Y and vasoactive intestinal peptide.

Conclusion

Patients with SLE generally have abnormal or borderline results of CVRTs, which indicate prevalent abnormalities of the ANS in SLE. Performance of CVRTs requires good standardization of test conditions and familiarity with the proper administration and interpretation of these tests.

Autonomic function as indicated by heart rate deceleration capacity and deceleration runs in type 2 diabetes patients with or without essential hypertension

Purpose

Sympathovagal imbalance is a common underlying disorder in hypertension and diabetes. This study characterized autonomic nervous system function, indicated by heart rate deceleration capacity (DC) and deceleration runs (DRs), in patients with type 2 diabetes mellitus (T2DM), with or without concomitant essential hypertension.

Subjects and methods

We recruited 50 healthy subjects, 50 patients with T2DM, and 95 with T2DM and essential hypertension. DC, DRs (DR₂, DR₄, and DR₈, ie, episodes of 2, 4, or 8 consecutive beat-to-beat heart rate decelerations, respectively), and heart rate variability were determined by dynamic electrocardiogram. Biochemical markers of glucose and lipid metabolism, including glycated hemoglobin (HbA1c) and high-density lipoprotein cholesterol (HDL-C), were measured from blood samples.

Results

Both T2DM groups featured lower DC, SD of all normal-to-normal sinus RR intervals over 24 h (SDNN), root mean square of the successive normal sinus RR interval difference, and all DR values, but higher average heart rate (AHR) and acceleration capacity (AC), than healthy subjects. There were significant associations between the following: DC and HbA1c, systolic blood pressure (SBP), AHR, age, and HDL-C; DR₂ and AHR, SBP, and HbA1c; DR₄ and HbA1c, age, SBP, and HDL-C; and DR₈ and HbA1c, AHR, and age. In both T2DM groups, HbA1c correlated negatively with DC, DR₂, and SDNN, and positively with AC and AHR; homeostasis model assessment-insulin resistance index correlated negatively with DC, all DRs, and SDNN, and positively with AC.

Conclusion

Compared with healthy subjects, T2DM patients with or without essential hypertension have lower DC and DRs. DC and DRs correlate negatively with blood glucose and insulin resistance index.

South Asians: why are they at a higher risk for cardiovascular disease?

PURPOSE OF REVIEW

We comment on the high prevalence of cardiovascular disease (CVD) in South Asians (SA). The effect of various risk factors, for example biochemical, genetic, lifestyle, socioeconomic factors and psychosocial stress on CVD risk is discussed.

RECENT FINDINGS

'Prediabetes' is common in SA, but its relationship with coronary artery disease (CAD) is not significant unlike for the white population. At the same time, 'prediabetes' in SA is associated with an increased risk for cerebrovascular disease (CeVD). The differentiating factor could be the high lipids in Europeans and their relationship to CAD. Likewise, higher diastolic blood pressure in SA may explain the risk of CeVD. Small, dense, low-density lipoprotein (LDL), low high-density lipoprotein-cholesterol (HDL-C) concentration and high triglycerides may contribute to atherosclerosis. Thrombotic factors such as increased levels of plasminogen activator inhibitor, fibrinogen, lipoprotein (a) and homocysteine have been shown to be associated with increased CVD. Impaired cerebrovascular autoregulation and sympathovagal activity, increased arterial stiffness and endothelial dysfunction may increase CVD risk further. In addition, environmental and dietary factors may exaggerate the unfavourable cardiovascular profile through genetic factors.

SUMMARY

The implications of the findings suggest comprehensive screening of SA for CVD. Cultural differences should be considered while designing prevention strategies specifically targeting barriers for uptake of preventive service.

Impact of treatment strategies on outcomes in patients with stable coronary artery disease and type 2 diabetes mellitus according to presenting angina severity: A pooled analysis of three federally-funded randomized trials

BACKGROUND AND AIMS

The impact of treatment strategies on outcomes in patients with stable coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM) according to presenting angina has not been rigorously assessed.

METHODS

We performed a patient-level pooled-analysis (n = 5027) of patients with stable CAD and T2DM randomized to optimal medical therapy [OMT], percutaneous coronary intervention [PCI] + OMT, or coronary artery bypass grafting [CABG] + OMT. Endpoints were death/myocardial infarction (MI)/stroke, post-randomization revascularization (both over 5 years), and angina control at 1 year.

RESULTS

Increasing severity of baseline angina was associated with higher rates of death/MI/stroke (p = 0.009) and increased need for post-randomization revascularization (p = 0.001); after multivariable adjustment, only association with post-randomization revascularization remained significant. Baseline angina severity did not influence the superiority of CABG + OMT to reduce the rate of death/MI/stroke and post-randomization revascularization compared to other strategies. CABG + OMT was superior for angina control at 1 year compared to both PCI + OMT and OMT alone but only in patients with ≥ Class II severity at baseline. Comparisons between PCI + OMT and OMT were neutral except that PCI + OMT was superior to OMT for reducing the rate of post-randomization revascularization irrespective of presenting angina severity.

CONCLUSIONS

Presenting angina severity did not influence the superiority of CABG + OMT with respect to 5-year rates of death/MI/stroke and need for post-randomization revascularization. Presenting angina severity minimally influenced relative benefits for angina control at 1 year.

Heart rate variability in patients with systemic lupus erythematosus: a systematic review and methodological considerations

Aim The aim of this review was to summarize current knowledge about the scientific findings and potential clinical utility of heart rate variability measures in patients with systemic lupus erythematosus. Methods PubMed, Embase and Scopus databases were searched for the terms associated with systemic lupus erythematosus and heart rate variability, including controlled vocabulary, when appropriate. Articles published in English and available in full text were considered. Finally, 11 publications were selected, according to the systematic review protocol and were analyzed. Results In general, heart rate variability, measured in the time and frequency domains, was reported to be decreased in patients with systemic lupus erythematosus compared with controls. In some systemic lupus erythematosus studies, heart rate variability was found to correlate with inflammatory markers and albumin levels. A novel heart rate variability measure, heart rate turbulence onset, was shown to be increased, while heart rate turbulence slope was decreased in systemic lupus erythematosus patients. Reports of associations of changes in heart rate variability parameters with increasing systemic lupus erythematosus activity were inconsistent, showing decreasing heart rate variability or no relationship. However, the low/high frequency ratio was, in some studies, reported to increase with increasing disease activity or to be inversely correlated with albumin levels. Conclusions Patients with systemic lupus erythematosus have abnormal heart rate variability, which reflects cardiac autonomic dysfunction and may be related to inflammatory cytokines but not necessarily to disease activity. Thus measurement of heart rate variability could be a useful clinical tool for monitoring autonomic dysfunction in systemic lupus erythematosus, and may potentially provide prognostic information.

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.

Very High Frequency Oscillations of Heart Rate Variability in Healthy Humans and in Patients with Cardiovascular Autonomic Neuropathy

Literature reports on the very high frequency (VHF) range of 0.4-0.9 Hz in heart rate variability (HRV) are scanty. The VHF presence in cardiac transplant patients and other conditions associated with reduced vagal influence on the heart encouraged us to explore this spectral band in healthy subjects and in patients diagnosed with cardiac autonomic neuropathy (CAN), and to assess the potential clinical value of some VHF indices. The study included 80 healthy controls and 48 patients with spinocerebellar ataxia type 2 (SCA2) with CAN. The electrocardiographic recordings of short 5-min duration were submitted to three different spectral analysis methods, including the most generally accepted procedure, and the two novel methods using the Hilbert-Huang transform. We demonstrated the presence of VHF activity in both groups of subjects. However, VHF power spectral density, expressed in relative normalized units, was significantly greater in the SCA2 patients than that in healthy subjects, amounting to 36.1 ± 17.4% vs. 22.9 ± 14.1%, respectively, as also was the instantaneous VHF spectral frequency, 0.58 ± 0.05 vs. 0.64 ± 0.07 Hz, respectively. These findings were related to the severity of CAN. We conclude that VHF activity of HRV is integral to the cardiovascular autonomic control.

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.

Glycated albumin and its variability as an indicator of cardiovascular autonomic neuropathy development in type 2 diabetic patients

BACKGROUND

We investigated whether glycated albumin (GA) and its variability are associated with cardiovascular autonomic neuropathy (CAN) and further compared their associations with glycated hemoglobin (HbA1c).

METHODS

This retrospective longitudinal study included 498 type 2 diabetic patients without CAN. CAN was defined as at least two abnormal results in parasympathetic tests or presence of orthostatic hypotension. The mean, standard deviation (SD), and coefficient of variance (CV) were calculated from consecutively measured GA (median 7 times) and HbA1c levels (median 8 times) over 2 years. Logistic regression analysis was used to compare the associations between CAN and GA- or HbA1c-related parameters. Receiver operating characteristic (ROC) curve analysis was used to compare the predictive power for CAN between GA- and HbA1c-related parameters.

RESULTS

A total of 53 subjects (10.6%) developed CAN over 2 years. The mean, SD, and CV of GA or HbA1c were significantly higher in subjects with CAN. Higher mean GA and GA variability were associated with the risk of developing CAN, independent of conventional risk factors and HbA1c. In ROC curve analysis, the SD and CV of GA showed higher predictive value for CAN compared to the SD and CV of HbA1c, whereas the predictive value of mean GA did not differ from that of mean HbA1c. The mean, SD, and CV of GA showed additive predictive power to detect CAN development along with mean HbA1c.

CONCLUSIONS

Higher serum GA and its variability are significantly associated with the risk of developing CAN. Serum GA might be a useful indicator for diabetic complications and can enhance HbA1c's modest clinical prediction for CAN.

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.

Novel measure of autonomic remodeling associated with sudden cardiac arrest in diabetes

BACKGROUND

Diabetes is independently associated with an increased risk of sudden cardiac arrest (SCA), with a need to identify novel methods for risk stratification. Diabetic patients can develop autonomic dysfunction that has been associated with an increased risk of ventricular arrhythmogenesis and manifests as reduced heart rate variability (HRV). However, previously published studies have not accounted for resting heart rate (HR), important from both pathophysiological and prognosticating standpoints.

OBJECTIVE

We sought to evaluate autonomic remodeling of the sinus node response in SCA and diabetes while accounting for HR.

METHODS

We performed a case-control study in SCA cases (age 35-59 years; 2002-2014) from the ongoing Oregon Sudden Unexpected Death Study (catchment population ∼1 million), and archived 12-lead electrocardiograms recorded prior to the SCA event were compared with those of geographic controls. Short-term HRV was calculated from digitized 10-second electrocardiograms by using established methods. We analyzed 313 subjects (mean age 52.0 ± 5.5 years; 216 men, 69.0%) and compared 4 groups: 111 diabetic (49 cases, 62 controls) and 202 nondiabetic (80 cases, 122 controls) subjects.

RESULTS

Analysis of covariance showed an absence of the expected interaction between HRV and HR (HRV-HR) in diabetic patients with SCA (regression slope -0.008; 95% confidence interval -0.023 to 0.0071; P = .26). This finding, unique to this population of diabetic patients with SCA, was not detected using traditional HRV measures.

CONCLUSION

By incorporating resting HR in this analysis, we observed that this population of diabetic patients with SCA had loss of the expected HRV-HR relationship. This potentially novel noninvasive risk measurement warrants further investigation, especially at the level of the individual patient.

The relationship between right ventricular deformation and heart rate variability in asymptomatic diabetic patients

OBJECTIVE

To investigate heart rate variability (HRV) and right ventricular (RV) remodeling in asymptomatic diabetic patients, as well as the relationship between HRV indices and RV structure, function and deformation.

METHOD

This cross-sectional study included 59 asymptomatic patients with type 2 diabetes and 45 healthy controls without cardiovascular risk factors. All study subjects underwent 24-h Holter monitoring, laboratory analyses and complete two-dimensional echocardiography examination (2DE).

RESULTS

RV diastolic function and longitudinal deformation were significantly impaired in diabetic individuals comparing with controls. RV global longitudinal strain and layer-specific longitudinal strains were significantly decreased in diabetic group. The same trend of changes in RV deformation was observed for global RV and lateral wall. All parameters of time and frequency domain of HRV were reduced in diabetic subjects. RV endocardial longitudinal strain together with LV mass index, mitral E/e' ratio and HbA1c correlated with HRV parameters. However, multivariate linear regression analysis showed that only RV endocardial longitudinal strain and LV mass index are associated with HRV parameters independently of age, BMI, HbA1c, RV free wall thickness and pulmonary artery pressure.

CONCLUSIONS

RV subendocardial strain is independently associated with HRV parameters in the whole study population. This reveals potentially important role of determination of layer-specific RV longitudinal function as important marker of preclinical cardiac damage, but also indirectly show the impairment of cardiac autonomic function in diabetic patients.

Assessment of Autonomic Dysfunction in Acute Stroke Patients at a Tertiary Care Hospital

INTRODUCTION

In patients who present with acute cerebro-vascular disease, autonomic function testing is usually not given its due importance. This is because of the complex nature of the autonomic function tests and the relative technical difficulty faced in administering the tests to the patients. A simple and non-invasive method to assess the autonomic dysfunction is measurement of resting Heart Rate Variability (HRV).

AIM

To study the pattern of autonomic dysfunction among patients admitted with acute stroke and to study the relationship between autonomic dysfunction and the morbidity and mortality associated with acute stroke.

MATERIALS AND METHODS

The study was carried out on 97 patients who were admitted with diagnosis of acute stroke. Patients with conduction abnormalities on ECG were excluded from the study. Resting ECG tracings were obtained for a period of 5 minutes. The frequency domain analysis of HRV was performed by a Fast Fourier transform of the RR intervals. The High Frequency (HF) was representative of the parasympathetic activity while low frequency is representative of baroreceptor mediated parasympathetic and sympathetic activity and Low Frequency (LF)/HF ratio was a measure of the sympathovagal balance. Statistical analysis was carried out with student's t-test and chi-square test and p-value ≥ 0.05 was taken to be statistically significant.

RESULTS

The mean age of the patients was 60.84±14.12 years. A total of 41 patients were females and 77 patients had ischemic stroke. Out of the total 97, 60 patients had evidence suggestive of increased sympathetic activity with a mean LF/HF ratio of 2.03±0.88. These patients had significantly higher mean systolic BP, diastolic BP and National Institute of Health Stroke Scale (NIHSS) values when compared to patients with reduced LF/HF ratio (166.33±24.81 vs 148.54±19.42, p=0.0003, 100.33±18.73 vs 88.76±12.66, p=0.0013, 15.77±8.22 vs 11.49±6.63, p=0.0088 respectively). These patients also had a higher mortality rate.

CONCLUSION

This study highlights the problem of autonomic dysfunction among patients with stroke. Patients with autonomic dysfunction had higher morbidity and mortality in the acute phase of stroke in this study and also had higher blood pressure readings. This is a small scale study whose findings need to be validated further by larger population studies.

Intermittent hypoxia as a means to improve aerobic capacity in type 2 diabetes

Physical inactivity and a low maximal aerobic capacity (VO_2max) strongly predict morbidity and mortality in patients with type 2 diabetes (T2D). Patients with T2D have a reduced VO_2max when compared with healthy individuals of similar age, weight, and physical activity levels, and this lower aerobic capacity is usually attributed to a reduced oxygen delivery to the working muscles. The oxygen carrying capacity of the blood, as well as increases in cardiac output and blood flow, contribute to the delivery of oxygen to the active muscles during exercise. Hemoglobin mass (Hb mass), a key determinant of oxygen carrying capacity, is suggested to be reduced in patients with T2D following the observation of a lower blood volume (BV) in combination with normal hematocrit levels in this population. Therefore, a lower Hb mass, in addition to a reported lower BV and impaired cardiovascular response to exercise, likely contributes to the reduced oxygen delivery and VO_2max in patients with T2D. While exercise training increases Hb mass, BV, and consequently VO_2max, the majority of patients with T2D are not physically active, highlighting the need for alternative methods to improve VO_2max in this population. Exposure to hypoxia triggers the release of erythropoietin, the hormone regulating red blood cell production, which increases Hb mass and consequently BV. Exposure to mild intermittent hypoxia (IH), characterized by few and short episodes of hypoxia at a fraction of inspired oxygen ranging between 10 and 14% interspersed with cycles of normoxia, increased red blood cell volume, Hb mass, and plasma volume in patients with coronary artery disease or chronic obstructive pulmonary disease, which resulted in an improved VO_2max in both populations. We hypothesize that 12 exposures to mild IH over a period of 4weeks will increase Hb mass, BV, cardiac function, and VO_2max in patients with T2D. Therefore, exposures to mild IH may increase oxygen delivery and VO_2max without the need to perform exercise in patients with T2D.

Electrochemical Skin Conductance May Be Used to Screen for Diabetic Cardiac Autonomic Neuropathy in a Chinese Population with Diabetes

Aims. This study aimed to assess whether the electrochemical skin conductance (ESC) could be used to screen for diabetic cardiac autonomic neuropathy (DCAN) in a Chinese population with diabetes. Methods. We recruited 75 patients with type 2 diabetes mellitus (T2DM) and 45 controls without diabetes. DCAN was diagnosed by the cardiovascular autonomic reflex tests (CARTs) as gold standard. In all subjects ESCs of hands and feet were also detected by SUDOSCAN™ as a new screening method. The efficacy was assessed by receiver operating characteristic (ROC) curve analysis. Results. The ESCs of both hands and feet were significantly lower in T2DM patients with DCAN than those without DCAN (67.33 ± 15.37 versus 78.03 ± 13.73, P = 0.002, and 57.77 ± 20.99 versus 75.03 ± 11.41, P < 0.001). The ROC curve analysis showed the areas under the ROC curve were both 0.75 for ESCs of hands and feet in screening DCAN. And the optimal cut-off values of ESCs, sensitivities, and specificities were 76 μS, 76.7%, and 75.6% for hands and 75 μS, 80.0%, and 60.0% for feet, respectively. Conclusions. ESC measurement is a reliable and feasible method to screen DCAN in the Chinese population with diabetes before further diagnosis with CARTs.

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.

The Association of Resting Heart Rate with the Presence of Diabetes in Korean Adults: The 2010-2013 Korea National Health and Nutrition Examination Survey

Background

Previous epidemiologic studies have shown that elevated resting heart rate (HR) is associated with higher cardiovascular disease (CVD) morbidity and mortality. Although the relationship between elevated HR and CVD is well established, the association between resting HR and diabetes has been relatively understudied, particularly in non-Western populations.

Objectives

We confirmed the association between the presence of type 2 diabetes and resting HR in the Korean adult population using data from the 2010–2013 Korea National Health and Nutrition Examination Survey (KNHANES).

Methods

Among 25,712 adults (≥ 19 years of age) who participated in the 2010–2013 KNHANES, a total of 22,512 subjects completed laboratory examinations and were included in this analysis. The fasting plasma glucose (FPG) level was categorized into the following five groups: normal fasting glucose (NFG) 1 (<90 mg/dL), NFG 2 (90–99 mg/dL), impaired fasting glucose (IFG) 1 (100–110 mg/dL), IFG 2 (111–125 mg/dL), and diabetes (≥ 126 mg/dL).

Results

The unadjusted weighted resting HRs were 69.6, 69.4, 69.8, 70.1, and 72.0 beats per minute (bpm) in the NFG 1, NFG 2, IFG 1, IFG 2, and diabetes groups, respectively (P<0.001). We assessed the adjusted weighted resting HR according to the FPG level after adjusting for age, sex, smoking history, high risk alcohol drinking, daily energy intake, waist circumference, serum total cholesterol level, serum triglyceride (TG) level, serum white blood cell (WBC) count, serum hemoglobin (Hb), and the presence of hypertension. The adjusted weighted resting HR significantly increased across the FPG groups (P<0.001). The weighted prevalence rates of diabetes were 6.8% (6.2–7.5%), 7.6% (6.7–8.5%), 8.0% (7.0–9.1%), and 11.8% (10.8–12.7%) in subjects with HR ≤ 64, 65–69, 70–75, and ≥ 76 bpm, respectively (P<0.001), after adjusting for the confounding factors mentioned above. Using resting HR ≤ 64 bpm as the control, resting HR ≥ 76 bpm was correlated with the presence of diabetes (adjusted OR 1.83, 95% CI 1.55–2.16, P<0.001). Each 10 bpm increment of HR increased the risk of the presence of diabetes by 35% (P<0.001). This association of high resting HR with the presence of diabetes was not influenced by the status of blood pressure (BP) medication.

Conclusion

We demonstrated that higher HR was associated with diabetes in a representative sample of Korean adults. These positive associations were independent of age, sex, current smoking, high risk alcohol drinking, daily energy intake, waist circumference, and the presence of hypertension and other potential confounders. This study suggests that individuals with higher resting HR are at risk of diabetes and that HR might provide an easy and simple surrogate marker for the risk of diabetes.

Factors influencing the quality of life perception in patients with type 2 diabetes mellitus

PURPOSE

To evaluate the impact of several factors on the patient's perception on quality of life in a group of patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

In this cross-sectional study, 198 patients with T2DM were enrolled according to a consecutive-case population-based study design. In all participants, the perception on the quality of life was measured using the quality of life index - diabetes version III proposed by Ferrans and Powers. We evaluated the impact of several anthropometric and diabetes-related (ie, diabetes history and quality of glycemic control) factors on the patient's perception on the quality of life.

RESULTS

The presence of diabetes complications was associated with a decreased quality of life: retinopathy (1 vs 5 points; P<0.001), chronic kidney disease (-1 vs 5 points; P<0.001), and neuropathy (-1 vs 5 points; P<0.001). A significant reverse correlation was found between the patient's quality of life and depression's severity (Spearman's r=-0.345; P<0.001) and body mass index (Spearman's r=-0.158; P=0.026). A positive association between the quality of life and the quality of diabetes-related self-care activities was found (Spearman's r=0.338; P<0.001). No significant association was found between the patient's quality of life and the quality of glycemic control, diabetes duration, age, gender, or smoking status.

CONCLUSION

To improve the patient's quality of life, special care should be given to the modifiable diabetes-related factors: the prevention and treatment of diabetes complications, treatment of depression, and weight loss in obese and overweight patients.

The relationship between heart rate variability and left ventricular layer-specific deformation in uncomplicated diabetic patients

The aim of this study was to investigate heart rate variability (HRV) and left ventricular (LV) remodeling in uncomplicated diabetic patients. Furthermore, we sought to investigate the association between HRV indices and LV structural, functional and mechanical parameters. This cross-sectional study included 50 uncomplicated patients with type 2 diabetes and 40 healthy controls without cardiovascular risk factors. All study subjects underwent 24-h Holter monitoring, laboratory analyses and complete two-dimensional echocardiography examination (2DE). LV structure and diastolic function were significantly deteriorated in the diabetic patients comparing with the controls. LV global longitudinal, circumferential and radial strains were significantly reduced in the diabetic group. LV endocardial, mid-miocardial and epicardial longitudinal and circumferential strains were significantly decreased, whereas LV twist was significantly increased, in the diabetic patients; 24-h, daytime and nighttime heart rates were higher in the diabetic patients. All parameters of time and frequency domain of HRV were reduced in the diabetic subjects. LV mass index, mitral E/e' ratio and 2DE LV endocardial and mid-miocardial longitudinal and circumferential strains correlated with HRV parameters. A multivariate regression analysis showed that E/e' ratio and 2DE LV layer-specific strains were associated with HRV parameters independently of age, BMI, systolic blood pressure and LV mass index. HRV and LV mechanics are significantly deteriorated in uncomplicated diabetic individuals. Parameters of LV remodeling are independently associated with HRV indices, which could indicate the importance of HRV determination in diabetics.

Clinical implication of body size phenotype on heart rate variability

We compared heart rate variability (HRV) values according to the following body size phenotypes: metabolically healthy normal weight (MHNW), metabolically unhealthy but normal weight (MUNW), metabolically healthy but obese (MHO), and metabolically unhealthy obese (MUO). We retrospectively analyzed a dataset from 1200 participants who had visited the Cardiovascular Center at Korea University Guro Hospital between March 2009 and February 2014 and underwent Holter monitoring for 24h. HRV was calculated from standard deviation of normal-to-normal R-R intervals (SDNN), standard deviation of the average normal-to-normal intervals (SDANN), and root mean square of successive differences (rMSSD) measurements, and study subjects were classified according to body mass index (BMI) and presence or absence of metabolic syndrome. Various HRV indices, including SDNN, SDANN, and rMSSD, were significantly lower in MUNW subjects than in MHNW or MHO subjects, while there were no significant differences between MUNW and MUO subjects. Although BMI had no significant correlation with any HRV indices, SDNN, SDANN, and rMSSD values had significant negative correlations with waist circumference and levels of C-reactive proteins, AST, ALT, fasting glucose, and HOMA-IR. A significant positive correlation was observed between HRV index and HDL level. Furthermore, the SDNN value significantly decreased with an increase in the number of metabolic syndrome components after adjusting for other covariates. Compared to MHNW or MHO subjects, Korean men and women with the MUNW phenotype exhibited decreased HRV, suggesting that low HRV is related to adverse cardiovascular outcomes in MUNW individuals.

Impact of Diabetes Type 1 in Children on Autonomic Modulation at Rest and in Response to the Active Orthostatic Test

Introduction

Cardiovascular autonomic neuropathy is one of the most common complications of diabetes mellitus type 1 (DM1), of which one of the first subclinical manifestations is changes in heart rate variability (HRV). Thus, analysis of HRV associated with the autonomic active orthostatic test is important in this population.

Objectives

To analyze the autonomic modulation responses induced by the implementation of the active orthostatic test, in children with DM1, and study the autonomic modulation by means of HRV indices.

Method

Data of 35 children were analyzed, of both sexes, aged between 7 and 15 years, who were divided into two groups: Diabetic (n = 16) and Control (n = 19). The following variables were collected initially: weight, height, body fat percentage, heart rate, blood pressure and casual blood glucose. Subsequently, for analysis of autonomic modulation, the beat-to-beat heart rate was captured by a heart rate monitor in the supine position for 30 minutes and after 10 minutes standing during performance of the active orthostatic test. HRV indices were calculated in the time and frequency domains. For data analysis, covariance analysis was used to compare groups and ANOVA for repeated measures to compare the effects of the active orthostatic test. These data were adjusted for age, sex, ethnicity, body fat percentage and casual blood glucose, with a 5% significance level.

Results

The results suggested that diabetic children at rest present a decrease in SDNN (50.4 vs. 75.2), rMSSD (38.7 vs 57.6) and LF [ms²] (693.6 vs 1874.6). During the active orthostatic test the children in both groups demonstrated a reduction in SDNN, RMSSD and LF [ms²] compared to the resting position, and this response was less pronounced in the diabetic group.

Conclusion

We conclude that regardless of age, sex, ethnicity, body fat percentage and casual blood glucose, performing the active orthostatic test promoted increased sympathetic modulation and reduced parasympathetic modulation in both groups, and this response was less pronounced in diabetic children, who presented reduced overall variability and parasympathetic modulation.

Risk factors of diabetic cardiac autonomic neuropathy in patients with type 1 diabetes mellitus: a meta-analysis

OBJECTIVES

We aimed to stratify the possible risk factors for diabetic cardiac autonomic neuropathy (CAN).

METHODS

We did a meta-analysis of risk factors of CAN. We did a web-based search for literature in MEDLINE/PubMed, Scopus database and CENTRAL database up to August 2015. We included clinical trials or cohort studies that provide data about relationship between CAN and variables of interest. Our risk factors of interest were age, sex, duration of diabetes, body mass index (BMI), systolic blood pressure (sBP) and diastolic blood pressure (dBP), glycated haemoglobin (HbA1c), high-density lipoprotein and low-density lipoprotein (HDL and LDL), triglycerides, retinopathy and nephropathy. We generated Forest plots, χ² test and I² as tests for heterogeneity, risk ratio (RR), mean difference (MD), CIs and p values by ReVMan V.5.3 software.

RESULTS

We found a total of 882 related items. We excluded 873 studies from the title and abstract and 4 studies after review of full reports. Four studies were included. Our meta-analysis showed significant association between CAN and age (MD=4.94 (3.46 to 6.42)), duration of diabetes (MD=4.51 (2.51 to 6.52)), HbA1c (MD=0.48 (0.28 to 0.67)), BMI (MD=0.55 (0.08 to 1.01)), serum triglycerides (MD=0.09 (0.01 to 0.17)), proliferative retinopathy (RR=3.69 (1.20 to 11.34)), microalbuminuria (RR=2.47 (1.43 to 4.29)), hypertension (RR=4.18 (2.52 to 6.91)) and sBP (MD=4.10 (2.20 to 6.00)). We neither discovered the absence of significant association between the development of CAN and male sex (RR=1.57 (0.45 to 5.39)), dBP (MD=0.89 (-0.36 to 2.14)), cholesterol level (MD=1.19 (-0.99 to 3.36)), LDL (MD=0.12 (-0.15 to 0.39)), nor HDL level (MD=-0.28 (-0.58 to 0.03)).

CONCLUSIONS

Age, duration of diabetes, HbA1c, BMI, serum triglycerides, proliferative retinopathy, microalbuminuria, hypertension and sBP are directly related to the risk of development of diabetic CAN.

Aldose reductase (-106) C/T gene polymorphism and possibility of macrovascular complications in Egyptian type 2 diabetic patients

INTRODUCTION

Over the past three decades, the number of people with diabetes mellitus (DM) has more than doubled globally, making it one of the most important public health challenges to all nations. Aldose reductase (AR) is a rate-limiting enzyme in the polyol pathway, which has been implicated in the pathogenesis of diabetic microvascular complications; however, the association of the AR gene with diabetic macrovascular complications has rarely been investigated.

AIM

The study aimed to identify the possible association between C(-106) T polymorphism of the AR gene and diabetic macroangiopathy in a cohort of Egyptian patients with type 2 DM.

SETTINGS AND DESIGN

This study was conducted on 100 Egyptian subjects, the control group (n = 20) and the patient group (n = 80) with type 2 diabetes which were further subdivided into two subgroups with (n = 48) and without macroangiopathic complications (n = 32) as evidenced by carotid intima-media thickness, electrocardiography (ECG) ischemic changes, cerebrovascular insufficiency, and peripheral vascular insufficiency.

SUBJECTS AND METHODS

All studied subjects were subjected to detailed history taking, clinical examination, ECG, carotid ultrasonography, routine laboratory investigations, and molecular studies including the detection of AR C(-106) T gene polymorphisms using the polymerase chain reaction (PCR)/restriction fragment length polymorphism technique.

RESULTS

The genotype distribution and allele frequency of AR C(-106) T showed no statistical significance also the genotypes were not associated with any of the different studied parameters.

CONCLUSIONS

The results suggest that the C(-106) T polymorphism in the AR gene is not involved in the pathogenesis of macroangiopathy in type 2 diabetes.

Cardiac autonomic nervous dysfunction detected by both heart rate variability and heart rate turbulence in prediabetic patients with isolated impaired fasting glucose

Objective:

Cardiac autonomic nervous dysfunction (CAND), a severe complication of diabetes, has also been shown to affect prediabetic patients. The role of isolated impaired fasting plasma glucose (IFG), a subtype of prediabetes, is not clear in the pathogenesis of CAND. The aim of this study was to examine the relationship between isolated IFG and cardiac autonomic function using heart rate variability (HRV) and heart rate turbulence (HRT) indices derived from 24-h Holter–electrocardiogram recordings.

Methods:

This observational, prospective, cross-sectional study examined 400 consecutive subjects divided into three groups according to oral glucose tolerance test results: the control group [Group I, fasting plasma glucose (FPG) <100 mg/dL and normal glucose tolerance, n=193], the isolated IFG group (Group II, FPG ≥100 and <126 mg/dL, n=134), and the isolated impaired glucose tolerance (IGT), both IFG and IGT, or newly diagnosed diabetes’ group (Group III, n=73). Patients with non-sinus rhythm, known diabetes mellitus, coronary artery disease, heart failure, severe valvular disease, or receiving medical therapy that may affect HRV and HRT indices were excluded. Time domain HRV parameters, turbulence onset (TO), turbulence slope (TS), and HRT category were examined. Chi-square, one-way analysis of variance, Kruskal–Wallis H, and Mann–Whitney U tests were used to compare variables where appropriate. The correlation between Holter data and FPG levels was analyzed using the Spearman’s test. Multiple linear regression analysis was performed to identify independent predictors of the HRV and HRT parameters.

Results:

Median (interquartile range 25–75) FPG levels in Groups I, II, and III were 89 (83/93) mg/dL, 109 (104/116) mg/dL, and 174 (150.5/197) mg/dL, respectively. There were significant differences in HRV and HRT parameters between and among all groups. While HRV parameters and TS decreased from Group I to Group III, TO and HRT category gradually increased. Additionally, FPG level was significantly correlated with SDNN, r=–0.220; SDNN index, r=–0.192; SDANN, r=–0.207; RMSSD, r=–0.228; pNN50, r=–0.226; TO, r=0.354; and TS, r=–0.331 (all p<0.001).

Conclusion:

CAND, as detected by both HRV and HRT, appear to be present in the isolated IFG subtype of prediabetes.

Disease-modifying antirheumatic drugs improve cardiovascular autonomic neuropathy in psoriatic arthritis

BACKGROUND

Cardiovascular autonomic neuropathy (CAN) is a significant risk predictor for sudden cardiac death in autoimmune rheumatic diseases. As yet, there is no therapeutic treatment of CAN in psoriatic arthritis (PsA). Even now, the impact of the most commonly employed disease-modifying antirheumatic drug (DMARD) therapy on CAN in PsA is not known. Hence, we investigated the impact of DMARDs on CAN in PsA.

METHODS

In this prospective, cross-sectional study, 20 patients of PsA and 20 age- and sex-matched healthy controls were recruited. CAN was diagnosed by applying the five cardiovascular reflex tests according to Ewing. Parasympathetic dysfunction was established by performing three tests: heart-rate response to deep breathing, standing, and Valsalva tests. Sympathetic dysfunction was examined by applying two tests: blood pressure response to standing, and handgrip tests. Disease severity was assessed by the 28-joint-count disease activity score (DAS-28) and the disease activity score in psoriatic arthritis (DAPSA).

RESULTS

Cardiovascular reflex tests were impaired significantly among the PsA patients compared with well-matched healthy subjects (p < 0.05). Parasympathetic dysfunction was more prominent than sympathetic dysfunction. After 12 weeks treatment, parasympathetic dysfunction (heart rate response to deep breath and standing) significantly (p < 0.05) improved in patients with PsA, while there was no significant improvement in sympathetic function.

CONCLUSION

These study results suggests parasympathetic autonomic dysfunction is more prominent than sympathetic dysfunction in PsA. Synthetic DMARDs improved parasympathetic dysfunction in PsA.

Cardiac Involvement in Peripheral Neuropathies

Cardiac autonomic neuropathy (CAN) is the least recognized and understood complication of peripheral neuropathy. However, because of its potential adverse effects including sudden death, CAN is one of the most important forms of autonomic neuropathies. CAN presents with different clinical manifestations including postural hypotension, exercise intolerance, fluctuation of blood pressure and heart rate, arrhythmia, and increased risk of myocardial infarction. In this article, the prevalence, clinical presentations, and management of cardiac involvement in certain peripheral neuropathies, including diabetic neuropathy, Guillain-Barré syndrome, chronic inflammatory polyneuropathy, human immunodeficiency virus-associated neuropathy, hereditary neuropathies, and amyloid neuropathy are examined in detail.

Preoperative Evaluation of Patients with Diabetes Mellitus

There are more than 29 million people in the United States with diabetes; it is estimated that by 2050, one in 3 individuals will have the disease. At least 50% of patients with diabetes are expected to undergo surgery in their lifetime. Complications from uncontrolled diabetes can impact multiple organ systems and affect perioperative risk. In this review, the authors discuss principles in diabetes management that will assist the perioperative clinician in caring for patients with diabetes.

Impaired Heart Rate Response to Exercise in Diabetes and Its Long-term Significance

OBJECTIVE

To investigate the effect of diabetes mellitus on exercise heart rate and the role of impaired heart rate in excess mortality in diabetes.

PATIENTS AND METHODS

Patients without cardiovascular disease who underwent exercise testing from September 1, 1993, through December 31, 2010, were included. Mortality was determined from Mayo Clinic records and the Minnesota Death Index. Multivariate linear regression was used to compare heart rate responses in patients with vs without diabetes. Cox regression was used to determine the effect of abnormal heart rate recovery and abnormal chronotropic index on survival.

RESULTS

A total of 21,396 patients (65.4% men) with a mean ± SD age of 51±11 years, including 1200 patients with diabetes (5.4%), were included. Patients with diabetes had a higher resting heart rate (81±14 vs 77±13 beats/min), lower peak heart rate (154±20 vs 165±19 beats/min), heart rate reserve (73±19 vs 88±19 beats/min), chronotropic index (0.86±0.22 vs 0.99±0.20), and heart rate recovery (15±8 vs 19±9 beats/min) vs patients without diabetes. There were 1362 deaths (6.4%) during a mean ± SD follow-up of 11.9±4.9 years. Adjusting for age, sex, and heart rate-lowering drug use, a chronotropic index less than 0.8 contributed significantly to risk in patients with diabetes (hazard ratio [HR], 2.21; 95% CI, 1.62-3.00; P<.001) and patients without diabetes (HR, 1.94; 95% CI, 1.71-2.20; P<.001), as did abnormal heart rate recovery (patients with diabetes: HR, 2.21; 95% CI, 1.60-5.05; P<.001; patients without diabetes: HR, 1.75; 95% CI, 1.55-1.97).

CONCLUSIONS

Patients with diabetes exhibit abnormal heart rate responses to exercise, which are independently predictive of reduced long-term survival in patients with diabetes as in patients without diabetes.

Which is responsible for cardiac autonomic dysfunction in non-diabetic patients with metabolic syndrome: Prediabetes or the syndrome itself?

AIMS

Cardiac autonomic dysfunction (CAD) is associated with both prediabetes and metabolic syndrome (MS). Heart rate variability (HRV) and heart rate turbulence (HRT) are reliable 24-h Holter-ECG findings of cardiac autonomic function. This study aimed to investigate the relation between MS and its components and CAD using HRV and HRT.

MATERIALS AND METHODS

The study included 80 non-diabetic patients with MS and 70 control subjects. All study population and the patients with MS were further analyzed for each diagnostic component of MS to investigate which criteria impaired HRV and HRT.

RESULTS

HRV and HRT parameters were disturbed in patients in the MS group. While impairment in HRV and HRT was significantly related to the presence of the fasting plasma glucose (FPG) criterion, there were no differences between groups in terms of the other 4 MS criteria. Moreover, FPG level was significantly correlated with SDNN (r=-0.352, p<0.001), SDNN index (r=-0.423, p<0.001), SDANN (r=-0.301, p<0.001), RMSSD (r=-0.237, p<0.001), pNN50 (r=-0.237, p<0.001), turbulence onset (TO) (r=0.365, p<0.001) and turbulence slope (TS) (r=-0.365, p<0.001). Among the MS diagnostic criteria, only FPG level was an independent determinant of all HRV and HRT parameters.

CONCLUSIONS

This study confirms the relation between MS and CAD. Increased FPG alone appears to be responsible for the mentioned findings among the 5 diagnostic criteria. Accordingly, CAD may be the result of prediabetes, not MS in patients with MS.

Impact of neuropathy on the adherence to diabetes-related self-care activities: a cross-sectional study

PURPOSE

The purpose of this study was to evaluate the impact of the presence and severity of neuropathy and depression on the patient's adherence to diabetes-related self-care activities (DRSCA) in a cohort of patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

In this cross-sectional, noninterventional study, 198 patients with T2DM were enrolled according to a population-based, consecutive-case enrollment principle. In all patients, the adherence to DRSCA was evaluated using the Summary of Diabetes Self-Care Activities (SDSCA) questionnaire; a higher SDSCA score is associated with a better adherence. The presence and severity of neuropathy was assessed using the Michigan Neuropathy Screening Instrument (MNSI) and the severity of depression using the Patient Health Questionnaire-9 (PHQ-9).

RESULTS

The presence of neuropathy was associated with a decreased SDSCA score (26 points vs 37 points; P<0.001), an increased severe depression prevalence (24.7% vs 4.3%; P<0.001), and an increased PHQ-9 score (12 points vs 7 points; P<0.001). The MNSI score was reverse correlated with SDSCA score (r=-0.527; P<0.001) and positively correlated with PHQ-9 score (r=0.495; P<0.001). The reverse correlation between MNSI score and SDSCA score was present for all the subcomponents of SDSCA questionnaire (diet, exercise, glycemic monitoring, and foot care).

CONCLUSION

The presence of neuropathy is associated with decreases in the quality of adherence to DRSCA in patients with T2DM and with increases in the symptomatology of depression. The significant, negative association between the severity of T2DM and the quality of disease self-management points to a possible loop-type relationship between these two components, being possible a reciprocal augmentation with negative consequences on the global management of the disease.

Aging, heart rate variability and patterns of autonomic regulation of the heart

OBJECTIVES

To evaluate the effects of aging, gender and body mass index on the heart rate variability (HRV), and to compare the patterns of global autonomic regulation (GAR) and parasympathetic outflow (PO) throughout the aging process.

DESIGN, SETTING AND PARTICIPANTS

CROSS-SECTIONAL: Large sample of community-based adults and elderly people. Individuals aged from 40 to 100 years, functionally independent and with satisfactory cognitive function defined as the self-capacity to interact with an interviewer (N= 1743).

MATERIAL AND METHODS

The study enrolled individuals of both genders, stratified into five age-groups. We did adjustments for hypertension, dyslipidemia and non-insulin-dependent diabetes, as well as the body mass index (BMI). All groups undertook long-term electrocardiograms and five time-domain HRV parameters were measured, three (SDNN, SDANN, SDNN-index) reflecting the GAR and two (rMSSD and pNN50) the PO.

RESULTS

SDNN, SDANN and SDNN-index decreased linearly with age and BMI, and women had lower values than men (p<0.001). There was a U-shaped pattern of rMSSD and pNN50, with the nadir between 60 and 69 years for both genders, and women had higher values than men (p<0.001). The lowest levels of all HRV variables were found in diabetics (p<0.001). There was no influence of hypertension or dyslipidemia.

CONCLUSIONS

The GAR decreased linearly with the age in both genders. It is comparatively lower in women, diabetics and overweight individuals. The PO presented the U-shape in both genders with the nadir at the 7th decade. It was also comparatively lower in men and diabetics. Hypertension and dyslipidemia imparted no significant influence.