Associations between the severity of metabolic syndrome and cardiovascular autonomic function in a Chinese population

Association between metabolic syndrome components and cardiac autonomic modulation in southern Indian adults with pre-metabolic syndrome: hyperglycemia is the major contributing factor

Metabolic syndrome (MetS) involves multi-factorial conditions linked to an elevated risk of type 2 diabetes mellitus and cardiovascular disease. Pre-metabolic syndrome (pre-MetS) possesses two MetS components but does not meet the MetS diagnostic criteria. Although cardiac autonomic derangements are evident in MetS, there is little information on their status in pre-MetS subjects. In this study, we sought to examine cardiac autonomic functions in pre-MetS and to determine which MetS component is more responsible for impaired cardiac autonomic functions. A total of 182 subjects were recruited and divided into healthy controls (n=89) and pre-MetS subjects (n=93) based on inclusion and exclusion criteria. We performed biochemical profiles on fasting blood samples to detect pre-MetS. Using standardized protocols, we evaluated anthropometric data, body composition, baroreflex sensitivity (BRS), heart rate variability (HRV), and autonomic function tests (AFTs). We further examined these parameters in pre-MetS subjects for each MetS component. Compared to healthy controls, we observed a significant cardiac autonomic dysfunction (CAD) through reduced BRS, lower overall HRV, and altered AFT parameters in pre-MetS subjects, accompanied by markedly varied anthropometric, clinical and biochemical parameters. Furthermore, all examined BRS, HRV, and AFT parameters exhibited an abnormal trend and significant correlation toward hyperglycemia. This study demonstrates CAD in pre-MetS subjects with reduced BRS, lower overall HRV, and altered AFT parameters. Hyperglycemia was considered an independent determinant of alterations in all the examined BRS, HRV, and AFT parameters. Thus, hyperglycemia may contribute to CAD in pre-MetS subjects before progressing to MetS.

Heart Rate Variability in Patients with Hypertension: the Effect of Metabolic Syndrome and Antihypertensive Treatment

Metabolic syndrome (MetS) is a combination of factors which, collectively, increase cardiovascular risk to a greater extent than each of them separately. Previous studies showed high cardiovascular risk to be associated with autonomic nervous system dysfunction. The purpose of this study was to assess the effects of antihypertensive treatment on heart rate variability (HRV) in patients with hypertension (HTN), depending on cooccurrence of MetS. 118 patients with uncontrolled HTN were enrolled to the study. HRV was compared among patients with and without MetS (MetS [+], n = 70) at baseline and following 12 months antihypertensive treatment. The HRV indices measured from RR intervals recorded form using 24-hour ambulatory electrocardiography. The measured HRV domains were the standard deviation of the average of NN intervals [SDNN], square root of the mean of the sum of the squares of differences between adjacent NN intervals [rMSSD], percentage of NN50 [pNN50], low frequency [LF], high frequency [HF], total power of variance of all NN intervals [TP], and LF/HF ratio. Baseline parameters: SDNN, rMSSD, pNN50, and HF were significantly lower in the MetS[+] compared to the MetS[-] subgroup (p < 0.05). After a 12-month antihypertensive treatment, MetS[+] patients achieved a significant improvement in parameters: SDNN, rMSSD, pNN50, and TP (p < 0.05), while the changes in HRV observed in the MetS[-] subgroup were not statistically significant. The cooccurrence of HTN and other components of MetS is associated with disturbances of the autonomic balance. HTN control has a beneficial effect on HRV, with the effect being more evident in patients with MetS.

Is the Brain a Key Player in Glucose Regulation and Development of Type 2 Diabetes?

Ever since Claude Bernards discovery in the mid 19th-century that a lesion in the floor of the third ventricle in dogs led to altered systemic glucose levels, a role of the CNS in whole-body glucose regulation has been acknowledged. However, this finding was later overshadowed by the isolation of pancreatic hormones in the 20th century. Since then, the understanding of glucose homeostasis and pathology has primarily evolved around peripheral mechanism. Due to scientific advances over these last few decades, however, increasing attention has been given to the possibility of the brain as a key player in glucose regulation and the pathogenesis of metabolic disorders such as type 2 diabetes. Studies of animals have enabled detailed neuroanatomical mapping of CNS structures involved in glucose regulation and key neuronal circuits and intracellular pathways have been identified. Furthermore, the development of neuroimaging techniques has provided methods to measure changes of activity in specific CNS regions upon diverse metabolic challenges in humans. In this narrative review, we discuss the available evidence on the topic. We conclude that there is much evidence in favor of active CNS involvement in glucose homeostasis but the relative importance of central vs. peripheral mechanisms remains to be elucidated. An increased understanding of this field may lead to new CNS-focusing pharmacologic strategies in the treatment of type 2 diabetes.

Analysis of a Screening System for Diabetic Cardiovascular Autonomic Neuropathy in China

Background

The aim of this study was to create a screening system for diabetic cardiovascular autonomic neuropathy (DCAN) in diabetic patients.

Material/Methods

A Chinese cohort of 455 diabetic participants was recruited between 2011 and 2013. Short-term heart rate variability testing was used to evaluate cardiovascular autonomic function. A simple model was developed using multiple variable regression to include only significant risk factors that were simple and easily assessed. A DCAN score was determined based on the coefficients of the multiple variable model. This score was tested on the entire cohort of 455 diabetic patients and another independent, external cohort of 115 diabetic patients.

Results

The screening system consisted of age, body mass index, duration of diabetes mellitus, and resting heart rate, and these factors were significantly (P<0.05) associated with DCAN. Receiver operating characteristic (ROC) curve analysis was done. The areas under the ROC curve were 0.798, 0.756, and 0.729 for the total sample, validation cohort, and external set, respectively. A cutoff DCAN score of 12 out of 25 produced optimal results for sensitivity (80.36%), specificity (58.27%), and percentage of patients that needed subsequent testing (43.55%) for the validation set.

Conclusions

The study concludes that a simple and practical DCAN screening can be applied for early intervention to delay or prevent the disease in the Chinese population.

Analysis of the association between glucose profiles and β-cell function for diabetic cardiovascular autonomic neuropathy in China

AIMS/INTRODUCTION

The purpose of the present study was to investigate the severity of glucose profiles and β-cell function associated with diabetic cardiovascular autonomic neuropathy (DCAN) in a Chinese sample.

MATERIALS AND METHODS

A community-based, cross-sectional study to analyze the risk factors of DCAN was carried out with 455 individuals recruited from a Chinese population. The glucose profile risk score was calculated to identify the association between the severity of the glucose profiles and DCAN. The associations of the severity of the glucose profiles and β-cell function with DCAN were analyzed using multivariable logistic regression.

RESULTS

Univariate analysis showed that the glucose profiles and homeostatic model assessment of insulin resistance were significantly associated with the DCAN outcome, respectively. Multivariable logistic regression showed that significant associations exist between glucose profile indices and DCAN, after controlling for potential confounding factors (P < 0.01 for all) in both models. Multivariable logistic regression also showed that parameters of β-cell function were associated with the DCAN outcome in the category model (P < 0.1 for all). The glucose profile risk score was independently and significantly associated with the DCAN outcome after controlling for confounding factors (P < 0.001 and P for a trend <0.001).

CONCLUSIONS

Our observations suggest that parameters of glucose profile indices and β-cell function are significantly and independently associated with DCAN, respectively. There was a tendency toward increased glucose profile risk score with increasing prevalence of DCAN.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Analysis of the Synergistic Effects of Fasting Plasma Glucose and Hypertension on Cardiovascular Autonomic Neuropathy

Background: The purpose of this study was to evaluate the associations of fasting plasma glucose (FPG) and hypertension (HTN) with cardiovascular autonomic neuropathy (CAN) and to estimate the extent to which the synergistic effects of FPG and HTN affect outcomes in a Chinese population. Method: We conducted a large-scale, population-based study to analyze the association and interaction of the two factors with CAN in a sample of 2,092 Chinese people. Univariate and multiple linear regression (MLR) analyses were employed to detect these relationships. Interaction on an additive scale can be calculated by using the relative excess risk due to interaction, the proportion attributable to interaction (AP), and the synergy index (S). Result: After adjusting for confounding factors, MLR showed that FPG and HTN were independently associated with CAN (p < 0.001 for both). A significant synergistic effect of FPG and HTN on CAN was detected (p = 0.046, RETI = 0.733, 95% CI 0.059-1.450; AP = 0.167, 95% CI -0.033 to 0.367; S = 1.275, 95% CI 0.140-2.410). Conclusion: Our findings suggest that FPG and HTN are independently associated with CAN, and they offer evidence to support the hypothesis that FPG and HTN have synergistic effects that influence the progression of CAN.

Clinical risk model assessment for cardiovascular autonomic dysfunction in the general Chinese population

BACKGROUND

The aim of this study was to evaluate the prevalence of cardiovascular autonomic (CA) dysfunction in the general Chinese population (instead of focusing on only patients with diabetes) and to develop a clinical risk model for the disease.

METHODS AND MATERIALS

We evaluated CA dysfunction prevalence in a dataset based on a population sample consisting of 2,092 individuals. Clinical risk models were derived from exploratory sets using multiple logistic regression analysis. The performance of the clinical risk models was tested in the validation sets.

RESULTS

CA dysfunction prevalence was 18.50% in the general Chinese population, while the prevalence was 24.14% in individuals aged ≥60 years. Its prevalence was 31.17, 24.69, and 21.26% in patients with diabetes, and hypertensive, and metabolic syndrome populations, respectively. Finally, we developed clinical risk models involving seven risk factors. The mean area under the receiver-operating curve was 0.758 (95% CI 0.724-0.793) for these models. The mean sensitivity and specificity of the clinical risk models was 75.0 and 66.2%, respectively.

CONCLUSION

CA dysfunction prevalence was high in the general Chinese population, and its prevalence was more frequent in individuals with diabetes, and hypertensive, and metabolic syndrome. Clinical risk models with a high value for predicting CA dysfunction were developed. CA dysfunction has become a major public health problem in China that requires strategies aimed at the prevention and treatment of the disease.

Diagnostic performance analysis for diabetic cardiovascular autonomic neuropathy based on short-term heart rate variability using Bayesian methods: preliminary analysis

OBJECTIVES

This study aimed to estimate the performance of diabetic cardiovascular autonomic neuropathy (DCAN) diagnostic tests in the absence of a gold standard.

BACKGROUND

The DCAN prevalence is rapidly growing in all populations worldwide. No document has been reported about diagnostic performance for DCAN based on short-term HRV without a gold standard.

METHODS

We conducted a cross-sectional study to perform diagnostic test in Chinese diabetic patients. A dataset contained 56 subjects who completed both the short-term HRV test and Ewing's test. Simultaneous inferences about the population prevalence and the performance of each diagnostic test were possible using the Bayesian approach.

RESULTS

The HRV test had a high sensitivity (0.837 and 0.821 for independence model) and specificity (0.838 and 0.797 for dependence model) to DCAN. In addition, the non-inferiority test rejected the hypothesis that the performance of the HRV test was inferior to that of Ewing's test (P < 0.05). The estimated DCAN prevalence in our study sample was more than 0.400.

CONCLUSION

Our findings provided evidence that short-term HRV were used for the DCAN diagnostic test with a high sensitivity and specificity. ClinicalTrial.org ID: NCT02461381.

Bayesian estimation of cardiovascular autonomic neuropathy diagnostic test based on short-term heart rate variability without a gold standard

OBJECTIVE

To evaluate the reference values for short-term heart rate variability (HRV), estimate the performance of cardiovascular autonomic neuropathy (CAN) diagnostic tests in the absence of a gold standard, and assess CAN prevalence in our dataset.

SETTING

Community and hospital health centre.

PARTICIPANTS

Of 2092 subjects available for data analysis, 371 healthy subjects were selected so the reference values for the short-term HRV test could be evaluated. An external dataset contained 88 subjects who completed both the short-term HRV test and Ewing's test.

INTERVENTION

Collection of information on clinical outcome.

PRIMARY AND SECOND OUTCOME MEASURES

Cardiovascular autonomic function evaluated by using the short-term HRV test and/or Ewing's test.

RESULTS

Cut-off points of 356.13, 55.45 and 36.64 ms2 were set for total power, low frequency and high frequency (HF), respectively. The diagnostic test for CAN based on the mentioned reference value was created. The HRV test had a high sensitivity (80.01-85.09%) and specificity (82.30-85.20%) for CAN. In addition, the non-inferiority test rejected the null hypothesis that the performance of the HRV test was inferior to that of Ewing's test (p<0.05). The estimated CAN prevalence was 14.92% and 29.17% in the total sample and patients with diabetes, respectively.

CONCLUSIONS

Our findings provided reference values for short-term HRV, which were used for the CAN diagnostic test with high sensitivity and specificity. The estimated CAN prevalence was high in the Chinese population.

Normative reference of short-term heart rate variability and estimation of cardiovascular autonomic neuropathy prevalence in Chinese people

BACKGROUND

The cardiovascular autonomic neuropathy (CAN) prevalence is rapidly growing in all populations worldwide. This study aimed to evaluate the reference values for the short-term heart rate variable (HRV) and estimate CAN prevalence in our cross-sectional dataset.

METHODS

We conducted a large-scale, community-based, cross-sectional study in a Chinese population. Of 2,092 subjects available for data analysis, 371 healthy subjects were selected to reference the values for the short-term HRV. The short-term HRV analysis was performed for all subjects using a computer-aided examination and evaluation system for spectral analysis to investigate changes in autonomic regulation.

RESULTS

In the total sample, the reference value for total power was more than 356.13 ms(2). The cutoff points of 55.45 and 36.64 ms(2) were set for low frequency (LF) and high frequency (HF), respectively. The cutoff points of LFn and HFn were 6.40 and 4.83 ν, respectively. The normative reference of LF/HF ranged from 0.3 to 6.5. Using HRV test (model 1), the estimated age-adjusted CAN prevalence in the total sample was 16.83 %. The estimated age-adjusted CAN prevalence values were 31.07, 21.97 and 20.81 % in DM, HT, and MS patients, respectively.

CONCLUSION

Our findings provided reference values for short-term HRV. The estimated CAN prevalence was high in the Chinese population.

The analysis of a reference value for baroreflex sensitivity and cardiovascular autonomic neuropathy prevalence in a Chinese population

Background

Cardiovascular autonomic neuropathy (CAN) is rapidly growing in all populations worldwide. Baroreflex sensitivity (BRS) is easily applied as a diagnostic test to a large number of individuals in the general population. However, no study has reported the normal reference values of BRS for the CAN diagnostic test in a Chinese population. The aim of this study was to estimate the normative reference value of BRS, and assess CAN prevalence in our cross-sectional dataset.

Methods

We conducted a large-scale, community-based, cross-sectional study in a Chinese population. We performed data analysis on 2,092 subjects. Cardiovascular autonomic function was assessed using spontaneous BRS. A total of 349 healthy subjects were used to perform analysis for the reference value for BRS. The CAN prevalence was calculated in the overall sample, and in patients with diabetes mellitus, patients with hypertension and patients with metabolic syndrome.

Results

In the overall sample, the reference value for total power (TP.brs) was more than 1.96 ms/mmHg. The cut-off points of 1.74 ms/mmHg and 2.53 ms/mmHg were set as high frequency (HF.brs) and low frequency (LF.brs), respectively. CAN diagnostic tests based on the reference value were performed. The estimated CAN prevalence in the overall sample was 20.41% using the BRS test. CAN prevalence was 33.18%, 28.69% and 28.57% in patients with diabetes mellitus, patients with hypertension and patients with metabolic syndrome, respectively.

Conclusions

Our findings provided reference values for BRS. Estimated CAN prevalence was high in this Chinese population, which has become a major public health problem in China.

Association and predictive value analysis for resting heart rate and diabetes mellitus on cardiovascular autonomic neuropathy in general population

BACKGROUND

The purpose of this study was to evaluate the predictive value of DM and resting HR on CAN in a large sample derived from a Chinese population.

MATERIALS AND METHODS

We conducted a large-scale, population-based, cross-sectional study to explore the relationships of CAN with DM and resting HR. A total of 387 subjects were diagnosed with CAN in our dataset. The associations of CAN with DM and resting HR were assessed by a multivariate logistic regression (MLR) analysis (using subjects without CAN as a reference group) after controlling for potential confounding factors. The area under the receiver-operating characteristic curve (AUC) was used to evaluate the predictive performance of resting HR and DM.

RESULTS

A tendency toward increased CAN prevalence with increasing resting HR was reported (P for trend <0.001). MLR analysis showed that DM and resting HR were very significantly and independently associated with CAN (P < 0.001 for both). Resting HR alone or combined with DM (DM-HR) both strongly predicted CAN (AUC = 0.719, 95% CI 0.690-0.748 for resting HR and AUC = 0.738, 95% CI 0.710-0.766 for DM-HR).

CONCLUSION

Our findings signify that resting HR and DM-HR have a high value in predicting CAN in the general population.

The association and predictive value analysis of metabolic syndrome combined with resting heart rate on cardiovascular autonomic neuropathy in the general Chinese population

BACKGROUND

The purpose of this study was to explore the extent of associations of cardiovascular autonomic neuropathy (CAN) with metabolic syndrome (MetS) and resting heart reate (HR), and to evaluate the predictive value of MetS combined with HR on CAN in a large sample derived from a Chinese population.

MATERIALS AND METHODS

We conducted a large-scale, population-based, cross-sectional study to explore the relationships of CAN with MetS and resting HR. This study included 2092 participants aged 30-80 years, and a total of 387 subjects were diagnosed with CAN in our dataset. The associations of CAN with MetS and resting HR were assessed by a multivariate logistic regression (MLR) analysis (using subjects without CAN as a reference group) after controlling for potential confounding factors. The predictive performance of resting HR and MetS was evaluated using the area under the receiver-operating characteristic curve (AUC).

RESULTS

A tendency toward increased CAN prevalence with increasing resting HR was reported (p for trend < 0.001). MLR analysis showed that MetS and resting HR were very significantly and independently associated with CAN (β = 0.495 for MetS and β = 0.952 for HR, P < 0.001 for both). Resting HR alone and combined with MetS (MetS-HR) strongly predicted CAN (AUC = 0.719, P < 0.001 for resting HR and AUC = 0.735, P < 0.001 for MetS-HR).

CONCLUSION

Our findings signify that MetS and resting HR were very significantly and independently associated with CAN in the general Chinese population. Resting HR and MetS-HR both have a high value in predicting CAN in the general population.