Cardiac Autonomic Neuropathy and Risk of Incident Heart Failure Among Adults with Type 2 Diabetes

Cardiac autonomic neuropathy modified the association between obesity and hypoglycemia in type 2 diabetes

BACKGROUND

Previous studies have shown that increasing body mass index (BMI) was associated with decreased hypoglycemia in type 2 diabetes, but it remains uncertain whether this finding could be applied to patients with and without cardiac autonomic neuropathy (CAN).

METHODS

The study included 7789 participants with type 2 diabetes from action to control cardiovascular risk in diabetes (ACCORD) trail. CAN was defined as SDNN < 8.2 ms and RMSSD < 8.0 ms. Obesity was defined as BMI ≥ 30 kg/m2. Outcomes were identified as severe hypoglycemia requiring any assistance (HAA) or requiring medical assistance (HMA). We assessed the association between obesity and severe hypoglycemia in type 2 diabetes with or without CAN using COX regression models adjusted for baseline characteristics.

RESULTS

Over a median follow-up of 4.7 years, a total of 893 participants developed HAA and 584 participants developed HMA. Compared with non-obesity, obesity was associated with lower risk of severe hypoglycemia (HAA: hazard ratio [HR] 0.51, 95% confidence interval [CI] 0.38-0.68, P < 0.001; HMA: HR 0.57, 95% CI 0.40-0.82, P = 0.002) in CAN present group, but not in CAN absent group (HAA: HR 0.98, 95% CI 0.83-1.16, P = 0.830; HMA: HR 0.97, 95% CI 0.79-1.19, P = 0.754). Similarly, increasing BMI was associated with reduced severe hypoglycemic events in participants with CAN, but not in participants without CAN.

CONCLUSIONS

CAN modifies the association between obesity and hypoglycemia in type 2 diabetes. Type 2 diabetic individuals with CAN who are under weight control should pay attention to hypoglycemic events.

TRIAL REGISTRY

http://www.

CLINICALTRIALS

gov . Unique identifier: NCT00000620.

Relationship between ultra-short heart rate variability and short-term mortality in hospitalized COVID-19 patients

OBJECTIVE

To assess the association between ultra-short heart rate variability (US-HRV) and short-term mortality in patients with COVID-19 and develop prognostic prediction models to identify high-risk patients as early as possible.

METHODS

A retrospective cohort study was performed on 488 patients diagnosed with COVID-19 and hospitalized in the First Affiliated Hospital of Fujian Medical University from December 2022 to January 2023. 10-s electrocardiogram (ECG) data were available for these patients. The US-HRV parameters including standard deviation of all normal-to-normal R-R intervals (SDNN) and root mean square of successive differences between normal-to-normal R-R intervals (rMSSD) were calculated using Nalong ECG software. The endpoint was short-term mortality, including in-hospital mortality or mortality within 1 week after discharge.

RESULTS

Of the 488 patients, 76 (15.6%) died. The SDNN and rMSSD in the death group were significantly lower than those in the survival group (P < 0.001). The area under the receiver operating characteristic (ROC) curve (AUC) for SDNN and rMSSD to predict mortality was 0.761 and 0.715, respectively. The combined use of SDNN and rMSSD had an AUC of 0.774. The mortality rate in the group with SDNN ≤7.5 ms was higher than that of SDNN >7.5 ms group (P < 0.05). With the decrease of SDNN, the mortality of patients showed an upward trend, and the mortality of patients with SDNN ≤2 ms was the highest (66.7%). Multivariate logistic regression analysis identified SDNN as an independent predictor of prognosis (odds ratio (OR) = 5.791, 95% confidential interval (CI) 1.615-20.765, P = 0.007). The AUC of Model 1 (simple model) was 0.866 (95% CI 0.826-0.905). The AUC of Model 2 (comprehensive model) was 0.914 (95% CI 0.881-0.947).

CONCLUSION

SDNN was associated with short-term mortality and provided the additional discriminatory power of the risk stratification model for hospitalized COVID-19 patients.

Prevalence and prognostic significance of cardiac autonomic neuropathy in community-based people with type 2 diabetes: the Fremantle Diabetes Study Phase II

BACKGROUND

There is a paucity of contemporary data on the prevalence and prognostic significance of cardiac autonomic neuropathy (CAN) from community-based cohorts with type 2 diabetes assessed using gold standard methods. The aim of this study was to assess these aspects of CAN in the longitudinal observational Fremantle Diabetes Study Phase II (FDS2).

METHODS

FDS2 participants were screened at baseline using standardised cardiovascular reflex tests (CARTs) of heart rate variation during deep breathing, Valsalva manoeuvre and standing. CAN (no/possible/definite) was assessed from the number of abnormal CARTs. Multinomial regression identified independent associates of CAN status. Cox proportional hazards modelling determined independent baseline predictors of incident heart failure (HF) and ischaemic heart disease (IHD), and all-cause mortality.

RESULTS

Of 1254 participants assessed for CAN, 86 (6.9%) were outside CART age reference ranges and valid CART data were unavailable for 338 (27.0%). Of the remaining 830 (mean age 62.3 years, 55.3% males, median diabetes duration 7.3 years), 51.0%, 33.7% and 15.3% had no, possible or definite CAN, respectively. Independent associates of definite CAN (longer diabetes duration, higher body mass index and resting pulse rate, antidepressant and antihypertensive therapies, albuminuria, distal sensory polyneuropathy, prior HF) were consistent with those reported previously. In Kaplan-Meier analysis, definite CAN was associated with a lower likelihood of incident IHD and HF versus no/possible CAN (P < 0.001) and there was a graded increase in all-cause mortality risk from no CAN to possible and definite CAN (P < 0.001). When CAN category was added to the most parsimonious models, it was not a significant independent predictor of IHD (P ≥ 0.851) or HF (P ≥ 0.342). Possible CAN (hazard ratio (95% CI) 1.47 (1.01, 2.14), P = 0.046) and definite CAN (2.42 (1.60, 3.67), P < 0.001) increased the risk of all-cause mortality versus no CAN.

CONCLUSIONS

Routine screening for CAN in type 2 diabetes has limited clinical but some prognostic value.

The handgrip test - A historical test for diabetic autonomic neuropathy or a marker of something else?

Cardiovascular autonomic neuropathy (CAN) is a frequent complication of diabetes mellitus and is associated with increased morbidity and mortality in patients with diabetes. Hence, early and correct diagnosis of CAN is crucial. Standard cardiovascular reflex rests (CARTs) have been the gold standard of CAN assessment. Originally, CARTs consisted of five reflex tests, but measuring diastolic blood pressure response to sustained handgrip exercise has no longer been suggested as an established clinical test. Increasing body of evidence suggests that isometric handgrip test should no longer be used for the evaluation of sympathetic dysfunction during cardiovascular autonomic neuropathy assessment in diabetic patients. The associations of isometric handgrip test results with parameters of hypertension and markers of hypertension-related target-organ damage in diabetic and non-diabetic individuals point toward its potential role as a screening tool to identify patients with high cardiovascular risk. The current review summarizes historical view of standard cardiovascular reflex tests and latest data on isometric handgrip test.

Interplay of heart rate variability and resting heart rate on mortality in type 2 diabetes

AIMS

Heart rate variability (HRV) and resting heart rate (RHR) are usually analyzed and interpreted separately. We aimed to assess the interplay of HRV and RHR on mortality in type 2 diabetes.

METHODS

The study included 7,529 participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. HRV metrics included standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). Abnormal values were defined based on <25th percentile for HRV and >75th percentile for RHR. Interactions of HRV status and RHR status were tested on multiplicative and additive scales. Results were validated in a subset of patients with type 2 diabetes (n = 745) from the Multi-Ethnic Study of Atherosclerosis.

RESULTS

Low SDNN was associated with increased all-cause mortality in the high RHR group (HR 1.60; 95% CI 1.29-1.97), but not in the normal RHR group. Compared with those who had neither low SDNN nor high RHR, the presence of either low SDNN or high RHR was not significantly associated with an increased risk of all-cause mortality. In contrast, the combination of low SDNN and high RHR was associated with a significantly increased risk of all-cause mortality (HR 1.68; 95% CI 1.43-1.97). Significant multiplicative and additive interactions were found between HRV status and RHR status on risk of all-cause mortality (all Pinteraction < 0.05). Similar findings were observed for cardiovascular mortality, in analyses using rMSSD, and in the Multi-Ethnic Study of Atherosclerosis.

CONCLUSIONS

The association between HRV and mortality risk is modified by RHR levels. Furthermore, low HRV and high RHR have interdependent and synergistic associations with mortality risk.

Associations of polyneuropathy with risk of all-cause and cardiovascular mortality, cardiovascular disease events stratified by diabetes status

AIMS/INTRODUCTION

We investigated the association of polyneuropathy (PN) with all-cause and cardiovascular (CV) mortality and with cardiovascular disease (CVD) events stratified by diabetes status.

MATERIALS AND METHODS

This prospective cohort study used the UK Biobank. Polyneuropathy was defined based on nurse-led interviews or ICD codes for polyneuropathy. Cox proportional hazards models were used to investigate the association of polyneuropathy with clinical outcomes.

RESULTS

A total of 459,127 participants were included in the analysis. Polyneuropathy was significantly associated with all-cause and cardiovascular mortality, and with CVD events even after adjusting for CVD risk factors across all diabetes statuses. Metabolic parameters HbA1c , waist circumference, BMI and the inflammatory parameter C-reactive protein showed significant mediation effects for the association between polyneuropathy and CVD. Adherence to a favorable lifestyle was associated with a lower risk of all-cause and cardiovascular mortality regardless of polyneuropathy status.

CONCLUSIONS

Polyneuropathy was associated with all-cause and cardiovascular mortality, and with CVD events in subjects with diabetes or prediabetes, even those having normal glucose tolerance. This study suggests the importance of polyneuropathy as a risk factor for death and highlights the necessity of early diagnosis and lifestyle intervention for those with type 2 diabetes and polyneuropathy.

Cardiac Autonomic Dysfunction and Risk of Silent Myocardial Infarction Among Adults With Type 2 Diabetes

Background There is a paucity of large-scale epidemiological studies on the link between cardiac autonomic neuropathy (CAN) and the risk of silent myocardial infarction (SMI) in type 2 diabetes. We evaluated the association between CAN and the risk of SMI in a large sample of adults with type 2 diabetes. Methods and Results Participants with type 2 diabetes from the ACCORD (Action to Control Cardiovascular Risk in Diabetes) study without atherosclerotic cardiovascular disease at baseline were included. CAN was ascertained using heart rate variability indices calculated from 10-s resting electrocardiograms. The heart rate variability indices included standard deviation of all normal-to-normal R-R intervals and root mean square of successive differences between normal-to-normal R-R intervals. CAN was defined as both the standard deviation of all normal-to-normal R-R intervals and root mean square of successive differences between normal-to-normal R-R intervals less than the fifth percentile of the general population. We used Cox proportional hazards regression to generate hazard ratios (HRs) for incident SMI in relation to CAN measures. Among 4842 participants (mean age, 62.5 years; 46.6% women; 60.2% White), there were 73 incident SMI cases over a median follow-up of 4.9 years (incidence rate 3.1 out of 1000 person-years [95% CI, 2.5-3.9]). After adjusting for confounders, low heart rate variability was associated with a higher risk of SMI (HR, 1.67 [95% CI, 1.02-2.72] and HR, 1.56 [95% CI, 0.94-2.58] for low standard deviation of all normal-to-normal R-R intervals and root mean square of successive differences between normal-to-normal R-R intervals, respectively). Participants with CAN had a 1.9-fold greater risk of SMI (HR, 1.91 [95% CI, 1.14-3.20]). Conclusions In a large cohort of adults with type 2 diabetes, CAN was significantly associated with an increased risk of incident SMI.

The Effect of Exercise on Cardiovascular Autonomic Nervous Function in Patients with Diabetes: A Systematic Review

BACKGROUND

Diabetic neuropathy, including autonomic neuropathy, is a severe complication in patients with poorly controlled diabetes. Specifically, cardiovascular autonomic neuropathy (CAN) plays a significant prognostic role in cardiovascular morbidity and mortality. Exercise, an essential component of diabetes treatment, may have a therapeutic effect on patients with diabetes complicated by CAN. However, it remains unclear whether exercise has a therapeutic or protective effect in diabetes patients with CAN.

METHODS

The author conducted a systematic search of PubMed/MEDLINE, Embase, and The Cochrane Library, resulting in the identification of eight eligible randomized controlled trials for this review.

RESULTS

Exercise, including aerobic exercise combined with resistance training (RT), high-intensity interval training, and progressive RT, has shown a beneficial effect on cardiac autonomic function (CAF) in patients with type 2 diabetes, as measured by heart rate variability, heart rate recovery, and baroreflex sensitivity. However, most studies had low quality. Moreover, there were no relevant studies examining the effect of exercise on CAF in older patients, patients with poorly controlled diabetes, and patients with type 1 diabetes.

CONCLUSIONS

Exercise has the potential to manage patients with CAN by balancing sympathetic and parasympathetic nervous system functions; however, further studies are warranted in the future.

Morbidity and mortality of patients with diabetic neuropathy treated with pathogenetically oriented alpha-lipoic acid versus symptomatic pharmacotherapies - a nationwide database analysis from Hungary

AIMS

Diabetic neuropathy is associated with increased risk of morbidity and all-cause mortality. It is unclear whether these outcomes differ in patients with diabetic neuropathy treated with pathogenetically oriented vs symptomatic pharmacotherapies.

METHODS

We performed a retrospective (2009-2019) database analysis of patients treated with pathogenetically oriented alpha-lipoic acid (ALA) or symptomatic pharmacotherapies for diabetic neuropathy. We investigated clinical outcomes in propensity score matched patients in Hungary. Changes in hazard ratios and annualized event rates were assessed and sensitivity analyses performed.

RESULTS

Hazard ratios favored treatment with ALA vs symptomatic pharmacotherapies regarding acute myocardial infarction (HR 0.73, 95%CI: 0.60-0.89, p = 0.0016), stroke (HR 0.71, 95%CI: 0.62-0.82, p<0.0001), hospitalization for heart failure (HR 0.72, 95%CI: 0.66-0.78, p<0.0001), cancer events (HR 0.83, 95% CI: 0.76-0.92, p = 0.0002) and all-cause mortality (HR 0.55, 95% CI: 0.49-0.61, p<0.0001), but not for lower limb amputation (HR 1.05, 95%CI: 0.89-1.25, p = 0.5455). This association was supported by results of evaluating annual event rates and sensitivity analyses.

CONCLUSIONS

This retrospective database analysis revealed a lower occurrence of cardio- and cerebrovascular morbidity, cancer events and all-cause mortality in patients with diabetic neuropathy treated with pathogenetically oriented ALA vs symptomatic pharmacotherapies. This hypothesis-generating result requires further investigations.

Relationship between Heart Rate Variability and Postoperative Cognitive Dysfunction in Elderly Patients

Objectives: Postoperative cognitive dysfunction (POCD) is objectively measurable after anesthesia and surgery. Lower heart rate variability (HRV) is associated with poorer cognitive performance, but the relationship between HRV and POCD remains unclear. Methods: Elderly patients who underwent total hip replacement under general anesthesia from the Department of Bone and Joint Surgery, Affiliated Hospital of Southwest Medical University were enrolled. Neuropsychological tests, standard deviation of the interbeat interval (SDNN, a parameter of HRV), and plasma concentrations of glial cell line-derived neurotrophic factors (GDNF) were performed one day before (T_-1) and 7 days after (T₇) surgery. Results: POCD occurred in 35% of patients on 7 days after surgery. Lower SDNN(T₇) (OR=.91) and longer surgery time (OR=1.33) were associated with POCD. Compared with patients without POCD, there was higher variation SDNN (Δ SDNN) and plasma GDNF (ΔGDNF) in those with POCD from T_-1 to T₇ period. ΔGDNF is positively correlated with ΔSDNN (r = .61, p<.001). Conclusions: Lower SDNN (T₇) was associated with POCD and might be used as a warning indicator for the risk of POCD.

Diabetes Mellitus and Heart Failure: Epidemiology, Pathophysiologic Mechanisms, and the Role of SGLT2 Inhibitors

Diabetes mellitus (DM) and heart failure (HF) are frequently encountered afflictions that are linked by a common pathophysiologic background. According to landmark studies, those conditions frequently coexist, and this interaction represents a poor prognostic indicator. Based on mechanistic studies, HF can be propagated by multiple pathophysiologic pathways, such as inflammation, oxidative stress, endothelial dysfunction, fibrosis, cardiac autonomic neuropathy, and alterations in substrate utilization. In this regard, DM may augment myocardial inflammation, fibrosis, autonomic dysfunction, and lipotoxicity. As the interaction between DM and HF appears critical, the new cornerstone in DM and HF treatment, sodium-glucose cotransporter-2 inhibitors (SGLT2i), may be able to revert the pathophysiology of those conditions and lead to beneficial HF outcomes. In this review, we aim to highlight the deleterious pathophysiologic interaction between DM and HF, as well as demonstrate the beneficial role of SGLT2i in this field.

Detecting and treating the protean manifestations of diabetic autonomic neuropathy

The manifestations of diabetic autonomic neuropathy (DAN) are protean and clinically involve multiple systems, including the cardiovascular system, the gastrointestinal system, the genitourinary system as well as the sweat glands (sudomotor dysfunction) and the gallbladder. In addition, cardiac autonomic neuropathy (CAN) is associated with a correctible inability to appreciate and correct hypoglycaemia. While not a clinical problem, pupillary involvement should be the clue and the catalyst to investigate for other manifestations of DAN. This review outlines a practical approach to detecting and investigating the manifestations of DAN. Of particular importance is early detection of cardiovascular involvement where prompt therapy through glycaemic control can decrease the severity of CAN and decelerate the frequency and severity of retinopathy and nephropathy in addition to decreasing cardiovascular events and mortality. CAN also plays a role in accelerating other diabetic complications such as acute ischaemic stroke, heart failure, medial artery calcinosis, foot ulcers, peripheral artery disease and Charcot joints. Many therapies of DAN are available, which should not only decrease morbidity and mortality from DAN, but also improve the patient's quality of life. However, the therapies available are largely symptomatic.

Effect of SGLT-2 inhibitors on cardiac autonomic function in type 2 diabetes mellitus: a meta-analysis of randomized controlled trials

BACKGROUND

Cardiac autonomic neuropathy (CAN) is a common complication of type 2 diabetes mellitus (T2DM). We sought to determine whether sodium-glucose co-transporter-2 (SGLT-2) inhibitors affect indices of CAN in patients with T2DM.

METHODS

We searched for parallel group or cross-over randomized controlled trials (RCTs) enrolling adult subjects with T2DM, assigned to a SGLT-2 inhibitor versus placebo or active comparator and addressing their effect on CAN. PubMed, Cochrane Library and gray literature sources were searched. We set as primary efficacy outcome the change in the low-frequency-to-high-frequency (LF/HF) ratio. We set as secondary efficacy outcomes: first, the change in the standard deviation of all 5 min mean normal RR intervals and second, the change in the square root of the mean of the sum of the squares of differences between adjacent RR intervals (r-MSSD). Protocol has not been registered at a publicly available repository.

RESULTS

We pooled data from four RCTs in a total of 247 subjects with T2DM. SGLT-2 inhibitor treatment did not have a significant effect on LF/HF ratio (MD = - 0.11, 95% CI - 0.35 to 0.12, I² = 0%, p = 0.36). SGLT-2 inhibitor treatment did not have a significant impact either on SDNN (MD = - 2.83, 95% CI - 7.41 to 1.75, I² = 31%, p = 0.23), or on r-MSSD (MD = - 0.14, 95% CI - 3.52 to 3.25, I² = 46%, p = 0.94). Overall risk of bias was graded as low across the selected RCTs.

CONCLUSION

SGLT-2 inhibitor treatment in patients with T2DM does not seem to provide any significant beneficial effect on CAN indices.

Association of heart rate variability with progression of retinopathy among adults with type 2 diabetes

AIM

We evaluated the associations of heart rate variability (HRV) with incident vision-threatening retinopathy and retinopathy progression among adults with type 2 diabetes.

METHODS

Participants recruited to the ACCORD (Action to Control Cardiovascular Risk in Diabetes) study with HRV measures at baseline were analysed. HRV measures included standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). Low SDNN was defined as SDNN <8.2 ms; low rMSSD as rMSSD <8.0 ms. We used multivariable adjusted Cox proportional hazards and modified Poisson regression models to generate risk estimates for incident vision-threatening retinopathy and retinopathy progression, respectively.

RESULTS

A total of 5810 participants without incident vision-threatening retinopathy at baseline (mean age 62 years, 40.5% women, 63.5% White) were included. Over a median of 4.7 years, 280 incident vision-threatening retinopathy cases requiring treatment occurred. Low HRV (vs. normal HRV) was associated with higher risk of incident vision-threatening retinopathy (adjusted hazard ratio 1.32 [95%CI 1.03-1.71] and 1.14 [95%CI 1.01-1.28] for low SDNN and rMSSD, respectively). In the subset of 2184 participants with complete eye examinations at baseline and 4 years, 191 experienced retinopathy progression, and low HRV (vs. normal HRV) was associated with a higher risk of retinopathy progression (adjusted relative risks 1.36 [95%CI 1.01-1.83] and 1.36 [95%CI 1.01-1.84] for low SDNN and rMSSD, respectively).

CONCLUSIONS

Cardiac autonomic neuropathy, as assessed by low HRV, was independently associated with increased risks of incident vision-threatening retinopathy and overall retinopathy progression in a large cohort of adults with type 2 diabetes.