Severity and multiplicity of microvascular complications are associated with QT interval prolongation in patients with type 2 diabetes

Advances in diagnostic methods for early-stage diabetic polyneuropathy

Significant advancements have been made in diagnostic methods for early-stage diabetic polyneuropathy. Early and accurate diagnosis of diabetic polyneuropathy is crucial for preventing further complications and enabling timely intervention. Furthermore, there is a need for an objective numerical value to evaluate the early stage of diabetic polyneuropathy.

The association between variability of risk factors and complications in type 2 diabetes mellitus: a retrospective study

The variability in diabetes risk factors, such as uric acid and lipids, may influence the development of complications. This study aimed to investigate the influence of such variability on the occurrence of diabetic complications. A retrospective analysis of electronic medical records was conducted with type 2 diabetic patients who received treatment at a tertiary care hospital in Chengdu, Sichuan Province, between 2013 and 2022. The risk factor variability is presented as the standard deviation (SD). The associations between the variability and complications were examined using a binary logistic regression model. The study included 369 patients with type 2 diabetes. The findings revealed that outpatient special disease management served as a protective factor against the development of complications [OR = 0.53, 95% confidence interval (CI) (0.29-0.10)], particularly for the prevention of diabetic peripheral neuropathy [OR = 0.51, 95% CI (0.30-0.86)]. Variability in total cholesterol (TC-SD) was found to be a risk factor for the development of complications [OR = 2.42, 95% CI (1.18-4.97)] and acted as a risk factor for diabetic peripheral vasculopathy [OR = 2.50, 95% CI (1.25-5.02)]. TC-SD is a risk factor for the occurrence of diabetic peripheral neuropathy and diabetic peripheral vasculopathy, whereas outpatient special disease management functions as a protective factor against complications and diabetic peripheral neuropathy. Thus, in addition to glycaemic control, the regulation of lipid levels should be emphasized, particularly among patients without outpatient special disease management, to delay the onset of complications.

The optimal QTc selection in patients of acute myocardial infarction with poor perioperative prognosis

BACKGROUND

The predictive utility of QTc values, calculated through various correction formulas for the incidence of postoperative major adverse cardiovascular and cerebrovascular events (MACCE) in patients experiencing acute myocardial infarction (AMI), warrants further exploration. This study endeavors to ascertain the predictive accuracy of disparate QTc values for MACCE occurrences in patients with perioperative AMI.

METHODS

A retrospective cohort of three hundred fourteen AMI patients, comprising 81 instances of in-hospital MACCE and 233 controls, was assembled, with comprehensive collection of baseline demographic and clinical data. QTc values were derived employing the correction formulas of Bazett, Fridericia, Hodges, Ashman, Framingham, Schlamowitz, Dmitrienko, Rautaharju, and Sarma. Analytical methods encompassed comparative statistics, Spearman correlation analysis, binary logistic regression models, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA).

RESULTS

QTc values were significantly elevated in the MACCE cohort compared to controls (P < 0.05). Spearman's correlation analysis between heart rate and QTc revealed a modest positive correlation for the Sarma formula (QTcBaz) (ρ = 0.46, P < 0.001). Within the multifactorial binary logistic regression, each QTc variant emerged as an independent risk factor for MACCE, with the Sarma formula-derived QTc (QTcSar) presenting the highest hazard ratio (OR = 1.025). ROC curve analysis identified QTcSar with a threshold of 446 ms as yielding the superior predictive capacity (AUC = 0.734), demonstrating a sensitivity of 60.5% and a specificity of 82.8%. DCA indicated positive net benefits for QTcSar at high-risk thresholds ranging from 0 to 0.66 and 0.71-0.96, with QTcBaz, prevalent in clinical settings, showing positive net benefits at thresholds extending to 0-0.99.

CONCLUSION

For perioperative AMI patients, QTcSar proves more advantageous in monitoring QTc intervals compared to alternative QT correction formulas, offering enhanced predictive prowess for subsequent MACCE incidents.

Association between Severity of Diabetic Retinopathy and Cardiac Function in Patients with Type 2 Diabetes

Background

The purpose of this research was to assess the relationship between the severity of diabetic retinopathy (DR) and indexes of left ventricle (LV) structure and function in type 2 diabetes mellitus (T2DM).

Methods

Retrospective analysis of 790 patients with T2DM and preserved LV ejection fraction. Retinopathy stages were classified as no DR, early nonproliferative DR, moderate to severe nonproliferative DR, or proliferative DR. The electrocardiogram was used to assess myocardial conduction function. Echocardiography was used to evaluate myocardial structure and function.

Results

Patients were divided into three groups based on the DR status: no DR group (NDR, n = 475), nonproliferative DR group (NPDR, n = 247), and proliferative DR group (PDR, n = 68). LV interventricular septal thickness (IVST) increased significantly with more severe retinopathy (NDR: 10.00 ± 1.09; NPDR: 10.42 ± 1.21; and PDR: 10.66 ± 1.58; P < 0.001). Multivariate logistic regression analysis showed that the significant correlation of IVST persisted between subjects with no retinopathy and proliferative DR (odds ratio = 1.35, P = 0.026). Indices of myocardial conduction function were assessed by electrocardiogram differences among groups of retinopathy (all P < 0.001). In multiple-adjusted linear regression analyses, the increasing degree of retinopathy was closely correlated with heart rate (β = 1.593, P = 0.027), PR interval (β = 4.666, P = 0.001), and QTc interval (β = 8.807, P = 0.005).

Conclusion

The proliferative DR was independently associated with worse cardiac structure and function by echocardiography. Furthermore, the severity of retinopathy significantly correlated with abnormalities of the electrocardiogram in patients with T2DM.

A Cross-Sectional Study to Determine the Association of Corrected QT Interval With Microalbuminuria in Type 2 Diabetes Mellitus

Introduction Cardiac autonomic neuropathy (CAN) is a frequent and life-threatening complication of type 2 diabetes. Failure to diagnose can lead to high mortality and morbidity. In patients who have diabetes mellitus, microalbuminuria is an independent marker for cardiovascular disease. This study aimed to assess the corrected QT interval with microalbuminuria in type 2 diabetes mellitus. The objective of this study was to estimate the corrected QT interval in subjects with type 2 diabetes mellitus and to determine the association of the corrected QT interval with microalbuminuria type 2 diabetes mellitus. Methodology Ninety-five adult patients (>18 years to 65 years) diagnosed with type 2 diabetes mellitus with microalbuminuria were included in this study. Data were collected on the proforma through history taking and a general physical and systemic examination. An electrocardiograph was taken on the day of admission; the most prolonged QT interval was measured, and the RR interval was calculated. The data were statistically analyzed using IBM SPSS Statistics for Windows, Version 24 (Released 2016; IBM Corp., Armonk, New York, United States). Results There was a significant difference in the corrected QT interval prolongation prevalence between diabetic patients with microalbuminuria and without microalbuminuria (P-value <0.001). The mean corrected QT interval distribution did not differ significantly across various age groups of cases studied with microalbuminuria (P-value 0.98). The distribution of mean corrected QT interval did not differ significantly between the group of male cases and group of female cases studied with microalbuminuria (P-value 0.66). The mean corrected QT interval distribution did not differ significantly across various duration of diabetes groups among the cases studied with microalbuminuria (P-value 0.60). The mean corrected QT interval distribution did not differ significantly across different types of anti-diabetic treatment groups among the cases studied with microalbuminuria (P-value 0.64). Conclusion Type 2 diabetes has been prevalent in Indian and Asian populations. The early management of type 2 diabetes is necessary since the early stages of the disease can reduce the risk of CAN. Therefore, these patients should be diagnosed as early as possible and treated to reduce associated mortality and risk and to improve quality of care.

Prevalence of QT prolongation and its risk factors in patients with type 2 diabetes

BACKGROUND

QT prolongation increases cardiovascular mortality in diabetes. The risk factors for QT prolongation vary across different studies. There is no data on the QT prolongation in patients with diabetes from the Arab region, where diabetes is highly prevalent. Here we aimed to assess the prevalence of QT prolongation and its associated risk factors in patients with type 2 diabetes from Saudi Arabia.

METHOD

This was a retrospective, cross-sectional, hospital-based file review study. Data were collected from the medical records of patients with type 2 diabetes aged above 14 years and underwent ECG examination, and laboratory investigations were done within one month of ECG.

RESULTS

The study included 782 patients with a prevalence of QTc prolongation of 13%. Patients with prolonged QTc interval were characterized by older age, higher BMI, longer diabetes duration, lower total cholesterol and LDL-C, and more diabetic nephropathy, hypertension, and CVD cases. They were also more in insulin treatment, antihypertensive medications, loop diuretics, and potassium-sparring diuretics. Logistic regression analysis revealed the odds of prolonged QTc interval increased significantly with CVD (OR = 1.761, 95% CI:1.021-3.036, p = 0.042), and usage of loop diuretics (OR = 2.245, 95% CI:1.023-4.923, p = 0.044) after adjusting for age, gender, and duration of diabetes.

CONCLUSION

The risk factors associated with QTc prolongation in patients with type 2 diabetes are CVD, and loop diuretics. Age, BMI, and diabetes duration were more in people with QTc prolongation, whereas total cholesterol and LDL-C levels were lower. More patients had diabetic nephropathy, hypertension, and CVD with prolonged QTc.

The Association Between Microalbuminuria and QTc Prolongation in Patients With Type 2 Diabetes Mellitus: A Single-Centre Study From South India

BACKGROUND

One of the most significant complications of type 2 diabetes mellitus (T2DM) is diabetic nephropathy, the leading cause of end-stage renal disease. Another important clinical marker in patients with type 2 diabetes is QTc interval prolongation. We aimed to study the association between QTc interval prolongation and microalbuminuria in patients with T2DM.

OBJECTIVE

The primary objective of this study was to examine the association between QTc interval prolongation and microalbuminuria in patients with T2DM. The secondary objective was to correlate the prolongation of the QTc interval with the duration of T2DM.

MATERIALS AND METHODS

This study was conducted as a single-centre, prospective, observational study in a tertiary-care centre in South India, Amrita Institute of Medical Sciences and Research Center. The study was conducted over two years, between April 2020 and April 2022. Patients aged more than 18 with T2DM with and without microalbuminuria were recruited into the study and control groups, and various parameters, including QTC intervals, were recorded.

RESULTS

A total of 120 patients were enrolled in the study, with 60 patients with microalbuminuria forming the study group and 60 patients without microalbuminuria forming the control group. There was a statistically significant association between microalbuminuria with a prolonged QTc interval, hypertension, a longer duration of T2DM, higher haemoglobin AIc (HbA1c) levels, and higher serum creatinine values.

The Role of Inflammation and Therapeutic Concepts in Diabetic Retinopathy-A Short Review

Diabetic retinopathy (DR) as a microangiopathy is the most common complication in patients with diabetes mellitus (DM) and remains the leading cause of blindness among adult population. DM in its complicated pathomechanism relates to chronic hyperglycemia, hypoinsulinemia, dyslipidemia and hypertension-all these components in molecular pathways maintain oxidative stress, formation of advanced glycation end-products, microvascular changes, inflammation, and retinal neurodegeneration as one of the key players in diabetes-associated retinal perturbations. In this current review, we discuss the natural history of DR with special emphasis on ongoing inflammation and the key role of vascular endothelial growth factor (VEGF). Additionally, we provide an overview of the principles of diabetic retinopathy treatments, i.e., in laser therapy, anti-VEGF and steroid options.

Relationship Between Index of Cardiac Electrophysiological Balance, Frontal QRS-T Angle and Retinopathy in People with Type 2 Diabetes

BACKGROUND

Diabetic retinopathy (DR) is strongly associated with cardiovascular disease, which is a risk factor for sudden cardiac death (SCD). The index of cardiac electrophysiological balance (iCEB) and the frontal QRS-T angle are recommended to predict the risk of ventricular arrhythmias more than other ECG parameters. However, the relationships between these two markers and DR have not yet been explored. The aim of this study was to investigate the variation in the iCEB, corrected iCEB (iCEBc) and frontal QRS-T angle in different stages of DR and determine whether there are associations between these markers and DR.

METHODS

The sample comprised 665 patients with Type 2 diabetes mellitus (T2DM) who were classified into three groups: no DR (NDR), mild to moderate non-proliferative DR (NPDR), and vision-threatening DR (VTDR). Twelve-lead ECG was performed and the QT, QTc, QRS duration, iCEB, iCEBc and frontal QRS-T angle were recorded and compared across the groups.

RESULTS

The VTDR group had a significantly higher iCEBc and frontal QRS-T angle than the NDR and NPDR groups. After controlling for confounding variables, the correlations between the iCEBc (OR=2.217, 95% CI=1.464-3.358, P<0.001), frontal QRS-T angle (OR=1.017, 95% CI=1.008-1.025, P<0.001) and DR risk remained (P<0.05). Subjects in the fourth iCEBc quartile (adjusted OR=2.612, 95% CI=1.411-4.834, p=0.002) had a much higher chance of developing DR compared to those in the first quartile. In comparison to the first frontal QRS-T angle quartile, subjects in the third (adjusted OR=1.998, 95% CI=1.167-3.422, P=0.012) and fourth (adjusted OR=2.430, 95% CI=1.420-4.160, P=0.001) frontal QRS-T angle quartiles had significantly greater risks of DR.

CONCLUSION

With the progression of DR, the iCEBc and frontal QRS-T angle increase. An increased iCEBc and frontal QRS-T angle are associated with an increased risk of DR.

Heart rate-corrected QT interval prolongation is associated with decreased heart rate variability in patients with type 2 diabetes

We investigated the association between the heart rate-corrected QT interval (QTc interval) measured by standard electrocardiography and heart rate variability (HRV) in patients with type 2 diabetes mellitus (T2DM). From March 1, 2009, to December 12, 2009, 411 patients with T2DM who underwent resting 12-lead electrocardiography and cardiovascular autonomic function testing concurrently without the exclusion criteria were consecutively recruited in this cross-sectional study. Time- and frequency-domain HRV variables were assessed for 5 minutes by beat-to-beat HRV recording. The QT interval was corrected for the heart rate using Bazett's formula. QTc interval measurements of >440 ms were considered abnormally prolonged. The mean age and diabetes duration were 56.3 ± 10.6 years and 9.6 ± 7.3 years, respectively. A total of 90 patients had QTc interval prolongation (21.9%). The participants with a prolonged QTc interval were older (59.4 ± 10.1 years vs 55.5 ± 10.6 years, P = .002), were more likely to be a woman (72.2% vs 51.7%, P = .001), had a higher prevalence of hypertension (46.7% vs 33.4%, P = .022), had a higher hemoglobin A1c level (8.8% ± 2.2% vs 8.2% ± 1.8%, P = .045), and had decreased values for the variables measuring HRV, except for the low frequency (LF)/high frequency (HF) ratio (total power [TP], 147.7 [74.1-335.9] ms vs 328.7 [185.7-721.7] ms, P = .002). After adjusting for multiple confounders, QTc interval prolongation was associated with the lowest quartile of the HRV parameters of TP (odds ratio [OR] = 3.99; 95% confidence interval [CI]: 2.29-6.96), HF (OR = 3.20; 95% CI: 1.84-5.58), LF (OR = 3.68; 95% CI: 2.10-6.43), standard deviation of the normal-to-normal interval (OR = 3.31; 95% CI: 1.89-5.77), and root-mean-square of the successive differences (OR = 1.98; 95% CI: 1.13-3.47) in patients with T2DM. Decreased values for the variables measuring HRV, except for the LF/HF ratio, might be associated with QTc interval prolongation in patients with T2DM.

Effects of high glucose and insulin on the electrophysiological properties of cardiomyocytes derived from human-induced pluripotent stem cells

OBJECTIVES

The risk of arrhythmia increases in diabetic patients. However, the effects of hyperglycemia and insulin therapy on the electrophysiological properties of human cardiomyocytes remain unclear. This study is to explore the effects of high glucose and insulin on the electrophysiological properties and arrhythmias of cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs).

METHODS

Immunofluorescent staining and flow cytometry were used to analyze the purity of hiPSC-CMs generated from human skin fibroblasts of a healthy donor. The hiPSC-CMs were divided into 3 group (treated with normal medium, high glucose and insulin for 4 days): a control group (NM group, containing 5 mmol/L glucose), a high glucose group (HG group, containing 15 mmol/L glucose), and a high glucose combined with insulin (HG+INS group, containing 15 mmol/L glucose+100 mg/L insulin). Electrophysiological changes of hiPSC-CMs were detected by microelectrode array (MEA) before or after treatment with glucose and insulin, including beating rate (BR), field potential duration (FPD) (similar to QT interval in ECG), FPDc (FPD corrected by BR), spike amplitude and conduction velocity (CV). Effects of sotalol on electrophysiological properties and arrhythmias of hiPSC-CMs were also evaluated.

RESULTS

The expression of cardiac-specific marker of cardiac troponin T was high in the hiPSC-CMs. The purity of hiPSC-CMs was 99.06%. Compared with the NM group, BR was increased by (9.14±0.8)% in the HG group (P<0.01). After treatment with high glucose, FPD was prolonged from (460.4±9.0) ms to (587.6±23.7) ms in the HG group, while it was prolonged from (462.5±14.5) ms to (512.6±17.6) ms in the NM group. Compared with the NM group, FPD of hiPSC-CMs was prolonged by (16.8±1.4)% in the HG group (P<0.01). The FPDc of hiPSC-CMs was prolonged from (389.1±13.7) ms to (478.3±31.5) ms in the HG group, and that was prolonged from (387.7±21.6) ms to (422.6±32.9) ms in the NM group. Compared with the NM group, the FPDc of hiPSC-CMs was prolonged by (13.9±1.3)% in HG group (P<0.01). The spike amplitude and CV remained unchanged between the HG group and the NM group (P>0.05). Ten µmol/L of sotalol can induce significant arrhythmias from all wells in the HG group. After treatment with insulin and high glucose, compared with the HG group, BR was increased by (8.3±0.5)% in the HG+INS group (P<0.05). The FPD was prolonged from (463.4±9.7) ms to (532.6±12.8) ms in the HG+INS group, while it was prolonged from (460.4±9.0) ms to (587.6±23.7) ms in the HG group. Compared with the HG group, the FPD of hiPSC-CMs was shortened by (12.7±1.9)% in the HG+INS group (P<0.01). The FPDc of hiPSC-CMs was prolonged from (387.4±4.1) ms to (422.4±10.0) ms in the HG+INS group, and that was prolonged from (384.8±4.0) ms to (476.3±11.5) ms in HG group. Compared with the HG group, the FPDc of hiPSC-CMs was shortened by (14.7±1.1)% in HG group (P<0.01). After the insulin treatment, the spike amplitude of hiPSC-CMs was increased from (3.12±0.46) mV to (4.35±0.64) mV in the HG+INS group, while it was enhanced from (3.06±0.35) mV to (3.33±0.41) mV in the HG group. The spike amplitude of hiPSC-CMs was increased by (30.8±3.7)% in the HG+INS group compared with that in the HG group (P<0.05). The CV in the HG+INS group was increased from (0.23±0.08) mm/ms to (0.32±0.08) mm/ms after insulin treatment, which was increased from (0.21±0.04) mm/ms to (0.30±0.07) mm/ms in the HG group, but there was no significant difference in CV between the HG+INS group and the HG group (P>0.05). The induction experiment showed that 10 μmol/L of sotalol could prolong the FPDc of hiPSC-CMs by (78.9±11.6)% in the HG+INS group, but no arrhythmia was induced in each well.

CONCLUSIONS

High glucose can induce FPD/FPDc of hiPSC-CMs prolongation and increase the risk of arrhythmia induced by drugs. Insulin can reduce the FPD/FPDc prolongation and the risk of induced arrhythmia by high glucose.These results are important to understand the electrophysiological changes of the myocardium in diabetic patients and the impact of insulin therapy on its electrophysiology. Further study on the mechanism may provide new ideas and methods for the treatment of acquired and even inherited long QT syndrome.

Heart rate-corrected QT interval: A novel diagnostic biomarker for diabetic peripheral neuropathy

AIMS/INTRODUCTION

To explore the relationship between heart rate-corrected QT (QTc) interval and diabetic peripheral neuropathy (DPN), and whether QTc interval has diagnostic utility for DPN beyond nerve conduction velocity.

MATERIALS AND METHODS

A total of 965 patients with diabetes, including 473 patients with DPN and 492 patients without DPN, underwent standard 12-lead electrocardiography and detailed assessments of peripheral neuropathy.

RESULTS

Patients with DPN had longer QTc intervals than those without. Among participants, from the first to fourth quartile of QTc interval, the proportion of patients with DPN appreciably increased and the nerve conduction velocity obviously decreased (P for trend <0.001). The univariate and multivariate analyses showed that prolonged QTc interval was closely associated with increased risk of DPN (univariable odds ratio 1.112, 95% confidence interval 1.097-1.127, P < 0.001; multivariable odds ratio 1.118, 95% confidence interval 1.099-1.137, P < 0.001). Receiver operating characteristic analysis for the diagnosis of DPN showed a greater area under the curve for QTc interval of 0.894 than the median nerve motor conduction velocity of 0.691, median nerve sensory conduction velocity of 0.664 and peroneal nerve motor conduction velocity of 0.692. The optimal cut-off point of QTc interval for DPN was 428.5 ms with sensitivity of 0.715 and specificity of 0.920 (P < 0.001). The combination of QTc interval and nerve conduction testing increased the area under the curve for the diagnosis of DPN (from 0.736 to 0.916; P < 0.001).

CONCLUSIONS

QTc interval with 428.5 ms has more reliable diagnostic utility for DPN than nerve conduction velocity, and prolonged QTc interval is closely associated with an increased risk of DPN.

The Risk of QTc Prolongation in Non-Diabetic and Diabetic Patients Taking Tyrosine Kinase Inhibitors (TKIs)- A Patient Safety Project at a Private Oncology Practice

Objective: To assess the prevalence of QTc prolongation in both non-diabetic and diabetic patients on TKIs. Some TKIs have been reported to cause QTc prolongation, which is prevalent in diabetes. However, there is no Risk Evaluation and Mitigation Strategy using series ECG to monitor those patients.

Methods: Patients taking TKIs, with two ECGs recorded between 1 January 2010 and 31 December 2017 were selected from the electronic database. The QTc duration >450 ms was determined as prolonged. Percentage of QTc prolongation on participants were compared using Chi-Square test.

Results: This study included 313 patients (age 66.1 ± 0.8 years and 57.5% are female) taking TKIs. In non-Diabetic patients, the prevalence of QTc prolongation is 19.1% (n = 253) before and 34.8% (n = 253) after treatment with TKIs (p < 0.001), respectively. In diabetic patients, the prevalence of QTc prolongation is 21.7% (n = 60) before and 40% (n = 60) after treatment with TKIs (p = 0.03), respectively. In addition, we examined the effect of modifying risk factors for cardiovascular disease (CVD) on the prevalence of QTc prolongation caused by TKIs. In non-diabetic patients, the prevalence of QTc prolongation is 33.3% (n = 57) before and 34.2% (n = 196) after risk factors modification (p = 0.91), respectively. In diabetic patients, the prevalence of QTc prolongation is 50% (n = 24) before and 33.3% (n = 36) after risk factors modification (p = 0.20), respectively.

Conclusion: Use of TKIs is associated with a significantly increased risk of QTc prolongation for patients, particularly when patients are diabetic. Modification of risk factors for CVD does not significantly affect the prevalence of QTc prolongation caused by TKIs.

Type 2 Diabetes and Causes of Sudden Cardiac Death: A Systematic Review

Type 2 diabetes mellitus has been on the rise in recent years. A major cause of death in the United States is myocardial infarction with underlying coronary artery disease. Impairment of tissue insulin sensitivity in type 2 diabetes is a significant factor for sudden cardiac death. The complex pathophysiology stems from coexisting cardiovascular disease and complications of impaired tissue sensitivity to insulin. Long-term diabetics with underlying kidney disease and those requiring dialysis have systemic inflammation that adds to an increased risk of death. During times of pathological stress, myocardial tissue will express substrates and growth factors that cause conduction disequilibrium and predispose to sudden cardiac death. Diabetes is a modifiable risk factor in the prevention of sudden cardiac arrest. Specific prevention measures aimed towards lifestyle modification and medications are important to prevent diabetes and decrease mortality of future cardiac death. In recent times, drugs that compete with glucose in the proximal convoluted tubule of the nephron have clinical significance in lowering the risk of sudden cardiac arrest.

Update in the epidemiology, risk factors, screening, and treatment of diabetic retinopathy

Despite progress in the treatment of diabetic macular edema and diabetic retinopathy, the rate of lower fundus examination due to limitations of medical resources delays the diagnosis and treatment of diabetic retinopathy. Therefore, implementation of automated diabetic retinopathy screening program and the identification of more specific and sensitive biomarkers are important for facilitating the earlier detection of diabetic macular edema and diabetic retinopathy to decrease the prevalence of poor vision and blindness.

Association between heart rate-corrected QT interval and severe peripheral arterial disease in patients with type 2 diabetes and foot ulcers

BACKGROUND

A prolonged heart rate-corrected QT interval (QTc) has been associated with peripheral artery disease (PAD) in the general population. However, no study to date has identified a link between prolonged QTc and the severity of PAD in patients with diabetes mellitus and foot ulcers (DFUs). This study aimed to investigate this relationship.

METHODS

This multicenter study enrolled 281 patients with DFUs. The severity of PAD was classified into no severe PAD group (without stenosis or occlusion) and severe PAD group (with stenosis or occlusion) based on duplex ultrasonography. The association of prolonged QTc with severe PAD was evaluated in a multivariable mixed-effect logistic regression model, with the hospital as a random effect. Directed acyclic graphs were used to drive the selection of variables to fit the regression model.

RESULTS

Patients with severe PAD had longer QTc than those without. Based on the multivariable mixed-effect logistic regression model, a prolonged QTc was positively associated with severe PAD (odds ratio (OR) = 2.61; 95% CI: 1.07-6.35) and severe DFUs (Wagner grade score ≥ 3) (OR = 2.87; 95% CI: 1.42-5.81).

CONCLUSIONS

A prolonged QTc was associated with severe PAD in patients with DFUs. Further research is required to ascertain whether the association is causal.

Multiple daily insulin injections ameliorate QT interval by lowering blood glucose levels in patients with type 2 diabetes

BACKGROUND

A prolonged QT interval plays a causal role in fatal arrhythmia and is known to be a risk factor for sudden cardiac death. Although diabetic patients with microvascular complications tend to have a longer QT interval, the therapeutic effect of diabetes on the QT interval remains unclear. Here, we assessed the changes in QT interval in patients with type 2 diabetes (T2D) who received multiple daily insulin injections.

MATERIALS AND METHODS

Patients with T2D (n = 34) who were admitted to our hospital and initiated multiple daily insulin injections for glycemic control were enrolled in this study. Clinical measurements, including electrocardiogram, were taken on admission and discharge. The QT interval was measured manually in lead II on the electrocardiogram, and corrected QT interval (QTc) was calculated using Bazett's formula. The change in QTc (ΔQTc) during hospitalization (median, 15 days) and clinical parameters affecting ΔQTc were investigated.

RESULTS

QTc was shortened from 439 ± 24 to 427 ± 26 ms during hospitalization (p < 0.0001). ΔQTc was positively correlated with the changes in fasting plasma glucose (ΔFPG, r = 0.55, p = 0.0008) and glycated albumin (r = 0.38, p = 0.026) following insulin therapy, but not with the final dose of insulin (r = -0.20, p = 0.26). The multiple regression analyses revealed that ΔFPG was independently associated with ΔQTc.

CONCLUSIONS

Multiple daily insulin injections can ameliorate QT interval by lowering the blood glucose levels in T2D, suggesting that glycemic control is important for preventing patients with T2D from sudden cardiac death.

Kir2.1 Interactome Mapping Uncovers PKP4 as a Modulator of the Kir2.1-Regulated Inward Rectifier Potassium Currents

Kir2.1, a strong inward rectifier potassium channel encoded by the KCNJ2 gene, is a key regulator of the resting membrane potential of the cardiomyocyte and plays an important role in controlling ventricular excitation and action potential duration in the human heart. Mutations in KCNJ2 result in inheritable cardiac diseases in humans, e.g. the type-1 Andersen-Tawil syndrome (ATS1). Understanding the molecular mechanisms that govern the regulation of inward rectifier potassium currents by Kir2.1 in both normal and disease contexts should help uncover novel targets for therapeutic intervention in ATS1 and other Kir2.1-associated channelopathies. The information available to date on protein-protein interactions involving Kir2.1 channels remains limited. Additional efforts are necessary to provide a comprehensive map of the Kir2.1 interactome. Here we describe the generation of a comprehensive map of the Kir2.1 interactome using the proximity-labeling approach BioID. Most of the 218 high-confidence Kir2.1 channel interactions we identified are novel and encompass various molecular mechanisms of Kir2.1 function, ranging from intracellular trafficking to cross-talk with the insulin-like growth factor receptor signaling pathway, as well as lysosomal degradation. Our map also explores the variations in the interactome profiles of Kir2.1WTversus Kir2.1Δ314-315, a trafficking deficient ATS1 mutant, thus uncovering molecular mechanisms whose malfunctions may underlie ATS1 disease. Finally, using patch-clamp analysis, we validate the functional relevance of PKP4, one of our top BioID interactors, to the modulation of Kir2.1-controlled inward rectifier potassium currents. Our results validate the power of our BioID approach in identifying functionally relevant Kir2.1 interactors and underline the value of our Kir2.1 interactome as a repository for numerous novel biological hypotheses on Kir2.1 and Kir2.1-associated diseases.

Hormonal Signaling Actions on Kv7.1 (KCNQ1) Channels

Kv7 channels (Kv7.1-7.5) are voltage-gated K⁺ channels that can be modulated by five β-subunits (KCNE1-5). Kv7.1-KCNE1 channels produce the slow-delayed rectifying K⁺ current, I_Ks, which is important during the repolarization phase of the cardiac action potential. Kv7.2-7.5 are predominantly neuronally expressed and constitute the muscarinic M-current and control the resting membrane potential in neurons. Kv7.1 produces drastically different currents as a result of modulation by KCNE subunits. This flexibility allows the Kv7.1 channel to have many roles depending on location and assembly partners. The pharmacological sensitivity of Kv7.1 channels differs from that of Kv7.2-7.5 and is largely dependent upon the number of β-subunits present in the channel complex. As a result, the development of pharmaceuticals targeting Kv7.1 is problematic. This review discusses the roles and the mechanisms by which different signaling pathways affect Kv7.1 and KCNE channels and could potentially provide different ways of targeting the channel.

Key Strategies for Clinical Management and Improvement of Healthcare Services for Cardiovascular Disease and Diabetes Patients in the Coronavirus (COVID-19) Settings: Recommendations From the REPROGRAM Consortium

Patients with cardiovascular disease and diabetes are at potentially higher risk of infection and fatality due to COVID-19. Given the social and economic costs associated with disability due to these conditions, it is imperative that specific considerations for clinical management of these patients be observed. Moreover, the reorganization of health services around the pandemic response further exacerbates the growing crisis around limited access, treatment compliance, acute medical needs, and mental health of patients in this specific subgroup. Existing recommendations and guidelines emanating from respective bodies have addressed some of the pressure points; however, there are variations and limitations vis a vis patient with multiple comorbidities such as obesity. This article will pull together a comprehensive assessment of the association of cardiovascular disease, diabetes, obesity and COVID-19, its impact on the health systems and how best health systems can respond to mitigate current challenges and future needs. We anticipate that in the context of this pandemic, the cardiovascular disease and diabetes patients need a targeted strategy to ensure the harm to this group does not translate to huge costs to society and to the economy. Finally, we propose a triage and management protocol for patients with cardiovascular disease and diabetes in the COVID-19 settings to minimize harm to patients, health systems and healthcare workers alike.

Acquired long QT syndrome in chronic kidney disease patients

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in chronic kidney disease (CKD) patients. QT interval prolongation is a congenital or acquired condition that is associated with an increased risk of torsade de pointes (TdP), sudden cardiac death (SCD), and all-cause mortality in the general population. The prevalence of acquired long QT syndrome (aLQTS) is high, and various acquired conditions contribute to the prolonged QT interval in patients with CKD. More notably, the prolonged QT interval in CKD is an independent risk factor for SCD and all-cause mortality. In this review, we focus on the epidemiological characteristics, risk factors, underlying mechanisms and treatments of aLQTS in CKD, promoting the management of aLQTS in CKD patients.

Prevalence and risk factors of acquired long QT syndrome in hospitalized patients with chronic kidney disease

Patients with chronic kidney disease (CKD) have a high risk of fatal arrhythmias. The extended severe corrected QT (QTc) interval is a hallmark of ventricular arrhythmias and sudden cardiac death. The objective of this study was to evaluate the prevalence of acquired long QT syndrome (aLQTS) in hospitalized patients with CKD and search for potential risk factors to improve clinical risk stratification in patients with CKD. Information about patients with CKD was retrospectively collected in our hospital between January 2013 and June 2017. The prevalence of aLQTS in different stages of CKD was evaluated. The common risk factors for QTc prolongation in patients with CKD were compiled, and multivariable logistic regression analysis was used to evaluate how each factor was related to aLQTS in CKD. A total of 804 patients with CKD (299 females, 37.2%) participated in our study. The prevalence of aLQTS among all 804 patients was 56.97%, and the prevalence of QTc prolongation (>500 ms) was 10.07%. Among the elderly, impaired kidney function, hemodialysis, low serum potassium and low left ventricular ejection fraction (LVEF) were associated with QTc prolongation in patients with CKD. The prevalence of aLQTS is much higher and increases with the decline of kidney function in hospitalized patients with CKD, which is related to older age, impaired kidney function, hemodialysis, serum potassium and low LVEF.

Severity and multiplicity of microvascular complications are associated with QT interval prolongation in patients with type 2 diabetes

Aims/Introduction

A prolonged QT interval plays a causal role in life‐threatening arrhythmia, and becomes a risk factor for sudden cardiac death. Here, we assessed the association between microvascular complications and the QT interval in patients with type 2 diabetes.

Materials and Methods

Patients with type 2 diabetes (n = 219) admitted to Nippon Medical School Hospital (Tokyo, Japan) for glycemic control were enrolled. QT interval was measured manually in lead II on the electrocardiogram, and corrected for heart rate using Bazett's formula (QTc). Diabetic neuropathy, retinopathy and nephropathy were assessed by neuropathic symptoms or Achilles tendon reflex, ophthalmoscopy and urinary albumin excretion, respectively.

Results

In univariate analyses, female sex (P = 0.025), duration of type 2 diabetes (P = 0.041), body mass index (P = 0.0008), systolic blood pressure (P = 0.0011) and receiving insulin therapy (P < 0.0001) were positively associated with QTc. Patients with each of the three microvascular complications had longer QTc than those without: neuropathy (P = 0.0005), retinopathy (P = 0.0019) and nephropathy (P = 0.0001). As retinopathy or nephropathy progressed, QTc became longer (P < 0.001 and P < 0.001 for trend in retinopathy and nephropathy, respectively). Furthermore, QTc was prolonged with the multiplicity of the microvascular complications (P < 0.001 for trend). Multiple regression analyses showed that neuropathy, nephropathy and the multiplicity of the microvascular complications were independently associated with QTc.

Conclusions

Patients with type 2 diabetes with severe microvascular complications might be at high risk for life‐threatening arrhythmia associated with QT interval prolongation.