The relationship between insulin sensitivity and heart rate-corrected QT interval in patients with type 2 diabetes

Prevalence of Medication Associated with QTc Prolongation Used Among Critically Ill Patients

Background

Acquired prolonged corrected QT (QTc) interval can lead to life-threatening Torsade de Pointes (TdP) arrhythmia. Multiple risk factors including medications, comorbidities, and electrolyte imbalances contribute significantly to acquired manifestations of the QTc prolongation. Critically ill patients are particularly more vulnerable to TdP due to complex medical conditions, aging, and polypharmacy.

Objective

This study aimed to assess the prevalence of TdP-associated medication prescribing, identify risk factors for QTc prolongation and TdP, and determine primary predictors of high TdP medication usage in critically ill patients in Jordan.

Methods

We conducted a retrospective cross-sectional analysis of electronic medical records for patients from King Abdullah University Hospital who were admitted to Intensive Care Unit (ICU) between (July 2012-July 2022). We collected data on patients' demographics, clinical characteristics, comorbidities, laboratory results, and prescribed medications. Medications were categorized into three TdP risk levels according to CredibleMeds® assessment tool. Data were analyzed using descriptive statistics and a binary logistic regression model.

Results

Of the 13,300 patients (58.2% male, median age 62 years). Prescribing prevalence for medications with known TdP risk was 19%, possible risk (24.7%), conditional risk (21.6%), and confirmed conditional risk (8.3%). Common comorbidities included hypertension (40.9%), diabetes (33.3%), and cancer (15.4%). Drugs with known TdP risk included citalopram, amiodarone, clarithromycin, and ciprofloxacin. A binary regression model revealed that as age increased, the odds of TdP associated medication prescribing decreased (OR = 0.989, p < 0.001), while patients on more than five medications had higher odds (OR = 4.281, p < 0.001).

Conclusion

The study identified a notable prevalence of prescribing for medications with QTc prolongation/TdP risk in critically ill patients. Healthcare providers in the ICU should exercise caution to minimize the inadvertent prescription of TdP associated medications especially among older patients and those with polypharmacy.

Obesity and Cardiac Conduction Block Disease in China

Importance

Although a high body mass index (BMI) has been found to be associated with increased risk of cardiac conduction block (CCB) in older adults, no further studies have investigated the association between obesity and CCB in the general population.

Objective

To investigate the association between obesity and CCB, including its subtypes.

Design, Setting, and Participants

This cohort study used data from participants in the Kailuan Study in China (2006-2018) who had completed a physical examination in 2006 (baseline) and had not experienced CCB before baseline. Data analysis was conducted from March to September 2023.

Exposures

Obesity status was defined by BMI in 3 groups: normal weight (18.5 to <24), overweight (24 to <28), and obesity (≥28).

Main Outcome and Measures

The primary outcome was CCB, which was diagnosed from standard 12-lead electrocardiography. The primary end point included high-grade atrioventricular block (HAVB), complete right bundle branch block, complete left bundle branch block, left anterior fascicular block (LAFB), and left posterior fascicular block. First-degree atrioventricular block (FAVB), second-degree type 1 AVB, HAVB, complete and incomplete right and left bundle branch block, LAFB, and left posterior fascicular block were considered separately as secondary end points.

Results

Among 86 635 participants (mean [SD] age, 50.8 [11.9] years; 68 205 males [78.7%]), there were 33 259 individuals with normal weight (38.4%), 37 069 individuals with overweight (42.8%), and 16 307 individuals with obesity (18.8%). The mean (SD) follow-up was 10.6 (3.07) years. In the multivariable Cox proportional hazards regression analysis, obesity was associated with an increased risk of incident CCB (hazard ratio [HR], 1.21; 95% CI, 1.04-1.42) vs normal BMI. In secondary analysis, obesity was associated with an increased risk of FAVB (HR, 1.44; 95% CI, 1.21-1.73), HAVB (HR, 1.99; 95% CI, 1.03-3.82), and LAFB (HR, 1.29; 95% CI, 1.03-1.62) vs normal BMI. There was no association between obesity and other CCB subtypes. Obesity was associated with a greater increase in risk of CCB vs normal BMI in older (aged ≥65 years; HR, 1.44; 95% CI, 1.05-1.96) vs younger (aged <65 years; HR, 1.13; 95% CI, 0.96-1.34) participants (P for interaction < .001) and those with diabetes (HR, 2.16; 95% CI, 1.24-3.76) vs without diabetes (HR, 1.19; 95% CI, 1.02-1.39) (P for interaction = .02).

Conclusions and Relevance

This study found that obesity was associated with an increased risk of CCB, with greater increases in risk for FAVB, HAVB, and LAFB. Individuals who were older and those who had diabetes had larger increases in risk.

Strong independent association between third-degree AV-block and diabetes mellitus using a large database

BACKGROUND

Recent data suggests an association between DM and third-degree AV- Block. The goal of this study was to evaluate the independent association between diabetes and third-degree AV-Block using a very large database.

METHOD

We used ICD-9 Codes for DM and third-degree AV-block from the Nationwide Inpatient Sample (NIS) database. We randomly selected the 1992 and 2002 databases which are 10 years apart as two independent samples. We used uni- and multi-variate analysis to evaluate this association.

RESULTS

1992 database contained a total of 6,195,744 patients. Diabetes occurred in (0.5 %) of patients with third-degree AV-block vs. (0.2 %) of the control (OR: 2.15, CI 2.06-2.25, p < 0.0001). 2002 database contained a total of 7,853,982 patients. Diabetes occurred in (0.4 %) of patients with third-degree AV-block vs. (0.2 %) of the control (OR: 1.86, CI: 1.80-1.93, p < 0.0001). Using Multivariate analysis adjusting for age, congestive heart failure, and coronary artery disease, DM remained independently associated with third-degree AV block in both databases. (for 1999: OR: 2.54, CI 2.51-2.57, p < 0.0001 and for 2002 OR: 1.56, CI 1.55-1.57, p < 0.0001).

CONCLUSION

DM is independently associated with third-degree AV-block with persistent association over a period of 10 years. The cause of this association warrants further investigation.

Type 2 diabetes mellitus and higher rate of complete atrioventricular block: a Danish Nationwide Registry

AIMS

The present study aimed to determine the association between Type 2 diabetes mellitus (T2DM) and third-degree (complete) atrioventricular block.

METHODS AND RESULTS

This nationwide nested case-control study included patients older than 18 years, diagnosed with third-degree atrioventricular block between 1 July 1995 and 31 December 2018. Data on medication, comorbidity, and outcomes were collected from Danish registries. Five controls, from the risk set of each case of third-degree atrioventricular block, were matched on age and sex to fit a Cox regression model with time-dependent exposure and time-dependent covariates. Subgroup analysis was conducted with Cox regression models for each subgroup. We located 25 995 cases with third-degree atrioventricular block that were matched with 130 004 controls. The mean age was 76 years and 62% were male. Cases had more T2DM (21% vs. 11%), hypertension (69% vs. 50%), atrial fibrillation (25% vs. 10%), heart failure (20% vs. 6.3%), and myocardial infarction (19% vs. 9.2%), compared with the control group. In Cox regression analysis, adjusting for comorbidities and atrioventricular nodal blocking agents, T2DM was significantly associated with third-degree atrioventricular block (hazard ratio: 1.63, 95% confidence interval: 1.57-1.69). The association remained in several subgroup analyses of diseases also suspected to be associated with third-degree atrioventricular block. There was a significant interaction with comorbidities of interest including hypertension, atrial fibrillation, heart failure, and myocardial infarction.

CONCLUSION

In this nationwide study, T2DM was associated with a higher rate of third-degree atrioventricular block compared with matched controls. The association remained independent of atrioventricular nodal blocking agents and other comorbidities known to be associated with third-degree atrioventricular block.

The influence of different glucose tolerance on QTc interval: a population-based study

BACKGROUND

Corrected QT (QTc) interval has been reported to be associated with type 2 diabetes. This study aimed to explore the relationship between different glucose tolerance and QTc intervals among middle-aged and older Chinese individuals.

METHODS

We conducted a cross-sectional analysis that included 9898 subjects (3194 men and 6704 women) in a Chinese population. Glucose tolerance was studied during the oral glucose tolerance test (OGTT). Insulin, blood pressure, hemoglobin A1c (HbA1c), serum lipids, hepatic transaminases and waist-to-hip ratio were assessed. The QTc interval was derived from ECG recordings, and the subjects were stratified based on different glucose tolerance.

RESULTS

QTc interval levels were increased significantly in the subjects with abnormal glucose metabolism compared with the normal glucose regulation group. Multiple regression analyses showed that the QTc interval was significantly associated with fasting plasma glucose, 2-h OGTT plasma glucose and HbA1c. The odds ratio of prolonged QTc was 1.396 for impaired glucose regulation (IFG)/impaired fasting glucose (IGT) (95% CI 0.126-1.730), and 1.342 for type 2 diabetes (95% CI 0.142-1.577) after all potential confounders were adjusted.

CONCLUSIONS

Impaired glucose tolerance (IGR) and diabetes are associated with prolonged QTc intervals among middle-aged and older Chinese individuals. Abnormal glucose regulation can be used to monitor the QTc interval in the population.

Risk Factors for QT Prolongation in Patients with Chronic Hydroxychloroquine Use

BACKGROUND

Hydroxychloroquine is used as an antimalarial and immunomodulator, however it can induce QT prolongation that could potentially lead to fatal arrhythmia. We investigated changes in QT interval in long-term hydroxychloroquine users, and identified possible risk factors associated with significant QTc prolongation.

METHODS

We retrospectively enrolled 3603 patients who received long-term hydroxychloroquine treatment from 2009 to 2019, of whom 167 had electrocardiography (ECG) results before and during hydroxychloroquine therapy. Baseline characteristics, laboratory data, comorbidities, concurrent medications, and related clinical outcomes were reviewed.

RESULTS

Overall, 225 patients (6.2%) died within the study period, with 50 patients (1.4%) continuously receiving hydroxychloroquine treatment until death. Three patients had fatal ventricular arrhythmia. No significant change in corrected QT interval (QTc) was noted before and during hydroxychloroquine treatment (451.1 ± 39.9 ms vs. 456.0 ± 37.3 ms, P = 0.140) in the ECG cohort. Multivariable logistic regression showed that diabetes mellitus [odds ratio (OR): 9.55, 95% confidence interval (CI): 2.02-45.22; P = 0.005] and use of additional QT-prolonging drugs (OR: 2.89, 95% CI: 1.40-5.94; P = 0.004) were independent risk factors for significant QTc prolongation. Multiple linear regression, with the number of QT-prolonging drugs and comorbidities including diabetes mellitus, hypertension, and atrial fibrillation as explanatory variables, predicted QTc response (adjusted R² = 0.385) in the long-term hydroxychloroquine users.

CONCLUSIONS

In the long-term users of hydroxychloroquine, those with diabetes mellitus and concurrent use of additional QT-prolonging drugs were at a higher risk of significant QTc prolongation. Baseline QTc interval, concurrent medications, and comorbidities predicted QTc response.

Intracellular Redistribution of Left Ventricular Connexin 43 Contributes to the Remodeling of Electrical Properties of the Heart in Insulin-resistant Elderly Rats

The correlation between long-QT and connexin 43 (Cx43) status and localization in elderly rats was determined to demonstrate a correlation between insulin resistance (I-R), ischemia-reperfusion, aging, and heart dysfunction. Male Wistar rats are grouped as 24-month-old rats (Aged-group), those with metabolic syndrome (8 months old; MetS-group), or controls (8 months old; Con-group). Both experimental groups have long-QT and low heart rate. Immunohistochemical imaging and quantification showed marked decreases in Cx43 staining of intercalated disc with less localizations in the Aged-group and MetS-group. The lateralization of Cx43 on longitudinal cell membrane was significantly high in the MetS-group than in the Con-group with no significant change in the Aged-group. Its significant cytoplasmic internalization was higher in the Aged-group than in the MetS-group. There were marked decreases in phospho-Cx43 (pCx43) staining of intercalated disc with less localizations in both groups than in the Con-group. Furthermore, lateralization of pCx43 was significantly low in the Aged-group and MetS-group, whereas there were no significant changes in the cytoplasmic internalization of both groups compared with the Con-group. Furthermore, the ratio of pCx43 to Cx43 was significantly small in both groups. We determined increases in RhoA and endothelin-1 in both groups, further supporting decreases in pCx43. Our data indicate the important role of I-R on long-QT in aging heart through alterations in both Cx43 protein level and localizations, leading to an abnormal spreading of ventricular repolarization in I-R heart.

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.

Declining Levels and Bioavailability of IGF-I in Cardiovascular Aging Associate With QT Prolongation-Results From the 1946 British Birth Cohort

Background

As people age, circulating levels of insulin-like growth factors (IGFs) and IGF binding protein 3 (IGFBP-3) decline. In rat cardiomyocytes, IGF-I has been shown to regulate sarcolemmal potassium channel activity and late sodium current thus impacting cardiac repolarization and the heart rate-corrected QT (QTc). However, the relationship between IGFs and IGFBP-3 with the QTc interval in humans, is unknown.

Objectives

To examine the association of IGFs and IGFBP-3 with QTc interval in an older age population-based cohort.

Methods

Participants were from the 1946 Medical Research Council (MRC) National Survey of Health and Development (NSHD) British birth cohort. Biomarkers from blood samples at age 53 and 60-64 years (y, exposures) included IGF-I/II, IGFBP-3, IGF-I/IGFBP-3 ratio and the change (Δ) in marker levels between the 60-64 and 53y sampled timepoints. QTc (outcome) was recorded from electrocardiograms at the 60-64y timepoint. Generalized linear multivariable models with adjustments for relevant demographic and clinical factors, were used for complete-cases and repeated after multiple imputation.

Results

One thousand four hundred forty-eight participants were included (48.3% men; QTc mean 414 ms interquartile range 26 ms). Univariate analysis revealed an association between low IGF-I and IGF-I/IGFBP-3 ratio at 60-64y with QTc prolongation [respectively: β -0.30 ms/nmol/L, (95% confidence intervals -0.44, -0.17), p < 0.001; β-28.9 ms/unit (-41.93, -15.50), p < 0.001], but not with IGF-II or IGFBP-3. No association with QTc was found for IGF biomarkers sampled at 53y, however both ΔIGF-I and ΔIGF-I/IGFBP-3 ratio were negatively associated with QTc [β -0.04 ms/nmol/L (-0.08, -0.008), p = 0.019; β -2.44 ms/unit (-4.17, -0.67), p = 0.007] while ΔIGF-II and ΔIGFBP-3 showed no association. In fully adjusted complete case and imputed models (reporting latter) low IGF-I and IGF-I/IGFBP-3 ratio at 60-64y [β -0.21 ms/nmol/L (-0.39, -0.04), p = 0.017; β -20.14 ms/unit (-36.28, -3.99), p = 0.015], steeper decline in ΔIGF-I [β -0.05 ms/nmol/L/10 years (-0.10, -0.002), p = 0.042] and shallower rise in ΔIGF-I/IGFBP-3 ratio over a decade [β -2.16 ms/unit/10 years (-4.23, -0.09), p = 0.041], were all independently associated with QTc prolongation. Independent associations with QTc were also confirmed for other previously known covariates: female sex [β 9.65 ms (6.65, 12.65), p < 0.001], increased left ventricular mass [β 0.04 ms/g (0.02, 0.06), p < 0.001] and blood potassium levels [β -5.70 ms/mmol/L (-10.23, -1.18) p = 0.014].

Conclusion

Over a decade, in an older age population-based cohort, declining levels and bioavailability of IGF-I associate with prolongation of the QTc interval. As QTc prolongation associates with increased risk for sudden death even in apparently healthy people, further research into the antiarrhythmic effects of IGF-I on cardiomyocytes is warranted.

Comparison of Heart Rate Variability, QTc, and JT Interval Between Diabetic Patients and Healthy Controls: Role of Gender and Phases of Menstrual Cycle

Background and objectives

Type 2 Diabetes mellitus (T2DM) is a heterogeneous group of metabolic disorders with variable degrees of insulin resistance and altered glucose metabolism. Increased attention in studying the role of gonadal hormones in diabetes is not only due to their relation to insulin sensitivity, and glucose tolerance but also to the gender-specific nature of the prevalence of various diabetic complications. The cyclical change in the hormone level in females will make it necessary to consider the menstrual cycle while analyzing the risk factors for diabetes. Hence, the role of gender and menstrual cycle in T2DM are analyzed here using the simple non-invasive cardiovascular risk indices like heart rate variability (HRV), QT interval corrected for heart rate (QTc), and JT interval.

Materials and methods

In this analytical study, T2DM patients in the age group of 18-45 years with less than five years duration from diagnosis and taking not more than two anti-hyperglycemic drugs were included. Time and frequency domains of HRV analysis, QTc, and JT intervals were compared with age and BMI matched control group. The comparison of these parameters was also made between two genders in the diabetic group and they were analyzed across different phases of the menstrual cycle in female diabetic patients when physiological variation in the gonadal hormones occurred as a natural phenomenon.

Results

HRV parameters were reduced and the QTc and JT intervals were prolonged in diabetic patients of both genders. Reduction in low-frequency (LF) band power and high-frequency (HF) band power of HRV analysis in diabetic females were statistically significant in the luteal phase of the menstrual cycle in comparison with age and BMI-matched healthy controls. There was no significant difference in the HRV parameters, QTc, and JT interval between the male and female diabetic groups. HF band power is significantly reduced in the menstrual phase and relatively higher in the follicular phase when compared to the luteal phase among female diabetic patients.

Conclusion

The reduced sympathetic and parasympathetic activity were observed in diabetic patients of both genders and they were significant in the luteal phase of diabetic females compared to the healthy control group. Vagal activity is relatively higher in the follicular phase of the menstrual cycle in female diabetic patients.

The relationship between adenosine deaminase and heart rate-corrected QT interval in type 2 diabetic patients

BACKGROUND

Prolonged heart rate-corrected QT (QTc) interval may reflect poor prognosis of patients with type 2 diabetes (T2D). Serum adenosine deaminase (ADA) levels are related to hyperglycemia, insulin resistance (IR) and inflammation, which may participate in diabetic complications. We investigated the association of serum ADA levels with prolonged QTc interval in a large-scale sample of patients with T2D.

METHODS

In this cross-sectional study, a total of 492 patients with T2D were recruited. Serum ADA levels were determined by venous blood during fasting. QTc interval was estimated from resting 12-lead ECGs, and prolonged QTc interval was defined as QTc > 440 ms.

RESULTS

In this study, the prevalence of prolonged QTc interval was 22.8%. Serum ADA levels were positively associated with QTc interval (r = 0.324, P < 0.0001). The proportion of participants with prolonged QTc interval increased significantly from 9.2% in the first tertile (T1) to 24.7% in the second tertile (T2) and 39.0% in the third tertile (T3) of ADA (P for trend < 0.001). After adjusting for other possible risk factors by multiple linear regression analysis, serum ADA level was still significantly associated with QTc interval (β = 0.217, t = 3.400, P < 0.01). Multivariate logistic regression analysis showed that female (OR 5.084, CI 2.379-10.864, P < 0.001), insulin-sensitizers treatment (OR 4.229, CI 1.290-13.860, P = 0.017) and ADA (OR 1.212, CI 1.094-1.343, P < 0.001) were independent contributors to prolonged QTc interval.

CONCLUSIONS

Serum ADA levels were independently associated with prolonged QTc interval in patients with T2D.