Glycated hemoglobin and risk of first episode stroke in diabetic patients with atrial fibrillation: A cohort study

Impact of glycated hemoglobin on 2-year clinical outcomes in elderly patients with atrial fibrillation: sub-analysis of ANAFIE Registry, a large observational study

BACKGROUND

This ANAFIE Registry sub-analysis investigated 2-year outcomes and oral anticoagulant (OAC) use stratified by glycated hemoglobin (HbA1c) levels among Japanese patients aged ≥ 75 years with non-valvular atrial fibrillation (NVAF) with and without clinical diagnosis of diabetes mellitus (DM).

METHODS

The ANAFIE Registry was a large-scale multicenter, observational study conducted in Japan; this sub-analysis included patients with baseline HbA1c data at baseline. The main endpoints evaluated (stroke/systemic embolic events [SEE], major bleeding, intracranial hemorrhage, cardiovascular death, all-cause death, and net clinical outcome [a composite of stroke/SEE, major bleeding, and all-cause death]) were stratified by HbA1c levels (< 6.0%; 6.0% to < 7.0%; 7.0% to < 8.0%; and ≥ 8.0%).

RESULTS

Of 17,526 patients with baseline HbA1c values, 8725 (49.8%) patients had HbA1c < 6.0%, 6700 (38.2%) had 6.0% to < 7.0%, 1548 (8.8%) had 7.0% to < 8.0%, and 553 (3.2%) had ≥ 8.0%. Compared with other subgroups, patients with HbA1c ≥ 8.0% were more likely to have lower renal function, higher CHA₂DS₂-VASc and HAS-BLED scores, higher prevalence of non-paroxysmal AF, and lower direct OAC (DOAC) administration, but higher warfarin administration. The HbA1c ≥ 8.0% subgroup had higher event rates for all-cause death (log-rank P = 0.003) and net clinical outcome (log-rank P = 0.007). Similar trends were observed for stroke/SEE. In multivariate analysis, risk of all-cause death (adjusted hazard ratio [aHR]: 1.46 [95% confidence interval 1.11-1.93]) and net clinical outcome (aHR 1.33 [1.05-1.68]) were significantly higher in the HbA1c ≥ 8.0% subgroup. No significant differences were observed in risks of major bleeding or other outcomes in this and other subgroups. No interaction was observed between HbA1c and OACs. Use/non-use of antidiabetic drugs was not associated with risk reduction; event risks did not differ with/without injectable antidiabetic drugs.

CONCLUSIONS

Among elderly Japanese patients with NVAF, only HbA1c ≥ 8.0% was associated with increased all-cause death and net clinical outcome risks; risks of the events did not increase in other HbA1c subgroups. Relative event risks between patients treated with DOACs and warfarin were not modified by HbA1c level.

TRIAL REGISTRATION

UMIN000024006; date of registration: September 12, 2016.

Atrial fibrillation: primary prevention, secondary prevention, and prevention of thromboembolic complications: part 1

Atrial fibrillation (AF), is the most common sustained cardiac arrhythmia. It was once thought to be benign as long as the ventricular rate was controlled, however, AF is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a MEDLINE search to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched via the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare noninvasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

Diabetes mellitus and atrial fibrillation-from pathophysiology to treatment

Type 2 diabetes mellitus (T2DM) is a leading risk factor for cardiovascular complications around the globe and one of the most common medical conditions. Atrial fibrillation (AF) is the most common supraventricular arrhythmia, with a rapidly increasing prevalence. T2DM has been closely associated with the risk of AF development, identified as an independent risk factor. Regarding cardio-vascular complications, both AF and T2DM have been linked with high mortality. The underlying pathophysiology has not been fully determined yet; however, it is multifactorial, including structural, electrical, and autonomic pathways. Novel therapies include pharmaceutical agents in sodium-glucose cotransporter-2 inhibitors, as well as antiarrhythmic strategies, such as cardioversion and ablation. Of interest, glucose-lowering therapies may affect the prevalence of AF. This review presents the current evidence regarding the connection between the two entities, the pathophysiological pathways that link them, and the therapeutic options that exist.

Comprehensive comparison of stroke risk score performance: a systematic review and meta-analysis among 6 267 728 patients with atrial fibrillation

AIMS

Multiple risk scores to predict ischaemic stroke (IS) in patients with atrial fibrillation (AF) have been developed. This study aims to systematically review these scores, their validations and updates, assess their methodological quality, and calculate pooled estimates of the predictive performance.

METHODS AND RESULTS

We searched PubMed and Web of Science for studies developing, validating, or updating risk scores for IS in AF patients. Methodological quality was assessed using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). To assess discrimination, pooled c-statistics were calculated using random-effects meta-analysis. We identified 19 scores, which were validated and updated once or more in 70 and 40 studies, respectively, including 329 validations and 76 updates-nearly all on the CHA2DS2-VASc and CHADS2. Pooled c-statistics were calculated among 6 267 728 patients and 359 373 events of IS. For the CHA2DS2-VASc and CHADS2, pooled c-statistics were 0.644 [95% confidence interval (CI) 0.635-0.653] and 0.658 (0.644-0.672), respectively. Better discriminatory abilities were found in the newer risk scores, with the modified-CHADS2 demonstrating the best discrimination [c-statistic 0.715 (0.674-0.754)]. Updates were found for the CHA2DS2-VASc and CHADS2 only, showing improved discrimination. Calibration was reasonable but available for only 17 studies. The PROBAST indicated a risk of methodological bias in all studies.

CONCLUSION

Nineteen risk scores and 76 updates are available to predict IS in patients with AF. The guideline-endorsed CHA2DS2-VASc shows inferior discriminative abilities compared with newer scores. Additional external validations and data on calibration are required before considering the newer scores in clinical practice.

CLINICAL TRIAL REGISTRATION

ID CRD4202161247 (PROSPERO).

Relation of Hemoglobin A1C Levels to Risk of Ischemic Stroke and Mortality in Patients With Diabetes Mellitus and Atrial Fibrillation

Diabetes mellitus (DM) is associated with an increased risk of complications in atrial fibrillation (AF). This study aimed to assess the incidence and risks of ischemic stroke and mortality according to baseline HbA1c levels in patients with DM and AF. We conducted a cohort study using Clalit Health Services electronic medical records. The study population included all Clalit Health Services members aged ≥25 years, with the first diagnosis of AF between January 1, 2010, and December 31, 2016, who had a diagnosis of DM. The risk of stroke and all-cause death were compared according to HbA1c levels at the time of AF diagnosis: <7.0%, between 7% and 9%, and ≥9%. A total of 44,451 patients with DM and AF were identified. The median age was 75 years (interquartile 65 to 83), and 52.5% were women. During a mean follow-up of 38 months, higher levels of HbA1c were associated with an increased risk of stroke with a dose-dependent response when compared with patients with HbA1c <7% (Adjusted hazard ratio [aHR] =1.30 [95% confidence interval 1.10 to 2.05] for levels between 7% and 9% and 1.60 (95% confidence interval 1.25 to 2.03) for HbA1c >9%, even after adjusting for CHA₂DS₂-Vasc risk factors and use of oral anticoagulants. The risk for overall mortality was significantly higher in the HBA1C >9% group (aHR = 1.17 [1.07 to 1.28]). In conclusion, in this cohort of patients with AF and DM, HbA1c levels were associated with the risk of stroke in a dose-dependent manner even after accounting for other recognized risk factors for stroke.

Glycemic control and atrial fibrillation: an intricate relationship, yet under investigation

Atrial fibrillation (AF) and diabetes mellitus (DM) constitute two major closely inter-related chronic cardiovascular disorders whose concurrent prevalence rates are steadily increasing. Although, the pathogenic mechanisms behind the AF and DM comorbidity are still vague, it is now clear that DM precipitates AF occurrence. DM also affects the clinical course of established AF; it is associated with significant increase in the incidence of stroke, AF recurrence, and cardiovascular mortality. The impact of DM on AF management and prognosis has been adequately investigated. However, evidence on the relative impact of glycemic control using glycated hemoglobin levels is scarce. This review assesses up-to-date literature on the association between DM and AF. It also highlights the usefulness of glycated hemoglobin measurement for the prediction of AF and AF-related adverse events. Additionally, this review evaluates current anti-hyperglycemic treatment in the context of AF, and discusses AF-related decision-making in comorbid DM. Finally, it quotes significant remaining questions and sets some future strategies with the potential to effectively deal with this prevalent comorbidity.

Association of Diabetes Duration and Glycemic Control With Stroke Rate in Patients With Atrial Fibrillation and Diabetes: A Population-Based Cohort Study

Background

There are limited data on the association of diabetes duration and glycemic control with stroke risk in atrial fibrillation (AF). Our objective was to study the association of diabetes duration and glycated hemoglobin (HbA1c) with the rate of stroke in people with diabetes and newly diagnosed AF.

Methods and Results

This was a population‐based cohort study using linked administrative data sets. We studied 37 209 individuals aged ≥66 years diagnosed with AF in Ontario between April 2009 and March 2019, who had diabetes diagnosed 1 to 16 years beforehand. The primary outcome was hospitalization for stroke at 1 year. Cause‐specific hazard regression was used to model the association of diabetes duration and glycated hemoglobin (HbA1c) with the rate of stroke. Restricted cubic spline analyses showed increasing hazard ratios (HR) for stroke with longer diabetes duration that plateaued after 10 years and increasing HRs for stroke with HbA1c levels >7%. Relative to patients with <5 years diabetes duration, stroke rates were significantly higher for patients with ≥10 years duration (HR, 1.45; 95% CI, 1.16–1.82; P=0.001), while diabetes duration 5 to <10 years was not significantly different. Relative to glycated hemoglobin 6% to <7%, values ≥8% were associated with higher stroke rates (HR, 1.44; 95% CI, 1.12–1.84; P=0.004), while other HbA1c categories were not significantly different.

Conclusions

Longer diabetes duration and higher glycated hemoglobin were associated with significantly higher stroke rates in patients with AF and diabetes. Models for stroke risk prediction and preventive care in AF may be improved by considering patients’ diabetes characteristics.

Medical therapies for prevention of cardiovascular and renal events in patients with atrial fibrillation and diabetes mellitus

Atrial fibrillation (AF), type 2 diabetes mellitus (DM), and chronic kidney disease (CKD) are three global epidemics with significant effects on morbidity and mortality. Diabetes is a risk factor for AF, and a risk factor for thromboembolism, comorbidity, and mortality when AF is present. The pathophysiology of diabetes-related AF and interrelationships with cardiovascular events and renal events is not fully understood but is in part related to structural, electrical, electromechanical, and autonomic remodelling. The current practice guidelines offer limited recommendations on the management of patients with AF (or risk of AF) and diabetes with its own heterogeneity for the prevention of cardiovascular and renal events. This document discusses possible clinical approaches for these patients. In the last decade, there have been major improvements for the prevention of stroke in AF patients with direct oral anticoagulants, which are preferable to vitamin K antagonists for stroke prevention in DM. Because of the increased risk rate for several cardiovascular adverse events in diabetic patients, a similar relative risk reduction generally translates into greater absolute risk reduction in the diabetic population. Recent trials with non-insulin diabetes drugs using glucagon-like peptide-1 agonists and sodium-glucose cotransporter-2 inhibitors showed a significant reduction for the risk of major adverse cardiovascular events in patients with type 2 DM. Sodium-glucose cotransporter-2 inhibitors also showed a large reduction in hospitalization for heart failure and renal events, which need to be more completely evaluated in patients with AF. Mechanisms, risks, and optimal management of AF patients with DM who have or are under risk of developing heart failure or CKD are also discussed in this document. The benefits of medical therapies for these patients still need to be put into perspective, and gaps in evidence on some of these issues are likely to be addressed in future years.

Efficacy and Safety of Direct Oral Anticoagulants in Patients with Diabetes and Nonvalvular Atrial Fibrillation: Meta-Analysis of Observational Studies

Background

This meta-analysis was performed to compare the efficacy and safety of direct oral anticoagulants (DOACs) with vitamin K antagonists (VKAs) for stroke prevention in real-world patients with diabetes and nonvalvular atrial fibrillation (NVAF) through observational studies.

Methods

PubMed, Embase, and Web of Science databases were searched up to August 2020 for eligible studies. Outputs were presented as risk ratios (RRs) and corresponding 95% confidence intervals (CIs) by using a random-effect model.

Results

Seven observational studies involving 249,794 diabetic NVAF patients were selected. Compared with VKAs, the use of DOACs was associated with significantly reduced risks of stroke (RR = 0.56, 95% CI 0.45-0.70; p < 0.00001), ischemic stroke (RR = 0.61, 95% CI 0.48-0.78; p < 0.0001), stroke or systemic embolism (SSE) (RR = 0.81, 95% CI 0.68-0.95; p = 0.01), myocardial infarction (RR = 0.69, 95% CI 0.55-0.88; p = 0.002), major bleeding (RR = 0.75, 95% CI 0.63-0.90; p = 0.002), intracranial hemorrhage (RR = 0.50, 95% CI 0.44-0.56; p < 0.00001), and major gastrointestinal bleeding (RR = 0.77, 95% CI 0.62-0.95; p = 0.02), and a borderline significant decrease in major adverse cardiac events (RR = 0.87, 95% CI 0.75-1.00; p = 0.05) in NVAF patients with diabetes.

Conclusion

For patients with NVAF and diabetes in real-world clinical settings, DOACs showed superior efficacy and safety profile over VKAs and significantly reduced risks of stroke, ischemic stroke, SSE, myocardial infarction, major bleeding, intracranial hemorrhage, and major gastrointestinal bleeding.

Increased hemoglobin A1c level associates with low left atrial appendage flow velocity in patients of atrial fibrillation

BACKGROUND AND AIMS

High hemoglobin A1c (HbAlc) level is associated with increased cardiovascular disease risk and thromboembolic events [1]. The study sought to explored the association between HbAlc and left atrial appendage flow velocity (LAAV) among non-valvular atrial fibrillation (AF) patients.

METHODS AND RESULTS

A total of 249 consecutive non-valvular AF patients who underwent transesophageal echocardiography (TEE) were divided into two subgroups according to the median of LAAV level (<45 cm/s, ≥45 cm/s). Blood samples and other baseline clinical data of all patients were collected and analyzed. The low LAAV group included 126 patients and the high LAAV group included 123 patients. Patients in the low LAAV group were older and had a higher percentage of persistent AF, chronic heart failure, and higher CHA2DS2-VASc score (P < 0.05). HbAlc level in the low LAAV group was significantly higher than the high LAAV group [6.1 (5.7-6.5)% vs 5.9 (5.6-6.2)%, P = 0.010]. The low LAAV group had larger left atrial diameter (LAD), left atrial area (LAA), higher left atrial pressure (LAP), and lower left ventricular ejection fraction (LVEF) (P < 0.05). Spearman rank correlation analysis showed that the HbAlc level was negatively correlated with LAAV (r = -0.211, P = 0.001). Multivariate analysis indicated that female gender (OR = 2.233, 95% CI 1.110-4.492, P = 0.024), persistent AF (OR = 6.610, 95% CI 3.109-14.052, P < 0.001), and HbAlc (OR = 1.903, 95% CI 1.092-3.317, P = 0.023) were independent factors that associated with low LAAV in AF patients.

CONCLUSION

Increased HbAlc level is associated with decreased LAAV and may reflect a low contractile function of the left atrial appendage.

Pharmacotherapy for diabetes and stroke risk: Results from ROCKET AF

Background

Insulin use may be a better predictor of stroke risk and morbidity and mortality than diabetes in patients with atrial fibrillation (AF).

Objectives

Determine if the increased risk of stroke observed in patients with AF and diabetes is restricted to those treated with insulin.

Methods

We analyzed the association between diabetes and treatment and the occurrence of stroke/systemic embolism, myocardial infarction (MI), all-cause death, vascular death, composite outcomes, and bleeding risk in the ROCKET AF trial.

Results

In a cohort of 14,264 patients, there were 40.3% (n = 5746) with diabetes, 5.9% (n = 842) on insulin, 18.9% (n = 2697) on oral medications, and 11.9% (n = 1703) diet-controlled. Compared to those without diabetes, patients with non–insulin-treated diabetes had increased risks of stroke (hazard ratio [HR] 1.33, 95% confidence interval [CI] 1.06–1.68), MI (HR 1.64, 95% CI 1.17–2.30), all-cause death (HR 1.26, 95% CI 1.08–1.46), vascular death (HR 1.33, 95% CI 1.11–1.60), and composite outcomes (HR 1.37, 95% CI 1.18–1.157). Patients with insulin-treated diabetes had a significantly higher risk of MI (HR 2.31, 95% CI 1.33–4.01) and composite outcomes (HR 1.57, 95% CI 1.19–2.08) compared to those without diabetes. There were no significant differences between insulin-treated and non–insulin-treated diabetes for any outcome.

Conclusion

Among patients with AF and diabetes, there were no significant differences in outcomes in insulin-treated diabetes compared to non–insulin-treated diabetes.

Lifestyle as a Risk Factor for Atrial Fibrillation

The growing burden of atrial fibrillation health care resource utlization has created an urgent need to develop preventative strategies and opportunities to improve outcomes in the prevalent population. Modifiable risk factors contribute to both disease development and progression. In the prevalent atrial fibrillation population, modifying cardiovascular risk factors has decreased disease burden and progression. However, further research is required to determine the role of comprehensive cardiovascular risk factor modification programs in primary prevention. An understanding of strategies required to facilitate health behavior change is crucial to the effective implementation of cardiovascular risk factor management programs.

Diabetes and atrial fibrillation in hospitalized patients in the United States

BACKGROUND

Data on the burden of atrial fibrillation (AF) associated with diabetes among hospitalized patients are scarce. We assessed the AF-related hospitalizations trends in patients with diabetes, and compared AF outcomes in patients with diabetes to those without diabetes.

HYPOTHESIS

AF-related health outcomes differ between patient with diabetes and without diabetes.

METHODS

Using the National Inpatient Sample (NIS) 2004-2014, we studied trends in AF hospitalization rate among diabetic patients, and compared in-hospital case fatality rate, length of stay (LOS), cost and utilization of rhythm control therapies, and 30-day readmission rate between patients with and without diabetes. Logistic or Cox regression models were used to assess the differences in AF outcomes by diabetes status.

RESULTS

Over the study period, there were 4 325 522 AF-related hospitalizations, of which 1 075 770 (24.9%) had a diagnosis of diabetes. There was a temporal increase in AF hospitalization rate among diabetic patients (10.4 to 14.4 per 1000 hospitalizations among patients with diabetes; +4.4% yearly change, p-trend < .0001). Among AF patients, those with diabetes had a lower in-hospital mortality (adjusted odds ratio [aOR]: 0.68; 95% CI: 0.65-0.72) and LOS (aOR: 0.95; 95% CI: 0.94-0.96), but no difference in costs (aOR: 0.95; 95% CI: 0.94-0.96) and a higher 30-day rate of readmissions compared with no diabetes (aHR 1.05; 95% CI: 1.01-1.08), compared to individuals without diabetes.

CONCLUSION

AF and diabetes coexist among hospitalized patients, with rising trends over the last decade. Diabetes is associated with lower rates in-hospital adverse AF outcomes, but a higher 30-day readmission risk.

Prognostic significance of diabetes mellitus in patients with atrial fibrillation

Background

There are limited data on the association of diabetes mellitus (DM) and levels of glycated hemoglobin (HbA1c) with outcomes in patients with atrial fibrillation (AF).

Methods

This retrospective cohort study included patients who were recently hospitalized with a primary or secondary diagnosis of AF from December 2015 through June 2018. Kaplan–Meier curves and Cox-regression adjusted hazard ratios (aHR) were calculated for the primary outcome of all-cause mortality and for the secondary outcomes of cardiovascular (CV) mortality and the composite outcome of CV death or hospitalization. Competing-risk regression analyses were performed to calculate the cumulative risk of stroke, major bleeding, AF- or HF-hospitalizations adjusted for the competing risk of all-cause death. Spline curve models were fitted to investigate associations of HbA1c values and mortality among patients with AF and DM.

Results

In total 1109 AF patients were included, of whom 373 (33.6%) had DM. During a median follow-up of 2.6 years, 414 (37.3%) patients died. The presence of DM was associated with a higher risk of all-cause mortality (aHR = 1.40 95% confidence intervals [CI] 1.11–1.75), CV mortality (aHR = 1.39, 95% CI 1.07–1.81), sudden cardiac death (aHR = 1.73, 95% CI 1.19–2.52), stroke (aHR = 1.87, 95% CI 1.01–3.45) and the composite outcome of hospitalization or CV death (aHR = 1.27, 95% CI 1.06–1.53). In AF patients with comorbid DM, the spline curves showed a positive linear association between HbA1c levels and outcomes, with values 7.6–8.2% being independent predictors of increased all-cause mortality, and values < 6.2% predicting significantly decreased all-cause and CV mortality.

Conclusions

The presence of DM on top of AF was associated with substantially increased risk for all-cause or CV mortality, sudden cardiac death and excess morbidity. HbA1c levels lower than 6.2% were independently related to better survival rates suggesting that optimal DM control could be associated with better clinical outcomes in AF patients with DM.

Impact of Diabetes Mellitus on Stroke and Survival in Patients With Atrial Fibrillation

Although diabetes mellitus (DM) has been established as a risk factor for developing atrial fibrillation (AF) and is a known risk factor for stroke, it is unclear whether the presence or duration of DM is the primary adverse influence on the clinical course of AF. We retrospectively analyzed patients diagnosed with incident AF to examine the impact of DM on ischemic stroke and all-cause mortality. The diagnosis of DM was established by ICD-9 codes and review of medical records. To account for the significant differences in baseline characteristics of patients with and without diabetes, we matched 909 AF patients with DM with 909 AF patients without DM using propensity score matching based on 26 baseline variables. Cox regression analysis was used to identify independent factors associated with ischemic stroke and mortality. The mean age of the propensity matched cohort was 74 ± 11.5 years and 55.4% were male. Over a median follow-up period of 5.4 years (maximum 23.9 years), cumulative survival was significantly lower for patients with DM than those without DM; Log-rank p <0.001. In the propensity-matched comparison, the risk of mortality was significantly higher in the DM group compared with the non-DM group (hazard ratio 1.25; 95% confidence interval 1.12 to 1.69; p <0.001). Likewise, patients with DM had a higher risk of stroke (hazard ratio 1.32; 95% confidence interval 1.02 to 1.69; p = 0.03). Duration of DM was not associated with increased risk for stroke or mortality. In conclusion, the co-morbidity of DM represents an independent predictor of reduced survival and further highlights the excess risk of thromboembolism in patients with AF.

Effectiveness, safety, and major adverse limb events in atrial fibrillation patients with concomitant diabetes mellitus treated with non-vitamin K antagonist oral anticoagulants

BACKGROUND

Evidence of adverse clinical outcomes for non-vitamin K antagonist oral anticoagulant (NOACs) and warfarin in patients with atrial fibrillation (AF) and diabetes mellitus are limited. We investigated the effectiveness, safety, and major adverse limb events for NOACs versus warfarin among diabetic AF patients.

METHODS

In this nationwide retrospective cohort study collected from Taiwan National Health Insurance Research Database, we identified a total of 20,967 and 5812 consecutive AF patients with diabetes taking NOACs and warfarin from June 1, 2012, to December 31, 2017, respectively. We used propensity-score stabilized weighting to balance covariates across study groups.

RESULTS

NOAC was associated with a lower risk of major adverse cardiovascular events (MACE) (adjusted hazard ratio (aHR):0.88; [95% confidential interval (CI) 0.78-0.99]; P = 0.0283), major adverse limb events (MALE) (aHR:0.72;[95% CI 0.57-0.92]; P = 0.0083), and major bleeding (aHR:0.67;[95% CI 0.59-0.76]; P < 0.0001) compared to warfarin. NOACs decreased MACE in patients of ≥ 75 but not in those aged < 75 years (P interaction = 0.01), and in patients with ischemic heart disease (IHD) compared to those without IHD (P interaction < 0.01). For major adverse limb events, the advantage of risk reduction for NOAC over warfarin persisted in high risk subgroups including age ≥ 75 years, chronic kidney disease, IHD, peripheral artery disease, or use of concomitant antiplatelet drugs.

CONCLUSION

Among diabetic AF patients, NOACs were associated with a lower risk of thromboembolism, major bleeding, and major adverse limb events than warfarin. Thromboprophylaxis with NOACs should be considered in the diabetic AF population with a high atherosclerotic burden.

Glycemic status and risks of thromboembolism and major bleeding in patients with atrial fibrillation

Background

Studies specifically examining the association between glycated hemoglobin A1c (HbA1c) levels and ischemic stroke/systemic thromboembolism (IS/SE) risk in atrial fibrillation (AF) patients are limited. Here, we investigated the association between HbA1c levels and the risk of IS/SE, as well as major bleeding, among AF patients with or without oral anticoagulants (OACs). We also compared the effectiveness and safety of warfarin and direct oral anticoagulants (DOACs) in different HbA1c categories.

Methods

We utilized medical data from a multi-center healthcare provider in Taiwan, which included 34,036 AF patients with serum HbA1c data available within 3 months after AF being diagnosed. Patients were divided into seven study groups according to their HbA1c levels: < 5.4%, 5.4%–5.6%, 5.7%–5.9%, 6.0%–6.4%, 6.5%–6.9%, 7.0%–7.9%, and ≥ 8.0%. The risks of IS/SE and major bleeding were compared among the groups after adjusting for baseline stroke and bleeding risk factors.

Results

Compared with the patients with HbA1c level < 5.4%, IS/SE risk significantly increased at HbA1c levels higher than 6.5% [adjusted hazard ratio (HR): 1.20, 95% confidence interval (CI): 1.00–1.43 for HbA1c level 6.5%–6.9%; 1.32, (95% CI 1.11–1.57) for HbA1c level 7.0%–7.9%; and 1.48 (95% CI 1.25–1.76) for HbA1c level ≥ 8.0%]. These results were generally consistent in AF patients without OACs (n = 24,931). However, among 9105 patients receiving OACs, IS/SE risk was not higher for patients having higher HbA1c levels. The risk of major bleeding was comparable across all HbA1c categories. Compared with warfarin, DOACs were associated with lower risks of IS/SE (adjusted HR: 0.61, 95% CI 0.49–0.75) and major bleeding (adjusted HR: 0.30, 95% CI 0.21–0.42) without interactions across different HbA1c categories (all P interactions > 0.05).

Conclusion

For AF patients, IS/SE risk significantly increased once HbA1c levels exceeded 6.5%, and OACs may attenuate these associations. Compared with warfarin, DOACs were more effective and safer across broad HbA1c categories. Therefore, in addition to prescribing DOACs when indicated, more aggressive glycemic control to achieve an HbA1c level < 6.5% may be considered for eligible AF patients and should be tested in further prospective studies.

Glycemic Status and Thromboembolic Risk in Patients With Atrial Fibrillation and Type 2 Diabetes Mellitus: A Danish Cohort Study

Background Diabetes mellitus is associated with increased risk of stroke in patients with atrial fibrillation, and differences in glycemic status may affect this risk. We aimed to examine the effect of glycemic status evaluated by hemoglobin A1c (HbA1c) on the risk of thromboembolism among patients with atrial fibrillation and type 2 diabetes mellitus. Methods In this cohort study, we used data from Danish registries to identify patients with type 2 diabetes mellitus and incident nonvalvular atrial fibrillation in the period of May 1, 2005, through December 31, 2015. On the basis of the most recent HbA1c measurement before an incident atrial fibrillation diagnosis, patients were divided into the categories: HbA1c ≤48 mmol/mol, HbA1c=49-58 mmol/mol, and HbA1c >58 mmol/mol. Cox regression analysis was used to estimate hazard ratios for the outcome thromboembolism. Results The study population included 5386 patients with incident nonvalvular atrial fibrillation and type 2 diabetes mellitus. Compared with patients with HbA1c ≤48 mmol/mol, we observed a higher risk of thromboembolism among patients with HbA1c=49-58 mmol/mol (hazard ratio, 1.49; 95% CI, 1.09-2.05) and HbA1c >58 mmol/mol (hazard ratio, 1.59; 95% CI, 1.13-2.22) after adjusting for confounding factors. When stratified on diabetes mellitus duration, similar results were found among patients with diabetes mellitus duration of <10 years. Contrastingly, in patients with diabetes mellitus duration of ≥10 years, higher HbA1c levels were not associated with a higher risk of thromboembolism. Conclusions In patients with incident atrial fibrillation and type 2 diabetes mellitus, increasing levels of HbA1c were associated with a higher risk of thromboembolism. However, no association was found among patients with diabetes mellitus duration ≥10 years.

Type 1 versus type 2 diabetes and thromboembolic risk in patients with atrial fibrillation: A Danish nationwide cohort study

BACKGROUND

Atrial fibrillation is a common cause of stroke, and diabetes increases stroke risk. Stroke risk may vary depending on the type of diabetes. We investigated whether type 1 and type 2 diabetes are associated with different risks of thromboembolism among patients with atrial fibrillation.

METHODS

We used data from Danish nationwide registries to identify patients with a prior diagnosis of diabetes and an incident nonvalvular atrial fibrillation diagnosis in the period of January 1, 2005 to December 31, 2015. Cox regression analysis was used to estimate hazard ratios (HR) for the outcome thromboembolism.

RESULTS

The study population included 10,058 patients with a prior diagnosis of diabetes and an incident diagnosis of atrial fibrillation. At three-year follow-up, type 2 diabetes was not associated with a higher risk of thromboembolism compared to type 1 diabetes, with an adjusted HR of 1.15 (95% CI: 0.91-1.44). In an age-stratified analysis, patients aged below 65 years of age had an adjusted HR of 1.97 (95% CI: 1.07-3.61), whereas patients aged 65-74 years or ≥75 years had adjusted HRs of 0.99 (95% CI: 0.67-1.46) and 1.10 (95% CI: 0.80-1.51), respectively.

CONCLUSION

We found no overall credible association between the type of diabetes and risk of thromboembolism in this cohort of non-anticoagulated patients with incident atrial fibrillation. Nonetheless, the subset of patients aged below 65 years of age displayed a higher risk of thromboembolism among patients with type 2 diabetes as compared to patients with type 1 diabetes.

Methodologic Differences Across Studies of Patients With Atrial Fibrillation Lead to Varying Estimates of Stroke Risk

Background

Guidelines for anticoagulation in atrial fibrillation (AF) assume that stroke risk scheme point scores correspond to fixed stroke rates. However, reported stroke rates vary widely across AF cohort studies, including studies from the same country. Reasons for this variation are unclear. This study compares methodologies used to assemble and analyze large AF cohorts worldwide and assesses potential bias in estimating stroke rates.

Methods and Results

From a previous systematic review of AF cohorts, we analyzed studies including at least 5000 patients. We assessed methods used to generate rates of ischemic stroke off anticoagulants, according to a structured inventory of database interrogation methods. Nine studies (497 578 total patients) met our criteria. Overall cohort stroke rates ranged from 0.45% to 7.03% per year. In bivariate study‐level analysis, multiple features were associated with higher stroke rates, including AF identified as inpatients versus outpatients (rate ratio 2.60, 95% confidence interval, 1.19, 5.68), and lack of clinical validation of outcome events (rate ratio 4.09, 95% confidence interval, 1.06, 15.70). European studies reported rates more than 4‐fold higher than North American studies. International Classification of Diseases (ICD) coding schemes for outcomes varied widely. Multiple high rate features coexisted in the same studies.

Conclusions

Among AF cohort studies, differences in the composition, method of assembly, determination of clinical features and outcomes, and analytic approach were strongly associated with reported stroke rates. Our study highlights the need for standardized and validated methodologies for AF cohort assembly and analysis to generate accurate stroke rates to better support anticoagulation guidelines for patients with AF.

Relationship Between Glycated Hemoglobin and Stroke Risk: A Systematic Review and Meta-Analysis

BACKGROUND

Diabetes mellitus is a major risk factor for ischemic stroke. Rising hemoglobin A_1c (HbA_1c) levels are associated with microvascular diabetes mellitus complication development; however, this relationship has not been established for stroke risk, a macrovascular complication.

METHODS AND RESULTS

We conducted a systematic review and meta-analysis of observational cohort and nested case-control cohort studies assessing the association between rising HbA_1c levels and stroke risk in adults (≥18 years old) with and without type 1 or type 2 diabetes mellitus. Random-effects model meta-analyses were used to calculate pooled adjusted hazard ratios (HRs) and their precision. The systematic review yielded 36 articles, of which 29 articles (comprising n=532 779 participants) were included in our meta-analysis. Compared to non-diabetes mellitus range HbA_1c (<5.7%), diabetes mellitus range HbA_1c (≥6.5%) was associated with an increased risk of first-ever stroke with average HR (95% confidence interval) of 2.15 (1.76, 2.63), whereas pre-diabetes mellitus range HbA_1c (5.7-6.5%) was not (average HR [95% confidence interval], 1.19 [0.87, 1.62]). For every 1% HbA_1c increment (or equivalent), the average HR (95% confidence interval) for first-ever stroke was 1.12 (0.91, 1.39) in non-diabetes mellitus cohorts and 1.17 (1.09, 1.25) in diabetes mellitus cohorts. For every 1% HbA_1c increment, both non-diabetes mellitus and diabetes mellitus cohorts had a higher associated risk of first-ever ischemic stroke with average HR (95% confidence interval) of 1.49 (1.32, 1.69) and 1.24 (1.11, 1.39), respectively.

CONCLUSIONS

A rising HbA_1c level is associated with increased first-ever stroke risk in cohorts with a diabetes mellitus diagnosis and increased risk of first-ever ischemic stroke in non-diabetes mellitus cohorts. These findings suggest that more intensive HbA_1c glycemic control targets may be required for optimal ischemic stroke prevention.

Risk Factors for Failure of Direct Current Cardioversion in Patients with Type 2 Diabetes Mellitus and Atrial Fibrillation

Introduction

Type 2 diabetes mellitus (T2DM) is a well-recognised risk factor for cardiovascular disease and the prevalence of atrial fibrillation (AF) is higher among patients with T2DM. Direct current cardioversion (DCCV) is an important management option in persistent AF. We sought to determine independent risk factors for immediate and short-term outcomes of DCCV for treatment of AF in patients with T2DM.

Methods

Retrospective outcome analysis of DCCV for persistent AF in 102 T2DM patients compared with 102 controls.

Results

DCCV was successful in 68 (66.6%) people with T2DM compared to 86 (84.3%) in the control group (P = 0.003). After initial successful cardioversion, only 38 (37.2%) T2DM patients remained in sinus rhythm compared to 63 (61.8%) in the control group (P = 0.007) at a median follow-up of 74.5 days (IQR 69.4-77.4). Multiple logistic regression analysis showed that the presence of T2DM (P = 0.014), digoxin use (P = 0.01), statin use (P = 0.005), left-atrial size (P = 0.01), and LV ejection fraction (P = 0.008) were independent risk factors for immediate DCCV failure. T2DM (P = 0.034) was an independent risk factor for AF relapse. Among patients with T2DM, previous DCCV (P = 0.033), digoxin use (P = 0.035), left-atrial size (P = 0.01), LV ejection fraction (P = 0.036), and HbA1c (P = 0.011) predicted immediate failure of DCCV whilst digoxin use (P = 0.026) was an independent risk factor for relapse of AF.

Conclusion

T2DM, higher HbA1c, digoxin treatment, and structural and functional cardiac abnormalities are independent risk factors for immediate DCCV failure and AF relapse.

Hemoglobin A1c and risk of left atrial thrombus and spontaneous echo contrast in non-valvular atrial fibrillation patients

OBJECTIVES

To evaluate the relationship between hemoglobin A1c (HbA1c) and risk of left atrial thrombus/spontaneous echo contrast (LAT/SEC) in non-valvular atrial fibrillation (AF) patients.

METHODS

In this retrospective study, 1158 consecutive non-valvular AF patients undergoing transesophageal echocardiography prior to radiofrequency catheter ablation or electric cardioversion were enrolled. Baseline characteristics were collected and analyzed.

RESULTS

There were 87 (7.5%) patients with LAT/SEC. The HbA1c levels in the patients with LAT/SEC were significantly higher than that in patients without LAT/SEC (6.13 ± 0.41 vs. 5.89 ± 0.45 μmol/L, P < 0.001). The optimal cut-off point for HbA1c predicting LAT/SEC was 6.1% determined by receiver-operating characteristic curve. The area under the curve is 0.788 (95% confidence interval: 0.764-0.812). HbA1c ≥6.1% was an independent risk factor for LAT/SEC (odds ratio, 1.74; 95% confidence interval, 1.01-2.98; P = 0.045).

CONCLUSIONS

Elevated HbA1c indicated a significantly increased risk for LAT/SEC in non-valvular AF patients. HbA1c might have significance in predicting the risk for prothrombotic state in non-valvular AF patients.

Serum glycated hemoglobin level as a predictor of atrial fibrillation: A systematic review with meta-analysis and meta-regression

Background and Aim

Glycated hemoglobin (HbA1c) is a long-term measure of glucose control. Although recent studies demonstrated a potential association between HbA1c levels and the risk of atrial fibrillation (AF), the results have been inconsistent. The aim of this meta-analysis is to evaluate the utility of HbA1c level in predicting AF.

Methods

PubMed and the Cochrane Library databases were searched for relevant studies up to March 2016. Prospective cohort studies and retrospective case-control studies were included. Relative risk (RR) or odds ratio (OR) with 95% confidence intervals (CIs) of AF development were determined for different HbA1c levels. The random effect model was conducted according to the test of heterogeneity among studies. Subgroup analyses and meta-regression models were carried out to identify potential sources of heterogeneity.

Results

Eight prospective cohort studies with 102,006 participants and 6 retrospective case-control studies with 57,669 patients were finally included in the meta-analysis. In the primary meta-analysis, HbA1c levels were not associated with an increased risk of AF whether as a continuous (RR, 1.06; 95% CI, 0.96–1.18) or categorical variable (RR, 0.99; 95% CI, 0.83–1.18). Nevertheless, prospective studies showed about 10% increased risk of AF with elevated HbA1c levels both as a continuous (RR, 1.11; 95% CI, 1.06–1.16) and as a categorical variable (RR, 1.09; 95% CI, 1.00–1.18). In subgroup analyses, pooled results from studies with longer follow-up durations, published after 2012, aged < 63 years, with exclusion of cardiac surgery patients demonstrated an increased risk of AF for every 1% increase in HbA1c levels, while studies conducted in the United States with longer follow-up (more than 96 months), larger sample size and higher quality score (≥6) showed an increased risk of AF for higher HbA1c level as a categorical variable.

Conclusions

Elevated serum HbA1c levels may be associated with an increased risk of AF, but further data are needed. Serum HbA1c levels might be considered as a potential biomarker for prediction of AF.

Catheter ablation of atrial fibrillation is associated with reduced risk of stroke and mortality: A propensity score-matched analysis

BACKGROUND

Catheter ablation reduces recurrence of atrial fibrillation and improves quality of life. Only few studies have assessed the effect of catheter ablation on long-term outcomes.

OBJECTIVE

The purpose of this study was to assess the association between catheter ablation and risk of stroke and mortality in patients with atrial fibrillation.

METHODS

Using the computerized database of the largest health maintenance organization in Israel, we identified all adults hospitalized with a primary diagnosis of atrial fibrillation between January 1, 2005, and December 31, 2015. Of them, a total of 969 individuals who underwent catheter ablation during the same admission were matched, on the basis of the propensity of having ablation, with 3772 individuals who did not undergo catheter ablation during the same period. The cohort was followed for the occurrence of stroke or transient ischemic attack (TIA) and mortality until June 30, 2016.

RESULTS

Overall, 3953 (83.4%) of patient in both groups had a CHA₂DS₂VASc score of 2 or greater. The incidence rate of stroke/TIA was 2.10 and 3.26 per 100 person-years in the ablation group and the nonablation group, respectively. The crude hazard ratio [HR] for stroke/TIA was 0.61 (95% confidence interval [CI] 0.48-0.79) in the ablation group compared with the nonablation group. The results were similar after controlling for CHA₂DS₂-VASc score (HR 0.58; 95% CI 0.43-0.72). The adjusted HRs for stroke alone, TIA alone, and mortality were 0.62 (95% CI 0.47-0.82), 0.47 (95% CI 0.20-0.78), and 0.57 (95% CI 0.47-0.66), respectively.

CONCLUSION

Catheter ablation of atrial fibrillation is associated with a decreased risk of stroke/TIA and mortality in predominantly patients with a high CHA₂DS₂-VASc score.

Wide Variation in Reported Rates of Stroke Across Cohorts of Patients With Atrial Fibrillation

Background:

Oral anticoagulants decrease ischemic stroke rates in patients with atrial fibrillation (AF) but increase the risk of bleeding. For the average patient with AF, the threshold of annual ischemic stroke rate where the benefit of anticoagulation outweighs the bleeding risk (net clinical benefit) has been shown to be ≈1% to 2%. Guideline recommendations for oral anticoagulants in AF are based on the CHA 2 DS 2 -VASc stroke risk point scores, assuming that those scores translate to fixed stroke rates. However, the relationship between stroke point scores and annual stroke rates may vary substantially across populations. We sought to comprehensively assess the reported rates of stroke in patients with AF and the relationship of stroke rates to stroke risk point scores.

Methods:

A systematic review of cohort studies and randomized controlled trials enrolled patients with nonvalvular AF not treated with oral anticoagulants.

Results:

Of the 3552 studies screened, we identified 34 studies eligible for analysis. Overall stroke rates in cohort studies were highly heterogeneous (Q=5706.54, P <0.001; I 2 = 99.6%) and ranged from 0.45% to 9.28% per year, despite being of similar objective study quality. The mean North American stroke rate was less than one-third that of the mean European stroke rate ( P <0.0001). However, a random effects regression indicated that between-study variability was not significantly accounted for by cohort region, prospective versus retrospective design, calendar year of study, or outcome event cluster. At a CHA 2 DS 2 -VASc score of 1, 76% of cohorts reported ischemic stroke rates <1% per year and only 18% of cohorts reported a stroke rate >2% per year. At a CHA 2 DS 2 -VASc score of 2, 27% of cohorts reported stroke rates below 1% per year, 40% reported stroke rates between 1 and 2% per year, and 33% reported stroke rates >2% per year.

Conclusions:

Substantial variation exists across cohorts in overall stroke rates and rates corresponding to CHA 2 DS 2 -VASc point scores. These variations can affect the point score threshold for recommending oral anticoagulants in AF. The majority of cohorts did not observe stroke rates that would indicate a clear expected net clinical benefit for anticoagulating AF patients with CHA 2 DS 2 -VASc scores of 1 or 2.

High HbA1c is associated with higher risk of ischaemic stroke in Pakistani population without diabetes

CONTEXT

The role of glycated haemoglobin (HbA1c) in the prediction of ischaemic stroke in individuals without diabetes is underestimated.

AIMS

We performed a study to analyse the role of HbA1c in the risk prediction of ischaemic stroke in Pakistani population without diabetes. We further studied the difference between HbA1c values of individuals with diabetes and without diabetes with stroke.

SETTINGS AND DESIGN

Single centre, case-control.

MATERIALS AND METHODS

In phase I, a total of 233 patients without diabetes with ischaemic stroke and 245 as controls were enrolled. Association of HbA1c levels, lipid profiles and blood pressure recordings with ischaemic stroke was analysed. In phase II, comparison was done between diabetics and non-diabetics with stroke.

STATISTICAL ANALYSIS

Comparison of the mean variables was performed with Student's t-tests. Logistic regression analysis with ischaemic stroke as the dependent variable was performed for phase I.

RESULTS

In phase I, the ischaemic stroke group had significantly higher HbA1c levels (5.9±2.9% vs 5.5±1.6%) compared with controls (p<0.05). Triglyceride cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, diastolic blood pressure and HbA1c were the significant determinants of stroke (p<0.05). In phase II, mean HbA1c values were significantly higher in the diabetes group (7.6±2.1 vs 6.1±2.3) (p<0.05) but other parameters were not statistically significantly different (p>0.05).

CONCLUSIONS

Higher HbA1c indicated a significantly increased risk for ischaemic stroke. An HbA1c value above 5.6% (prediabetic range) predicted future risk of stroke and efforts to maintain glucose level within the normal range (≤5.6%) in individuals with high cardiovascular risk are important.

Evaluation of the association between diabetic retinopathy and the incidence of atrial fibrillation: A nationwide population-based study

BACKGROUND

Atrial fibrillation (AF) is prevalent among type 2 diabetic patients. However, the association between diabetic retinopathy (DR) and AF is controversial.

METHODS

We included 40,500 patients with type 2 diabetes (≥40years, mean age 62±11years, 53% men) without AF from the Korean National Insurance Service-National Sample Cohort (2002-2007). Subjects were classified without DR (non-DR, n=30,178), with DR (DR, n=8920), and with proliferative DR (PDR, n=1402).

RESULTS

During a mean 5.9-year follow-up, 1261 (3.1%) patients were newly diagnosed as having AF (4.9, 6.0, and 8.3 per 1000 person-years in the non-DR, DR, and PDR groups, respectively). In multivariate Cox proportional hazard models, patients in the DR and PDR groups had a significantly higher risk of AF than those in the non-DR group (DR group: hazard ratio [HR] 1.14, 95% confidence interval [CI] 1.00-1.30; PDR group: HR 1.46, 95% CI 1.13-1.87); p for trend <0.001). The risk of AF increased in patients with DR and end-stage renal disease (ESRD) (HR 2.39, 95% CI 1.31-3.96, p<0.001) and in those with PDR and ESRD (HR 3.59, 95% CI 1.96-5.97, p<0.001) compared to those without DR and ESRD.

CONCLUSIONS

The presence and severity of DR was significantly associated with the incidence of AF. Also, the presence of ESRD had an impact on the incidence of AF in patients with DR.