Increased risk of first-ever stroke in younger patients with atrial fibrillation not recommended for antithrombotic therapy by current guidelines: a population-based study in an East Asian cohort of 22 million people

Use of the CHA2DS2-VASc score to predict subsequent myocardial infarction in atrial fibrillation

BACKGROUND

The risk of subsequent myocardial infarction (MI) varies widely in patients with atrial fibrillation (AF). No convenient scoring system currently exists to identify MI in AF. While each element of the CHA2DS2-VASc (congestive heart failure; hypertension; age ≥75 years [doubled]; type 2 diabetes; previous stroke or thromboembolism [doubled]; vascular disease; age 65-75 years; and sex category) score can increase the likelihood of MI, this retrospective longitudinal study aimed to determine the accuracy of the CHA2DS2-VASc score in predicting subsequent MI risk in AF.

METHODS

A total of 29,341 patients with AF were enrolled and followed up from January 2010 until the first occurrence of MI or until December 2020. The primary endpoint was the occurrence of subsequent MI.

RESULTS

The average age of the study population was 71 years, and 43.2% were male. The mean CHA2DS2-VASc score was found to be higher in patients with AF who had experienced an MI than in those who had not (3.56 ± 1.92 vs. 3.32 ± 1.81, p < 0.001). During the long-term follow-up, the risk of subsequent MI increased by 22% with every one-point increase in the CHA2DS2-VASc score (hazard ratio 1.22, 95% confidence interval 1.19-1.25; p < 0.001). Kaplan-Meier analysis revealed that high CHA2DS2-VASc scores were more likely to experience an MI than those with low CHA2DS2-VASc scores (log-rank p < 0.001). Furthermore, the CHA2DS2-VASc score was a significant predictor of MI in multivariate regression analysis.

CONCLUSION

The CHA2DS2-VASc score is a valuable predictor of subsequent MI risk in patients with AF.

Identification of Markers Associated With Development of Stroke in "Clinically Low-Risk" Atrial Fibrillation Patients

Background

Stroke and thromboembolic events may still occur in “clinically low‐risk” atrial fibrillation (AF) patients as categorized by CHA₂DS₂‐VASc score. Our aim was to assess the proportion of “clinically low‐risk” patients using a nongender CHA₂DS₂‐VASc (ie, CHA₂DS₂‐VA) score of 0 to 1 among patients who experienced AF‐associated stroke and to identify markers associated with stroke in “clinically low‐risk” patients.

Methods and Results

We retrospectively recruited nonvalvular AF patients who experienced embolic stroke between 2013 and 2016 from 9 institutes in Korea. AF patients with CHA₂DS₂‐VA score of 0 to 1 at the time of stroke were analyzed and compared with “clinically low‐risk” AF patients without stroke. A total of 3033 subjects with AF‐associated stroke were recruited. Of these, 583 patients (19.2%) had CHA₂DS₂‐VA score of 0 to 1. On multivariate analysis, age (≥60 years), N‐terminal pro B‐type natriuretic peptide (≥300 pg/mL), creatinine clearance (<50 mL/min), and left atrial dimension (≥45 mm) were independently associated with stroke. With the combined application of these 4 factors (collectively, ABCD score) to the “clinically low‐risk” patients, the c‐index was 0.858 (95% CI 0.838–0.877; P<0.001).

Conclusions

The present study suggests a new insight into how additional use of markers can further refine stroke risk differentiation among AF patients initially classified as “clinically low‐risk.”

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT03147911.

High Incidence of Occult Atrial Fibrillation in Asian Patients with Cryptogenic Stroke

BACKGROUND

Occult atrial fibrillation (AF) is not uncommon in patients with stroke. In western cohorts, insertable loop recorders (ILRs) have been shown to be the gold-standard and are cost-effective for AF detection. Anticoagulation for secondary stroke prevention is indicated if AF is detected. The incidence of occult AF among Asian patients with cryptogenic stroke is unclear.

METHODS

Patients with cryptogenic stroke referred between August 2014 and February 2017 had ILRs implanted. Episodes of AF >2 minutes duration were recorded using proprietary algorithms within the ILRs, whereupon clinicians and patients were alerted via remote monitoring. All AF episodes were adjudicated using recorded electrograms. Once AF was detected, patients were counseled for anticoagulation.

RESULTS

Seventy-one patients with cryptogenic stroke, (age 61.9 ± 13.5 years, 77.5% male, mean CHA₂DS₂VASc score of 4.2 ± 1.3) had ILRs implanted. Time from stroke to the ILR implant was a median of 66 days. Duration of ILR monitoring was 345 ± 229 days. The primary endpoint of AF detection at 6 months was 12.9%; and at 12 months it was 15.2%. Median time to detection of AF was 50 days. The AF episodes were all asymptomatic and lasted a mean of 77 minutes (± 118.9). Anticoagulation was initiated in all but 1 patient found to have AF.

CONCLUSIONS

The incidence of occult AF is high in Asian patients with cryptogenic stroke and comparable to western cohorts. The combination of ILR and remote monitoring is a highly automated, technologically driven, and clinically effective technique to screen for AF.

The β-fibrinogen gene 455G/A polymorphism associated with cardioembolic stroke in atrial fibrillation with low CHA2DS2-VaSc score

Previous work has suggested that ischemic stroke (IS) may be more likely to occur in individuals with a genetic predisposition. In this study, we investigated the potential association of IS-relevant genetic risk factors with cardioembolic stroke (CES) in atrial fibrillation (AF) patients with low CHA2DS2-VaSc score. Genotyping was performed using the GenomeLab SNPstream genotyping platform for five IS-relevant SNPs (MMP-9 C1562T, ALOX5AP SG13S114A/T, MTHFR 677 C/T, FGB 455 G/A, and eNOS G298A) in 479 AF patients with CES and 580 age and sex-matched AF patients without CES. The multivariate analysis adjusted for potential confounders and demonstrated that FGB 455 G/A was independently associated with increased risk of CES in AF patients and the significance remained after Bonferroni correction in the additive, dominant, and recessive models with ORs of 1.548 (95% CI: 1.251–1.915, P = 0.001), 1.588 (95% CI: (1.226–2.057, P = 0.003), and 2.394 (95% CI: 1.357–4.223, P = 0.015), respectively. Plasma fibrinogen levels were significantly higher in patients with the A allele compared with patients with genotype of GG (3.29 ± 0.38 mg/dl vs. 2.87 ± 0.18 mg/dl, P < 0.001). We found for the first time that the A allele of FGB 455 G/A was a risk factor for CES in AF patients, probably by elevating the level of plasma fibrinogen.

Diabetes mellitus increased all-cause mortality rate among newly-diagnosed tuberculosis patients in an Asian population: A nationwide population-based study

AIMS

To investigate the effect of diabetes mellitus (DM) on all-cause mortality among patients with newly-diagnosed tuberculosis (TB) in an Asian population. We also identified risk factors for mortality in these patients.

METHODS

The data were obtained from the National Health Insurance Research Database and included 9831 newly-diagnosed TB individuals and 1627 TB mortality cases in the period of 2000-2010. The mortality data were divided into a DM group and a non-DM group. We measured the incidence density of mortality and identified the risk factors of mortality.

RESULTS

The all-cause mortality of newly-diagnosed TB patients progressively increased with an average rate of 16.5% during 2000-2010. DM is an independent risk factor for all-cause mortality with HRs 1.17-1.27 by various models. TB patients with ages above 75years had the highest risk of mortality (HR=11.93) compared with those under 45 years. TB patients with heart failure, peripheral vascular disease, ischemic heart disease, cerebral vascular disease, hypertension, chronic kidney disease, pulmonary disease, liver disease, cancer, peptic ulcer disease, gout, and autoimmune disease had higher mortality compared to those without the aforementioned factors.

CONCLUSIONS

The one-year all-cause mortality after TB diagnosis was high among TB patients in Taiwan and it tended to increase in the past decade. While treating these newly-diagnosed TB patients, it is crucial to detect the factors predisposing to death, such as old age, male gender, certain kinds of aforementioned factors and diabetes.

Predictive performance of the CHA2DS2-VASc rule in atrial fibrillation: a systematic review and meta-analysis

Essentials The widely recommended CHA2DS2-VASc shows conflicting results in contemporary validation studies. We performed a systematic review and meta-analysis of 19 studies validating CHA2DS2-VASc. There was high heterogeneity in stroke risks for different CHA2DS2-VASc scores. This was not explained by differences between setting of care, or by performing meta-regression.

SUMMARY

Background The CHA2DS2-VASc decision rule is widely recommended for estimating stroke risk in patients with atrial fibrillation (AF), although validation studies show ambiguous and conflicting results. Objectives To: (i) review existing studies validating CHA2DS2-VASc in AF patients who are not (yet) anticoagulated; (ii) meta-analyze estimates of stroke risk per score; and (iii) explore sources of heterogeneity across the validation studies. Methods We performed a systematic literature review and random effects meta-analysis of studies externally validating CHA2DS2-VASc in AF patients not receiving anticoagulants. To explore between-study heterogeneity in stroke risk, we stratified studies to the clinical setting in which patient enrollment started, and performed meta-regression. Results In total, 19 studies were evaluated, with over two million person-years of follow-up. In studies recruiting AF patients in hospitals, stroke risks for scores of 0, 1 and 2 were 0.4% (approximate 95% prediction interval [PI] 0.2-3.2%), 1.2% (95% PI 0.1-3.8%), and 2.2% (95% PI 0.03-7.8%), respectively. These were consistently higher than those in studies recruiting patients from the open general population, with risks of 0.2% (95% PI 0.0-0.9%), 0.7% (95% PI 0.3-1.2%) and 1.5% (95% PI 0.4-3.3%) for scores of 0, 1, and 2, respectively. Heterogeneity, as reflected by the wide PIs, could not be fully explained by meta-regression. Conclusions Studies validating CHA2DS2-VASc show high heterogeneity in predicted stroke risks for different scores.

The Global Burden of Atrial Fibrillation and Stroke: A Systematic Review of the Clinical Epidemiology of Atrial Fibrillation in Asia

BACKGROUND

Our previous review reported great variability in the incidence and prevalence of atrial fibrillation (AF) in non-Western cohorts, especially from Asian countries; in recent years, epidemiologic studies on AF have been increasingly reported from Asia.

METHODS

The goal of this updated systematic review was to present the current knowledge base of AF epidemiology in Asian countries since our previous review. We also explored AF incidence and the risk of stroke in AF by using a meta-analysis, with I² testing the heterogeneity. Third, "real-world" antithrombotic drug use for ischemic stroke (IS) prevention associated with AF was studied.

RESULTS

A total of 58 articles from eight countries in Asia were included in the analysis. The summary annual incidence of AF was 5.38 (95% CI, 4.53-6.24; I² = 99.5%; n = 10) per 1,000 person-years, and the IS annual risk in AF was 3.0% (1.60%-4.95%; I² = 99.8%; n = 8) when meta-analysis was performed on hospital- and community-based studies. Hospital- and community-based AF prevalence ranged from 0.37% to 3.56% and 2.8% to 15.8%, respectively. IS prevalence in AF ranged from 1.9% to 6.0% and 0.36% to 28.3% in community- and hospital-based studies. Warfarin use in Chinese subjects is relatively low (1.0%-4.1%) compared with Japanese subjects (49.1%-70.0%) in community-based studies. The rate of warfarin use was < 50% in hospital-based studies.

CONCLUSIONS

The incidence and prevalence of AF have increased in recent years, although great variability still exists in Asian countries. Variability in annual IS risk in patients with AF was apparent between hospital- and community-based studies. However, the rate of warfarin use was < 50% in hospital studies from Asian countries.

2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Both the incidence and prevalence of AF are increasing, and the burden of AF is becoming huge. Many innovative advances have emerged in the past decade for the diagnosis and management of AF, including a new scoring system for the prediction of stroke and bleeding events, the introduction of non-vitamin K antagonist oral anticoagulants and their special benefits in Asians, new rhythm- and rate-control concepts, optimal endpoints of rate control, upstream therapy, life-style modification to prevent AF recurrence, and new ablation techniques. The Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology aimed to update the information and have appointed a jointed writing committee for new AF guidelines. The writing committee members comprehensively reviewed and summarized the literature, and completed the 2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the Management of Atrial Fibrillation. This guideline presents the details of the updated recommendations, along with their background and rationale, focusing on data unique for Asians. The guidelines are not mandatory, and members of the writing committee fully realize that treatment of AF should be individualized. The physician's decision remains most important in AF management.

CHA2DS2-VASc Recalibration With an Additional Age Category (50-64 Years) Enhances Stroke Risk Stratification in Chinese Patients With Atrial Fibrillation

BACKGROUND

Chinese patients with atrial fibrillation (AF) and a low CHA₂DS₂-VASc have a disproportionately high ischemic stroke risk; nonetheless, little is known about the impact of age on ischemic stroke risk in this population. In this study, we aimed to examine the age-related ischemic stroke risk in Chinese patients with nonvalvular AF without other risk factors for stroke.

METHODS

This was a hospital-based observational registry.

RESULTS

A total of 1198 Chinese patients with AF (mean age, 73.6 ± 16.5 years; male sex, 53.3%) were included in this analysis. The mean CHA₂DS₂-VASc and HAS-BLED score were 1.81 ± 1.00 and 1.32 ± 0.77, respectively, and none of the patients was prescribed antiplatelet or anticoagulation therapy. After a mean follow-up of 2.95 years, there were 234 ischemic strokes (19.5%), with an annual ischemic stroke incidence of 6.62%/y. The overall annual ischemic stroke risk was 0.43%/y, 5.87%/y, 7.49%/y, and 8.04%/y for age groups < 50 years, 50-64 years, 65-74 years, and ≥ 75 years, respectively. There was a 10- to 20-fold gradient in ischemic stroke risk that increased sharply after the age of 50 years. The hazard ratios were 1.0, 13.0, 19.3, and 21.6 for age groups < 50 years, 50-64 years, 65-74 years and ≥ 75 years, respectively (P for trend < 0.0001). Similar trends were also observed in both male and female patients with AF.

CONCLUSIONS

Chinese patients with AF and a low CHA₂DS₂-VASc were at a disproportionally high risk of ischemic stroke. Chinese patients between 50 and 64 years have a high risk for stroke despite a low CHA₂DS₂-VASc and a low bleeding risk. Only patients aged < 50 years have a truly low risk.

High diabetes mellitus prevalence with increasing trend among newly-diagnosed tuberculosis patients in an Asian population: A nationwide population-based study

AIMS

Our aims were to investigate the prevalence of diabetes mellitus (DM) among patients with newly-diagnosed tuberculosis (TB) and to determine its associated factors in an Asian population.

METHODS

The data were obtained from the National Health Insurance Research Database and included 9831 newly-diagnosed TB individuals in the period of 2000-2010. The data were divided into a DM group and a non-DM group. We measured the prevalence and the associated comorbidities of DM.

RESULTS

During 2000-2010, the prevalence of DM progressively increased, with an average prevalence rate of 27.9%. The patients with ages of 55-64 years had the highest association of DM (OR=3.53) compared with those under 45 years. TB patients with heart failure, ischemic heart disease, cerebral vascular disease, hypertension, dyslipidemia, chronic kidney disease, and liver disease were more likely to associate with DM (ORs=1.27, 1.23, 1.30, 2.32, 3.26, 1.6, and 1.68, respectively) compared to those without the variables.

CONCLUSIONS

The prevalence of DM among TB patients in Taiwan was high and tended to increase in the past decade. Clinically, inquiring about DM history and screening routinely for those without DM history among TB patients should be carried out in Taiwan.