Association between γ-glutamyltransferase level and incidence of atrial fibrillation: A nationwide population-based study

Association between the accumulation of elevated serum γ-glutamyltransferase level and risk of atrial fibrillation: a nationwide cohort study

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The association between AF and γ-Glutamyltransferase (GGT) was not fully established. This study demonstrated the independent association of cumulative GGT score and AF incidence with the dose-response relationship. Using the Korean National Health Insurance Corporation database, adult subjects who had 4 consecutive annual health examinations from 2009 to 2012 were enrolled. A cumulative GGT score was calculated as the cumulative number of the highest GGT quartile amongst four examinations (0-4 times). A multivariable Cox proportional hazards regression analysis was performed. Among a total of 3,500,847 people included, AF was developed in 27,752 people (0.793%) during a median of 8.0 years of follow up. The incidence rate of AF and adjusted hazard ratio were increased by a stepwise manner in the higher quartile group and cumulative GGT score group. In subgroup analysis, this trend was more prominent in the elderly, people without hypertension, non-obese people, and people without any four comorbidities (diabetes mellitus, hypertension, dyslipidemia, and obesity). Our results suggest multiple accumulation of elevated GGT levels in health examination might be a useful marker for risk stratification of AF development, especially in the elderly and healthy population.

Association of gamma-glutamyl transferase variability with risk of venous thrombosis

Gamma-glutamyl transferase (GGT) is a biomarker of inflammation, and is known to be associated with stroke and atrial fibrillation. Venous thromboembolism (VT), a not uncommon thrombotic disorder, shares similar mechanisms with other thrombotic disorders including these stroke and atrial fibrillation. Given these associations, we intended to investigate the potential association between variability in GGT and VT. The study included data from the National Health Insurance Service-Health Screening Cohort, comprising 1,085,105 participants with health examinations 3 or more times from 2003 to 2008. Variability indexes were the coefficient of variation, standard deviation, and variability independent of the mean. The occurrence of venous thromboembolism (VT) was defined with more than one claim of the following ICD-10 codes: deep VT (I80.2-80.3), pulmonary thromboembolism (I26), intraabdominal venous thrombosis (I81, I82.2, I82.3), or other VT (I82.8, I82.9). To determine the relationship of quartiles of GGT with incident VT risk, Kaplan-Meier survival curve and logrank test were used. Cox's proportional hazard regression was used to investigate the risk of VT occurrence by GGT quartile (Q1-Q4). A total of 1,085,105 subjects were incorporated in the analysis, and the average follow-up was 12.4 years (interquartile range 12.2-12.6). VT occurred in 11,769 (1.08%) patients. The GGT level was measured 5,707,768 times in this stud. Multivariable analysis showed that GGT variability were positively associated with the occurrence of VT. Compared to the Q1, the Q4 showed an adjusted HR of 1.15 (95% CI 1.09-1.21, p < 0.001) when using coefficient of variation, 1.24 (95% CI 1.17-1.31, p < 0.001) when using standard deviation, and 1.10 (95% CI 1.05-1.16, p < 0.001) when using variability independent of the mean. Increased variability of GGT may be related to an increased risk of VT. Maintaining a stable GGT level would be beneficial in reducing the risk of VT.

Risk prediction for new-onset atrial fibrillation using the Minnesota code electrocardiography classification system

Background

Few risk models are available to predict future onset of atrial fibrillation (AF) in workers. We aimed to develop risk prediction models for new-onset AF, using annual health checkup (HC) data with electrocardiogram findings.

Methods and Results

We retrospectively included 56,288 factory or office workers (mean age = 51.5 years, 33.0% women) who underwent a HC at a medical center and fulfilled the following criteria; age ≥ 40 years, no history of AF, and greater than 1 annual follow-up HC in 2013–2016. Using Cox models with the Akaike information criterion, we developed and compared prediction models for new-onset AF with and without the Minnesota code information. We externally validated the discrimination accuracy of the models in a general Japanese population cohort, the Hisayama cohort. During the median 3.0-year follow-up, 209 (0.37%) workers developed AF. Age, sex, waist circumference, blood pressure, LDL cholesterol, and γ-GTP were associated with new-onset of AF. Using the Minnesota code information, the AUC significantly improved from 0.82 to 0.84 in the derivation cohort and numerically improved from 0.78 to 0.79 in the validation cohort, and from 0.77 to 0.79 in the Hisayama cohort. The NRI and IDI significantly improved in all and male subjects in both the derivation and validation cohorts, and in female subjects in both the validation and the Hisayama cohorts.

Conclusions

We developed useful risk model with Minnesota code information for predicting new-onset AF from large worker population validated in the original and external cohorts, although study interpretation is limited by small improvement of AUC.

Nonalcoholic fatty liver disease and the risk of atrial fibrillation stratified by body mass index: a nationwide population-based study

We evaluated the association between nonalcoholic fatty liver disease (NAFLD) and incident atrial fibrillation (AF) and analyzed the impact of NAFLD on AF risk in relation to body mass index (BMI). A total of 8,048,055 subjects without significant liver disease who were available fatty liver index (FLI) values were included. Subjects were categorized into 3 groups based on FLI: < 30, 30 to < 60, and ≥ 60. During a median 8-year of follow-up, 534,442 subjects were newly diagnosed as AF (8.27 per 1000 person-years). Higher FLI was associated with an increased risk of AF (hazard ratio [HR] 1.053, 95% confidence interval [CI] 1.046–1.060 in 30 ≤ FLI < 60, and HR 1.115, 95% CI 1.106–1.125 in FLI ≥ 60). In underweight subjects (BMI < 18.5 kg/m²), higher FLI raised the risk of AF (by 1.6-fold in 30 ≤ FLI < 60 and by twofold in FLI ≥ 60). In normal- and overweight subjects, higher FLI was associated with an increased risk of AF, but the HRs were attenuated. In obese subjects, higher FLI was not associated with higher risk of AF. NAFLD as assessed by FLI was independently associated with an increased risk of AF in nonobese subjects with BMI < 25 kg/m². The impact of NAFLD on AF risk was accentuated in lean subjects with underweight.

Association between routine biomarkers and atrial fibrillation in patients undergoing implantation of a dual-chamber pacemaker

BACKGROUND

Elderly patients having a permanent pacemaker frequently have atrial remodeling. We examined the association between routine biomarkers and atrial fibrillation (AF) in patients receiving a dual-chamber pacemaker for sinus node disease (SND) or second-/third-degree atrioventricular block.

METHODS

We recorded clinical, laboratory, and electrocardiographic parameters as well as pacemaker lead parameters at implantation. The final analysis included 217 patients with SND and 393 patients with atrioventricular block. Notably, 102/217 (47%) of the SND patients (median age: 77 years, 54% men) and 54/393 (14%) of the atrioventricular block patients (median age: 79 years, 54% men) had AF history (paroxysmal or persistent).

RESULTS

Multivariable analysis showed that red blood cell distribution width (RDW) (OR: 1.17; 95% CI: 1.05-1.36; P = .05) and serum γ-glutamyl transferase (γGT) levels (OR: 1.15; 95% CI: 1.03-1.28; P = .04) were independently associated with AF history in patients with SND. In ROC curve analysis, the area under the curve (AUC) was 0.648; P < .01 for RDW, and 0.753; P < .01 for γGT. A RDW cut-off point of 14 was associated with AF with a sensitivity of 67% and a specificity of 68%, while a γGT cut-off point of 21 was associated with AF with a sensitivity of 80% and a specificity of 65%. In patients with second-/third-degree atrioventricular block, there were no significant independent correlations between AF and the parameters studied.

CONCLUSIONS

In elderly patients with SND, RDW and γGT have an independent association with AF history. Our study failed to show any corresponding associations in patients with advanced disorders of atrioventricular conduction.

Liver enzyme variability and risk of heart disease and mortality: A nationwide population-based study

BACKGROUND & AIMS

Liver enzymes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyltransferase (GGT), have been suggested as surrogate markers of various cardiovascular diseases. However, previous studies assessed liver enzymes only once at baseline. We investigated the association between liver enzyme variability and the risk of mortality and cardiovascular outcomes in general population.

METHODS

A total of 6 496 271 subjects participating in ≥3 health examinations within the previous 5 years including the index year (2009-2010) were included. Variability was measured using variability independent of the mean. Cox proportional hazard models adjusting demographic factors, comorbidities, blood pressure, total cholesterol, glomerular filtration rate and baseline liver enzyme level were used.

RESULTS

During a median follow-up of 6 years, there were 106 413 deaths (1.6%), 53 385 myocardial infarctions (MI, 0.8%), 65 143 atrial fibrillations (AF, 1.0%) and 50 139 congestive heart failures (CHF, 0.7%). High variability in AST, ALT and GGT was associated with a higher risk for all-cause mortality, MI, AF and CHF. The degree of association was largest for GGT variability. For the highest quartile of GGT variability relative to the lowest quartile, the hazard ratios (95% confidence intervals) were 1.32 (1.28-1.35) for all-cause mortality, 1.16 (1.11-1.20) for MI, 1.28 (1.18-1.38) for AF and 1.25 (1.20-1.30) for CHF. These findings were consistent regardless of alcohol consumption, body mass index and degree of fatty liver. Sensitivity analysis also revealed similar results.

CONCLUSIONS

Higher visit-to-visit variability of liver enzymes was an independent predictor of all-cause mortality and cardiovascular events.

Cardiovascular Research Using the Korean National Health Information Database

The Korean National Health Information Database (NHID) contains nationwide claims data, including sociodemographic data, health care utilization, health screening data, and healthcare provider information. To compensate for the limitations of randomized clinical trials, real-world observational studies using claims data have emerged as a novel research tool. We summarized the structure of the Korean NHID and the recent researches conducted in the field of cardiovascular science. Epidemiological studies, prescription patterns, temporal trends, comparison of effectiveness and safety of treatments, variability index using laboratory data, and rare intractable disease constitute interesting topics of research in cardiovascular science using the NHID. The operational definition of covariates and clinical outcomes is important for researchers interested in using the NHID data as new tools to prove their hypothesis. A step-by-step approach adopted by a team of data scientists, epidemiologists, statisticians, and clinical researchers may be most effective while designing research studies. The ultimate direction of research using the NHID should aim to improve the welfare of the public by promoting public health, reducing medical costs, and guiding healthcare policies.

Crohn's disease and ulcerative colitis are associated with different lipid profile disorders: a nationwide population-based study

BACKGROUND

The relationships between lipid profiles and IBD remain elusive.

AIM

To determine the association of IBD with serum lipid profiles.

METHODS

A nationwide population-based study was performed using claims data from the Korean National Healthcare Insurance service. A total of 9 706 026 subjects undergoing medical check-ups in 2009 were enrolled and followed up until 2016. Individuals who developed Crohn's disease (CD) or ulcerative colitis (UC) were identified during follow-up. Adjusted hazard ratio (aHR) by age, sex, body mass index, cigarette smoking, alcohol drinking, exercise, income and underlying comorbidities was calculated to define the impact of serum lipid profiles on developing IBD.

RESULTS

During a median follow-up of 7.3 years, IBD was detected in 7,058 (0.07%) individuals. Compared with the highest quartile of serum total cholesterol (TC) levels, lower TC levels were associated with higher incidence of CD (aHR: Q1, 2.52; Q2, 1.52; Q3, 1.27), but not UC. Lower serum LDL-C levels were associated with higher incidence of CD (aHR: Q1, 1.92; Q2, 1.47; Q3, 1.22), but not UC. Moreover, lower serum HDL-C levels were associated with higher incidence of CD (aHR: Q1, 2.49; Q2, 1.90; Q3, 1.43), but not UC. In contrast, lower serum triglyceride levels were associated with higher incidence of UC (aHR: Q1, 1.22; Q2, 1.19; Q3, 1.19), but not CD.

CONCLUSIONS

Low serum TC, LDL-C and HDL-C levels were associated with CD. Low serum triglyceride levels were related to UC.

Effects of Gamma-Glutamyl Transferase on Stroke Occurrence Mediated by Atrial Fibrillation

Background and Purpose

Gamma-glutamyl transferase (GGT) is reported to be associated with stroke independently of the conventional risk factors. However, the underlying mechanism remains to be identified. This study focused on atrial fibrillation (AF), which also reportedly has a close association with GGT.

Methods

Acute ischemic stroke patients who were admitted to the Seoul National University Hospital within 7 days of stroke onset were analyzed. Multinomial logistic regression was performed to assess the relationship between GGT and cardioembolic stroke. Mediation analysis based on binary logistic regression was used to determine whether AF mediates the relationship between GGT and cardioembolic stroke.

Results

AF was found in 132 (15.0%) of 880 eligible patients with acute ischemic stroke, and 270 (30.7%) patients were categorized as cardioembolic stroke. High GGT levels in acute ischemic stroke patients was associated with cardioembolic stroke [odds ratio (OR)=3.42, 95% CI=1.59–7.37], but not with large-artery atherosclerosis stroke (OR=1.10, 95% CI=0.54–2.23). Approximately half (53.9%) of the total effect of GGT levels on cardioembolic stroke was mediated by AF.

Conclusions

The GGT level was significantly associated with cardioembolic stroke via AF. The results obtained in the present study may explain why GGT is associated with stroke.

Effect of the variability of blood pressure, glucose level, total cholesterol level, and body mass index on the risk of atrial fibrillation in a healthy population

BACKGROUND

The variability of metabolic parameters might have an impact on the pathophysiology of atrial fibrillation (AF).

OBJECTIVE

The purpose of this study was to evaluate the effect of the variability of 4 metabolic components including systolic blood pressure (BP), glucose level, total cholesterol (TC) level, and body mass index (BMI) on the risk of AF in the healthy population without hypertension, diabetes, or dyslipidemia.

METHODS

We identified 6,819,829 adult subjects without hypertension, diabetes, or dyslipidemia who had ≥3 health checkups provided by the Korean National Health Insurance Corporation between 2005 and 2012. Glucose level, BP, TC level, and BMI were measured at each visit. Variability was defined as variability independent of the mean (VIM), and VIM of each parameter was divided into 4 groups. High variability was defined as having values in the highest quartile of each parameter.

RESULTS

During a mean follow-up of 5.3 ± 1.1 years, 31,302 subjects were newly diagnosed with AF (0.86 per 1000 person-years). Subjects with the highest VIM quartile of BP, TC level, and BMI showed an increased risk of AF compared with those with the lowest VIM quartile, whereas glucose level variability had a marginal association. The composite of the high variability of metabolic parameters showed a graded risk of AF. After multivariable adjustment, subjects having 1, 2, 3, and 4 parameters of the highest VIM had an ∼7%, 13%, 20%, and 35% increased risk of AF compared with those without any highest variability of metabolic parameters.

CONCLUSION

The variability of metabolic parameters showed a close association with the risk of AF in those without cardiovascular comorbidities.

Oxidative stress and atrial fibrillation: an update

Atrial remodelling involves electrophysiological and structural abnormalities that promote the development and perpetuation of atrial fibrillation. Experimental and clinical data indicate that oxidative stress is implicated in the pathophysiology of atrial remodelling. The mechanistic links between atrial remodelling and oxidative stress are complex with several underlying diseases and conditions may affect these pathways. Therefore, the development of antioxidant interventions in this setting remains difficult. Besides classical antioxidant compounds, several agents with pleiotropic effects, including anti-inflammatory and antioxidant, have been tested in experimental and clinical settings with variable results. Strategies applying conventional antioxidants in specific situations such as postoperative atrial fibrillation show beneficial effects, especially the two-step regimen of antioxidants combination. Of note, there are limited data on the development of strategies that target specific sources of reactive oxygen species implicated in atrial remodelling. Lifestyle, diet, and risk factors modification is a complementary promising approach. This updated review provides a concise and critical overview of all available data regarding oxidative stress and its modulation in atrial fibrillation. Future directions on this exciting field are also discussed.