Association between non-alcoholic fatty liver disease and risk of new-onset atrial fibrillation in healthy adults

Liver stiffness as a cornerstone in heart disease risk assessment

Metabolic dysfunction-associated steatotic liver disease (MASLD) typically presents with hepatic fibrosis in advanced disease, resulting in increased liver stiffness. A subset of patients further develops liver cirrhosis and hepatocellular carcinoma. Cardiovascular disease is a common comorbidity in patients with MASLD and its prevalence is increasing in parallel. Recent evidence suggests that especially liver stiffness, whether or not existing against a background of MASLD, is associated with heart diseases. We conducted a narrative review on the role of liver stiffness in the prediction of highly prevalent heart diseases including heart failure, cardiac arrhythmias (in particular atrial fibrillation), coronary heart disease, and aortic valve sclerosis. Research papers were retrieved from major scientific databases (PubMed, Web of Science) until September 2023 using 'liver stiffness' and 'liver fibrosis' as keywords along with the latter cardiac conditions. Increased liver stiffness, determined by vibration-controlled transient elastography or hepatic fibrosis as predicted by biomarker panels, are associated with a variety of cardiovascular diseases, including heart failure, atrial fibrillation, and coronary heart disease. Elevated liver stiffness in patients with metabolic liver disease should lead to considerations of cardiac workup including N-terminal pro-B-type natriuretic peptide/B-type natriuretic peptide determination, electrocardiography, and coronary computed tomography angiography. In addition, patients with MASLD would benefit from heart disease case-finding strategies in which liver stiffness measurements can play a key role. In conclusion, increased liver stiffness should be a trigger to consider a cardiac workup in metabolically compromised patients.

Fatty liver index (FLI): more than a marker of hepatic steatosis

Fatty liver index (FLI) was developed as a simple and accurate marker of hepatic steatosis. FLI is derived from an algorithm based on body mass index, waist circumference, and levels of triglycerides and gamma-glutamyltransferase, and it is widely used in clinical and epidemiological studies as a screening tool for discriminating between healthy and nonalcoholic fatty liver disease (NAFLD) subjects. However, a systematic review of the literature regarding FLI revealed that this index has more extensive relationships with biochemical and physiological parameters. FLI is associated with key parameters of lipid, protein and carbohydrate metabolism, hormones, vitamins and markers of inflammation, or oxidative stress. FLI can be a predictor or risk factor for a number of metabolic and nonmetabolic diseases and mortality. FLI is also used as an indicator for determining the effects of health-related prevention interventions, medications, and toxic substances on humans. Although in most cases, the exact mechanisms underlying these associations have not been fully elucidated, they are most often assumed to be mediated by insulin resistance, inflammation, and oxidative stress. Thus, FLI may be a promising marker of metabolic health due to its multiple associations with parameters of physiological and pathological processes. In this context, the present review summarizes the data from currently available literature on the associations between FLI and biochemical variables and physiological functions. We believe that this review will be of interest to researchers working in this area and can provide new perspectives and directions for future studies on FLI.

A systematic review and meta-analysis of cohort studies on the potential association between NAFLD/MAFLD and risk of incident atrial fibrillation

Background and objective

The association between atrial fibrillation (AF) and non-alcoholic fatty liver disease (NAFLD) or metabolic-associated fatty liver disease (MAFLD) has been explored in recent cohort studies, however, the results have been controversial and inconclusive. This meta-analysis aimed to explore this potential association.

Methods

We systematically searched PubMed, Embase, and Web of Science databases to identify all relevant cohort studies investigating the association between NAFLD/MAFLD and AF published from database inception to October 30, 2022. Random-effects models were utilized to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for summary purposes. Additionally, subgroup and sensitivity analyses were performed.

Results

A total of 13 cohort studies with 14 272 735 participants were included. Among these, 12 cohort studies with 14 213 289 participants (median follow-up of 7.8 years) showed a significant association between NAFLD and an increased risk of incident AF (HR = 1.18, 95% CI: 1.12-1.23, P < 0.00001). Our subgroup analyses mostly yielded similar results, and the results of sensitivity analyses remained unchanged. However, meta-analysis of data from 2 cohort studies with 59 896 participants (median follow-up of 2.15 years) showed that MAFLD was not linked to incident AF (HR = 1.36, 95% CI: 0.63-2.92, P = 0.44).

Conclusion

Current evidence shows that NAFLD may be linked to a slightly higher risk of developing AF, particularly among Asian populations and those diagnosed with NAFLD using FLI criteria. Nevertheless, there is not enough evidence to support the proposed association between MAFLD and an increased risk of AF. To better understand this relationship, future studies should consider factors such as specific population, the severity of NAFLD/MAFLD, diagnostic methods of NAFLD and AF, and cardiometabolic risk factors.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022371503.

Correlation between the triglyceride-glucose index and the onset of atrial fibrillation in patients with non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is associated with atrial fibrillation (AF). Insulin resistance (IR) is the main cause of the high prevalence of AF in NAFLD patients. The triglyceride-glucose index (TyG) is a novel IR-related indicator implicated in the incidence and severity of NAFLD. However, the role of TyG in determining the risk for AF in patients with NAFLD remains unclear.

METHODS

A retrospective study was conducted on 912 patients diagnosed with NAFLD via ultrasonography. These patients were divided into two groups: (1) NAFLD+ AF and (2) NAFLD+ non-AF. Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to assess the correlation between the TyG index and the high risk for AF. A receiver operating characteristic (ROC) curve was constructed to evaluate the predictive value for the TyG index for AF. Restricted cubic splines (RCS) were used to test the linear correlation between TyG and the risk for AF.

RESULTS

A total of 204 patients with AF and 708 patients without AF were included in this study. The LASSO logistic regression analysis showed that TyG was an independent risk factor for AF (odds ratio [OR] = 4.84, 95% confidence interval [CI] 2.98-7.88, P < 0.001). The RCS showed that the risk for AF increased linearly with TyG over the entire TyG range; this risk was also evident when the patients were analyzed based on sex (P for nonlinear > 0.05). In addition, the correlation between TyG and AF was a consistent finding in subgroup analysis. Furthermore, ROC curve analysis showed that TyG levels combined with traditional risk factors improved the predictive value for atrial fibrillation.

CONCLUSION

The TyG index is useful in assessing the risk for atrial fibrillation in patients with NAFLD. Patients with NAFLD and increased TyG indices have higher risks for atrial fibrillation. Therefore, TyG indices should be assessed when managing patients with NAFLD.

Association between metabolic dysfunction-associated fatty liver disease and supraventricular and ventricular tachyarrhythmias in patients with type 2 diabetes

BACKGROUND

Currently, it remains uncertain whether metabolic dysfunction-associated fatty liver disease (MAFLD) is associated with increased risk of supraventricular and ventricular tachyarrhythmias in people with type 2 diabetes mellitus (T2DM).

METHODS

We retrospectively examined the data of 367 ambulatory patients with T2DM who underwent 24-hour Holter monitoring between 2015 and 2022 for clinical indications, and who did not have pre-existing permanent atrial fibrillation (AF), kidney failure or known liver diseases. Paroxysmal supraventricular tachycardia (PSVT), paroxysmal AF and episodes of ventricular tachyarrhythmias (i.e., presence of ventricular tachycardia, >30 premature ventricular complexes per hour, or both) were recorded. The presence and severity of MAFLD was diagnosed by ultrasonography and fibrosis-4 (FIB-4) index.

RESULTS

Patients with T2DM who had MAFLD (n = 238) had a significantly greater prevalence of PSVT (51.7% vs. 38.8%), paroxysmal AF (6.3% vs. 1.3%) and combined ventricular tachyarrhythmias (31.9% vs. 20.2%) compared to their counterparts without MAFLD (n = 129). MAFLD was significantly associated with a greater than two-fold risk of having PSVT (adjusted-odds ratio [OR] 2.04, 95% confidence interval 1.04-4.00) or ventricular tachyarrhythmias (adjusted-OR 2.44, 95%CI 1.16-5.11), after adjusting for age, sex, smoking, alcohol intake, diabetes-related factors, comorbidities, medication use and left ventricular ejection fraction on echocardiography. The risk of supraventricular and ventricular tachyarrhythmias was even greater amongst patients with MAFLD and FIB-4 ≥ 1.3.

CONCLUSIONS

In ambulatory patients with T2DM, the presence and severity of MAFLD was strongly associated with an increased risk of supraventricular and ventricular arrhythmias on 24-hour Holter monitoring.

Cardiovascular Morbidity and Mortality Related to Non-alcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis

Whether non-alcoholic fatty liver disease (NAFLD) is a cardiovascular (CV) risk factor is debated. We performed a systematic review and meta-analysis to assess the CV morbidity and mortality related to NAFLD in the general population, and to determine whether CV risk is comparable between lean and non-lean NAFLD phenotypes. We searched multiple databases, including PubMed, Embase, and the Cochrane Library, for observational studies published through 2022 that reported the risk of CV events and mortality. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) for all-cause mortality, CV mortality, myocardial infarction (MI), stroke, atrial fibrillation (AF), and major adverse cardiovascular and cerebrovascular events (MACCE) were assessed through random-effect meta-analysis. We identified 33 studies and a total study population of 10,592,851 individuals (mean age 53±8; male sex 50%; NAFLD 2, 9%). Mean follow-up was 10±6 years. Pooled ORs for all-cause and CV mortality were respectively 1.14 (95% CI, 0.78-1.67) and 1.13 (95% CI, 0.57-2.23), indicating no significant association between NAFLD and mortality. NAFLD was associated with increased risk of MI (OR 1.6; 95% CI, 1.5-1.7), stroke (OR: 1.6; 95% CI, 1.2-2.1), atrial fibrillation (OR: 1.7; 95% CI, 1.2-2.3), and MACCE (OR: 2.3; 95% CI, 1.3-4.2). Compared with non-lean NAFLD, lean NAFLD was associated with increased CV mortality (OR: 1.50; 95% CI, 1.1-2.0), but similar all-cause mortality and risk of MACCE. While NAFLD may not be a risk factor for total and CV mortality, it is associated with excess risk of non-fatal CV events. Lean and non-lean NAFLD phenotypes exhibit distinct prognostic profiles and should receive equitable clinical care.

Sex-specific metabolic risk factors and their trajectories towards the non-alcoholic fatty liver disease incidence

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease. This study examined sex-specific associations between NAFLD and metabolic factors and investigated the trajectory of risk factors.

METHODS

We retrospectively investigated 16,140 individuals from Beijing Health Management Cohort. Univariate and multivariate time-dependent Cox regression analyses were performed to identify independent risk factors for new-onset NAFLD. The trajectory of risk factors was investigated using the latent growth curve model and growth mixture model.

RESULTS

Over a median follow-up of 3.15 years, 2,450 (15.18%) participants developed NAFLD. The risk factors for NAFLD in men were increased body mass index (BMI); waist circumference (WC); triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), haemoglobin (Hb), and serum uric acid (SUA) levels; and platelet (PLT) count and decreased serum creatinine-to-body weight (sCr/bw) and high-density lipoprotein cholesterol (HDL-C) levels. In women, the risk factors were increased BMI, WC, and fasting plasma glucose (FPG), TG, LDL-C, SUA, white blood cell (WBC), and PLT and decreased sCr/bw and HDL-C levels. In addition, BMI, LDL-C, sCr/bw and PLT changing trajectories were associated with NAFLD in men; BMI, WC, TG, LDL-C, SUA and sCr/bw trends was associated with NAFLD risk in women.

CONCLUSIONS

Development of NAFLD is associated with BMI, LDL-C, sCr/bw and PLT changing trajectories in men; BMI, WC, TG, LDL-C, SUA and sCr/bw trends are associated an increased risk of NAFLD in women. Deterioration of metabolic risk factors status can be a predictor of NAFLD many years before its occurrence.

Associations between non-alcoholic fatty liver disease and cognitive impairment and the effect modification of inflammation

This study aimed to evaluate the association between non-alcoholic fatty liver disease (NAFLD) and cognitive impairment and explore the effect modification by the inflammatory status. A total of 4400 community-based participants aged 50–64 years from the Cardiovascular and Metabolic Disease Etiology Research Center were included in this cross-sectional study. NAFLD was identified as the Fatty Liver Index 30 or higher in the absence of excessive alcohol consumption. Cognitive impairment was defined as the total score of the Mini-Mental State Examination (cutoff 24). The inflammatory status was evaluated using white blood cell (WBC) and high-sensitivity C-reactive protein (hsCRP). Multivariate logistic regression analyses were performed. Stratified analyses by the WBC count (the highest quartile) and the hsCRP level (≥ 1.0 mg/dL vs. < 1.0 mg/dL) were conducted. Participants with NAFLD showed an increased prevalence of cognitive impairment (odds ratio [OR] = 1.26; 95% confidence interval [CI] = 1.04–1.52) compared with the non-NAFLD population. In women, this association was significantly stronger in the highest quartile WBC group than in lower WBC group (OR = 1.81; 95% CI = 1.19–2.74 vs. OR = 1.02; 95% CI = 0.78–1.33, p-interaction = 0.05). NAFLD was positively associated with a higher proportion of cognitive impairment, and this association was stronger in women with higher inflammatory status.

Liver stiffness not fatty liver disease is associated with atrial fibrillation: The Rotterdam study

BACKGROUND & AIMS

Fatty liver disease has become the most prevalent chronic liver disease globally and is linked to cardiovascular disease, including arrhythmias. However, there have been inconsistent reports on the association between fatty liver disease and atrial fibrillation, while the role of liver stiffness in this association remains unclear.

METHODS

Within the Rotterdam Study, a large prospective ongoing cohort, participants attending the abdominal ultrasound program between 2009-2014 were included. Exclusion criteria were no atrial fibrillation data or >20% missing data across analysis variables. Steatosis was assessed by ultrasound, liver stiffness by transient elastography and atrial fibrillation by 12-lead electrocardiograms. Incident atrial fibrillation was based on medical records and complete until 2014. Logistic and Cox-regression were used to quantify associations between fatty liver disease and atrial fibrillation.

RESULTS

We included 5,825 participants (aged 69.5±9.1, 42.9% male), 35.7% had steatosis, liver stiffness measurement was available in 73.3%, and 7.0% had prevalent atrial fibrillation. Steatosis was not associated with prevalent atrial fibrillation in fully adjusted models (odds ratio [OR] 0.80; 95% CI 0.62-1.03), findings were consistent for non-alcoholic or metabolic dysfunction-associated fatty liver disease. Liver stiffness was significantly associated with prevalent atrial fibrillation (OR 1.09 per kPa, 95% CI 1.03-1.16); however, this was only persistent among those without steatosis (OR 1.18 per kPa, 95% CI 1.08-1.29). Lastly, no associations were found between steatosis (hazard ratio 0.88; 95% CI 0.59-1.33; follow-up 2.1 [1.1-3.2] years) and incident atrial fibrillation.

CONCLUSIONS

Fatty liver disease was not associated with prevalent or incident atrial fibrillation, while liver stiffness was significantly associated with atrial fibrillation, especially among those without steatosis. This association might be driven by venous congestion instead of fibrogenesis, but this awaits further validation. We recommend assessing cardiovascular health in participants with high liver stiffness, especially in the absence of overt liver disease.

CLINICAL TRIAL NUMBER

NTR6831.

LAY SUMMARY

There have been inconsistent reports about the potential links between fatty liver disease and atrial fibrillation (an irregular and often very fast heart rhythm). Herein, we show that liver stiffness (which is a marker of liver fibrosis), but not fatty liver disease, was associated with a higher prevalence of atrial fibrillation. We hypothesis that atrial fibrillation, rather than fibrosis, may be the cause of increased liver stiffness in participants without overt liver disease.

Less Known but Clinically Relevant Comorbidities of Atrial Fibrillation: A Narrative Review

BACKGROUND

The important risk factors for atrial fibrillation (AF) in the general population are not always equally important in specific and relatively prevalent diseases.

OBJECTIVE

The main goal of this narrative review is to focus attention on the presence and the relationship of AF with several important diseases, such as cancer or sepsis, in order to: 1) stimulate further research in the field, and 2) draw attention to this relationship and search for AF in clinical practice.

METHODS

We searched PubMed, SCOPUS, Elsevier, Wiley, Springer, Oxford Journals, Cambridge, SAGE, and Google Scholar for less-known comorbidities of AF. The search was limited to publications in English. No time limits were applied.

RESULTS

AF is widely represented in cardiovascular and other important diseases, even in those in which AF is rarely mentioned. In some specific clinical subsets of AF patients (e.g., patients with sepsis or cancer), the general risk factors for AF may not be so important. Patients with new-onset AF have a several-fold increase in relative risk of cancer, deep vein thrombosis, and pulmonary thromboembolism (PTE) during the follow-up.

CONCLUSION

AF presence, prognosis, and optimal therapeutic approach are insufficiently recognised in several prevalent diseases, including life-threatening ones. There is a need for a better search for AF in PTE, pulmonary oedema, aortic dissection, sepsis, cancer and several gastrointestinal diseases. Improved AF detection would influence treatment and improve outcomes.

A nationwide survey of the association between nonalcoholic fatty liver disease and the incidence of asthma in Korean adults

Background

Asthma and nonalcoholic fatty liver disease (NAFLD) are chronic diseases known to be associated with metabolic abnormalities. We aimed to clarify the association between NAFLD and asthma incidence in a large population-based cohort.

Methods and findings

We selected 160,603 individuals without comorbidities from the National Health Insurance Service-National Sample cohort between 2009 and 2014. NAFLD was defined using a surrogate marker, fatty liver index (FLI). During a median of 5.08 years’ follow-up, 16,377 subjects (10.2%) were newly diagnosed with asthma and categorized into three groups according to FLI. The cumulative incidence of asthma was higher in subjects with higher vs. lower FLIs (FLI < 30, 10.1%; 30 ≤ FLI < 60, 10.8%; FLI ≥ 60, 10.5%). Higher FLI was associated with an increased incidence of asthma (Hazard ratios (HR)_{highest vs. lowest FLI}, 1.25; 95% CI, 1.15–1.36). The results using another definition of NAFLD, as measured by the hepatic steatosis index (HSI), were similar to the primary results. This association was more pronounced in women than in men (HR 1.46; 95% CI, 1.13–1.64 vs. HR 1.07; 95% CI, 0.94–1.20).

Conclusions

This study demonstrated that NAFLD, as measured by FLI and HSI, may influence the incidence rates of asthma in adults, especially in women.

Non-alcoholic Fatty Liver Disease and the Risk of Incident Atrial Fibrillation in Young Adults: A Nationwide Population-Based Cohort Study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a multisystem disease including cardiovascular. However, the association between NAFLD and the risk of incident atrial fibrillation (AF), especially in young adults, remains unclear. We aimed to evaluate the association between NAFLD as assessed by the fatty liver index (FLI) and the risk of AF in young adults.

METHODS

We identified individuals aged 20-39 years who underwent health examinations conducted by the Korean National Health Insurance Corporation between January 2009 and December 2012. Individuals with significant liver disease, heavy alcohol consumption, or prevalent AF were excluded. We categorized based on FLI: <30, 30 to <60, and ≥60. Incident AF was evaluated as the primary outcome.

RESULTS

We included 5,333,907 subjects (mean age, 31 ± 5 years; men, 57%). During a mean follow-up of 7.4 ± 1.1 years, 12,096 patients had newly diagnosed AF (incidence rate 0.31 per 1,000 person-years). After adjustment, subjects with FLI 30 to <60 and FLI ≥60 showed a higher risk of AF compared to those with FLI <30 (hazard ratio [HR] 1.21, 95% confidence interval [CI, 1.15-1.27] and HR 1.47, 95% CI [1.39-1.55], p < 0.001, respectively). In women, the increased AF risk was accentuated in the higher FLI group than in the individuals with FLI <30, compared with men (p-for-interaction = 0.023). A higher incident AF risk in the higher FLI groups was consistently observed in various subgroups.

CONCLUSION

Among young adults, NAFLD assessed using FLI was positively correlated with the AF risk. These findings support the evidence of AF screening in young adults with high FLI scores.

The prevalence of MAFLD and its association with atrial fibrillation in a nationwide health check-up population in China

BACKGROUND AND AIMS

The epidemiological characteristics of MAFLD and its relationship with atrial fibrillation (AF) are limited in China. Therefore, we explored the epidemiological characteristics of MAFLD from adults along with the association of MAFLD and 12-ECG diagnosed AF in a nationwide population from health check-up centers.

METHODS

This observational study used cross-sectional and longitudinal studies with 2,083,984 subjects from 2009 to 2017. Age-, sex-, and regional-standardized prevalence of MAFLD was estimated. Latent class analysis (LCA) was used to identify subclusters of MAFLD. Multivariable logistic regression and mixed-effects Cox regression models were used to analyze the relationship between MAFLD and AF.

RESULTS

The prevalence of MAFLD increased from 22.75% to 35.58% during the study period, with higher rates in males and populations with high BMI or resided in northern regions. The MAFLD population was clustered into three classes with different metabolic features by LCA. Notably, a high proportion of MAFLD patients in all clusters had overweight and prediabetes or diabetes. The MAFLD was significantly associated with a higher risk of AF in the cross-sectional study and in the longitudinal study. In addition, the coexistence of prediabetes or diabetes had the largest impact on subsequent AF.

CONCLUSION

Our findings suggested a high prevalence of MAFLD and a high prevalence of other metabolic diseases in the MAFLD population, particularly overweight and glucose dysregulation. Moreover, MAFLD was associated with a significantly higher risk for existing and subsequent subclinical AF in the Chinese population.

Relationship between non-alcoholic fatty liver disease and cardiac arrhythmia: a systematic review and meta-analysis

Objective

We performed a meta-analysis to create a quantitative estimate of the association between non-alcoholic fatty liver disease (NAFLD) and the risk of cardiac arrhythmia (including atrial fibrillation (AF), prolonged QT interval, premature atrial/ventricular contraction [PAC/PVC] and heart block).

Methods

A literature review was conducted using PubMed, Embase, Web of Science and the Cochrane Library database to identify observational studies of the link between NAFLD and cardiac arrhythmia. Effect sizes were expressed as odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs). The method of analysis of AF was also analysed separately, according to the effect estimate (OR or HR).

Results

Nineteen studies of 7,012,960 individuals were included. NAFLD was independently associated with higher risks of AF (OR 1.71, 95% CI: 1.14–2.57; HR 1.12, 95% CI: 1.11–1.13), prolonged QT interval (OR 2.86, 95% CI: 1.64–4.99), PAC/PVC (OR 2.53, 95% CI: 1.70–3.78) and heart block (OR 2.65, 95% CI: 1.88–3.72). The heterogeneity of the data with respect to AF and prolonged QT was moderate on sensitivity analysis.

Conclusions

We found a significantly higher risk of cardiac arrhythmia in patients with NAFLD, but the observational design of the studies does not permit conclusions regarding causality.

Early cardiac electrical and structural changes in patients with non-obese non-alcoholic fatty liver disease

Background    Obese non-alcoholic fatty liver disease (NAFLD) was found to increase the risk of developing atrial fibrillation (AF) regardless of the metabolic syndrome subgroups that may accompany it. In this study, the effect of NAFLD on the structural and electrical functions of the heart was investigated using tissue Doppler echocardiography (TDE) in non-obese NAFLD patients without any known risk factors for AF.Material and methods    The study included 43 female patients (31.3±3.8 years), who had stage 2-3 hepatosteatosis detected by liver ultrasonography and diagnosed as non-obese NAFLD (patient group), and 31 healthy women (control group, 32.5±3.6 years). In addition to standard echocardiographic parameters, inter- and intra-atrial electromechanical delay (EMD) were evaluated by TDE.Results    Interatrial EMD (PA lateral - PA tricuspid) and intraatrial EMD (PA septum - PA tricuspid) were significantly longer in patient group (16.1±3.4 vs. 12.5±2.3 ms, p&lt;0.001, and 8.4±1.6 vs. 6.6±1.6 ms, p&lt;0.001, respectively). At the subclinical level. atrial size, left ventricular diastolic function, and left ventricular wall thickness measurements were greater in the patient group.Conclusion    Inter-atrial and intra-atrial EMD were detected in young women with non-obese NAFLD. In addition, at the subclinical level, structural and functional impairment was detected However, large-volume prospective studies are required to cobfirm these findings regarding the development of AF in non-obese NAFLD patients.

Nonalcoholic Fatty Liver Disease: An Emerging Driver of Cardiac Arrhythmia

Cardiac arrhythmias and the resulting sudden cardiac death are significant cardiovascular complications that continue to impose a heavy burden on patients and society. An emerging body of evidence indicates that nonalcoholic fatty liver disease (NAFLD) is closely associated with the risk of cardiac arrhythmias, independent of other conventional cardiometabolic comorbidities. Although most studies focus on the relationship between NAFLD and atrial fibrillation, associations with ventricular arrhythmias and cardiac conduction defects have also been reported. Mechanistic investigations suggest that a number of NAFLD-related pathophysiological alterations may potentially elicit structural, electrical, and autonomic remodeling in the heart, contributing to arrhythmogenic substrates in the heart. NAFLD is now the most common liver and metabolic disease in the world. However, the upsurge in the prevalence of NAFLD as an emerging risk factor for cardiac arrhythmias has received little attention. In this review, we summarize the clinical evidence and putative pathophysiological mechanisms for the emerging roles of NAFLD in cardiac arrhythmias, with the purpose of highlighting the notion that NAFLD may serve as an independent risk factor and a potential driving force in the development and progression of cardiac arrhythmias.

Nonalcoholic fatty liver disease is associated with increased risk of atrial fibrillation

BACKGROUND & AIMS

Whether nonalcoholic fatty liver disease (NAFLD) is associated with risk of incident atrial fibrillation (AF) independent of established cardiovascular risk factors remains controversial. We aimed to provide a quantitative estimate of the association between NAFLD and risk of AF after adjustment for cardiometabolic risk factors.

METHODS

In this study, we searched PubMed and Embase for studies published from database inception until January 31, 2020. Cohort studies reported adjusted relative risks (RRs) and 95% confidence intervals (CIs) for AF of NAFLD compared with non-NAFLD were included for analysis.

RESULTS

A total of 6 cohort studies were included, comprising 614 673 individuals for analysis. The median follow-up duration was 10.0 years with 7271 cases of incident AF. Compared with non-NAFLD, minimally adjusted models without adjustment for cardiometabolic risk factors showed that NAFLD was associated with increased risk of AF (RR 1.65, 95% CI 1.23-2.20, I²  = 63.0%). After adjustment for multiple cardiometabolic risk factors, the association between NAFLD and risk of AF was still higher than that in non-NAFLD (RR 1.19, 95% CI 1.04-1.31, I²  = 54.0%). There was significant heterogeneity for the risk of AF between minimally and maximally adjusted models (I²  = 77.1%, P for heterogeneity = 0.04). Compared with non-NAFLD, the absolute risk increase in NAFLD for AF was 1.3 (95% CI 0.5-2.1) per 1000 person-years.

CONCLUSIONS

NAFLD is associated with increased risk of incident AF. The strength of the association between NAFLD and AF is partially attributed to the co-existing cardiometabolic risk factors.

The risk of atrial fibrillation in patients with non-alcoholic fatty liver disease and a high hepatic fibrosis index

Previous epidemiological studies focusing on the association between liver disease and atrial fibrillation (AF) show interesting but inconsistent findings. Patients with liver disease have a higher AF risk; however, it is unknown whether the liver fibrosis index can predict AF risk. The medical records of a healthy population undergoing routine health examinations at Healthcare System Gangnam Center, Seoul National University Hospital, were reviewed retrospectively. After excluding subjects with a history of liver disease and known cardiovascular disease, 74,946 subjects with nonalcoholic fatty liver disease (NAFLD) were evaluated. The mean age was 51 ± 11 years, and 71.9% were male. AF was found in 380 (0.5%) subjects. Using univariate analyses, age, male sex, body mass index, hypertension, and diabetes were significantly associated with AF. The fibrosis 4 index (FIB 4) showed significant correlations with AF [unadjusted odds ratio (OR) 3.062 and 95% confidence interval (CI) 2.605-3.600, p = 0.000; adjusted OR 2.255 and 95% CI 1.744-2.915, p = 0.000, with cardiometabolic risk factors adjusted]. In conclusion, NAFLD subjects with higher FIB 4 were associated with increased AF risk. The noninvasive determination of liver fibrosis indices can have clinical implications on the early identification of NAFLD in patients at risk for AF.