Underweight is a risk factor for atrial fibrillation: A nationwide population-based study

Validation of diagnostic codes of major clinical outcomes in a National Health Insurance database

Background and objectives

The Korean National Health Insurance Service (NHIS) database has been widely used for cardiovascular research. We validated the primary diagnostic codes of major clinical outcomes, including acute myocardial infarction (AMI), gastrointestinal bleeding (GIB), stroke, and intracranial hemorrhage (ICH) used for Korea NHIS claims.

Subjects and methods

From 2016 to 2017, 800 patients with primary diagnostic codes of AMI, GIB, stroke, or ICH at discharge were randomly selected from a single tertiary medical center in Korea (200 patients per each diagnosis). The positive predictive value (PPV), sensitivity, and specificity of the primary diagnostic codes were calculated using hospital medical record review as the gold standard. Further improvement in the diagnostic validity of the codes was assessed by combining clinical information such as duration of hospitalization, blood transfusion, brain imaging studies, or prescription records of antithrombotic agents.

Results

Among 200 patients with AMI as the primary discharge diagnosis, 184 patients were clinically confirmed (PPV of 92.0%). For GIB, 184 (92.0%) patients with the primary discharge diagnosis were verified to have true GIB events, showing PPV of 92%. For stroke, 181 (90.5%) patients were clinically confirmed with true stroke events. For ICH, 143 (71.5%) patients were verified to be true ICH events. In stroke and ICH, the PPV and specificity improved after combining with the hospitalization duration, imaging studies, and prescription of antithrombotic agents.

Conclusions

For major clinical outcomes in the NHIS database, the primary diagnostic codes showed favorable reliability. For stroke and ICH, considerations of relevant clinical information could improve the accuracy of diagnosis.

Gender Differences in Arrhythmias: Focused on Atrial Fibrillation

There are significant differences in clinical presentation and treatment of atrial fibrillation (AF) between women and men. The primary goal of AF management is to restore sinus rhythm and to prevent various complications, including stroke and heart failure. In many areas of AF, such as prevalence, clinical manifestations, morbidity, risk factors, pathophysiology, treatment strategies, and complications, gender-specific variability is observed and needs to be further addressed by large-scale population researches or randomized clinical trials, which help to promote the customization of AF treatment programs, hence to maximize the success rate of AF therapy in both sexes. This review highlights our current understanding of these gender differences in AF and how these differences affect treatment decisions on AF.

Bodyweight fluctuation is associated with increased risk of incident atrial fibrillation

BACKGROUND

Obesity and weight gain are established risk factors for atrial fibrillation (AF).

OBJECTIVE

The purpose of this study was to investigate whether bodyweight variability is also a risk factor for AF development.

METHODS

A nationwide population-based cohort of 8,091,401 adults from the Korean National Health Insurance Service database without a history of AF and with ≥3 measurements of bodyweight over a 5-year period were followed up for incident AF. Intraindividual bodyweight variability was calculated using variability independent of mean, and high bodyweight variability was defined as the quartile with the highest variability (Q4) with Q1-Q3 as reference.

RESULTS

During median 8.1 years of follow-up, each increase of 1 SD in bodyweight variability was associated with a 5% increased risk of AF development, and the quartile with the highest bodyweight variability showed 14% increased risk of AF development compared to the quartile with the lowest variability (hazard ratio 1.14; 95% confidence interval 1.12-1.15), after adjustment for baseline bodyweight, height, age, sex, lifestyle factors, and comorbidities. High bodyweight variability was significantly associated with AF development in all baseline body mass index (BMI) groups except the very obese (BMI ≥30), and this association was stronger in subjects with lower bodyweight. High bodyweight variability was associated with increased risk of incident AF in all weight change groups, with a stronger association in those who lost weight.

CONCLUSION

Bodyweight fluctuation was independently associated with an increased risk of AF development, especially in individuals with low bodyweight, and regardless of weight gain or loss.

The impact of body weight and diabetes on new-onset atrial fibrillation: a nationwide population based study

Background

Being obese or underweight, and having diabetes are important risk factors for new-onset atrial fibrillation (AF). However, it is unclear whether there is any interaction between body weight and diabetes in regard to development of new-onset AF. We aimed to evaluate the role of body weight status and various stage of diabetes on new-onset AF.

Methods

This was a nationwide population based study using National Health Insurance Service (NHIS) data. A total of 9,797,418 patients who underwent national health check-ups were analyzed. Patients were classified as underweight [body mass index (BMI) < 18.5], normal reference group (18.5 ≤ BMI < 23.0), upper normal (23.0 ≤ BMI < 25.0), overweight (25.0 ≤ BMI < 30.0), or obese (BMI ≥ 30.0) based on BMI. Diabetes were categorized as non-diabetic, impaired fasting glucose (IFG), new-onset diabetes, diabetes < 5 years, and diabetes ≥ 5 years. Primary outcome end point was new-onset AF. New-onset AF was defined as one inpatient or two outpatient records of International Classification of Disease, Tenth Revision (ICD-10) codes in patients without prior AF diagnosis.

Results

During 80,130,161 patient*years follow-up, a total of 196,136 new-onset AF occurred. Obese [hazard ration (HR) = 1.327], overweight (HR = 1.123), upper normal (HR = 1.040), and underweight (HR = 1.055) patients showed significantly increased risk of new-onset AF compared to the normal reference group. Gradual escalation in the risk of new-onset AF was observed along with advancing diabetic stage. Body weight status and diabetes were independently associated with new-onset AF and at the same time, had synergistic effects on the risk of new-onset AF with obese diabetic patients having the highest risk (HR = 1.823).

Conclusions

Patients with obesity, overweight, underweight, and diabetes had significantly increased risk of new-onset AF. Body weight status and diabetes had synergistic effects on the risk of new-onset AF. The risk of new-onset AF increased gradually with advancing diabetic stage. This study suggests that maintaining optimal body weight and glucose homeostasis might prevent new-onset AF.

Weight and weight change and risk of atrial fibrillation: the HUNT study

Aims

Although obesity has been associated with risk of atrial fibrillation (AF), the associations of long-term obesity, recent obesity, and weight change with AF risk throughout adulthood are uncertain.

Methods and results

An ambispective cohort study was conducted which included 15 214 individuals. The cohort was created from 2006 to 2008 (the baseline) and was followed for incident AF until 2015. Weight and height were directly measured at baseline. Data on previous weight and height were retrieved retrospectively from measurements conducted 10, 20, and 40 years prior to baseline. Average body mass index (BMI) over time and weight change was calculated. During follow-up, 1149 participants developed AF. The multivariable-adjusted hazard ratios were 1.2 (95% confidence interval 1.0–1.4) for average BMI 25.0–29.9 kg/m2 and 1.6 (1.2–2.0) for average BMI ≥30 kg/m2 when compared with normal weight. The association of average BMI with AF risk was only slightly attenuated after adjustment for most recent BMI. In contrast, current BMI was not strongly associated with the risk of AF after adjustment for average BMI earlier in life. Compared with stable BMI, both loss and gain in BMI were associated with increased AF risk. After adjustment for most recent BMI, the association of BMI gain with AF risk was largely unchanged, while the association of BMI loss with AF risk was weakened.

Conclusion

Long-term obesity and BMI change are associated with AF risk. Obesity earlier in life and weight gain over time exert cumulative effects on AF development even after accounting for most recent BMI.

Antithrombotic Therapy in Patients With Atrial Fibrillation After Percutaneous Coronary Intervention During 2-Year Follow-Up, from a Nationwide Population Study

Patients with atrial fibrillation (AF) who underwent percutaneous coronary intervention (PCI) are recommended to receive oral anticoagulants (OAC) and concomitant antiplatelet agents followed by OAC monotherapy continued beyond a year after PCI. However, long-term prescription patterns of antithrombotic therapy in real-world clinical practice were not fully investigated. From the National Health Insurance Service database of Korea, we obtained records of patients with AF who underwent PCI between 2009 and 2013. Patients without repeated PCI or death within 2 years following the procedure were included. Prescription records of antithrombotic therapy including anticoagulants and antiplatelet agents were reviewed at 3-month intervals after discharge. We investigated 8,891 patients. At discharge, 76.1% of the patients received dual antiplatelet therapy (DAPT) and only 17.1% received OAC. Although the proportion of patients receiving DAPT gradually decreased, >70% of patients received only antiplatelet agents (DAPT or single antiplatelet therapy) a year after PCI. During the 2-year follow-up, the proportion of patients receiving OAC remained <20%, and only 1.5% of the patients received OAC monotherapy a year after PCI. Female gender, previous myocardial infarction, peripheral vascular disease, and prescription of DAPT at discharge were associated with underprescription of OAC a year after PCI. In conclusion, a significant proportion (76%) of patients with AF who underwent PCI were not prescribed OAC at discharge despite the high risk of stroke contrary to the current guidelines. Most patients continued to receive antiplatelet agents without OAC beyond the 1-year time point after PCI.

Increased risk of atrial fibrillation in patients with inflammatory bowel disease: A nationwide population-based study

BACKGROUND

Inflammatory bowel disease (IBD), a chronic inflammatory disease of the gastrointestinal tract, could play a role in the pathophysiology of atrial fibrillation (AF).

AIM

To investigate the association between IBD and AF development.

METHODS

We performed a population-based cohort study using records in the Korean National Health Insurance Services database between 2010 and 2014. A total of 37696 patients with IBD (12349 with Crohn’s disease and 25397 with ulcerative colitis) were identified. The incidence rate of newly diagnosed AF in patients with IBD was compared with that in a 3 times larger cohort of 113088 age- and sex-matched controls without IBD.

RESULTS

During 4.9 ± 1.3 years of follow-up, 1120 patients newly diagnosed with AF (348 in the IBD group and 772 in controls) were identified. After adjustments using multivariable Cox proportional hazards, patients with IBD were at a 36% [95% confidence interval (CI) 20%-54%] higher risk of AF than controls. The association between IBD and the development of AF was stronger in younger than in older patients. Patients without cardiovascular risk factors showed a higher risk of AF primarily. Additionally, patients receiving immun-omodulators [Hazard ration (HR) 1.46, 95%CI 1.31-1.89], systemic corticosteroids (HR 1.37, 95%CI 1.10-1.71), or biologics agents (HR 2.38, 95%CI 1.51-3.75) were at higher risk of AF than patients without them.

CONCLUSION

IBD significantly increased the risk of AF, and the impact of IBD on developing AF was in patients with moderate to severe disease.

Comparison of Once-Daily Administration of Edoxaban and Rivaroxaban in Asian Patients with Atrial Fibrillation

It is unclear whether the two once-daily dosing non-vitamin K antagonist oral anticoagulants (NOACs), edoxaban and rivaroxaban, have similar effectiveness and safety in Asian patients with non-valvular atrial fibrillation (AF). This study aimed to compare the effectiveness and safety of edoxaban and rivaroxaban in a Korean population with non-valvular AF. Using the Korean National Health Insurance Service database from January 2014 to December 2016, we compared the risk of ischemic stroke, intracranial hemorrhage (ICH), hospitalization for gastrointestinal (GI) bleeding, hospitalization for major bleeding, all-cause death, and composite outcome in a 3:1 propensity score matched cohort in patients with AF who were naïve to rivaroxaban (n = 12,369) and edoxaban (n = 4,123). Hazard ratios for the six clinical outcomes were analyzed using Cox regression analysis with rivaroxaban as the reference. Baseline characteristics were balanced between the two groups (median age, 71 years; median CHA₂DS₂-VASc score, 3; 56% of patients received a reduced dose). Edoxaban users showed comparable results in all six clinical outcomes (all p = nonsignificant) when compared to rivaroxaban users for total, standard, and reduced doses. We provide for the first time the comparison of effectiveness and safety between the two once-daily NOACs in a large-scale Asian AF population. In both standard and reduced dose regimens, edoxaban showed comparable effectiveness and safety compared to rivaroxaban.

Association of Congestive Heart Failure and Death with Ankylosing Spondylitis : A Nationwide Longitudinal Cohort Study in Korea

Objective

We attempted to discover that Ankylosing spondylitis (AS) has a comprehensive relationship with congestive heart failure and death.

Methods

We used a nationwide database managed by the Korean National Health Insurance Service from 2010 to 2014. Twelve thousand nine hundred eighty-eight patients with a diagnosis of AS and 64940 age- and sex- stratified matching subjects without AS were enrolled in the AS and control groups. Incidence probabilities of 6 years congestive heart failure and death in each group were calculated. The Cox proportional hazard regression analysis was used to estimate the hazard ratio. We divided the AS and control groups into subgroups according to sex, age, income, and comorbidities.

Results

During the follow-up period, 102 patients (0.79%) in the AS group and 201 patients (0.32%) in the control group developed congestive heart failure (p<0.0001). In addition, 211 (1.62%) subjects in the AS group died during the follow-up period compared to 639 (0.98%) subjects in the control group (p<0.0001). The adjusted hazard ratio of congestive heart failure and death in the AS group was 2.28 (95% confidence interval [CI], 1.80–2.89) and 1.66 (95% CI, 1.42–1.95), respectively. The hazard ratios of congestive heart failure and death were significantly increased in all of the subgroups.

Conclusion

The incidence rates of congestive heart failure and death were increased in AS patients.

Association of metabolic syndrome and chronic kidney disease with atrial fibrillation: A nationwide population-based study in Korea

AIMS

Metabolic syndrome (MetS) and chronic kidney disease (CKD) are significant risk factors for incident atrial fibrillation (AF). Few studies have reported the synergistic effect of MetS and CKD on development of AF. We investigated the individual and synergistic effects of MetS and CKD on the risk of incident AF.

METHODS

We studied a retrospective cohort comprising 22,886,663 Koreans whose data was obtained from the national health claims database established by the Korean National Health Insurance Service between 2008 and 2013. Patients were classified into a MetS and a CKD group and followed-up until 2016 for new-onset AF. A Cox proportional hazards model assessed the independent and synergistic effect of MetS and CKD on the risk of incident AF.

RESULTS

The prevalence of MetS and CKD in these patients was 27.4% and 5.4%, respectively. During a mean follow-up of 5.4 years, AF developed in 225,529 patients (1% of the total cohort). The adjusted hazard ratio (HR) for incident AF was 1.38 (95% confidence interval [CI] 1.36-1.39) for MetS, and 1.35 (95% CI 1.34-1.37) for CKD. Patients with MetS and CKD showed a higher risk of AF (HR 1.75, 95% CI 1.73-1.78) than that observed in those without MetS and CKD.

CONCLUSIONS

The combination of MetS and CKD showed a high risk of development of AF in a large-scale nationwide cohort. Further studies are warranted to determine whether pharmacological and/or lifestyle interventions can control/manage these modifiable risk factors to reduce the risk of development of AF.

Association between adult height, myocardial infarction, heart failure, stroke and death: a Korean nationwide population-based study

Background

The association between adult height and cardiovascular (CV) events and mortality has been suggested, albeit inconsistently. We sought to discover the comprehensive relationship between height, CV-related morbidity and all-cause death according to age.

Methods

We investigated the association between adult height and myocardial infarction (MI), heart failure (HF), stroke incidence and mortality in 16 528 128 Korean patients who underwent regular health check-ups (2005-08). Height was stratified by decile according to age (20-39 years, 40-59 years and ≥60 years) and gender.

Results

During a 9-year follow-up period, 590 346 participants died and 232 093 were admitted to hospital for MI, 201 411 for HF and 267 566 for stroke. An inverse relationship between height and MI, HF, stroke and all-cause death was observed in the overall cohort analysis. The association was unchanged after adjusting for CV risk and behavioural and adulthood socioeconomic factors. Both male and female sex showed an inverse relationship with height in adulthood, CV events and mortality. Adult height showed an inverse association in all CV events and mortality, especially in the older groups (≥40 years). In a subgroup analysis of body mass index, there was an inverse relationship between height, CV events and mortality in each group.

Conclusions

Shorter height in adulthood was strongly related to an increased risk of MI, HF, stroke and all-cause death. A suitable environment and appropriate nutrition early in life could influence adult height and eventually reduce the risk of CV events and mortality.

Temporal trends in prevalence and antithrombotic treatment among Asians with atrial fibrillation undergoing percutaneous coronary intervention: A nationwide Korean population-based study

Background

We investigated the recent 10-year trends in the number of patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) in relation to prescription patterns of antithrombotic therapy.

Methods

We analyzed the annual prevalence of PCI and patterns of antithrombotic therapy after PCI, including antiplatelets and oral anticoagulants (vitamin K antagonists and non-vitamin K antagonist oral anticoagulants [NOACs]), in patients with AF between 2006 and 2015 by using the Korean National Health Insurance Service database. Independent factors associated with triple therapy (oral anticoagulant plus dual antiplatelet) prescription were assessed using multivariable logistic regression analysis.

Results

The number of patients with AF undergoing PCI increased gradually from 2006 (n = 2,140) to 2015 (n = 3,631) (p_trend<0.001). In 2006, only 22.7% of patients received triple therapy after PCI although 96.2% of them were indicated for anticoagulation (CHA₂DS₂-VASc score ≥2). The prescription rate of triple therapy increased to 38.3% in 2015 (p_trend<0.001), which was mainly attributed to a recent increment of NOAC-based triple therapy from 2013 (17.5% in 2015). Previous ischemic stroke or systemic embolism, old age, hypertension, and congestive heart failure were significantly associated with a higher triple therapy prescription rate, whereas previous myocardial infarction, PCI, and peripheral arterial disease were associated with triple therapy underuse.

Conclusions

From 2006 to 2015, the number of patients with AF undergoing PCI and the prescription rate of triple therapy increased gradually with a recent increment of NOAC-based antithrombotic therapy from 2013. Previous myocardial infarction, peripheral artery disease, and PCI were associated with underuse of triple therapy.

Mortality and causes of death in patients with atrial fibrillation: A nationwide population-based study

Background

Patients with atrial fibrillation are known to have a high risk of mortality. There is a paucity of population-based studies about the impact of atrial fibrillation on the mortality risk stratified by age, sex, and detailed causes of death.

Methods

A total of 15,411 patients with atrial fibrillation from the Korean National Health Insurance Service-National Sample Cohort were enrolled, and causes of death were identified according to codes of the 10th revision of the International Classification of Diseases.

Results

From 2002 to 2013, a total of 4,479 (29%) deaths were confirmed, and the crude mortality rate for all-cause death was 63.3 per 1,000 patient-years. Patients with atrial fibrillation had a 3.7-fold increased risk of all-cause death compared with the general population. The standardized mortality ratio for all-cause death was the highest in young patients and decreased with increasing age (standardized mortality ratio 21.93, 95% confidence interval 7.60–26.26 in patients aged <20 years; standardized mortality ratio 2.77, 95% confidence interval 2.63–2.91 in patients aged ≥80 years). Women with atrial fibrillation exhibited a greater excess mortality risk than men (standardized mortality ratio 3.81, 95% confidence interval 3.65–3.98 in women; standardized mortality ratio 3.35, 95% confidence interval 3.21–3.48 in men). Cardiovascular disease was the leading cause of death (38.5%), and cerebral infarction was the most common specific disease. Patients with atrial fibrillation had an about 5 times increased risk of death due to cardiovascular disease compared with the general population.

Conclusions

Patients with atrial fibrillation had a 4 times increased risk of mortality compared with the general population. However, the impact of atrial fibrillation on mortality decreased with age and in men. Cerebral infarction was the most common cause of death, and more attention should be paid to reducing the risk of stroke.

Body Mass Index and Risks of Incident Ischemic Stroke Subtypes: The Japan Public Health Center-Based Prospective (JPHC) Study

BACKGROUND

The association of body mass index (BMI) with risks of ischemic stroke subtypes have not been established.

METHODS

Cumulative average BMI was calculated using self-reported body weight and height obtained from baseline (Cohort I in 1990, and Cohort II from 1993-1994) and 5- and 10-year questionnaire surveys of Japan Public Health Center-based prospective (JPHC) study. A total of 42,343 men and 46,413 women aged 40-69 years were followed-up for the incidence of lacunar, large-artery occlusive, and cardioembolic strokes. A sub-distribution hazard model was used to estimate sub-distribution hazard ratios (SHRs) and the 95% confidence intervals (CIs).

RESULTS

During a median of 20.0 years of follow-up, we documented 809 and 481 lacunar, 395 and 218 large-artery occlusive, and 568 and 298 cardioembolic strokes in men and women, respectively. After adjustment for baseline age, updated smoking, alcohol consumption, leisure-time physical activity, and histories of hypertension, dyslipidemia, and diabetes mellitus, cumulative average BMI was positively linearly associated with lacunar (trend P = 0.007), large-artery occlusive (trend P = 0.002), and cardioembolic (trend P < 0.001) strokes in men, and with lacunar (trend P < 0.001) and large-artery occlusive (trend P = 0.003) strokes in women. There were approximately two-fold excess risk of cardioembolic stroke in both sexes and of lacunar and large-artery occlusive strokes in women for cumulative average BMI ≥30 kg/m² compared to BMI 23-<25 kg/m².

CONCLUSION

Cumulative average BMI showed a positive linear effect on sub-distribution hazards of lacunar, large-artery occlusive, and cardioembolic strokes in both sexes, except for cardioembolic stroke in women.

Development and validation of a risk prediction model for severe hypoglycemia in adult patients with type 2 diabetes: a nationwide population-based cohort study

Purpose

There is a scarcity of long-term prediction models for severe hypoglycemia (SH) in subjects with type 2 diabetes mellitus (T2DM). In this study, a model was developed and validated to predict the risk of SH in adult patients with T2DM.

Patients and methods

Baseline and follow-up data from patients with T2DM who received health evaluations from January 1, 2009, to December 31, 2010 (n=1,676,885) were analyzed as development (n=1,173,820) and validation (n=503,065) cohorts using the National Health Insurance Database (DB) in Korea. New SH episodes were identified using ICD-10 codes. A Cox proportional hazards regression model and Cox model coefficients were used to derive a risk scoring system, and 14 predictive variables were selected. A risk score nomogram based on the risk prediction model was created to estimate the 1-year risk of SH.

Results

In the development cohort, a total of 5,325 (0.45%) patients experienced SH episodes during the follow-up period. After multivariable adjustment, older age, female sex, current smoker, drinking, low body mass index, lack of exercise, previous SH events, insulin or multiple oral hypoglycemic agent use, presence of hypertension or chronic kidney disease, longer duration of diabetes, low or high glucose level, and high Charlson Comorbidity Index score were found to be significant risk factors for the development of SH and were incorporated into the risk model. The concordance indices were 0.871 (95% confidence interval, 0.863-0.881) in development cohort and 0.866 (95% CI, 0.856-0.879) in the validation cohort. The calibration plot showed a nearly 45° line, which indicates that this model predicts well an absolute SH event.

Conclusion

This 14-variable prediction model for SH events may be a useful tool to identify high-risk patients and guide prevention of SH in adult patients with T2DM.

To be thin but not healthy - The body-image dilemma may affect health among female university students in China

An increasing number of young girls have attached great importance to their body-image in China. Body-image dissatisfaction has resulted in increased weight loss behavior. The aim of this study was to investigate the factors that were associated with underweight body-image in female college students. Self-administered questionnaires were completed by 2,023 young female participants from eight Chinese universities. In addition, 160 participants were involved in a qualitative study. The ideal body-image and the factors that influence weight were determined using descriptive and analytical statistics. We found that 1,484 out of 2,023 participants (73.36%) had taken action to lose weight in the past six months. Among these participants, 618 (30.55%, out of 2023) participants were already underweight, and 1,161 (57.39%, out of 2023) would like to be much thinner, which would lead to more underweight individuals. Moreover, non-scientific physical activity and diets were found to lead participants to the underweight subgroup. The participants’ Body Mass Index (BMI), peer advice and western culture influenced the problematic thin-ideal (ideal BMI < 18.5 was considered as the problematic thin-ideal) (P<0.05). Together, western influences leading to the “problematic thin-ideal” and “unhealthy weight-control behavior” have brought about an increased prevalence of desired underweight body-image among female college students in China, which might be harmful for their health.

Systemic lupus erythematosus is a risk factor for cardiovascular disease: a nationwide, population-based study in Korea

OBJECTIVE

To investigate the incidence and clinical significance of cardiovascular disease in systemic lupus erythematosus patients.

METHODS

We included systemic lupus erythematosus patients ( n = 18,575) without previous cardiovascular disease and age- and sex-matched individuals without systemic lupus erythematosus (controls; n = 92,875) from the Korean National Health Insurance Service database (2008-2014). Both cohorts were followed up for incident cardiovascular disease and death until 2015.

RESULTS

During follow up, myocardial infarction occurred in 203 systemic lupus erythematosus patients and 325 controls (incidence rate: 1.76 and 0.56 per 1000 person-years, respectively), stroke occurred in 289 patients and 403 controls (incidence rate: 2.51 and 0.70 per 1000 person-years, respectively), heart failure occurred in 358 patients and 354 controls (incidence rate 3.11 and 0.61 per 1000 person-years, respectively), and death occurred in 744 patients and 948 controls (incidence rate 6.54 and 1.64 per 1000 person-years, respectively). Patients with systemic lupus erythematosus had higher risks for myocardial infarction (hazard ratio: 2.74, 95% confidence interval: 2.28-3.37), stroke (hazard ratio: 3.31, 95% confidence interval: 2.84-3.86), heart failure (hazard ratio: 4.60, 95% confidence interval: 3.96-5.35), and cardiac death (hazard ratio: 3.98, 95% confidence interval: 3.61-4.39).

CONCLUSIONS

Here, systemic lupus erythematosus was an independent risk factor for cardiovascular disease, thus cardiac assessment and management are critical in systemic lupus erythematosus patients.

A U-shaped relationship of body mass index on atrial fibrillation recurrence post ablation: A report from the Guangzhou atrial fibrillation ablation registry

Background

Obesity or overweight is related to worse outcomes in patients with atrial fibrillation (AF) following catheter ablation (CA). The role of being underweight in relation to recurrent arrhythmias post AF ablation is less certain. We conducted a retrospective study to investigate the association of body mass index (BMI) with arrhythmia outcomes in AF patients undergoing CA.

Methods

In a cohort of 1410 AF patients (mean age 57.2 ± 11.6 years; 68% male) undergoing single CA, the association between BMI and AF ablation outcome was analyzed using BMI as a continuous variable and by four BMI categories (<18.5 kg/m², 18.5-24 kg/m², 25-29 kg/m², and ≥ 30 kg/m²).

Result

We observed a positive association between a cut off value of BMI and risk of AF recurrence post AF ablation. BMI ≥26.36 kg/m² was related to more AF recurrence (c-statistic 0.55, 95%CI 0.51–0.58; P < 0.01) with 50% increased risk of AF recurrence (HR 1.50, 95% CI 1.22–1.86; P < 0.01). Recurrence rates in the four BMI categories were 33.3%, 23.2%, 27.2 and 41.8%, respectively (P < 0.01).

Kaplan-Meier analysis showed that BMI categories of <18.5 kg/m² and ≥ 30 kg/m² were all associated with more AF recurrence (P = 0.01). Both underweight (HR 1.85, 95%CI 1.12–3.08; P = 0.02) and obesity (HR 1.78, 95%CI 1.17–2.72; P = 0.01) significantly increased the risk of AF recurrence in a Cox proportional hazard model.

Conclusion

BMI had good predictive value for AF ablation outcomes with a cut off value of ≥26.36 kg/m². Apart from being obese/overweight, being underweight might also be a risk factor for AF recurrence post ablation.

Risk factors for new-onset atrial fibrillation: A focus on Asian populations

The incidence of new-onset atrial fibrillation (NOAF) is increasing both in the Asian populations and Western countries. Several demographic and clinical risk factors were independently associated with NOAF, including ageing, male sex, obesity, obstructive sleep apnea syndrome, hypertension, coronary artery disease, renal dysfunction and heart failure. However, some differences in the incidence of NOAF, the prevalence of some risk factors and lifestyle or environmental conditions may exist between Asian and Western countries. Early recognition and holistic management of risk factors in an integrated manner may help reduce the burden of NOAF and its complications. While some risk scores have been developed to predict the risk of NOAF, thus far none are currently recommended or adequately validated to be used as a screening tool especially in the Asian population. The present semi-systematic review article aims to provide a comprehensive overview on the risk factors associated to NOAF, focusing on those explored in the Asian populations.

Clinical implication of an impaired fasting glucose and prehypertension related to new onset atrial fibrillation in a healthy Asian population without underlying disease: a nationwide cohort study in Korea

Aims

For healthy populations without comorbidities, whether prehypertension and impaired fasting glucose (IFG) are associated with new onset atrial fibrillation (AF) is not well known.

Methods and results

We included 366 507 subjects (age ≥20 years) not diagnosed with non-valvular AF from the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC) from 2003 to 2008. In total, 139 306 subjects diagnosed with AF-related comorbidities were excluded, and a 227 102 healthy population was followed up until 2013. The body mass index (BMI), blood pressure (BP), and fasting blood glucose (BG) level were acquired during National health check-ups. Subjects with IFG [hazard ratio (HR) 1.16, P = 0.017] had a higher AF risk and the diastolic BP (HR 1.11, P = 0.045) was a stronger indicator for an AF incidence than the systolic BP. After dividing the subjects into two mutually exclusive groups, AF incidence was increased dramatically by the combination effect of both prehypertension and an IFG in BMI <25 kg/m2 group, but, in BMI ≧25 kg/m2 group, did not show this tendency. An IFG related to AF risk was more prominent in the BMI <25 kg/m2 population (HR 1.18, P = 0.025) than those with a BMI ≥25 kg/m2, and subjects with both an IFG and prehypertension had a greater AF risk (HR 1.27, P = 0.016) than those without.

Conclusion

Even in a healthy Asian populations without comorbidities, prehypertension and IFG were important risk factors of AF. Specifically, when prehypertension, including systolic and diastolic BPs, was finally combined with the IFG, the risk of new onset AF was increased especially in the BMI <25 kg/m2 group.

Increased Risk of Atrial Fibrillation in the Early Period after Herpes Zoster Infection: a Nationwide Population-based Case-control Study

BACKGROUND

Herpes zoster (HZ) is a chronic inflammatory disease that could result in autonomic dysfunction, often leading to atrial fibrillation (AF).

METHODS

From the Korean National Health Insurance Service database of 738,559 subjects, patients newly diagnosed with HZ (n = 30,685) between 2004 and 2011, with no history of HZ or AF were identified. For the non-HZ control group, 122,740 age- and sex-matched subjects were selected. AF development in the first two-years following HZ diagnosis, and during the overall follow-up period were compared among severe (requiring hospitalization, n = 2,213), mild (n = 28,472), and non-HZ (n = 122,740) groups.

RESULTS

There were 2,204 (1.4%) patients diagnosed with AF during follow-up, and 825 (0.5%) were diagnosed within the first two years after HZ. The severe HZ group showed higher rates of AF development (6.4 per 1,000 patient-years [PTPY]) compared to mild-HZ group (2.9 PTPY) and non-HZ group (2.7 PTPY). The risk of developing AF was higher in the first two-years after HZ diagnosis in the severe HZ group (10.6 PTPY vs. 2.7 PTPY in mild-HZ group and 2.6 PTPY in non-HZ group).

CONCLUSION

Severe HZ that requires hospitalization shows an increased risk of incident AF, and the risk is higher in the first two-years following HZ diagnosis.

Association of ischemic stroke with ankylosing spondylitis: a nationwide longitudinal cohort study

BACKGROUND

The purpose of this nationwide age- and sex-matched longitudinal follow-up study was to investigate the risk of developing ischemic stroke in ankylosing spondylitis (AS).

METHODS

The data in this study, spanning from January 1, 2010 to December 31, 2014, was obtained from a database maintained by the Korean National Health Insurance Service. A total of 12,988 patients with a diagnosis of AS were enrolled. The control group consisted of 64,940 age-sex-stratified matching subjects without AS. The 6year ischemic stroke incidence rate for each group was calculated using the Kaplan-Meier method. Cox proportional hazards regression analysis was used to estimate the hazard ratio of ischemic stroke.

RESULTS

During the follow-up period, 73 patients (0.56%) in the AS group and 250 patients (0.38%) in the control group developed ischemic stroke (p = 0.0041). The hazard ratio of ischemic stroke in the AS group was 1.46 (95% confidence interval [95% CI], 1.13-1.90) after adjusting for age and sex. The adjusted hazard ratio of ischemic stroke in the AS group was 1.35 (95% CI, 1.04-1.75) after controlling for demographics and comorbid medical disorders. According to subgroup analysis, in female and diabetes and non-hypertension and dyslipidemia subgroups, ischemic stroke incidence rates were significantly higher in AS patients than those in control group.

CONCLUSION

Our nationwide longitudinal study suggests an increased risk of ischemic stroke in AS patients.

Risk of ischemic stroke in metabolically healthy obesity: A nationwide population-based study

Background

Whether metabolically healthy obese (MHO) individuals are at increased risk of ischemic stroke is not well known. We investigated the association of the MHO phenotype with ischemic stroke.

Methods

A total of 354,083 adults (age 45.8 ± 14.2 years) from the Korean National Health Insurance Service–National Sample Cohort enrolled in 2004–2008 were followed-up for incident ischemic stroke until 2013. Subjects meeting none of the metabolic syndrome criteria were classified as ‘metabolically healthy’. The cohort was categorized into four groups according to obesity and metabolic status: metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), MHO, and metabolically unhealthy obese (MUO).

Results

Ischemic stroke was newly diagnosed in 4,884 (1.4%) individuals during a mean follow-up of 7.4 ± 1.5 years. Stroke incidence rates for the MHNW, MUNW, MHO, and MUO groups were 0.56, 2.61, 0.61, and 2.76 per 1,000 person-years, respectively. While risk for stroke increased significantly in metabolically unhealthy groups, it was not increased in MHO compared to the MHNW group on multivariate analysis. In metabolically healthy individuals, obesity did not increase the risk for ischemic stroke, regardless of the severity of obesity. Meanwhile, in metabolically unhealthy individuals, being obese was significantly associated with increased risk of stroke.

Conclusions

MHO individuals were not at increased risk for ischemic stroke. However, obesity increased risk for ischemic stroke in persons with metabolic risk factors; therefore, maintaining normal weight may be more important for this population. Also, metabolic unhealthiness showed greater association than obesity with stroke.

Epidemiology of atrial fibrillation

BACKGROUND

The most common type of arrhythmia in the USA and in European countries is atrial fibrillation (AF). The prevalence of AF is increasing worldwide with advances in technology, better prediction methods and increased awareness among healthcare professionals and patients.

METHODS

This article summarises the literature on the epidemiology of AF worldwide according to continents, age and ethnicity/race, and also includes the prevalence of AF in stroke patients.

RESULTS

In Australia, Europe and the USA, the current estimated prevalence of AF is about between 1% and 4%, with lower prevalence evident in Asia (0.49%-1.9%). AF prevalence is highest among Whites. In Western Europe, Australia and North America 70% of people with AF are aged >65 years, whereas the average age of AF patients in other geographical regions is often lower.

CONCLUSIONS

Although the prevalence of AF worldwide is increasing steadily, large variation can be seen between studies and countries. Further epidemiological studies should be undertaken globally, especially in Asian and African countries so that a better and more accurate picture of the incidence and prevalence of AF can be captured, to enable stroke prevention strategies to be appropriately implemented to prevent or reduce the risk of stroke, the most severe consequence of AF.

Severe hypoglycemia is a risk factor for atrial fibrillation in type 2 diabetes mellitus: Nationwide population-based cohort study

AIMS

This study investigated the association between severe hypoglycemia (SH) and new onset atrial fibrillation (AF) and all-cause mortality in adult patients with type 2 diabetes mellitus (T2DM).

METHODS

Retrospective data on patients with T2DM aged between 30 and 75years who received healthcare checkups from January 1, 2005 to December 31, 2008 were analyzed using the National Health Insurance Database in Korea. The primary outcome was newly diagnosed non-valvular AF occurring after SH episode using ICD-10 codes.

RESULTS

Among 1,509,280 subjects, 10,864 (0.72%) patients had experienced SH events in the three years prior to health examination, and a total of 48,916 (3.24%) first-time AF episodes occurred during the follow-up period of 8.5years. The incidence of AF was significantly higher in the group with SH than the group without SH. After multivariable adjustment, previous SH was a significant risk factor for the development of AF (HR 1.10, 95% CI 1.01-1.19). All-cause mortality was also significantly increased in patients with previous SH events and prior SH with subsequent AF occurrence, compared to patients without SH events.

CONCLUSIONS

Prior SH events were associated with a higher risk of new onset AF and all-cause mortality in patients with T2DM.

Prevalence of Non-valvular Atrial Fibrillation Based on Geographical Distribution and Socioeconomic Status in the Entire Korean Population

BACKGROUND AND OBJECTIVES

Prevalence of atrial fibrillation (AF) varies based on geographical location and socioeconomic status. We aimed to evaluate the prevalence of AF and utilization of antithrombotic therapy based on geographical regions and income levels in the entire Korean population.

METHODS

We performed a cross-sectional analysis of Korean adults (aged ≥20 years) using the 2015 National Health Insurance Service database (n=41,505,679). The study population was stratified into 17 geographical regions and 21 income levels.

RESULTS

We identified 276,842 patients diagnosed with AF. Overall prevalence of AF in suburban/rural regions was significantly higher than that observed in urban regions (0.72% vs. 0.61%, respectively, p<0.001). Elderly patients (age ≥75 years) showed a higher prevalence of AF and comorbidities related to AF development showed a higher prevalence among the population residing in suburban/rural regions. Among AF patients with a CHA₂DS₂-VASc score ≥2, oral anticoagulation (OAC) therapy utilization was lower in the suburban/rural regions than that observed in the urban regions (48.2% vs. 51.8%, respectively, p<0.001). The relationship between income levels and AF prevalence showed a J-shaped curve. The OAC prescription rate showed a positive correlation with income levels. Non-vitamin K antagonist oral anticoagulants tended to be more commonly prescribed among the higher income groups.

CONCLUSIONS

Geographical location of residence and income levels were closely associated with the prevalence of AF and antithrombotic therapy utilization. This information may provide further insights for more effective surveillance of AF and stroke prevention for improved clinical outcomes.

Temporal trends of antithrombotic therapy for stroke prevention in Korean patients with non-valvular atrial fibrillation in the era of non-vitamin K antagonist oral anticoagulants: A nationwide population-based study

Background

Following their introduction, the non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly prescribed in Asia for stroke prevention in patients with non-valvular atrial fibrillation (AF). Few contemporary data are available on temporal trends in antithrombotic therapy use in Asian countries, in the era of NOACs.

Methods and results

Using the National Health Insurance Service database of the entire Korean adult AF population, the use of aspirin, vitamin K antagonist, and NOACs between 2008 and 2015 were analyzed (n = 276,246 in 2015). Most of the included cohort had CHA₂DS₂-VASc score ≥ 2 (78.2% in 2008 and 83.2% in 2015), yet approximately 17% were prescribed no antithrombotic therapy throughout the study period. Aspirin prescription consistently decreased (from 48.2% to 31.5%) over time, while OAC prescription significantly increased from 34.7% to 50.6%. NOAC prescriptions accounted for 50% of total OAC prescription in 2015. Similar trends in antithrombotic therapy were found both in men and in women, but women were more likely to be undertreated with OAC. Female gender, presence of vascular disease and prior intracranial hemorrhage were associated with OAC underuse.

Conclusions

Between 2008 and 2015, a greater proportion of AF patients received OAC treatment with increasing NOAC prescription trends in the recent 3 years. A substantial proportion (approx. 50%) of Korean patients with AF still remain undertreated.

Trend of Prevalence of Atrial Fibrillation and use of Oral Anticoagulation Therapy in Patients With Atrial Fibrillation in South Korea (2002-2013)

BACKGROUND

This study examined the annual prevalence of atrial fibrillation (AF) and its associated comorbidities, as well as the prevalence of warfarin therapy in South Korean patients with AF.

METHODS

The National Health Insurance Service-National Sample Cohort database was searched for subjects aged ≥30 years diagnosed with AF from 2002-2013. The prevalence of AF was analyzed by sex and age, as was the current status of warfarin therapy in AF patients according to CHA₂DS₂-VASc score and comorbidities.

RESULTS

The age-standardized prevalence of AF in men and women was 0.15% and 0.14%, respectively, in 2002, increasing to 0.54% and 0.39%, respectively, in 2013. In 2013, the prevalence of AF in men and women aged 30-39 years was 0.08% and 0.03%, respectively, increasing to 2.35% and 1.71%, respectively, in those in aged ≥60 years. During 2002-2013, the prevalence of AF in men significantly increased among subjects aged ≥30 years and increased in women aged ≥60 years. The age-standardized prevalence of hypertension and diabetes mellitus among AF patients were markedly increased during 2002-2013. Of these AF patients, 86.1% had a CHA₂DS₂-VASc score of ≥2; however, only 39.1% of these were receiving warfarin.

CONCLUSIONS

The age-standardized prevalence of AF increased 2.89-fold over the 12-year study period. The total number of patients with AF in South Korea has been drastically increasing, due to not only aging society but also increasing age-specific prevalence of AF, especially in middle-aged and elderly individuals. The rate of warfarin therapy increased slightly over the study period but remains low.

Cirrhosis is a risk factor for atrial fibrillation: A nationwide, population-based study

BACKGROUND & AIMS

Information is lacking regarding whether cirrhosis is associated with atrial fibrillation development. We aimed to investigate the incidence and clinical significance of atrial fibrillation in cirrhotic patients.

METHODS

Cirrhotic patients (n=3596; mean age, 54.7±12.3 years; male, 72.5%) without previous atrial fibrillation were selected from the Korean National Health Insurance Service National Sample Cohort database between 2004 and 2008. Age- and sex-matched controls (n=17 980) were randomly sampled in a 5:1 ratio from non-cirrhotic individuals. Both cohorts were followed up for incident atrial fibrillation and death until 2013.

RESULTS

During 9 years of follow-up, atrial fibrillation was newly detected in 113 (3.1%) cirrhosis patients and 385 (2.1%) controls (incidence: 3.48 and 2.16 per 1000 person-years respectively). Cirrhotic patients were at higher risk for atrial fibrillation development compared to controls (hazard ratio, 1.46; 95% confidence interval, 1.18-1.80) after multivariate adjustment. On subgroup analysis, cirrhosis increased the risk for atrial fibrillation, especially in younger (age younger than 65 years) men without comorbidities (CHA₂ DS₂ -VASc score, 0). Cirrhotic patients showed increased overall mortality compared to controls (hazard ratio, 4.80; 95% confidence interval, 4.47-5.15) as well as increased cardiovascular mortality (hazard ratio, 1.37; 95% confidence interval, 1.07-1.75). However, there was no significant association between development of atrial fibrillation and increased mortality in cirrhosis patients (P=.188 and .260).

CONCLUSIONS

Cirrhosis was an independent risk factor for atrial fibrillation development, especially in younger, otherwise healthy men, stressing the importance of cardiac assessment in cirrhotic patients. Meanwhile, atrial fibrillation development in cirrhosis patients was not associated with increased mortality.

Increased Risk of Atrial Fibrillation and Thromboembolism in Patients with Severe Psoriasis: a Nationwide Population-based Study

Psoriasis increases the risk of atrial fibrillation (AF) and thromboembolic events (TE). There is limited information on the effect of psoriasis severity on AF and TE. In this study, psoriasis patients were enrolled from the Korean National Insurance Service-National Sample Cohort (2004–2008). Diagnosis and disease severity were determined from claims data. Newly diagnosed non-valvular AF and TE were identified during a 9.6-year follow-up. The effect of psoriasis severity on AF and TE was evaluated. We identified 13,385 psoriasis patients (1,947 with severe psoriasis). Severe psoriasis significantly increased the risk of AF (adjusted hazard ratio [HR_adjust] 1.44 [95% confidence interval (CI) 1.14–1.82], p = 0.002) and TE (HR_adjust 1.26 [95% CI 1.07–1.47], p = 0.005); mild psoriasis did not show any significant effects. Results were similar after propensity-score matching. Risk increments of AF and TE were prominent in patients with greater cardiovascular risk. A possible limitation of our study is that it has a retrospective design, and the effect of unmeasured confounders and risk of misclassification could bias the results. To conclude, our results showed that severe, but not mild, psoriasis significantly increased AF and TE risk. AF surveillance and active stroke prevention would be beneficial in such cases.

Proteinuria Detected by Urine Dipstick Test as a Risk Factor for Atrial Fibrillation: A Nationwide Population-Based Study

Proteinuria is one of the well-known risk factors for cardiovascular disease. However the impact of proteinuria on the incidence of atrial fibrillation (AF) is unclear. In this study, we investigated the association between proteinuria detected using urine dipstick test and the risk of AF. A total of 18,201,275 individuals were analyzed, who had no prior AF and had received biennial health checkups provided by the National Health Insurance Service between 2005 and 2008 in Korea. Incidences of AF were ascertained through the end of 2015. During a mean follow-up of 9.6 years, a total of 324,764 (1.8%) developed AF (1.86 per 1,000 person-years). In Cox regression models, proteinuria was associated with an increased risk of AF: adjusted HR and 95% CI of AF occurrence were 1.13 (1.10-1.16), 1.34 (1.31-1.38), 1.53 (1.48-1.58), 1.82 (1.71-1.94), and 1.86 (1.61-2.16) in individuals with trace, 1+, 2+, 3+, and 4+ proteinuria, respectively, compared with those without proteinuria. The result was consistent even after additional adjustment for estimated glomerular filtration rate. In addition, the risk of AF further increased or decreased according to the follow-up dipstick test results. Thus, proteinuria measured with a dipstick test might be considered a potent risk factor for AF development.

Risk of stroke in congestive heart failure with and without atrial fibrillation

BACKGROUND

Heart failure has been associated with an increased risk for ischemic stroke. This study estimated the risk of stroke and thromboembolism for patients with congestive heart failure (CHF) in the context of the general population, especially compared to those with atrial fibrillation (AF).

METHODS

Data of patients discharged alive from 2003 to 2012 were extracted from the National Health Insurance Corporation sample cohort. Subjects were classified into control (n=90,277), CHF (n=4533), AF (n=1187), and CHF plus AF (n=1213) groups.

RESULTS

CHF was associated with an increased risk for ischemic stroke, which was significant after various adjustment models. Annualized stroke risk was 0.54 (0.52-0.57) per 100 person-years for the control group, 2.00 (1.79-2.21) for the CHF group, 2.27 (1.84-2.69) for the AF group, and 2.87 (2.38-3.36) for the CHF plus AF group. The CHA₂DS₂-VASc scoring schema had a moderate discriminatory value for stroke risk in patients with CHF as well as in AF. The risk of stroke for the CHF group was comparable to that of the AF group when stratified according to the CHA₂DS₂-VASc scores. Those with CHA₂DS₂-VASc score of 0 or 1 were at low risk for stroke for both CHF and AF.

CONCLUSION

Patients with CHF are at increased risk for ischemic stroke and thromboembolism. This study showed that the CHA₂DS₂-VASc schema can help stratify stroke risk for individual CHF patients. Stroke is a frequent complication among patients with CHF; therefore, safe and effective strategies to prevent stroke are needed.

CHA 2 DS 2 -VASc Score (Congestive Heart Failure, Hypertension, Age ≥75 [Doubled], Diabetes Mellitus, Prior Stroke or Transient Ischemic Attack [Doubled], Vascular Disease, Age 65–74, Female) for Stroke in Asian Patients With Atrial Fibrillation

Background and Purpose—

The CHA 2 DS 2 -VASc stroke score (congestive heart failure, hypertension, age ≥75 (doubled), diabetes mellitus, prior stroke or transient ischemic attack (doubled), vascular disease, age 65–74, female) is used in most guidelines for risk stratification in atrial fibrillation (AF), but most data for this score have been derived in Western populations. Ethnic differences in stroke risk may be present. Our objective was to investigate risk factors for stroke in AF and application of the CHA 2 DS 2 -VASc score in an Asian AF population from Korea.

Methods—

A total of 5855 oral anticoagulant–naive nonvalvular AF patients aged ≥20 years were enrolled from Korea National Health Insurance Service Sample cohort from 2002 to 2008 and were followed up until December 2013.

Results—

The incidence rates (per 100 person-years) of ischemic stroke were 3.32 in the total population, being 0.23 in low-risk (CHA 2 DS 2 -VASc score 0 [male] or 1 [female]) and 4.59 in high-risk patients (CHA 2 DS 2 -VASc ≥2). Incidence rates of ischemic stroke or the composite thromboembolism end point showed a clear increase with increasing CHA 2 DS 2 -VASc score. On multivariable analysis, significant associations between CHA 2 DS 2 -VASc risk factors and ischemic stroke were observed; however, the significance of vascular disease or diabetes mellitus was attenuated after multivariate adjustment, and female sex (hazard ratio, 0.73; 95% confidence interval, 0.64–0.84) had a lower risk of ischemic stroke than males. Patients who were categorized as low risk consistently had an event rate <1% per year.

Conclusions—

The performance of CHA 2 DS 2 -VASc score in Asians is comparable with that in Western populations. The score shows good performance in defining the truly-low-risk AF patients for stroke/thromboembolism.

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.

Atrial fibrillation risk in metabolically healthy obesity: A nationwide population-based study

BACKGROUND

Metabolically healthy obese (MHO) individuals are reported to have a marginal increase in cardiovascular risk; however, their atrial fibrillation (AF) risk is unclear. We aimed to assess AF risk in MHO individuals and identify whether AF development is associated with obesity or influenced by metabolic comorbidities.

METHODS

A retrospective cohort of 389,321 individuals (age, 45.6±14.5years; male, 52.1%) was extracted from the Korean National Health Insurance sample database between 2004 and 2006 and followed-up for new-onset AF until 2013. Subjects with diabetes mellitus, hypertension, and/or dyslipidemia were classified as "metabolically unhealthy." The cohort was stratified into four groups according to obesity and metabolic healthiness: metabolically healthy non-obese (MHNO), metabolically unhealthy non-obese (MUNO), MHO, and metabolically unhealthy obese (MUO).

RESULTS

AF was newly diagnosed in 5106 (1.3%) individuals during a mean follow-up of 7.5±1.5years. The AF incidence rates for the MHNO, MUNO, MHO, and MUO groups were 0.76, 2.66, 1.10, and 2.88 per 1000 person-years, respectively. Compared with the MHNO group, the MHO group had increased AF risk (adjusted hazard ratio, 1.30; 95% CI, 1.14-1.48) on multivariate analysis. One fourth of the MHO cohort became metabolically unhealthy, contributing to increased AF risk. Obesity was an independent risk factor for AF, and increased AF risk by 20%. Metabolic unhealthiness increased AF risk by around 40%, and of its components, hypertension contributed the most.

CONCLUSIONS

MHO individuals are at increased risk for AF development, and obesity was independently associated with elevated AF risk.

Trends in the incidence and prevalence of atrial fibrillation and estimated thromboembolic risk using the CHA2DS2-VASc score in the entire Korean population

BACKGROUND

Data on the epidemiology of atrial fibrillation (AF) and temporal trends are not well established in the Korean population. We aimed to estimate the incidence and prevalence of AF in Korea between 2008 and 2015.

METHODS

Using the National Health Insurance Service database, we analyzed as a nationwide cohort the entire Korean adult population from 2008 to 2015 (n=41,505,679 in 2015). AF was identified by using diagnostic codes.

RESULTS

During an 8-year period representing 314,311,360 person-years of follow-up, 496,341 individuals were newly diagnosed with AF. The incidence of AF increased to >1.12-fold as follows: from 15.34 to 17.14 per 10,000 person-years (p<0.001). We also found a 1.68-fold increase in the prevalence of AF, from 0.46% in 2008 to 0.67% in 2015 (p<0.001). The incidence and prevalence of AF increased with advancing age. The median age of the AF patients increased from 68 to 71years (p<0.001). The prevalence of diabetes and heart failure in AF subjects increased (p<0.001). The percentage of patients with a CHA₂DS₂-VASc score of ≥2, who were strongly recommended for anticoagulation treatment, increased from 80.2% to 86.8% (p<0.001).

CONCLUSION

The incidence and prevalence of AF gradually increased from 2008 to 2015. The proportion of AF patients who were candidates for anticoagulation therapy also significantly increased owing to population aging and increasing comorbidities (i.e., heart failure and diabetes). These findings may provide a framework to understand the actual disease burden and establish the optimal management strategy for AF.

Body mass index, abdominal fatness, fat mass and the risk of atrial fibrillation: a systematic review and dose-response meta-analysis of prospective studies

Different adiposity measures have been associated with increased risk of atrial fibrillation, however, results have previously only been summarized for BMI. We therefore conducted a systematic review and meta-analysis of prospective studies to clarify the association between different adiposity measures and risk of atrial fibrillation. PubMed and Embase databases were searched up to October 24th 2016. Summary relative risks (RRs) were calculated using random effects models. Twenty-nine unique prospective studies (32 publications) were included. Twenty-five studies (83,006 cases, 2,405,381 participants) were included in the analysis of BMI and atrial fibrillation. The summary RR was 1.28 (95% confidence interval: 1.20-1.38, I² = 97%) per 5 unit increment in BMI, 1.18 (95% CI: 1.12-1.25, I² = 73%, n = 5) and 1.32 (95% CI: 1.16-1.51, I² = 91%, n = 3) per 10 cm increase in waist and hip circumference, respectively, 1.09 (95% CI: 1.02-1.16, I² = 44%, n = 4) per 0.1 unit increase in waist-to-hip ratio, 1.09 (95% CI: 1.02-1.16, I² = 94%, n = 4) per 5 kg increase in fat mass, 1.10 (95% CI: 0.92-1.33, I² = 90%, n = 3) per 10% increase in fat percentage, 1.10 (95% CI: 1.08-1.13, I² = 74%, n = 10) per 5 kg increase in weight, and 1.08 (95% CI: 0.97-1.19, I² = 86%, n = 2) per 5% increase in weight gain. The association between BMI and atrial fibrillation was nonlinear, p _nonlinearity < 0.0001, with a stronger association at higher BMI levels, however, increased risk was observed even at a BMI of 22-24 compared to 20. In conclusion, general and abdominal adiposity and higher body fat mass increase the risk of atrial fibrillation.

Neuro-atriomyodegenerative origin of atrial fibrillation and superimposed conventional risk factors: continued search to configure the genuine etiology of "eternal arrhythmia"

Atrial fibrillation (AF) is the most challenging rhythm disturbance worldwide. Arrhythmia and its behavior represent complex pathogenesis highly opposing to contemporary curative modalities. Increasing age of patients carries a certain level of risk for AF. Some underlying diseases in concordance with aging actually accelerate the occurrence of AF. Underestimated superimposed risk factors - aging plus any known risk factor or condition (hypertension, diabetes etc.) - elicit great interest and concern. In light of these concerns we offer an elaborated universal hypothesis in attempt to elucidate the genuine origin of AF substrate. Putative chronic toxicity - toxins and/or involution related pseudo-toxins potentially generate micro- and macro-structural changes in atrial myocardium thus inciting both intracellular damage (degeneration of myocites, apoptosis) and extracellular fibrotic proliferation (interstitial fibrosis, formation of matrices, degeneration of cells with fibrotic replacement). The co-products of related underlying diseases in cooperation with cellular senescence, endogenous overproduction of specific lipids/lipoproteins and other pro-atherosclerotic and/or inflammatory components generate a total atrial response - vascular/microvascular damage, intracellular and extracellular injuries. These organizational arrangements covering the entire atrial myocardium and perhaps ganglionated plexi/autonomic branches of the nervous system eventually cause clinical havoc - atrial overstretch, atrial adaptation/maladaptation, electromechanical dysfunction, arrhythmias, heart failure, etc. In essence, valvular heart disease potentially evokes similar changes "violating" thin atrial walls to obey the same scenario. Depicted atriomyodegenerative processes most likely represent the true nature of AF substrate development. Available clinical and morphological evidence potentially designates the atriomyodegenerative or plausible neuro-atriomyodegenerative origin of AF. Deductively fusion of reasons rather than purely heterogeneity is responsible for AF induction. Thus, the uniform approach and synoptic vision of clinical and pathohistological entity may offer an alternative or refreshed viewpoint in AF substrate formation.

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.