Uric Acid Level and New-Onset Atrial Fibrillation in the Japanese General Population - Longitudinal Study

Effect of hyperuricemia on paroxysmal atrial fibrillation after catheter ablation and influence of alcohol consumption

Background

Evidence regarding the association between hyperuricemia and arrhythmia recurrence after catheter ablation for paroxysmal atrial fibrillation (AF) is scarce. We investigated whether hyperuricemia predicts arrhythmia recurrence after catheter ablation for paroxysmal AF and the relationship between hyperuricemia and alcohol consumption in AF recurrence.

Methods

Patients who underwent catheter ablation for paroxysmal AF were divided into the hyperuricemia (index serum uric acid [UA] >7.0 mg/dL; n = 114) and control (UA ≤7.0 mg/dL; n = 609) groups and were followed for a median of 24 (12-48) months after ablation.

Results

The hyperuricemia group had more patients with an alcohol intake of ≥20 g/day (33.3% vs. 22.7%, p = .017) and a lower incidence of AF-free survival (p = .019). Similarly, those with an alcohol intake of ≥20 g/day had a lower incidence of AF-free survival than other patients. Multivariate Cox regression analysis revealed the following independent predictors of AF recurrence (adjusted hazard ratio, 95% confidence interval): hyperuricemia (1.64, 1.12-2.40), female gender (1.91, 1.36-2.67), brain natriuretic peptide level >100 pg/mL (1.59, 1.14-2.22), and alcohol consumption ≥20 g/day (1.49, 1.03-2.15) (all p < .05). In addition, causal mediation analysis revealed that alcohol consumption of ≥20 g/day directly affected AF recurrence, independent of hyperuricemia.

Conclusions

Patients with hyperuricemia may be at a high risk of arrhythmia recurrence after catheter ablation for paroxysmal AF. Although high alcohol consumption may contribute to increased UA levels, the presence of hyperuricemia may independently predict AF recurrence.

Progress of uric acid in cardiovascular disease

Due to the global prevalence of hyperuricemia (HUA), there is growing interest in research on uric acid (UA). HUA is a common condition that has various adverse consequences, including gout and kidney disease. However, recent studies have also implicated UA in the development of cardiovascular diseases (CVD) such as atrial fibrillation (AF) and coronary heart disease (CHD). Experimental and clinical research has extensively demonstrated the detrimental effects of elevated serum UA levels on cardiovascular health. Furthermore, serum UA levels have been identified as predictors of CVD outcomes following percutaneous coronary intervention (PCI) and catheter ablation. Additionally, the use of UA-lowering therapy holds important implications for the management of CVD. This review aims to consolidate the current evidence on the relationship between serum UA and CVD.

Sex-specific associations between serum uric acid levels and risk of hypertension for different diagnostic reference values of high blood pressure

The association between uric acid (UA) and hyperuricemia with 5-year hypertension incidence using different blood pressure (BP) diagnostic references in men and women without cardiometabolic diseases is unknown. We used the checkup data from Kagoshima Kouseiren Hospital. All participants with hypertension or on BP medication, diabetes, dyslipidemia, obesity, estimated glomerular filtration rate<60 ml/min/1.73m2, metabolic syndrome, history of gout, and UA-lowering medication were excluded. UA was categorized into sex-specific quartiles and hyperuricemia was defined as UA > 7 mg/dl in men and UA > 6 mg/dl in women. We performed multivariate logistic regression to assess the effects of UA on hypertension development. The 5-year hypertension incidence was defined as subsets of BP ≥ 140/90 mmHg in cohort 1 and BP ≥ 130/80 mmHg in cohort 2. The study enrolled 21,443 participants (39.8%, men) in cohort 1 and 15,245 participants (36.5%, men) in cohort 2. The incidence of hypertension in cohorts 1 and 2 over 5 years was 16.3% and 29.7% in men and 10.9% and 21.4% in women, respectively. When comparing the fourth to the first UA quartile, there was an association with hypertension in men in cohort 1, with odds ratio (OR): 1.36 (95% confidence interval [CI], 1.13-1.63, p < 0.01) and cohort 2, OR: 1.31 (95%CI, 1.09-1.57, p < 0.01), respectively, but not in women. Additionally, an association between hyperuricemia and hypertension was observed in men only in cohort 1, with OR: 1.23 (95%CI, 1.07-1.42, p = 0.02), and in women in cohort 2, OR: 1.57 (95%CI, 1.14-2.16, p < 0.01). The effect of UA on the development of hypertension is influenced by sex and incidence differs with the BP reference used. Uric acid effect on the development of hypertension is affected by sex and incidence differs with the BP reference used.

Gender differences in the relationship between serum uric acid and the long-term prognosis in heart failure: a nationwide study

BACKGROUND

Serum uric acid (SUA) is an important pathogenetic and prognostic factor for heart failure (HF). Gender differences are apparent in HF. Furthermore, gender differences also exist in the association between SUA and prognosis in various cardiovascular diseases. However, the gender difference for SUA in the prediction of long-term prognosis in HF is still ambiguous.

METHODS

A total of 1593 HF patients (897 men, 696 women) from the National Health and Nutrition Examination Survey (NHANES) 1999-2018 cycle were enrolled in our final analysis. Participants were categorized according to gender-specific SUA tertile. We assessed the association between SUA and long-term prognosis of HF patients, defined as all-cause mortality and cardiovascular mortality, in different genders via Kaplan-Meier curve analysis, Cox proportional hazard model, and Fine-Gray competing risk model. The restricted cubic spline (RCS) was performed to investigate the dose-response relationship between SUA and outcomes.

RESULTS

Gender differences exist in demographic characteristics, clinical parameters, laboratory tests, and medication of HF patients. After a median follow-up of 127 months (95% CI 120-134 months), there were 853 all-cause deaths (493 events in men, 360 events in women) and 361 cardiovascular deaths (206 events in men, 155 events in women). Kaplan-Meier analysis showed that SUA had gender difference in the prediction of cardiovascular mortality (Log-rank p < 0.001, for male, Log-rank p = 0.150, for female), but not in all-cause mortality. Multivariate Cox regression analysis revealed that elevated SUA levels were associated with higher all-cause mortality and cardiovascular mortality in men (HR 1.11, 95% CI 1.05-1.18, p < 0.001, for all-cause death; HR 1.18, 95% CI 1.09-1.28, p < 0.001, for cardiovascular death), but not in women (HR 1.05, 95% CI 0.98-1.12, p = 0.186, for all-cause death; HR 1.01, 95% CI 0.91-1.12, p = 0.902, for cardiovascular death). Even using non-cardiovascular death as a competitive risk, adjusted Fine-Gray model also illustrated that SUA was an independent predictor of cardiovascular death in men (SHR 1.17, 95% CI 1.08-1.27, p < 0.001), but not in women (SHR 0.98, 95% CI 0.87 - 1.10, p = 0.690).

CONCLUSIONS

Gender differences in the association between SUA and long-term prognosis of HF existed. SUA was an independent prognostic predictor for long-term outcomes of HF in men, but not in women.

A Predictive Model of New-Onset Atrial Fibrillation After Percutaneous Coronary Intervention in Acute Myocardial Infarction Based on the Lymphocyte to C-Reactive Protein Ratio

Purpose

Lymphocyte to C-reactive protein ratio (LCR) is a recognized systemic inflammatory marker and novel prognostic indicator for several cancers. This study investigated the relationship between preoperative LCR and new-onset atrial fibrillation (NOAF) in patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI).

Patients and Methods

Patients with AMI (n=662) with no history of atrial fibrillation (AF) were enrolled and classified into NOAF and non-NOAF groups based on the occurrence of postoperative NOAF during hospitalization. Logistic regression models were used to analyze NOAF risk factors and to assess the association between preoperative LCR and NOAF incidence. We constructed a new nomogram from the selected NOAF risk factors, and tested its predictive performance, degree of calibration, and clinical utility using receiver operating characteristic and calibration curves, decision curve analysis, and clinical impact curves.

Results

Overall, 84 (12.7%) patients developed NOAF during hospitalization. The LCR was significantly lower in the NOAF group. Preoperative LCR accurately predicted NOAF after AMI and was correlated with increased NOAF risk. Age, body mass index, diabetes, serum albumin levels, uric acid levels, left atrium (LA) diameter, left ventricular ejection fraction, left circumflex artery stenosis > 50%, and Killip class II status were independent predictors of NOAF after AMI. In addition, a new nomogram combined with LCR was constructed to stratify the risk of NOAF in patients with AMI. The performance of the new nomogram was satisfactory, as shown by the receiver operating characteristic curve, calibration curve, decision curve analysis and clinical impact curve.

Conclusion

Preoperative LCR was an independent predictor of NOAF in patients with AMI after PCI. The novel nomogram combined with LCR could rapidly and individually identify and treat patients at a high risk of NOAF.

Exploring the Multifaceted Nexus of Uric Acid and Health: A Review of Recent Studies on Diverse Diseases

The prevalence of patients with hyperuricemia or gout is increasing worldwide. Hyperuricemia and gout are primarily attributed to genetic factors, along with lifestyle factors like consuming a purine-rich diet, alcohol and/or fructose intake, and physical activity. While numerous studies have reported various comorbidities linked to hyperuricemia or gout, the range of these associations is extensive. This review article focuses on the relationship between uric acid and thirteen specific domains: transporters, genetic factors, diet, lifestyle, gout, diabetes mellitus, metabolic syndrome, atherosclerosis, hypertension, kidney diseases, cardiovascular diseases, neurological diseases, and malignancies. The present article provides a comprehensive review of recent developments in these areas, compiled by experts from the Young Committee of the Japanese Society of Gout and Uric and Nucleic Acids. The consolidated summary serves to enhance the global comprehension of uric acid-related matters.

Uric acid significantly correlates with the presence of low-voltage areas at the endocardial mapping in patients with non-valvular atrial fibrillation

BACKGROUND AND AIMS

Interest in the role of atrial substrate in maintaining Atrial Fibrillation (AF) is growing. Fibrosis is the culprit in the electrical derangement of the myocytes. Many cardiovascular risk factors are known to be linked to atrial scarring; among them Uric Acid (UA) is emerging. The purpose of our study is to find whether UA is associated with Left Atrium (LA) with pathological substrate.

METHODS AND RESULTS

81 patients who underwent radiofrequency transcatheter ablation for nonvalvular AF at the cardiological department of the Niguarda Hospital were enrolled in an observational, cross-sectional, single-center study. UA levels were analysed before the procedure. High density electroanatomic mapping of the LA was performed and patients were divided according to the presence or not of areas of pathological substrate (bipolar voltage <0.5 mV in sinus rhythm). 19 patients showed a LA with pathological substrate. These subjects showed a significant higher prevalence of persistent phenotype of AF (84.2 vs. 25.8%, p < 0.001). UA levels were significantly higher in the group of patients with LA with pathological substrate (6.8 ± 1.9 vs 5.3 ± 1.4 mg/dL, p < 0.001) as well as the prevalence of hyperuricemia (26.5 vs. 6.5%, p = 0.021). The association between uric acid LA with pathological substrate remains significant even after correction for confounding factors (age, left ventricular dysfunction, valvular disease, arrythmia phenotype and furosemide use) and also when the ratio UA/creatinine was evaluated.

CONCLUSIONS

In a population of patients who underwent AF ablation, higher UA levels were significantly associated with pathological LA substrate at electro-anatomical mapping.

Elevated Uric Acid Is Associated With New-Onset Atrial Fibrillation: Results From the Swedish AMORIS Cohort

Background The role of uric acid is gaining increasing importance in the evaluation of cardiovascular disease, but its relationship with atrial fibrillation (AF) is unclear. This study aims to investigate the association between uric acid levels and risk of new-onset AF. Methods and Results A total of 339 604 individuals 30 to 60 years of age and free from cardiovascular disease at baseline (1985-1996) in the Swedish AMORIS (Apolipoprotein-Mortality Risk) cohort were followed until December 31, 2019 for incident AF. Cox regression models were used to examine the association between uric acid and AF, adjusting for potential confounders and stratifying by incident cardiovascular disease. Over a mean follow-up of 25.9 years, 46 516 incident AF cases occurred. Compared with the lowest uric acid quartile, each of the upper 3 quartiles were associated with an increased risk of AF in a dose-response manner. Adjusted hazard ratios were 1.09 (95% CI, 1.06-1.12) for second quartile, 1.19 (95% CI, 1.16-1.23) for third quartile, and 1.45 (95% CI, 1.41-1.49) for fourth quartile. The association was similar among individuals with and without incident hypertension, diabetes, heart failure, or coronary heart disease. The dose-response pattern was further supported in a subsample of individuals with repeated measurements of uric acid. Conclusions Elevated uric acid was associated with an increased risk of AF, not only among people with cardiovascular disease and cardiovascular risk factors but also among those without. Future investigations are needed to examine whether lowering uric acid is relevant for AF prevention.

Nutritional Status as a Risk Factor for New-Onset Atrial Fibrillation in Acute Myocardial Infarction

Purpose

Our study aimed to identify new-onset atrial fibrillation (NOAF) risk factors in acute myocardial infarction (AMI) patients after treatment with percutaneous coronary intervention (PCI) and investigate whether their nutritional status can be a predicting factor of NOAF.

Patients and Methods

We analyzed 662 AMI patients after PCI for NOAF occurrence during follow-up hospitalization and divided them into an NOAF and non-NOAF group. The patients' nutritional status was assessed using the controlling nutritional status (CONUT) score and geriatric nutritional risk index (GNRI). The Kaplan‒Meier analysis was used to assess NOAF-free survival in varying degrees of malnutrition. Cox proportional hazards models were used to identify the risk factors for NOAF.

Results

Eighty-four (12.7%) patients developed NOAF during hospitalization. There was a statistically significant difference in the occurrence of NOAF among different categories of nutritional status. The CONUT score and GNRI classifications were independent predictors of NOAF. NOAF occurrence was associated with older age, higher uric acid levels, higher N-terminal pro-B-type natriuretic peptide levels, greater left atrial size, and worse Killip class upon admission.

Conclusion

The nutritional status can affect NOAF occurrence in AMI patients after PCI. The CONUT score and GNRI are ideal tools for evaluating the nutritional status of AMI patients, with an excellent predictive effect on NOAF.

Hyperuricemia Is Associated With the Risk of Atrial Fibrillation Independent of Sex: A Dose-Response Meta-Analysis

Background:

Conflicting findings of the association between serum uric acid (SUA) and atrial fibrillation (AF) have been reported in both men and women. The sex-specific associations between SUA and the risk of AF are unclear, although hyperuricemia is independently associated with the risk of AF. We performed this meta-analysis to assess the sex-specific effect of SUA on the risk of AF.

Methods

The PubMed, EMBASE, and Cochrane Library databases were searched up to October 3, 2021, for studies that reported sex-specific associations of SUA levels with AF. Linear relationships were assessed by the generalized least squares trend estimation. This study was registered with PROSPERO (42020193013).

Results

Ten eligible studies with 814,804 participants (415,779 men and 399,025 women) were identified. In the category analysis, high SUA was associated with an increased risk of AF in both men (OR: 1.42; 95% CI, 1.18–1.71, I² = 34%) and women (OR: 2.02; 95% CI, 1.29–3.16, I² = 70%). In the dose-response analysis, for each 60 μmol/L (1 mg/dL) increase in the SUA level, the risk of AF increased by 15% (OR: 1.15; 95% CI, 1.07–1.25, I² = 74%) in men and 35% (OR: 1.35; 95% CI, 1.18–1.53, I² = 73%) in women. There was a borderline difference in the impact of SUA on the risk of AF between men and women (P for interaction = 0.05). A significant linear relationship between SUA and the risk of AF was observed in men (P for non-linearity = 0.91) and women (P for non-linearity = 0.92).

Conclusions

This study suggested that there was a significant linear relationship between SUA and the risk of AF among men and women, with a higher risk estimate for women. Additional trials are required to assess the effect of reduced SUA therapy on AF incidence.

Systematic Review Registration

https:www.crd.york.ac.uk/PROSPERO/, identifier: CRD 42020193013.

Time-varying serum uric acid predicts new-onset atrial fibrillation in treated hypertensive patients. The LIFE Study

Aim: The Losartan Intervention For Endpoint reduction in hypertension (LIFE) Study showed less new-onset atrial fibrillation (AF) in hypertensive patients receiving losartan- vs. atenolol-based treatment. Because losartan reduces serum uric acid (SUA) levels, the aim of the present study was to investigate relations of SUA with new-onset AF in the study. Methods: Hypertensive patients with electrocardiographic (ECG) left ventricular hypertrophy (LVH) and no prior AF (n = 8,243) were treated for 5.0 ± 0.4 years with losartan- or atenolol-based therapy. Associations of SUA with new-onset AF documented by Minnesota coding were assessed by Cox models using SUA and systolic blood pressure as time-varying covariates to take into account changes of SUA related to losartan or diuretic treatment, changes in renal function, and aging. Results: Time-varying SUA was associated with new AF defined by Minnesota code [hazard ratio (HR) = 1.19 per 16.8 μmol/L (1 mg/dL), (95% confidence intervals (CIs), 1.12–1.26), P < 0.0001], independent of losartan treatment [HR = 0.75 (95% CIs, 0.61–0.93), P = 0.007], older age [HR = 1.95 per 7.0 years (95% CIs, 1.73–2.20), P < 0.0001], male sex [HR = 1.46 (95% CIs, 1.09–1.94), P = 0.010] and higher Cornell voltage-duration product [HR = 1.10 per 1,023 ms·mm (95% CIs, 1.01–1.21), P = 0.034]. Similar results were obtained in Cox models with SUA levels partitioned according to baseline quartiles and in which AF was defined by physician reports or by both Minnesota coding and physician reports. Conclusions: In-treatment SUA is a strong predictor for new-onset AF in hypertensive patients, independent of effects of antihypertensive treatment, age, sex, and ECG-LVH. Further research is needed to clarify how uric acid may provoke AF (ClinicalTrials.gov identifier: NCT00338260).

The Relationship between Uric Acid and the Development, Complication, and Prognosis of Atrial Fibrillation: The Views from a Clinical Study

A large number of studies suggest that uric acid (UA) is related to the occurrence, complications, and prognosis of atrial fibrillation (AF). However, the guidelines did not clearly elaborate on this issue. The current research results need to be summarized to analyze the association between UA and AF. This study found that in the current clinical research on the relationship between UA and AF, studies mainly focus on the development or complications of AF. A lot of repetitive work does not deepen awareness of this question. In contrast, studies investigating the effects of UA-lowering therapy on the management of AF are limited. The only reports deny the protective effect of UA-lowering therapy. For now, we suggest that UA is close to the occurrence and progression of AF; therefore, it may have important significance as a clinical marker. The role of UA-lowering therapy in the management of AF is one of the next key issues to be explored. It will be a meaningful topic to focus on the latest research on AF ablation and to conduct a secondary analysis to explore the prognostic impact of UA on the latest treatment methods for AF. Multiomics techniques may allow us to have a deeper understanding of the role of UA in AF management in the future.

Uric acid and incident atrial fibrillation of 14 years population-based cohort study: The Suita Study

BACKGROUND

Higher baseline uric acid (UA) was significantly associated with higher atrial fibrillation (AF) incidence in Japanese women. However, no prospective study is evident in the association between UA and incident AF in Japanese urban residents.

METHODS

A total of 6863 participants (aged 30-79 years; 47% men) without prior AF were followed for 13.9 years on average in the Suita Study. According to the UA categories, cox proportional hazards regression models were used to estimating the Hazard Ratios (HRs) and 95% confidence intervals (CIs) for incident AF.

RESULTS

During 95178 person-years of follow-up, we observed 311 cases of incident AF (204 cases in men and 107 cases in women). Compared to the subjects with UA of 4.0-4.9 mg/dL, multivariable-adjusted HR (95% CIs) of incident AF was 1.50 (1.01-2.25) (P = .047) for the subjects with UA ≥7.0 mg/dL.

CONCLUSION

High UA was associated with an increased risk for incident AF in the Japanese population.

Genetically predicted serum uric acid levels and the risk of coronary artery disease in patients with diabetes: A Mendelian randomization study

BACKGROUND AND AIMS

Serum uric acid (SUA) levels have been reported to be associated with an increased risk of coronary artery disease (CAD) among patients with diabetes in observational study. Whether this relationship is causal remains unclear. The current study aimed to explore the causal association between SUA and the risk of CAD in patients with diabetes.

METHODS AND RESULTS

A two-sample Mendelian randomization (MR) approach was employed to evaluate the causal effect of SUA on the risk of CAD in patients with diabetes. A total of 28 single nucleotide polymorphisms (SNPs) related to SUA were identified as instruments. Genetic association with CAD were obtained from a recently published genome-wide association study (GWAS) of 15,666 patients with diabetes (3968 CAD cases and 11,696 controls). The fixed-effects inverse variance-weighted method was employed to estimate the causal effect for the primary analysis, and other robust methods were employed for sensitivity analyses. In addition, the whole analyses were repeated using 9 non-pleiotropic SNPs. Genetic determined SUA levels were not significantly associated with the risk of CAD in patients with diabetes in the primary analysis (odds ratio = 1.13, 95% confidence interval: 0.98-1.16, P = 0.09). Consistent results were observed in the sensitivity analyses using various robust methods. In addition, this finding was confirmed by the repeated analyses using 9 non-pleiotropic SNPs.

CONCLUSIONS

This two-sample MR study does not support a causal effect of genetically predicted SUA levels on the risk of CAD in patients with diabetes.

Sex-specific relationship between abdominal obesity and new-onset atrial fibrillation in the general Japanese population

The incidence of atrial fibrillation (AF) is expected to increase with increasing obesity and number of geriatric patients in Japan. Although higher body mass index and abdominal obesity are associated with an increased risk of AF, the sex-specific relationship between abdominal obesity and new-onset AF is unclear. This study aimed to investigate the sex-specific relationship between abdominal obesity and new-onset AF. This retrospective study evaluated the annual health checkup data of 67,379 adults (33,562 males; age, 54 ± 10 years) without baseline AF from April 2008 to March 2016. Participants were grouped according to waist circumference (WC): large-WC group (males, ≥ 85 cm; females, ≥ 90 cm) and normal-WC group. Logistic regression analyses were performed to determine the strength of the association between abdominal obesity and new-onset AF, overall and separately for males and females. During a median follow-up of 5 years, 280 (0.4%) new cases of AF were recorded. Univariate analysis revealed a significant increase in new-onset AF in males (odds ratio [OR], 1.97; 95% confidence interval [CI], 1.49-2.60; p < 0.001) but not in females (OR, 1.69; 95% CI, 0.96-2.97; p = 0.068) in the large-WC group. After adjusting for clinical variables, multivariate analysis revealed that a large WC was significantly associated with new-onset AF in males (OR, 1.76; 95% CI, 1.31-2.36; p < 0.001) but not in females (OR, 1.22; 95% CI, 0.68-2.18; p = 0.514). Abdominal obesity is associated with an increased risk of new-onset AF in men.

The Key Role of Uric Acid in Oxidative Stress, Inflammation, Fibrosis, Apoptosis, and Immunity in the Pathogenesis of Atrial Fibrillation

Atrial fibrillation (AF) is a highly prevalent cardiac arrhythmia that leads to numerous adverse outcomes including stroke, heart failure, and death. Hyperuricemia is an important risk factor that contributes to atrium injury and AF, but the underlying molecular mechanism remains to be elucidated. In this review, we discussed the scientific evidence for clarifying the role of hyperuricemia in the pathogenesis of AF. Experimental and Clinical evidence endorse hyperuricemia as an independent risk factor for the incidence of AF. Various in vivo and in vitro investigations showed that hyperuricemia might play a critical role in the pathogenesis of AF at different UA concentrations through the activation of oxidative stress, inflammation, fibrosis, apoptosis, and immunity.

Correlation between the elevated uric acid levels and circulating renin-angiotensin-aldosterone system activation in patients with atrial fibrillation

Background

The aim of the present study was to investigate the correlation between the elevated uric acid (UA) levels and activation of the circulating renin-angiotensin-aldosterone system (RAAS) in patients with atrial fibrillation (AF).

Methods

A total of 233 outpatients and inpatients of the Cardiology Department from January 1, 2019, to December 31, 2019, were selected and divided into the sinus rhythm group (SR) with 84 cases, the paroxysmal AF group (pAF) with 76 cases, and the persistent AF group (PAF) with 73 patients. The general clinical data and the serum levels of UA of the enrolled patients were collected, and the radioimmunoassay was adopted to detect the levels of renin (Renin), angiotensin II (Ang II), and aldosterone (Ald).

Results

Renin, AngII, Ald, and UA in the PAF group were significantly higher than those in the pAF group, and the levels of the above indicators in the pAF group were significantly higher than those in the SR group (P<0.001). The left atrium anteroposterior diameter (LAD) and the left ventricular end-diastolic diameter (LVEDD) were significantly increased in the PAF group (P<0.001). The Pearson correlation analysis showed that the levels of the high sensitivity C-reactive protein (hsCRP), AngII Renin, Ald, LVEDD, and LAD were positively correlated with the serum levels of UA (r=0.174, 0.273, 0.34, 0.385, 0.138, respectively, P<0.05 in all). The left ventricular ejection fraction (LVEF) was negatively correlated with the UA level (r=-0.177, P<0.05). Multiple linear regression analysis showed that UA (β=0.103) and LAD (β=2.162) were independent risk factors for Renin. The independent risk factor for Ang II was UA (β=0.167). The independent risk factor for Ald was UA (β=0.283) and LAD (β=8.721) (P<0.05).

Conclusions

Elevated UA might cause excessive activation of the RAAS, aggravate the oxidative stress, and participate in the atrial remodeling, thereby promoting the occurrence and persistence of AF.

Hyperuricemia as a Risk Factor for Cardiovascular Diseases

Serum uric acid level above 7 mg/dl is defined as hyperuricemia, which gives rise to the monosodium urate (MSU), causing gout and urolithiasis. Hyperuricemia is an independent risk factor as well as a marker for hypertension, heart failure, atherosclerosis, atrial fibrillation, and chronic kidney disease. MSU crystals, soluble uric acid (UA), or oxidative stress derived from xanthine oxidoreductase (XOR) might be plausible explanations for the association of cardio-renovascular diseases with hyperuricemia. In macrophages, MSU activates the Nod-like receptor family, pyrin　domain containing 3(NLRP3) inflammasome, and proteolytic processing mediated by caspase-1 with enhanced interleukin (IL)-1β and IL-18 secretion. Soluble UA accumulates intracellularly through UA transporters (UAT) in vascular and atrial myocytes, causing endothelial dysfunction ad atrial electrical remodeling. XOR generates reactive oxygen species (ROS) that lead to cardiovascular diseases. Since it remains unclear whether asymptomatic hyperuricemia could be a risk factor for cardiovascular and kidney diseases, European and American guidelines do not recommend pharmacological treatment for asymptomatic patients with cardio-renovascular diseases. The Japanese guideline, on the contrary, recommends pharmacological treatment for hyperuricemia with CKD to protect renal function, and it attaches importance of the cardio-renal interaction for the treatment of asymptomatic hyperuricemia patients with hypertension and heart failure.

Serum uric acid and incident atrial fibrillation: A systematic review and dose-response meta-analysis

The exposure-effect association between serum uric acid and atrial fibrillationis not well known. We conduct a meta-analysis to quantitatively examine the exposure-effect relationship between serum uric acid and atrial fibrillation. Prospective studies (including cohort or nested case-control) that reported the serum uric acid and atrial fibrillation were identified through electronic searches using EMBASE, PubMed, and the Cochrane Library database. The exposure-effect analysis was performed using a stage robust error meta-regression. Eleven studies were included, with a total of 6831 cases of atrial fibrillation among 527 908 individuals. Both the highest (risk ratio (RR), 1.9; 95% confidence interval (CI), 1.64-2.23; I2  = 0%) and intermediate (RR, 1.36; 95% CI, 1.16-1.59; I2  = 36%) level of serum uric acid were associated with increased risks of atrial fibrillation compared to the patients with the lowest level of serum uric acid. In the exposure-effect analysis, for each 1 mg/dL increase in serum uric acid level, the incidence of atrial fibrillation increased by 21% (RR, 1.21; 95% CI, 1.12-1.32; I2  = 78%). Furthermore, a significant positive linear relationship between serum uric acid and the risk of atrial fibrillation, Pnonlinearity  = 0.47 was found. The exposure-effect analysis demonstrated that serum uric acid over 5.0 mg/dL significantly increased the risk of atrial fibrillation. There was a positive linear association between serum uric acid and risk of atrial fibrillation, both in subjects with noruricaemia and hyperuricaemia. More studies are needed to explore the impact of serum uric acid reduction on the incidence of atrial fibrillation.

Sex Differences in the Effects of Weight Reduction on Future Blood Pressure Elevation in a Mildly Obese Middle-Aged Population

Background: The effectiveness of weight loss (WL) in preventing blood pressure (BP) elevation is common knowledge; however, the effect of sex differences is not known. Methods and Results: Health checkup data from Kagoshima Kouseiren Medical Healthcare Center for middle-aged participants (40-49 years old) with mild obesity (body mass index [BMI] 25.0-29.9 kg/m2) who had examination data for 2 follow-up time-points (after 3 and 10 years) were analyzed. Propensity score (PS) matching using data from the first examination was used to match participants with a decrease in BMI ≥1.0 kg/m2 at 3 years (WL group) with those with a BMI decrease <1.0 kg/m2 or weight gain (non-WL group). BP values were compared after 3 and 10 years between the 2 groups, as was the prevalence of hypertension after 10 years. PS matching resulted in 232 men and 160 women in each group. Among women, systolic BP (SBP) and hypertension prevalence after 10 years were significantly lower in the WL than non-WL group (P<0.01 and P<0.05, respectively). There were no significant differences in SBP and hypertension prevalence after 10 years in men in the 2 groups. Conclusions: There were sex differences in the effectiveness of WL in preventing future BP elevation in mildly obese middle-aged participants: WL prevented future BP elevation and hypertension onset in women, but not in men.

Adenosine and the Cardiovascular System: The Good and the Bad

Adenosine is a nucleoside that impacts the cardiovascular system via the activation of its membrane receptors, named A₁R, A_2AR, A_2BR and A₃R. Adenosine is released during hypoxia, ischemia, beta-adrenergic stimulation or inflammation and impacts heart rhythm and produces strong vasodilation in the systemic, coronary or pulmonary vascular system. This review summarizes the main role of adenosine on the cardiovascular system in several diseases and conditions. Adenosine release participates directly in the pathophysiology of atrial fibrillation and neurohumoral syncope. Adenosine has a key role in the adaptive response in pulmonary hypertension and heart failure, with the most relevant effects being slowing of heart rhythm, coronary vasodilation and decreasing blood pressure. In other conditions, such as altitude or apnea-induced hypoxia, obstructive sleep apnea, or systemic hypertension, the adenosinergic system activation appears in a context of an adaptive response. Due to its short half-life, adenosine allows very rapid adaptation of the cardiovascular system. Finally, the effects of adenosine on the cardiovascular system are sometimes beneficial and other times harmful. Future research should aim to develop modulating agents of adenosine receptors to slow down or conversely amplify the adenosinergic response according to the occurrence of different pathologic conditions.