Hyperuricemia is independently associated with increased risk of atrial fibrillation: A meta-analysis of cohort studies

The Uric Acid-to-High-Density Lipoprotein Cholesterol Ratio: A New Biomarker for Predicting Arrhythmia Recurrence After Atrial Fibrillation Ablation

Background: We aimed to assess the uric acid-to-high-density lipoprotein cholesterol (HDL-C) ratio (UHR) and several other parameters with respect to their performance in detecting recurrence among patients with atrial fibrillation (AF) who underwent ablation. Methods: This retrospective cohort study analyzed data from patients who underwent radiofrequency or cryoablation for paroxysmal, persistent, or long persistent AF between September 2021 and September 2023. After ablation, patients were monitored for 24 h, with an ECG Holter used for symptomatic cases. Follow-up visits occurred at 1, 3, and 12 months. Collected data included demographics, comorbidities, echocardiographic measurements, clinical data, ablation type, medication use, and a comprehensive set of laboratory findings. Results: The study included 163 patients, with AF recurrence in 39 (23.93%) patients. Mean age was 57.49 ± 11.22 years, and 59.51% of participants were male. There was no significant difference between recurrent and non-recurrent groups in terms of age or sex distribution. Univariate analysis showed that recurrent patients had significantly larger left atrium diameter, higher percentages of persistent/long AF, and elevated levels of CRP, uric acid, UHR, and uric acid-to-creatinine ratio (UCR). Logistic regression analysis revealed that high left atrium diameter, long persistent AF presence, high CRP and uric acid levels, and high UCR and UHR values greater than 15.1 were independent predictors of AF recurrence. A UHR value of >15.1 was found to predict recurrence with 61.54% sensitivity and 70.97% specificity. Conclusions: Despite low sensitivity, UHR appears to be an independent biomarker that can predict AF recurrence. Including UHR in future risk assessment tools may be beneficial to enhance their accuracy.

The association between hyperuricemia and atrial fibrillation recurrence after catheter ablation

Background

Hyperuricemia (HU) has been reported to be associated with a high incidence of atrial fibrillation (AF). However, the relationship between HUA and recurrent AF after catheter ablation (CA) is unclear.

Methods

Four hundred consecutive AF patients (paroxysmal/persistent AF [PAF/PsAF]: 200/200) who underwent the initial CA were retrospectively enrolled. HU was defined as serum uric acid (SUA) level >7.0 mg/dL. We measured SUA levels 1 day before (pre-CA) and 1 month after CA (post-CA). A second-generation 28 mm cryoballoon was used for pulmonary vein isolation (PVI) for PAF, while PVI plus linear ablation (roof and mitral isthmus lines) by radiofrequency catheter was conducted for PsAF.

Results

During 57 ± 24 months of follow-up, AF recurred in 16% and 42% in PAF and PsAF patients (p < .0001). Pre-CA SUA level in PsAF was significantly higher than that in PAF (6.5 ± 1.3 vs. 5.8 ± 1.3 mg/dL, p < .001). SUA level was significantly decreased after CA in both PAF and PsAF (5.8 ± 1.3 vs. 5.6 ± 1.3 mg/dL; p < .01 and 6.5 ± 1.3 vs. 6.1 ± 1.2 mg/dL; p < .0001, respectively). The association between pre-/post-CA HU and recurrent AF was not identified in PAF, while the incidence of post-CA HU was significantly higher in patients with recurrent AF than those without in PsAF (36% vs. 15%, p < .001). In multivariable analysis, longer AF duration and the presence of post-CA HU were identified as independent predictors of AF recurrence in PsAF (OR:1.01, 95%CI:1.003-1.011, p = .0001 and OR:2.77, 95%CI:1.333-5.755, p = .007, respectively).

Conclusions

SUA level was significantly higher in PsAF than PAF patients. The presence of post-CA HU was strongly related to AF recurrence in PsAF patients.

Association of Hyperuricemia with Impaired Left Ventricular Systolic Function in Patients with Atrial Fibrillation and Preserved Kidney Function: Analysis of the POL-AF Registry Cohort

Hyperuricemia is associated with the risk of developing atrial fibrillation (AF) and heart failure. However, coexisting chronic kidney disease and certain cardiovascular drugs make it difficult to determine whether hyperuricemia is a risk factor or merely a marker of pathology. We retrieved data from the Polish Atrial Fibrillation (POL-AF) registry, which included consecutive patients hospitalized with AF from January to December, 2019. We included 829 patients (mean age: 72.7 ± 11.1 years) with data on serum uric acid (UA, mean: 6.56 ± 1.78 mg/dL) and estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2. We found that UA and ejection fraction (EF) were significantly correlated (r = −0.15, p < 0.05), but not EF and eGFR or eGFR and UA. A multiple regression analysis adjusted for age, body mass index, eGFR, and UA, showed that UA was significantly associated with a reduced EF (R2: 0.021; p < 0.001). The UA cut-off indicative of an EF < 40% was 6.69 mg/dL (AUC, area under the curve: 0.607; 95% CI: 0.554−0.660; p = 0.001). Among drugs known to effect UA concentrations, we found that only diuretics were used more frequently in patients with high UA (above the median) than in patients with low UA (77.5% vs. 67%, p < 0.001). Among patients that used diuretics, UA remained significantly correlated with EF. Thus, we showed that reduced EF was associated with UA in patients with AF and normal renal function, independent of eGFR and diuretic use.

Relationship between serum uric acid levels and different types of atrial fibrillation: An updated meta-analysis

AIM

Increasing evidence supports the hypothesis that high serum uric acid (SUA) levels are related to atrial fibrillation (AF). However, the incidence of AF in patients with hyperuricemia and SUA levels in different types of AF is not entirely clear. This meta-analysis was designed to evaluate the relationship between SUA and incidence of AF, and the variation in SUA levels in different types of AF.

DATA SYNTHESIS

Relevant reports were searched for in Embase, PubMed and the Cochrane Library. A fixed-effects model combining relative risk (RR) and the corresponding 95% confidence interval (95% CI) was used to evaluate the correlation between SUA and AF. The standardized mean differences (SMDs) of SUA values were calculated using a random-effects model to evaluate the differences in SUA levels among different types of AF. A total of 31 studies with 504,958 participants were included in this research. The results from 8 cohort studies showed that high SUA levels significantly increased the incidence of AF [RR (95% CI): 1.92 (1.68-2.20); P < 0.01]. The results from 29 studies revealed that SUA levels elevated in patients with AF [SMD (95% CI): 0.55 (0.43-0.66); P < 0.001]. Meanwhile, SUA levels in new-onset AF [SMD (95%CI): 0.24 (0.10-0.38); P = 0.001], paroxysmal AF [SMD (95%CI): 0.52 (0.33-0.72); P < 0.001] and persistent AF [SMD (95%CI): 1.23 (0.98-1.48); P < 0.001] were significantly higher than that in patients without AF.

CONCLUSIONS

High SUA levels had an obvious correlation with the occurrence rate of AF. In addition, SUA levels were significantly different among patients with new-onset, paroxysmal and persistent AF.

Association Between Uric Acid, Carotid Intima-Media Thickness, and Cardiovascular Events: Prospective Results From the IMPROVE Study

Background The association between elevated serum uric acid (SUA), cardiovascular disease (CVD) risk, and carotid atherosclerosis has long been explored, and contrasting results have been reported. Therefore, the role of SUA as an independent risk factor for vascular events (VEs) and carotid atherosclerosis deserves further attention. We investigated the relationship between SUA, incident VEs, carotid intima-media thickness (cIMT), and cIMT progression in subjects at moderate-to-high CVD risk. Methods and Results In the IMPROVE (IMT-Progression as Predictors of VEs) study, 3686 participants (median age 64 years; 48% men) with ≥ 3 vascular risk factors, free from VEs at baseline, were grouped according to SUA quartiles (division points: 244-284-328 µmol/L in women, 295-336-385 µmol/L in men). Carotid-IMT and its 15-month progression, along with incident VEs, were recorded. A U-shaped association between SUA and VEs was observed in men, with 2.4-fold (P = 0.004) and 2.5-fold (P = 0.002) increased CVD risk in the first and fourth SUA quartiles as compared with the second. Adjusted hazard ratios (HRs) for cerebro-VEs in men were the highest (first and fourth quartile versus second: HR, 5.3, P = 0.010 and HR, 4.4, P = 0.023, respectively). SUA level was independently associated with cIMT progression in men (β = 0.068, P = 0.014). No significant association between SUA levels, CVD end points, and cIMT progression were found in women. Conclusions Both low and high SUA levels are associated with an increased risk of VEs in men at moderate-to-high CVD risk but not in women. Only elevated SUA levels predict cIMT progression and at a lesser but not significant extent in women.

Hyperuricemia as a Marker of Reduced Left Ventricular Ejection Fraction in Patients with Atrial Fibrillation: Results of the POL-AF Registry Study

Background: Hyperuricemia is an established risk factor for cardiovascular disease, including atrial fibrillation (AF). The prevalence of hyperuricemia and its clinical significance in patients with already diagnosed AF remain unexplored. Methods: The Polish Atrial Fibrillation (POL-AF) registry includes consecutive patients with AF hospitalized in 10 Polish cardiology centers from January to December 2019. This analysis included patients in whom serum uric acid (SUA) was measured. Results: From 3999 POL-AF patients, 1613 were included in the analysis. The mean age of the subjects was 72 ± 11.6 years, and the mean SUA was 6.88 ± 1.93 mg/dL. Hyperuricemia was found in 43% of respondents. Eighty-four percent of the respondents were assigned to the high cardiovascular risk group, and 45% of these had SUA >7 mg/dL. Comparison of the extreme SUA groups (<5 mg/dL vs. >7 mg/dL) showed significant differences in renal parameters, total cholesterol concentration, and left ventricular ejection fraction (EF). Multivariate regression analysis showed that SUA >7 mg/dL (OR 1.74, 95% CI 1.32–2.30) and GFR <60 mL/min/1.73 m² (OR 1.94, 95% CI 1.46–2.48) are significant markers of EF <40% in the study population. Female sex was a protective factor (OR 0.74, 95% CI 0.56–0.97). The cut-off point for SUA with 60% sensitivity and specificity indicative of an EF <40% was 6.9 mg/dL. Conclusions: Although rarely assessed, hyperuricemia appears to be common in patients with AF. High SUA levels may be a significant biomarker of reduced left ventricular EF in AF patients.

Association between plasma uric acid and insulin resistance in type 2 diabetes: A Mendelian randomization analysis

OBJECTIVE

Circulating uric acid levels were associated with insulin resistance, but the causality is unclear. We aimed to investigate the association between plasma uric acid and insulin resistance in newly diagnosed type 2 diabetes (T2D).

METHODS

We enrolled 1,938 patients who underwent a 75-g oral glucose tolerance test. Insulin resistance was estimated based on the homeostatic model assessment index (HOMA2-IR) and the Matsuda index. Uric acid was measured in fasting plasma by uricase-peroxidase method. We genotyped single nucleotide polymorphisms (SNPs) that were recently identified as top hits in genome-wide association studies of uric acid levels. A weighted genetic risk score (wGRS) was calculated based on the associations between selected SNPs and uric acid levels.

RESULTS

The adjusted β coefficients for Ln-transformed Matsuda index and HOMA2-IR per 1 mg/dL uric acid increment were -0.070 (95%CI: -0.089, -0.052) and 0.057 (95%CI: 0.039, 0.075). These associations were more pronounced among women than men. In Mendelian randomization analysis, the wGRS raised uric acid by 0.225 mg/dL (95%CI: 0.138, 0.312) per SD increase of the score. However, no association was observed between the wGRS and insulin resistance indices whether in men or women.

CONCLUSIONS

Elevated plasma uric acid was associated with higher risk of insulin resistance, along with observation of gender difference in such association. However, our study does not support a causal role of plasma uric acid on insulin resistance among newly diagnosed T2D patients.

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.

Increased Overall Heart Rate Irregularity Risk by Hyperuricemia in the General Population: Results from the Korean National Health and Nutrition Examination Survey

Background and objectives: Hyperuricemia is one of the well-known cardiovascular risk factors. There is a growing interest in the association between hyperuricemia and arrhythmia. We used the representative sample data of Korean population to study the association between hyperuricemia and heart rate irregularity (HRI) that reflects total arrhythmia. Materials and Methods: We performed weighted multivariate logistic regression analysis to assess the association between hyperuricemia and HRI. Results: Of the 10,827 subjects, 1308 (13.2%) had hyperuricemia and 130 (1%) had HRI. In the presence of hyperuricemia, HRI was three times higher than that in the absence of hyperuricemia (OR 2.98, 95% CI 1.71–5.18). The risk of HRI was highest in subjects with both hypertension and hyperuricemia. In the subgroup analysis, the association of hyperuricemia with HRI was most pronounced in the smoker group. Conclusions: Hyperuricemia was highly correlated with HRI in adult Korean representative sample data. Hyperuricemia was associated with a nearly tripled risk for HRI. Hypertension has a synergistic effect with hyperuricemia on HRI. Further research is warranted to clarify the relationship between hyperuricemia and arrhythmia and its mechanism.

Comparative effectiveness of allopurinol and febuxostat for the risk of atrial fibrillation in the elderly: a propensity-matched analysis of Medicare claims data

AIMS

Gout is associated with a higher risk of atrial fibrillation (AF). Comparative effectiveness of allopurinol or febuxostat for reducing the AF risk is unknown, which was our study's main objective.

METHODS AND RESULTS

We used the 5% Medicare Beneficiary cohort (≥65 years) from 2006 to 2012 to identify people with a new filled prescription for allopurinol or febuxostat, with a baseline period of 365 days without respective medication and without AF. We used 5:1 propensity-matched Cox regression analyses to assess whether allopurinol use differed from febuxostat use regarding the hazard ratio (HR) of incident AF. We found 25 732 eligible episodes in 23 135 beneficiaries. Of these, 2311 incident allopurinol or febuxostat use episodes (9%) ended in incident AF with crude incidence rates of 8.0 and 10.5 per 100 person-years, respectively. In propensity-matched analyses, compared with allopurinol, febuxostat was associated with higher HR of AF, 1.25 [95% confidence interval (CI) 1.05-1.48]. Compared with allopurinol <200 mg/day, febuxostat 80 mg/day was associated with significantly higher HR of AF, 1.62 (95% CI 1.16-2.27), but not febuxostat 40 mg/day or higher allopurinol doses. Compared with 1-180 days of allopurinol use, febuxostat use for 1-180 days was associated with significantly higher HR of AF, 1.36 (95% CI 1.10-1.67), but longer durations were not.

CONCLUSION

Febuxostat was associated with a higher risk of AF compared with allopurinol in older adults. Increased AF risk was noted with febuxostat 80 mg/day dose and was most evident in the first 6 months of use. These findings need replication.

Preoperative uric acid predicts in-hospital death in patients with acute type a aortic dissection

Background

The present study aimed to evaluate the value of admission serum uric acid (UA) level in predicting in-hospital risk of death in patients with acute type A aortic dissection (AAAD).

Methods

From January 2016 to June 2019, 186 consecutive patients with AAAD who underwent thoracic aortic surgery were retrospectively studied. Serum UA levels were measured on admission. Forward conditional logistic regression was performed to identify independent risk factors for in-hospital death. Receiver operating characteristic (ROC) analysis was performed to assess the most clinical useful level of serum UA for predicting postoperative in-hospital mortality.

Results

Increased level of serum UA was found in non-survivors compared with those survived (446 ± 123 vs 371 ± 111 umol/L, p < 0.001). Age (OR = 1.063, 95% CI 1.016–1.112, p = 0.009), UA (OR = 1.006, 95% CI 1.002–1.010, p = 0.002), D-dimer (OR = 1.025, 95% CI 1.005–1.013, p = 0.012), operation time (OR = 1.009, 95% CI 1.005–1.013, p < 0.001) and extent of aortic replacement (OR = 0.412, 95% CI 0.220–0.768, p = 0.005) were identified as independent risk factors of in-hospital mortality in AAAD patients. The best cut-off value of admission serum UA in predicting in-hospital mortality was determined to be 415 umol/L. Subgroup analysis showed that in the subgroup of total arch replacement, UA was significantly associated with in-hospital death (OR = 1.010, 95% CI 1.005–1.015, p < 0.001), while in patients underwent ascending aorta replacement or hemiarch replacement, the relationship was no longer significant (OR = 1.001, 95% CI 0.996–1.006, p = 0.611).

Conclusions

Elevated serum UA level on admission is an independent predictor of in-hospital mortality in patients with AAAD.

Risk factors for recurrence of atrial fibrillation

OBJECTIVE

Atrial fibrillation (AF) is a progressive disease, associated with increased risk of mortality, stroke, heart failure, and worsens quality of life. There is a high incidence of AF recurrence despite the treatment. The aim of the study was to assess the time to recurrence of AF after sinus rhythm restoration with electrical or pharmacological cardioversion and to identify the risk factors.

METHODS

This study included 101 patients with AF (56% females) at a mean age of 68.02±7 years, after sinus rhythm restoration in a clinical observation of 1-year placebo-controlled treatment with spironolactone (1: 1). The patients were analyzed on the basis of AF recurrence, hospitalization, demographic parameters, comorbidities, embolic risk, and value of biomarker galectin-3 (Gal-3).

RESULTS

The average number of AF recurrences was1.62 per patient per year. The median time of occurrence of at least one new episode was 48 days, 95% confidence interval (CI) 14.24-81.76. Female patients experienced significantly more recurrences than male-53.3% vs. 28.6% hazard ration (HR) =1.76, 95% CI 1.02-3.03, p=0.036. The recurrences were more common with increased age, although not significantly. Patients with arterial hypertension had a threefold risk of recurrences than those without hypertension (p=0.025), independently of the treatment. CHA2DS2-VASc score was significantly associated with AF recurrent episodes. Patients with gout had a twofold increased risk, without statistical significance (p=0.15). There was no difference in the AF episodes according to treatment with spironolactone. The levels of Gal-3 did not affect the number of AF recurrences (p=0.9).

CONCLUSION

AF is associated with frequent recurrences after restoration of sinus rhythm in the majority of the patients. Most of them occurred within the first 3 months. Female sex, arterial hypertension, and CHA2DS2-VASc score were significant predictors of AF recurrence. Spironolactone did not reduce AF recurrences.

Uric acid: from a biological advantage to a potential danger. A focus on cardiovascular effects

Non-communicable diseases represent nowadays the most common cause of death worldwide, having largely overcome infectious diseases. Among them, cardiovascular diseases constitute the majority. Given these premise, great efforts have been made by scientific societies to emphasize the fundamental role of cardiovascular prevention and risk factors control. In addition to classical cardiovascular risk factors such as smoking, arterial hypertension, hypercholesterolemia and male gender, new risk factors are emerging from international literature. Among them, uric acid is the protagonist. Several evidences show a direct role of hyperuricemia in the determinism of metabolic and vascular disorders. From the other hand, some researchers have demonstrated that uric acid is only a marker of cardiovascular damage and not a risk factor for its development. Aim of this review is to evaluate the scientific evidences on the role of uric acid in cardiovascular diseases in order to shed light on this confusing topic.

High prevalence of hyperuricaemia and its impact on non-valvular atrial fibrillation: the cross-sectional Guangzhou (China) Heart Study

OBJECTIVES

There are country and regional variations in the prevalence of hyperuricaemia (HUA). The prevalence of HUA and non-valvular atrial fibrillation (NVAF) in southern China is unknown.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

A total of 11 488 permanent residents aged 35 or older from urban and rural areas of Guangzhou, China were enrolled. A questionnaire was used to compile each participant's demographic information and relevant epidemiological factors for HUA and NVAF. All participants were assessed using a panel of blood tests and single-lead 24-hour ECG.

MAIN OUTCOME MEASURES

HUA was defined as serum uric acid level >420 μmol/L in men and >360 μmol/L in women. NVAF was diagnosed as per guidelines.

RESULTS

The prevalence of HUA was 39.6% (44.8% in men and 36.7% in women), and 144 residents (1.25%) had NVAF. Prevalence of HUA increased with age in women but remained stably high in men. After adjusting for potential confounders, age, living in urban areas, alcohol consumption, central obesity, elevated fasting plasma glucose level, elevated blood pressure, lower high-density lipoprotein cholesterol level and elevated triglycerides level were associated with increased risk of HUA. Residents with HUA were at higher risk for NVAF. Serum uric acid level had a modest predictive value for NVAF in women but not men.

CONCLUSIONS

HUA was highly prevalent among citizens of southern China and was a predictor of NVAF among women.

The difficult relationship between uric acid and cardiovascular disease

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

BACKGROUND

The independent role of uric acid (UA) as a risk factor for atrial fibrillation (AF) has not been fully elucidated.

METHODS AND RESULTS

We studied 111,566 subjects (53,416 men; 58,150 women) who underwent annual health check-ups. We divided them by sex into tertile of baseline UA. To investigate the predictive power of UA for new-onset AF, we performed Cox proportional hazard analysis including UA tertiles, body mass index, creatinine, smoking and drinking status, and presence of hypertension, diabetes, and dyslipidemia. During 4.1 years, 467 men (0.87%) and 180 women (0.31%) had AF (P<0.001). Cut-off points for tertiles of UA were as follows: women, ≤3.9, 4.0-4.8, and ≥4.9 mg/dL; men, ≤5.4, 5.5-6.4, and ≥6.5 mg/dL. Hazard ratio (HR) for third to first tertile was 1.74 (95% CI: 1.15-2.70; P=0.008), whereas there were no differences between tertiles in men. Rate of new-onset AF was significantly higher in the group with initially increased UA (ΔUA ≥0.3 mg/dL) than that with unchanged UA (ΔUA, -0.2 or +0.2 mg/dL) in the third tertile of baseline UA in both sexes.

CONCLUSIONS

Higher baseline UA was significantly associated with higher AF incidence in women. Initial increase in UA was significantly associated with AF incidence when baseline UA was ≥6.5 mg/dL in men, and ≥4.9 mg/dL in women.

Epidemiological Characteristics of Atrial Fibrillation in Southern China: Results from the Guangzhou Heart Study

Precise prevalence of atrial fibrillation (AF) and the associated risk factors in southern China are rarely reported. This large population-based follow-up study, the Guangzhou Heart Study, was conducted from 2015 to 2017 to fill up this gap. Permanent residents aged 35 years and above in Guangzhou city were enrolled and demographic factors of participants were collected by a structured questionnaire. Examinations of physical, electrocardiographic and biochemical indicators were performed following a standard operation procedure designed prior to the field investigation. Descriptive statistics were used to evaluate basic characteristics of the study participants, and multivariate logistic regression model was performed to assess the AF prevalence-related factors. The detailed study design, the baseline characteristics and the prevalence of AF were reported here. In total, 12,013 residents were enrolled, and the percentage of participants from rural and urban areas was 53.92% and 46.08%, respectively. In total, 90.57% participants aged 40-79 years old and the proportion of women was more than men (64.98% vs. 35.02%). Overall, the prevalence of AF among the participants was 1.46%. Increasing age, male sex and widowed marital status were associated with higher AF prevalence (P-value < 0.05). The prevalence of AF increased with age and climbed to approximately 5% in residents aged 80 years and over. Residents with abnormal higher blood level of total cholesterol tended to have a lower AF prevalence but a higher prevalence of AF was observed in female participants with lower level of high density lipoprotein cholesterol land higher level uric acid (all P-value < 0.05). Personal illness such as hypertension, diabetes mellitus, dyslipidemia, myocardial infarction, heart failure, stroke and transient ischemic were significantly linked to the attack of AF (all P-value < 0.05). This study will be rich resource for investigating environmental exposure and individual genetic diathesis of AF and other common cardiovascular diseases in Chinese population.

Gout and the risk of incident atrial fibrillation in older adults: a study of US Medicare data

Objective

To assess the association of gout with new-onset atrial fibrillation (AF) in the elderly.

Methods

We used the 5% Medicare data from 2005 to 2012 to assess whether a diagnosis of gout was associated with incident AF. We used multivariable Cox regression adjusted for demographics, Charlson-Romano comorbidity index, common cardiovascular medications, allopurinol and febuxostat use, to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

Among 1 647 812 eligible people, 9.8% had incident AF. The mean age was 75 years, 42% were male, 86% were white and the mean Charlson-Romano index score was 1.52. We noted 10 604 incident AF cases in people with gout and 150 486 incident AF cases in people without gout. The crude incidence rates of AF in people with and without gout were 43.4 vs 16.3 per 1000 patient-years, respectively. After multivariable-adjustment, gout was associated with a higher HR of incident AF, 1.92 (95% CI 1.88 to 1.96), with minimal attenuation of HR in sensitivity models that replaced the Charlson-Romano index score with a categorical variable, HR was 1.91 (95% CI 1.87 to 1.95). In another model that adjusted for AF-specific risk factors including hypertension, hyperlipidaemia and coronary artery disease and individual Charlson-Romano index comorbidities, the HR was slightly attenuated at 1.71 (95% CI 1.67 to 1.75). Older age, male sex, white race and higher Charlson-Romano index score were each associated with higher hazard of incident AF.

Conclusion

A diagnosis of gout almost doubled the risk of incident AF in the elderly. Future studies should explore the pathogenesis of this association.

Gout and arrhythmias: In search for causation beyond association

Gout is a systemic disease, characterized by the formation and deposition of crystals in tissues (mainly in and around the joints) of individuals with elevated serum uric acid levels. Lately, a considerable number of reports relating elevated uric acid and/or gout with rhythm disorders, such as atrial fibrillation, have been published. This review summarizes evidence linking common arrhythmias and hyperuricemia/gout and discusses questions or controversies that surround it. Overall, existing evidence may not be overwhelming, but strongly suggests a positive correlation between uric acid levels and common rhythm disorders. Needless to say that such a link - as a univariate association between the two - is to be expected, given the extensive overlap of risk factors and comorbidities of hyperuricemia/gout and arrhythmias. However, the observed associations seem to persist - in most studies - after extensive adjustment for potential confounders. Still, multivariable analyses of epidemiologically collected data cannot substitute for proof coming from basic and clinical studies. There is obviously a need for further basic research to establish a causal relationship between uric acid effects and arrhythmias, as well as translational studies and clinical trials to investigate the therapeutic implications of such a relationship. Simply put, we are fairly certain that there is association, but proof of causation is what we are still in want of.

Hyperuricemia is associated with an increased prevalence of paroxysmal atrial fibrillation in patients with type 2 diabetes referred for clinically indicated 24-h Holter monitoring

PURPOSE

Several studies have reported an association between hyperuricemia and increased risk of permanent atrial fibrillation (AF) in patients with and without type 2 diabetes mellitus (T2DM). Currently, no published data are available on the relationship between hyperuricemia and risk of paroxysmal AF.

METHODS

We retrospectively evaluated 245 T2DM outpatients without pre-existing AF, cancer, cirrhosis and end-stage renal disease, who underwent a 24-h ECG-Holter monitoring for various clinical indications. Hyperuricemia was defined as a serum uric acid level >7 mg/dl for men and >6 mg/dl for women or allopurinol use. The diagnosis of paroxysmal AF was confirmed in affected individuals on the basis of 24-h ECG-Holter monitoring by experienced cardiologists.

RESULTS

Hyperuricemia was observed in 59 (24.1%) patients, whereas paroxysmal AF was found in 11 (4.5%) patients. The prevalence of paroxysmal AF was higher in patients with hyperuricemia than in those without hyperuricemia (10.2 vs. 2.7%, p = 0.026). Logistic regression analysis showed that hyperuricemia was associated with an increased risk of prevalent paroxysmal AF. This association remained significant even after adjustment for age, metabolic syndrome and chronic kidney disease (adjusted-odds ratio 4.01, 95% CI 1.08-14.9; p = 0.039). Similar results were found when we used serum uric acid levels as a continuous measure.

CONCLUSIONS

This study shows for the first time that hyperuricemia is independently associated with an approximately fourfold increased risk of prevalent paroxysmal AF in patients with T2DM. These findings may partly explain the increased risk of permanent atrial fibrillation and cardiovascular death observed among patients with hyperuricemia.

Association between serum uric acid and atrial fibrillation: a cross-sectional community-based study in China

OBJECTIVES

To investigate the effects of gender on the association of serum uric acid (SUA) levels and atrial fibrillation (AF) prevalence in a community-based Chinese population.

SETTING

Data were obtained from annual Jidong Oilfield employee and family member health checkups. The Jidong community is geographically located in Tangshan City in northern China.

PARTICIPANTS

A total of 9078 residents were invited to take part in the survey and provided informed consents. Individuals without data of ECG or SUA were excluded, leaving 8937 residents in our study.

PRIMARY AND SECONDARY OUTCOME MEASURES

SUA was measured at baseline using the uricase-peroxidase method. Hyperuricaemia was defined as a SUA level >7.0 mg/dL in men and >5.7 mg/dL in women. AF was diagnosed based on ECG findings and/or any medical history of AF from referring physicians. The crude and independent association between SUA levels and AF prevalence was evaluated with logistic regression analysis.

RESULTS

AF prevalence was 0.6% (53/8937). Participants with hyperuricaemia had a higher AF prevalence compared with those with normal SUA levels (1.1% vs 0.5%; P=0.02). Hyperuricaemia was correlated with AF after adjustment for various cardiovascular risk factors in all participants (P=0.03, OR 2.051, 95% CI 1.063 to 3.856). This correlation was particularly stronger in women compared with men (P<0.001, OR 6.366, 95% CI 2.553 to 15.871 in women and P=0.96, OR 1.025, 95% CI 0.400 to 2.626 in men).

CONCLUSIONS

We demonstrated a significant association between increased SUA levels and AF prevalence in a Chinese population. Our data indicate that there is a gender-specific mechanism underlying the relationship between SUA and AF.

Relation of elevated serum uric acid levels to first-degree heart block and other cardiac conduction defects in hospitalized patients with type 2 diabetes

AIMS

Several studies have reported that moderately elevated serum uric acid levels are associated with an increased risk of tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus (T2DM). It is currently unknown whether an association also exists between elevated serum uric acid levels and cardiac conduction defects in patients with T2DM.

METHODS

We retrospectively analyzed a hospital-based sample of 967 patients with T2DM discharged from our Division of Endocrinology over the years 2007-2014. Standard electrocardiograms were performed on all patients and were interpreted by expert cardiologists.

RESULTS

Overall, 267 (27.6%) patients had some type of conduction defects on electrocardiograms (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block). Patients in the 3rd serum uric acid tertile had a higher prevalence of any cardiac conduction defects than those belonging to 2nd or 1st tertile, respectively (35.8% vs. 25.0% vs. 22.6%; p<0.0001). Elevated serum uric acid levels were associated with a nearly twofold increased risk of cardiac conduction defects after adjustment for age, sex, hemoglobin A1c, diabetes duration, metabolic syndrome, chronic kidney disease, chronic obstructive pulmonary disease, ischemic heart disease, valvular heart disease and medication use (adjusted-odds ratio 1.84, 95% confidence intervals 1.2-2.9; p=0.009).

CONCLUSIONS

Moderately elevated serum uric acid levels are associated with an increased prevalence of any cardiac conduction defects in hospitalized patients with T2DM, independent of multiple risk factors and potential confounding variables.

Serum uric acid and atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) represents a significant health concern, due to the increased prevalence, morbidity, and mortality.

METHODS AND RESULTS

There is a growing body of evidence correlating serum uric acid (SUA) with cardiovascular diseases such as arterial hypertension and AF.

CONCLUSION

Thus, a question arises as to whether SUA levels have a role in the pathophysiology of AF development.

Serum uric acid levels and multiple health outcomes: umbrella review of evidence from observational studies, randomised controlled trials, and Mendelian randomisation studies

Objective To map the diverse health outcomes associated with serum uric acid (SUA) levels.Design Umbrella review.Data sources Medline, Embase, Cochrane Database of Systematic Reviews, and screening of citations and references.Eligibility criteria Systematic reviews and meta-analyses of observational studies that examined associations between SUA level and health outcomes, meta-analyses of randomised controlled trials that investigated health outcomes related to SUA lowering treatment, and Mendelian randomisation studies that explored the causal associations of SUA level with health outcomes.Results 57 articles reporting 15 systematic reviews and144 meta-analyses of observational studies (76 unique outcomes), 8 articles reporting 31 meta-analyses of randomised controlled trials (20 unique outcomes), and 36 articles reporting 107 Mendelian randomisation studies (56 unique outcomes) met the eligibility criteria. Across all three study types, 136 unique health outcomes were reported. 16 unique outcomes in meta-analyses of observational studies had P<10-6, 8 unique outcomes in meta-analyses of randomised controlled trials had P<0.001, and 4 unique outcomes in Mendelian randomisation studies had P<0.01. Large between study heterogeneity was common (80% and 45% in meta-analyses of observational studies and of randomised controlled trials, respectively). 42 (55%) meta-analyses of observational studies and 7 (35%) meta-analyses of randomised controlled trials showed evidence of small study effects or excess significance bias. No associations from meta-analyses of observational studies were classified as convincing; five associations were classified as highly suggestive (increased risk of heart failure, hypertension, impaired fasting glucose or diabetes, chronic kidney disease, coronary heart disease mortality with high SUA levels). Only one outcome from randomised controlled trials (decreased risk of nephrolithiasis recurrence with SUA lowering treatment) had P<0.001, a 95% prediction interval excluding the null, and no large heterogeneity or bias. Only one outcome from Mendelian randomisation studies (increased risk of gout with high SUA levels) presented convincing evidence. Hypertension and chronic kidney disease showed concordant evidence in meta-analyses of observational studies, and in some (but not all) meta-analyses of randomised controlled trials with respective intermediate or surrogate outcomes, but they were not statistically significant in Mendelian randomisation studies.Conclusion Despite a few hundred systematic reviews, meta-analyses, and Mendelian randomisation studies exploring 136 unique health outcomes, convincing evidence of a clear role of SUA level only exists for gout and nephrolithiasis.