Chronic kidney disease and prevalent atrial fibrillation: the Chronic Renal Insufficiency Cohort (CRIC)

Cardiovascular impact in patients undergoing maintenance hemodialysis: Clinical management considerations

Patients undergoing maintenance hemodialysis develop both structural and functional cardiovascular abnormalities. Despite improvement of dialysis technology, cardiovascular mortality of this population remains high. The pathophysiological mechanisms of these changes are complex and not well understood. It has been postulated that several non-traditional, uremic-related risk factors, especially the long-term uremic state, which may affect the cardiovascular system. There are many cardiovascular changes that occur in chronic kidney disease including left ventricular hypertrophy, myocardial fibrosis, microvascular disease, accelerated atherosclerosis and arteriosclerosis. These structural and functional changes in patients receiving chronic dialysis make them more susceptible to myocardial ischemia. Hemodialysis itself may adversely affect the cardiovascular system due to non-physiologic fluid removal, leading to hemodynamic instability and initiation of systemic inflammation. In the past decade there has been growing awareness that pathophysiological mechanisms cause cardiovascular dysfunction in patients on chronic dialysis, and there are now pharmacological and non-pharmacological therapies that may improve the poor quality of life and high mortality rate that these patients experience.

Stroke in Patients with Chronic Kidney Disease…: How do we Approach and Manage it?

Renal failure is a potent risk factor for stroke, which is a leading cause of morbidity and mortality worldwide. The risk of stroke is 5–30 times higher in patients with chronic kidney disease (CKD), especially on dialysis. Case fatality rates are also higher reaching almost 90%. It is therefore important to understand the factors that predispose to stroke in this vulnerable population to better apply preventive strategies. The heightened risk of stroke in CKD represents the interplay of the vascular co-morbidities that occur with renal impairment and factors specific to renal failure such as malnutrition-inflammation-atherosclerosis complex, the effect of uremic toxins, dialysis techniques, vascular access, and the use of anticoagulants to maintain flow in the extracorporeal circuit. Old age, hypertension, diabetes, and previous cerebrovascular disease are all risk factors for stroke with the period of dialysis initiation constituting the highest risk period for developing new stroke. Patients with CKD-stage 3–5 have worse survival and diminished functional outcomes following stroke. Thrombolytic therapy for stroke in CKD has shown an increased risk of symptomatic intracranial hemorrhage or serious systemic hemorrhage, and the therapeutic effects may be attenuated. Benefit of statin therapy in dialysis patient as preventive therapy has not been shown to be beneficial. Control of hypertension and the judicious use of antiplatelet agents form the mainstay of stroke prevention. The benefit of antiplatelet therapies and oral anticoagulants has to be balanced against the real and increased risk of bleeding that is most evident in dialysis cohorts. An increased risk of vascular calcification particularly intracerebral vascular calcification has been seen in patientsreceiving warfarin as prophylaxis in atrial fibrillation. Newer anticoagulants have not been tested in patients with glomerular filtration rate <30 ml/min and hence have to be used with caution. This article is a review of stroke in patients with CKD and approach to managing it.

New oral anticoagulants in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) develop bleeding and thrombotic tendencies, so the indication of anticoagulation at the onset of atrial fibrillation (AF) is complex. AF is the most common chronic cardiac arrhythmia, and thromboembolism and ischemic stroke in particular are major complications. In recent years, new oral anticoagulant drugs have been developed, and they have shown superiority over the classical AVK in preventing stroke, systemic embolism and bleeding risk, constituting an effective alternative to those resources.

Associations of Epicardial, Abdominal, and Overall Adiposity With Atrial Fibrillation

Background—

Although adiposity is increasingly recognized as a risk factor for atrial fibrillation (AF), the importance of epicardial fat compared with other adipose tissue depots remains uncertain. We sought to characterize and compare the associations of AF with epicardial fat and measures of abdominal and overall adiposity.

Methods and Results—

We conducted a meta-analysis of 63 observational studies including 352 275 individuals, comparing AF risk for 1-SD increases in epicardial fat, waist circumference, waist/hip ratio, and body mass index. A 1-SD higher epicardial fat volume was associated with a 2.6-fold higher odds of AF (odds ratio, 2.61; 95% confidence interval [CI], 1.89–3.60), 2.1-fold higher odds of paroxysmal AF (odds ratio, 2.14; 95% CI, 1.45–3.16) and, 5.4-fold higher odds of persistent AF (odds ratio, 5.43; 95% CI, 3.24–9.12) compared with sinus rhythm. Likewise, a 1-SD higher epicardial fat volume was associated with 2.2-fold higher odds of persistent compared with paroxysmal AF (odds ratio, 2.19; 95% CI, 1.66–2.88). Similar associations existed for postablation, postoperative, and postcardioversion AF. In contrast, associations of abdominal and overall adiposity with AF were less extreme, with relative risks per 1-SD higher values of 1.32 (95% CI, 1.25–1.41) for waist circumference, 1.11 (95% CI, 1.08–1.14) for waist/hip ratio, and 1.22 (95% CI, 1.17–1.27) for body mass index.

Conclusions—

Strong and graded associations were observed between increasing epicardial fat and AF. Moreover, the strength of associations of AF with epicardial fat is greater than for measures of abdominal or overall adiposity. Further studies are needed to assess the mechanisms and clinical relevance of epicardial fat.

Use of Oral Anticoagulation in the Management of Atrial Fibrillation in Patients with ESRD: Pro

Warfarin has had a thin margin of benefit over risk for the prevention of stroke and systemic embolism in patients with ESRD because of higher bleeding risks and complications of therapy. The successful use of warfarin has been dependent on the selection of patients with nonvalvular atrial fibrillation at relatively high risk of stroke and systemic embolism and lower risks of bleeding over the course of therapy. Without such selection strategies, broad use of warfarin has not proven to be beneficial to the broad population of patients with ESRD and nonvalvular atrial fibrillation. In a recent meta-analysis of use of warfarin in patients with nonvalvular atrial fibrillation and ESRD, warfarin had no effect on the risks of stroke (hazard ratio, 1.12; 95% confidence interval, 0.69 to 1.82; P=0.65) or mortality (hazard ratio, 0.96; 95% confidence interval, 0.81 to 1.13; P=0.60) but was associated with increased risk of major bleeding (hazard ratio, 1.30; 95% confidence interval, 1.08 to 1.56; P<0.01). In pivotal trials, novel oral anticoagulants were generally at least equal to warfarin for efficacy and safety in nonvalvular atrial fibrillation and mild to moderate renal impairment. Clinical data for ESRD are limited, because pivotal trials excluded such patients. Given the very high risk of stroke and systemic embolism and the early evidence of acceptable safety profiles of novel oral anticoagulants, we think that patients with ESRD should be considered for treatment with chronic anticoagulation provided that there is an acceptable bleeding profile. Apixaban is currently indicated in ESRD for this application and may be preferable to warfarin given the body of evidence for warfarin and its difficulty of use and attendant adverse events.

Are Existing Risk Scores for Nonvalvular Atrial Fibrillation Useful for Prediction or Risk Adjustment in Patients With Chronic Kidney Disease?

BACKGROUND

Comparative effectiveness studies are common in patients with nonvalvular atrial fibrillation (NVAF) and chronic kidney disease (CKD), but the accuracy of current thromboembolic (n = 4) and bleeding (n = 3) prediction scores used for risk adjustment are uncertain in these patients because previous studies have included few CKD patients.

METHODS

This was a retrospective cohort study, using Cox models adjusted for time-varying coefficients, of nonanticoagulated adults with incident NVAF and kidney function (defined into Kidney Disease: Improving Global Outcomes [KDIGO] CKD categories) between 2002 and 2013.

RESULTS

Of 58,451 patients (mean age 66 years, 31.3% with CKD) followed for a median of 31 months, 21.3% died, 12.6% had a thromboembolic event (4.2 per 100 patient-years), and 7.8% had a major bleed (2.6 per 100 patient-years). There were graded associations between kidney function and all-cause mortality (adjusted hazard ratio [aHR], 1.88 [95% confidence interval (CI), 1.79-1.98] for very high vs low risk KDIGO category), major bleeding (aHR, 1.61 [95% CI, 1.47-1.76]), and thromboembolic events (aHR, 1.13 [95% CI, 1.04-1.23]). All 7 prediction scores had significantly poorer c statistics in patients with CKD: 0.50-0.59; all P < 0.0001 compared with those with normal kidney function (c statistics 0.69-0.70 for the 4 thromboembolic risk scores and 0.60-0.68 for the 3 bleeding risk scores). Inclusion of KDIGO category did not improve calibration or discrimination statistics for current prediction scores.

CONCLUSIONS

Existing NVAF risk scores exhibit poor discrimination in patients with CKD, limiting their utility for clinical decision-making or for risk adjustment in comparative effectiveness studies. Although CKD is an independent risk factor for adverse events, adding KDIGO class to current risk scores did not improve their performance.

Atrial Fibrillation and Risk of ESRD in Adults with CKD

BACKGROUND AND OBJECTIVES

Atrial fibrillation frequently complicates CKD and is associated with adverse outcomes. Progression to ESRD is a major complication of CKD, but the link with atrial fibrillation has not been fully delineated. In this study, we examined the association of incident atrial fibrillation with the risk of ESRD in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied participants in the prospective Chronic Renal Insufficiency Cohort Study without atrial fibrillation at entry. Incident atrial fibrillation was identified by study visit ECGs, self-report, and hospital discharge diagnostic codes, with confirmation by physician adjudication. ESRD through 2012 was ascertained by participant self-report, medical records, and linkage to the US Renal Data System. Data on potential confounders were obtained from self-report, study visits, and laboratory tests. Marginal structural models were used to study the potential association of incident atrial fibrillation with risk of ESRD after adjustment for time-dependent confounding.

RESULTS

Among 3091 participants, 172 (5.6%) developed incident atrial fibrillation during follow-up. During mean follow-up of 5.9 years, 43 patients had ESRD that occurred after development of incident atrial fibrillation (11.8/100 person-years) compared with 581 patients without incident atrial fibrillation (3.4/100 person-years). In marginal structural models with inverse probability weighting, incident atrial fibrillation was associated with a substantially higher rate of ESRD (hazard ratio, 3.2; 95% confidence interval, 1.9 to 5.2). This association was consistent across important subgroups by age, sex, race, diabetes status, and baseline eGFR.

CONCLUSIONS

Incident atrial fibrillation was associated with higher risk of developing ESRD in CKD. Additional study is needed to identify potentially modifiable pathways through which atrial fibrillation was associated with a higher risk of progression to ESRD. More aggressive monitoring and treatment of patients with CKD and atrial fibrillation may improve outcomes in this high-risk population.

Stroke and Chronic Kidney Disease: Epidemiology, Pathogenesis, and Management Across Kidney Disease Stages

Cerebrovascular disease and stroke are very common at all stages of chronic kidney disease (CKD), likely representing both shared risk factors as well as synergy among risk factors. More subtle ischemic brain lesions may be particularly common in the CKD population, with subtle manifestations including cognitive impairment. For individuals with nondialysis CKD, the prevention, approach to, diagnosis, and management of stroke is similar to the general, non-CKD population. For individuals with end-stage renal disease, far less is known regarding strategies to prevent stroke. Stroke prophylaxis using warfarin in dialysis patients with atrial fibrillation in particular remains of uncertain benefit. End-stage renal disease patients can be managed aggressively in the setting of acute stroke. Outcomes after stroke at all stages of CKD are poor, and improving these outcomes should be the subject of future clinical trials.

Increased risk of atrial fibrillation in end-stage renal disease patients on dialysis: A nationwide, population-based study in Taiwan

End-stage renal disease (ESRD) patients commonly have a higher risk of developing cardiovascular diseases than general population. Chronic kidney disease is an independent risk factor for atrial fibrillation (AF); however, little is known about the AF risk among ESRD patients with various modalities of renal replacement therapy. We used the Taiwan National Health Insurance Research Database to determine the incident AF among peritoneal dialysis (PD) and hemodialysis (HD) patients in Taiwan.Our ESRD cohort include Taiwan National Health Insurance Research Database, we identified 15,947 patients, who started renal replacement therapy between January 1, 2002 and December 31, 2003. From the same data source, 47,841 controls without ESRD (3 subjects for each patient) were identified randomly and frequency matched by gender, age (±1 year), and the year of the study patient's index date for ESRD between January 1, 2002 and December 31, 2003.During the follow-up period (mean duration: 8-10 years), 3428 individuals developed the new-onset AF. The incidence rate ratios for AF were 2.07 (95% confidence interval [CI] = 1.93-2.23) and 1.78 (95% CI = 1.30-2.44) in HD and PD groups, respectively. After we adjusted for age, gender, and comorbidities, the hazard ratios for the AF risk were 1.46 (95% CI = 1.32-1.61) and 1.32 (95% CI = 1.00-1.83) in HD and PD groups, respectively. ESRD patients with a history of certain comorbidities including hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, heart failure, valvular heart disease, and chronic obstructive pulmonary disease (COPD) have significantly increased risks of AF.This nationwide, population-based study suggests that incidence of AF is increased among dialysis ESRD patients. Furthermore, we have to pay more attention in clinical practice and long-term care for those ESRD patients with a history of certain comorbidities.

The Association of Acute Kidney Injury and Atrial Fibrillation after Cardiac Surgery in an Asian Prospective Cohort Study

Acute kidney injury (AKI) and atrial fibrillation (AF) after cardiac surgery are common occurrences and increase patient morbidity and mortality. Inflammation plays a role in increased incidence of AF in patients with chronic kidney disease (CKD); reactive oxygen species and inflammatory markers which are increased in patients with CKD were found to affect the proper functioning of the intracellular ion channels, connexions (transmembrane proteins found in intercellular gap junctions), and electrical homogeneity of the extracellular matrix which are essential for electrical stability and proper conduction of electrical impulses in the atrium. However, it is not known if similar mechanisms are also involved in AKI. We tested the hypothesis that patients with AKI after cardiac surgery have a higher incidence of postoperative AF.Data from 2885 patients, who had undergone cardiac surgery between August 2008 and July 2012 from the Singapore's 2 major heart centers, were obtained prospectively. Postoperative AKI was defined using the Acute Kidney Injury Network criteria. The primary outcome was postoperative AF, and subjects were considered to have postoperative AF if the AF lasted more than an hour, affected hemodynamics, or required medical treatment.The incidence of AKI was 29.7% and the incidence of postoperative AF was 16.8%. A total of 27.7% of AKI patients developed AF. Patients with AKI had a 2-fold increased risk of developing AF (relative risk [RR], 1.716; 95% confidence interval [CI], 1.433-2.055; P < 0.001). The following factors were found to independently increase the risk of AF in patients with AKI: age (RR, 1.011; 95% CI, 1.000-1.022; P = 0.04), low preoperative hemoglobin (RR, 0.942; 95% CI, 0.888-1.000; P = 0.05), low preoperative estimated glomerular filtration rate (eGFR) (RR, 0.987; 95% CI, 0.980-0.994; P < 0.001), and lowest hematocrit during bypass (RR, 0.943; 95% CI, 0.910-0.978; P < 0.001).Patients with AKI are more likely to develop postoperative AF. These patients were older and had lower preoperative hemoglobin, eGFR, and lower nadir hematocrit during bypass. Identification of high-risk AKI patients with early prevention and treatment of AF should reduce the long-term morbidity and mortality among Asian patients undergoing cardiac surgery.

Interleukin-6 Is a Risk Factor for Atrial Fibrillation in Chronic Kidney Disease: Findings from the CRIC Study

Atrial fibrillation (AF) is the most common sustained arrhythmia in patients with chronic kidney disease (CKD). In this study, we examined the association between inflammation and AF in 3,762 adults with CKD, enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study. AF was determined at baseline by self-report and electrocardiogram (ECG). Plasma concentrations of interleukin(IL)-1, IL-1 Receptor antagonist, IL-6, tumor necrosis factor (TNF)-α, transforming growth factor-β, high sensitivity C-Reactive protein, and fibrinogen, measured at baseline. At baseline, 642 subjects had history of AF, but only 44 had AF in ECG recording. During a mean follow-up of 3.7 years, 108 subjects developed new-onset AF. There was no significant association between inflammatory biomarkers and past history of AF. After adjustment for demographic characteristics, comorbid conditions, laboratory values, echocardiographic variables, and medication use, plasma IL-6 level was significantly associated with presence of AF at baseline (Odds ratio [OR], 1.61; 95% confidence interval [CI], 1.21 to 2.14; P = 0.001) and new-onset AF (OR, 1.25; 95% CI, 1.02 to 1.53; P = 0.03). To summarize, plasma IL-6 level is an independent and consistent predictor of AF in patients with CKD.

Usefulness of New-Onset Atrial Fibrillation, as a Strong Predictor of Heart Failure and Death in Patients With Native Left-Sided Infective Endocarditis

Atrial fibrillation (AF) is the most common cardiac arrhythmia in adults and has been independently related to increased morbidity and mortality. AF is a frequent arrhythmia in infective endocarditis (IE). Nevertheless, there are no data on how AF affects the clinical outcome of patients with endocarditis. Our purpose was to investigate patient characteristics, microbiology, echocardiographic findings, in-hospital course, and prognosis of patients with IE who develop new-onset AF (NAF) and compare them with those who remained in sinus rhythm (SR) or had previous AF (PAF). From 1997 to 2014, 507 consecutive patients with native left-sided IE were prospectively recruited at 3 tertiary care centers. We distinguished 3 groups according to the type of baseline heart rhythm during hospitalization and previous history of AF: NAF group (n = 52), patients with no previous history of AF and who were diagnosed as having NAF during hospitalization; SR group (n = 380), patients who remained in SR; and PAF group (n = 75), patients with PAF. Patients with NAF were older than those who remained in SR (68.3 vs 59.6 years, p <0.001). At admission, heart failure was more common in NAF group (53% vs 34.3%, p <0.001), whereas stroke (p = 0.427) was equally frequent in all groups. During hospitalization, embolic events occurred similarly (p = 0.411). In the multivariate analysis, NAF was independently associated with heart failure (odds ratio 3.56, p <0.01) and mortality (odds ratio 1.91, p = 0.04). In conclusion, the occurrence of NAF in patients with IE was strongly associated with heart failure and higher in-hospital mortality independently from other relevant clinical variables.

Renal function after repeat catheter ablation for long-standing persistent atrial fibrillation : Low CHA2DS2-VASc score and sinus rhythm predict improved renal function

BACKGROUND

Renal impairment and atrial fibrillation (AF) often coexist. Catheter ablation is an effective way to reduce the burden of AF and improve symptoms; however, little is known about the relationship between renal function and AF and its role in the progression of AF for patients undergoing repeat catheter ablation.

METHODS

In all, 171 patients with long-standing persistent AF ablation were enrolled in the study. The patients were divided into two groups according to their delta estimated glomerular filtration rate (eGFR) values, which was defined as the eGFR before the repeat procedure minus the eGFR before the initial procedure. Patients with decreasing eGFR (delta eGFR < 0) were categorized as group I, while individuals with no change or increasing eGFR (delta eGFR≥ 0) were categorized as group II. eGFR was estimated at baseline and at the 12-month and 24-month follow-up visits.

RESULTS

After a mean follow-up of 31.4 ± 13.2 months, group I had a significantly higher arrhythmia recurrence rate than group II (71.2 vs. 49.2 %, p < 0.001). On multivariable analyses, eGFR changes after the repeat procedure were associated with arrhythmia recurrence, hypertrophic cardiomyopathy, and CHA2DS2-VASc score. Patients with arrhythmia recurrence and those with a CHA2DS2-VASc score of ≥ 3 were more likely to show an eGFR decline at follow-up.

CONCLUSION

Patients with long-standing persistent AF, with a failed initial ablation procedure and undergoing a repeat ablation procedure, appear to have a higher risk of arrhythmia recurrence. During the follow-up period, patients without arrhythmia recurrence and those with a CHA2DS2-VASc score of < 3 show improved renal function.

Effect of renal function on whole blood and fibrin clot formation in atrial fibrillation patients on warfarin

OBJECTIVE

Atrial fibrillation (AF) brings a risk of thrombosis, requiring oral coagulation, and is associated with renal impairment. The two processes may be linked, as altered fibrin clot structure is present in end-stage renal failure. We hypothesised that progressively deteriorating renal function is linked to altered whole blood and fibrin clot properties and fibrinolysis.

METHODS

Thrombogenesis and fibrinolysis in 200 warfarinised AF patients was assessed by thromboelastography (TEG), a micro-plate assay (MPA) and the international normalized ratio (INR). Renal function was determined by creatinine clearance and two versions of the estimated glomerular filtration rate (eGFR).

RESULTS

Two TEG indices independently reflecting thrombogenesis were linked to creatinine clearance (p < 0.01), whilst a third, reflecting clot strength, was linked to the eGFR (p < 0.001). MPA indices of thrombogenesis and clot density (p < 0.001), and an index of fibrinolysis (p < 0.001) were linked to the eGFR. The time for 50% of the fibrin clot to lyse was linked to creatinine clearance (p = 0.001). The INR was unrelated to any renal function index, and the CHA2DS2VASc score was unrelated to any index.

CONCLUSION

In warfarinised AF patients, renal function is linked to whole blood clot and fibrin clot formation, structure and dissolution, but has no effect on the INR. Key messages Despite oral anticoagulation, patients with atrial fibrillation (AF) still suffer from stroke and venous thromboembolism. The effect of renal function in warfarinised patients with AF is unknown and may account for excess thrombosis and/or haemorrhage. Using two different laboratory methods, our data point to an effect of renal function on clot structure and function that is independent of an effect of warfarin.

Effect of diseases on response to vitamin K antagonists

INTRODUCTION

The purpose of this review article is to summarize the literature on diseases that are documented to have an effect on response to warfarin and other VKAs.

METHODS

We searched the English literature from 1946 to September 2015 via PubMed, EMBASE, and Scopus for the effect of diseases on response vitamin K antagonists including warfarin, acenocoumarol, phenprocoumon, and fluindione.

DISCUSSION

Among many factors modifying response to VKAs, several disease states are clinically relevant. Liver disease, hyperthyroidism, and CKD are well documented to increase response to VKAs. Decompensated heart failure, fever, and diarrhea may also elevate response to VKAs, but more study is needed. Hypothyroidism is associated with decreased effect of VKAs, and obese patients will likely require higher initial doses of VKAs.

CONCLUSION

In order to minimize risks with VKAs while ensuring efficacy, clinicians must be aware of the effect of disease states when prescribing these oral anticoagulants.

Primary prevention of atrial fibrillation with beta-blockers in patients with end-stage renal disease undergoing dialysis

Current evidence suggests that beta-blocker lower the risk of development of atrial fibrillation (AF) and in-hospital stroke after cardiac surgery. This study was to assess whether beta-blockers could decrease incidence of new-onset AF in patients with end stage renal disease (ESRD). We identified patients from a nation-wide database called Registry for Catastrophic Illness, which encompassed almost 100% of the patients receiving dialysis therapy in Taiwan from 1995 to 2008. Propensity score matching and Cox’s proportional hazards regression model were used to estimate hazard ratios (HRs) for new-onset AF. Among 100066 patients, 41.7% received beta-blockers. After a median follow-up of 1500 days, the incidence of new-onset AF significantly decreased in patients treated with beta-blockers (HR = 0.483, 95% confidence interval = 0.437-0.534). The prevention of new-onset AF was significantly better in patients taking longer duration of beta-blockers therapy (P for time trend <0.001). The AF prevention effect remains robust in subgroup analyses. In conclusion, beta-blockers seem effective in the primary prevention of AF in ESRD patients. Hence, beta-blockers may be the target about upstream treatment of AF.

Stroke Risk Factors Beyond the CHA₂DS₂-VASc Score: Can We Improve Our Identification of "High Stroke Risk" Patients With Atrial Fibrillation?

The prevention of stroke and other thromboembolic events plays a crucial role in the management of patients with atrial fibrillation. Not all patients with atrial fibrillation are equal in terms of thromboembolic risk; therefore, not all will benefit from oral anticoagulation treatment. The general principle is that the expected benefit of anticoagulation in reduction of thromboembolic risk must exceed the expected harm caused by possible bleeding. Some guidelines have focused on a categorical approach to stroke prevention, with a focus on identifying patients at high risk for oral anticoagulation. Various current guidelines recommend assessment of stroke risk using the CHADS2 or CHA2DS2-VASc scores to initially detect patients at low risk who require no antithrombotic therapy. However, the scores do not incorporate all possible risk factors causing a high thromboembolic risk. Factors such as impaired renal function, obstructive sleep apnea, and echocardiographic and biochemical or coagulation parameters can also predict adverse thromboembolic events. The present review aims to describe biomarkers whether blood, urine, imaging (cardiac or cerebral), or clinical that go beyond the CHA2DS2-VASc score and potentially aid stroke risk assessment. Although useful in some cases, the presented parameters should be perhaps used to further refine initial identification of patients at low risk, after which effective stroke prevention can be offered to those with ≥1 additional stroke risk factors.

Renal function assessment in atrial fibrillation: Usefulness of chronic kidney disease epidemiology collaboration vs re-expressed 4 variable modification of diet in renal disease

AIM: To compare the performance of the re-expressed Modification of Diet in Renal Disease equation vs the new Chronic Kidney Disease Epidemiology Collaboration equation in patients with non-valvular atrial fibrillation.

METHODS: We studied 911 consecutive patients with non-valvular atrial fibrillation on vitamin-K antagonist. The performance of the re-expressed Modification of Diet in Renal Disease equation vs the new Chronic Kidney Disease Epidemiology Collaboration equation in patients with non-valvular atrial fibrillation with respect to either a composite endpoint of major bleeding, thromboembolic events and all-cause mortality or each individual component of the composite endpoint was assessed using continuous and categorical ≥ 60, 59-30, and < 30 mL/min per 1.73 m² estimated glomerular filtration rate.

RESULTS: During 10 ± 3 mo, the composite endpoint occurred in 98 (10.8%) patients: 30 patients developed major bleeding, 18 had thromboembolic events, and 60 died. The new equation provided lower prevalence of renal dysfunction < 60 mL/min per 1.73 m² (32.9%), compared with the re-expressed equation (34.1%). Estimated glomerular filtration rate from both equations was independent predictor of composite endpoint (HR = 0.98 and 0.97 for the re-expressed and the new equation, respectively; P < 0.0001) and all-cause mortality (HR = 0.98 for both equations, P < 0.01). Strong association with thromboembolic events was observed only when estimated glomerular filtration rate was < 30 mL/min per 1.73 m²: HR is 5.1 for the re-expressed equation, and HR = 5.0 for the new equation. No significant association with major bleeding was observed for both equations.

CONCLUSION: The new equation reduced the prevalence of renal dysfunction. Both equations performed similarly in predicting major adverse outcomes.

Role of Indoxyl Sulfate as a Predisposing Factor for Atrial Fibrillation in Renal Dysfunction

Background

Renal dysfunction is a major risk factor for atrial fibrillation (AF). The uremic toxin indoxyl sulfate may contribute to the progression of cardiac fibrosis and AF substrate in renal dysfunction.

Methods and Results

Male Sprague–Dawley rats were assigned randomly to the following groups: 5/6 nephrectomy (5/6Nx) with vehicle, 5/6Nx with AST‐120, sham procedure with vehicle, and sham procedure with AST‐120. Vehicle and AST‐120 were administered for 4 weeks. Serum levels of IS were significantly increased in 5/6Nx groups. Expression of malondialdehyde, an indicator of oxidative stress, was upregulated in the left atrium of 5/6Nx groups and was accompanied by an increase in expression of NADPH oxidase 2 and 4. Monocyte‐mediated inflammatory signals such as CD68, monocyte chemoattractant protein 1, and vascular cell adhesion molecule 1 were also upregulated in 5/6Nx groups. Interstitial fibrosis was promoted heterogeneously, and expression of profibrotic indicators such as transforming growth factor β1, α‐smooth muscle actin, and collagen type 1 was upregulated in left atrium tissue of 5/6Nx groups. In cultured atrial fibroblasts, incubation with IS upregulated expression of the markers of oxidative stress, inflammation, and profibrotic factors. These results suggest the direct effects of IS on the progression of AF substrate. AF was consistently and invariably induced by atrial extrastimuli in 5/6Nx groups in electrophysiological experiments. AST‐120 treatment significantly alleviated renal dysfunction–induced oxidative stress, inflammation, and atrial fibrosis and, consequently, attenuated AF inducibility.

Conclusions

Indoxyl sulfate facilitates atrial fibrosis and AF and thus is a novel therapeutic target for prevention of renal dysfunction–induced AF.

Comparison of novel oral anticoagulants versus vitamin K antagonists in patients with chronic kidney disease

PURPOSE OF REVIEW

Novel oral anticoagulants (NOACs) including apixaban, dabigatran and rivaroxaban have been approved by international regulatory agencies to prevent venous thromboembolism as well as treat atrial fibrillation and venous thromboembolism in individuals with chronic kidney disease (CKD). However, alterations in their metabolism in the setting of CKD may impact their efficacy and lead to an increased risk of bleeding. This review summarizes the current literature on the efficacy and safety of these agents in individuals with moderate CKD.

RECENT FINDINGS

In clinical trials, the use of the NOACs in patients with moderate CKD has demonstrated efficacy and safety similar to those seen with vitamin K antagonists. However, no universal reversal agent for the anticoagulant effect of the NOACs exists in the setting of bleeding. Limited data have demonstrated that hemodialysis has been effectively used to aid in reversing the effects of dabigatran, and the use of prothrombin complex concentrate has also been used for serious and major adverse bleeding events with some success.

SUMMARY

As the use of the NOACs in patients with CKD increases, it will be important to monitor their safety, and clinicians who prescribe them should carefully monitor kidney function and recognize the potential for adverse effects.

Elevated Serum Beta-Trace Protein Levels are Associated With the Presence of Atrial Fibrillation in Hypertension Patients

Beta-trace protein (BTP) has emerged as a novel biomarker of cardiovascular risk. In this study, the authors aimed to assess the relationship between BTP levels and presence of atrial fibrillation in patients who had controlled hypertension (HTN) and normal renal function. A total of 80 controlled HTN patients with paroxysmal atrial fibrillation (PAF) and 80 age- and sex-matched controls with controlled HTN were enrolled. Serum BTP levels were measured by enzyme-linked immunosorbent assay. BTP levels were found to be significantly higher in patients with PAF (P<.001). Other parameters including mean systolic and diastolic blood pressure values, serum creatinine levels, and glomerular filtration rate were similar between the two groups. Along with left atrial diameter (odds ratio, 1.504; P<.001), BTP levels (odds ratio, 1.015; P<.001) were independently associated with the presence of PAF. BTP levels were increased in controlled HTN patients with PAF compared with controls, and this association was observed within normal renal functions as reflected by normal glomerular filtration rate.

Stroke prevention in the elderly atrial fibrillation patient with comorbid conditions: focus on non-vitamin K antagonist oral anticoagulants

Stroke prevention in elderly atrial fibrillation patients remains a challenge. There is a high risk of stroke and systemic thromboembolism but also a high risk of bleeding if anticoagulants are prescribed. The elderly have increased chronic kidney disease, coronary artery disease, polypharmacy, and overall frailty. For all these reasons, anticoagulant use is underutilized in the elderly. In this manuscript, the benefits of non-vitamin K antagonist oral anticoagulants compared with warfarin in the elderly patient population with multiple comorbid conditions are reviewed.

Prognostic impact of atrial fibrillation on clinical outcomes of acute coronary syndromes, heart failure and chronic kidney disease

Atrial fibrillation (AF) is the most common type of sustained arrhythmia, which is now on course to reach epidemic proportions in the elderly population. AF is a commonly encountered comorbidity in patients with cardiac and major non-cardiac diseases. Morbidity and mortality associated with AF makes it a major healthcare burden. The objective of our article is to determine the prognostic impact of AF on acute coronary syndromes, heart failure and chronic kidney disease. Multiple studies have been conducted to determine if AF has an independent role in the overall mortality of such patients. Our review suggests that AF has an independent adverse prognostic impact on the clinical outcomes of acute coronary syndromes, heart failure and chronic kidney disease.

Individual and Combined Risk Factors for Incident Atrial Fibrillation and Incident Stroke: An Analysis of 3 Million At-Risk US Patients

BACKGROUND

The incremental effects of risk factor combinations for atrial fibrillation (AF) and stroke are incompletely understood. We sought to quantify the risks of incident AF and stroke for combinations of established risk factors in a large US sample.

METHODS AND RESULTS

Patients with no evidence of AF or stroke in 2007 were stratified by combinations of the following risk factors: heart failure, hypertension, diabetes, age 65 to 74, age ≥75, coronary artery disease, and chronic kidney disease. Patients with ≥2 of the first 5 or ≥3 of the first 7, classified as "high-risk," and an age-matched sample of patients with fewer risk factors, classified as "low-risk," were followed over 2008-2010 for incident AF and stroke. Annualized incidence rates and risks were quantified for each combination of factors by using Cox regression. Annualized incidence rates for AF, stroke, and both were 3.59%, 3.27%, and 0.62% in 1 851 653 high-risk patients and 1.32%, 1.48%, and 0.18% in 1 156 221 low-risk patients, respectively. Among patients with 1 risk factor, those with age ≥75 had the highest hazards of incident AF and stroke (HR 9.2, 6.9). Among patients with 2 risk factors, those with age ≥75 and heart failure had the highest annualized incidence rates of AF and stroke (10.2%, 5.9%). The combination of age ≥75 and hypertension was prevalent and had the highest incidences of AF and stroke.

CONCLUSIONS

Adults with combinations of known risk factors are at increased risk of incident AF and stroke, but combinations of risk factors are not always additive.

Effect of Atorvastatin on Serum Levels of Total Cholesterol and High-Sensitivity C-reactive Protein in High-Risk Patients with Atrial Fibrillation in Asia

PURPOSE

The aim of this meta-analysis was to investigate the effects of atorvastatin on serum levels of high-sensitivity C-reactive protein (hs-CRP) and total cholesterol in atrial fibrillation (AF) patients in Asia.

METHODS

By searching English and Chinese language-based electronic databases (ie, PubMed, EBSCO, Ovid, SpringerLink, Wiley, Web of Science, Wanfang database, China National Knowledge Infrastructure, and VIP database), we identified 13 studies relevant to our topic of interest. Data were collected from the 13 studies and analyzed with Comprehensive Meta-Analysis software (version 2.0, Biostat Inc., Englewood, New Jersey).

FINDINGS

Initially, our database searches retrieved 356 studies (45 in English, 311 in Chinese). Thirteen studies were selected for the meta-analysis following stringent criteria. The data included 1239 patients with AF, of whom 634 were treated with atorvastatin and included in the treatment group, and 605 patients were treated with conventional treatment and included in the control group. The results of our meta-analysis suggested that the serum levels of hs-CRP (mg/L) and total cholesterol (mmol/L) in the treatment group were significantly lower than those of the control group (hs-CRP: standardized mean difference = 0.962; 95% CI, 0.629-1.295, P < 0.001; total cholesterol: standardized mean difference = 1.400; 95% CI, 0.653-2.146, P < 0.001).

IMPLICATIONS

The findings of this study suggest that atorvastatin may be very effective in decreasing serum levels of hs-CRP and total cholesterol to prevent cardiovascular events.

Oral anticoagulant therapy in atrial fibrillation patients at high stroke and bleeding risk

Atrial fibrillation (AF) is associated with a 5-fold greater risk of ischemic stroke or systemic embolism compared with normal sinus rhythm. Cardioembolic AF-related strokes are often more severe, fatal or associated with greater permanent disability and higher recurrence rates than strokes of other aetiologies. These strokes may be effectively prevented with oral anticoagulant (OAC) therapy, using either vitamin K antagonists (VKAs) or non-vitamin K antagonist OACs (NOACs) such as the direct thrombin inhibitor dabigatran or direct factor Xa inhibitors rivaroxaban, apixaban or edoxaban. Most AF patients have a positive net clinical benefit from OAC, excluding those with AF and no conventional stroke risk factors. Balancing the risks of stroke and bleeding is necessary for optimal use of OAC in clinical practice, and modifiable bleeding risk factors must be addressed. Concerns remain over 'non-changeable' bleeding risk factors such as older age, significant renal or hepatic impairment, prior stroke(s) or prior bleeding event(s) and active malignancies. Such AF patients are often termed 'special' AF populations, due to their 'special' risk profile that includes increased risks of both thromboembolic and bleeding events, and due to fear of bleeding complications these AF patients are often denied OAC. Evidence shows, however, that the absolute benefits of OAC are the greatest in patients at the highest risk, and NOACs may offer even a greater net clinical benefit compared to warfarin particularly in these high risk patients. In this review article, we summarize available data on stroke prevention in AF patients at increased risk of both stroke and bleeding and discuss the use of NOACs for thromboprophylaxis in these 'special' AF populations.

Renal Impairment and Prognosis of Patients with Atrial Fibrillation Undergoing Coronary Intervention - The AFCAS Trial

BACKGROUND

Renal impairment is a well-known risk factor for cardiovascular complications, but the effect of different stages of renal impairment on thrombotic/thromboembolic and bleeding complications in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) remains largely unknown. We sought to evaluate the incidence and clinical impact of four stages of renal impairment in patients with AF undergoing PCI.

METHODS

We assessed renal function by estimated glomerular filtration rate (eGFR) and outcomes in 781 AF patients undergoing PCI by using the data from a prospective European multicenter registry. End-points included all-cause mortality, major adverse cardiac and cerebrovascular events (MACCE) and bleeding events at 12 months.

RESULTS

A total of 195 (25%) patients had normal renal function (eGFR ≥90 mL/min), 290 (37%) mild renal impairment (eGFR 60-89), 263 (34%) moderate renal impairment (eGFR 30-59) and 33 (4%) severe renal impairment (eGFR <30). Degree of renal impairment remained an independent predictor of mortality and MACCE in an adjusted a Cox regression model. Even patients with mild renal impairment had a higher risk of all-cause mortality (HR 2.25, 95%CI 1.02-4.98, p=0.04) and borderline risk for MACCE (HR 1.56, 95%CI 0.98- 2.50, p=0.06) compared to those with normal renal function.

CONCLUSIONS

Renal impairment is common in patients with AF undergoing PCI and even mild renal impairment has an adverse prognostic effect in these patients requiring multiple antithrombotic medications.

Renal function and non-vitamin K oral anticoagulants in comparison with warfarin on safety and efficacy outcomes in atrial fibrillation patients: a systemic review and meta-regression analysis

OBJECTIVE

To investigate the relative effect of warfarin versus non-vitamin K oral anticoagulants (NOACs) in thrombotic and bleeding outcomes in subgroups of atrial fibrillation (AF) patients with varying degrees of renal dysfunction.

METHODS

Systemic review and meta-regression analyses on NOACs versus warfarin, supplemented with indirect comparisons were conducted. The eligibility criteria for inclusion were randomised controlled trials comparing NOACs against warfarin for stroke prevention in AF patients. Outcomes of interest were stroke or systemic embolism (SE) and major bleeding.

RESULTS

Five studies comprising 72,845 AF patients randomised to either a NOAC or warfarin were included in the meta-regression analysis. A shift in strata from no renal impairment to renal impairment resulted in a non-significant impact on bleeding and stroke/SE, indicating similar safety and efficacy, despite renal function status. Apixaban was associated with less major bleeding compared to dabigatran and rivaroxaban but not edoxaban in patients with moderate renal impairment. For efficacy outcomes, only dabigatran 150 mg was statistically significantly favoured compared to edoxaban 30 mg. For efficacy outcomes in mild renal impairment, both dabigatran 150 mg and rivaroxaban 10 mg (J-ROCKET) were statistically significantly favoured against edoxaban 30 mg.

CONCLUSION

Non-vitamin K oral anticoagulants had similar efficacy and safety compared to warfarin across different levels of renal function. Indirect comparisons suggest that apixaban and edoxaban were associated with a better safety profile in patients with moderate renal impairment. However, caution is warranted when interpreting indirect comparisons of drugs investigated in different trials. Prescribers should fit the most appropriate NOAC to the AF patient characteristics (and vice versa) to individualise effective stroke prevention.

Understanding and Managing Atrial Fibrillation in Patients with Kidney Disease

Chronic kidney disease (CKD) is on the rise due to the increased rate of related comorbidities such as diabetes and hypertension. Patients with CKD are at higher risk of cardiovascular events and atrial fibrillation is more common in this patient population. It is estimated that the prevalence of chronic atrial fibrillation in patients with CKD is two to three times higher than general population. Furthermore, patients with CKD are less likely to stay in sinus rhythm. Atrial fibrillation presents a major burden in this population due to difficult treatment decisions in the setting of a lack of evidence from randomized clinical trials. Patients with CKD have higher risk of stroke with more than half having a CHADS2 score ≥ 2. Anticoagulation have been shown to significantly decrease embolic stroke risk, however bleeding complications such as hemorrhagic stroke is twofold higher with warfarin. Although newer novel anticoagulation drugs have shown promise with lower intracranial hemorrhage risk in comparison to warfarin, lack clinical trial data in CKD and the unavailability of an antidote remains an issue. In this review, we discuss the treatment options available including anticoagulation and the evidence behind them in patients with chronic kidney disease suffering from atrial fibrillation.

Renal denervation suppresses atrial fibrillation in a model of renal impairment

Background

A close association exists between renal impairment (RI) and atrial fibrillation (AF) occurrence. Increased activity of the sympathetic nervous system (SNS) may contribute to the development of AF associated with RI. Renal denervation (RDN) decreases central sympathetic activity.

Objective

The main objective of the study was to explore the effects of RDN on AF occurrence and its possible mechanisms in beagles with RI.

Methods

Unilateral RI was induced in beagles by embolization of small branches of the renal artery in the right kidney using gelatin sponge granules in Model (n = 6) and RDN group (n = 6). The Sham group (n = 6) underwent the same procedure, except for embolization. Then animals in RDN group underwent radiofrequency ablation of the renal sympathetic nerve. Cardiac electrophysiological parameters, blood pressure, left ventricular end-diastolic pressure, and AF inducibility were investigated. The activity of the SNS, renin-angiotensin-aldosterone system (RAAS), inflammation and atrial interstitial fibrosis were measured.

Results

Embolization of small branches of the renal artery in the right kidney led to ischemic RI. Heart rate, P wave duration and BP were increased by RI, which were prevented or attenuated by RDN. Atrial effective refractory period was shortened and AF inducibility was increased by RI, which were prevented by RDN. Antegrade Wenckebach point was shortened, atrial and ventricular rates during AF were increased by RI, which were attenuated or prevented by RDN. Levels of norepinephrine, renin and aldosterone in plasma, norepinephrine, angiotensin II, aldosterone, interleukin-6 and high sensitivity C-reactive protein in atrial tissue were elevated, and atrial interstitial fibrosis was enhanced by RI, which were attenuated by RDN.

Conclusions

RDN significantly reduced AF inducibility, prevented the atrial electrophysiological changes in a model of RI by combined reduction of sympathetic drive and RAAS activity, and inhibition of inflammation activity and fibrotic pathway in atrial tissue.

Primary prevention of atrial fibrillation with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in patients with end-stage renal disease undergoing dialysis

Current evidence suggests that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) reduce the incidence of new atrial fibrillation (AF) in a variety of clinical conditions, including the treatment of left ventricular dysfunction or hypertension. Here we assessed whether ACEIs and ARBs could decrease incidence of new-onset AF in patients with end-stage renal disease (ESRD). We identified patients from the Registry for Catastrophic Illness, a nation-wide database encompassing almost all of the patients receiving dialysis therapy in Taiwan from 1995 to 2008. Propensity score matching and Cox proportional hazards regression models were used to estimate hazard ratios for new-onset AF. Among 113,186 patients, 13% received ACEIs, 14% received ARBs therapy, and 9% received ACEIs or ARBs alternatively. After a median follow-up of 1524 days, the incidence of new-onset AF significantly decreased in patients treated with ACEIs (hazard ratio 0.587, 95% confidence interval 0.519-0.663), ARBs (0.542, 0.461-0.637), or ACEIs/ARBs (0.793, 0.657-0.958). The prevention of new-onset AF was significantly better in patients taking longer duration of ACEI or ARB therapy. The effect remained robust in subgroup analyses. Thus both ACEIs and ARBs appear to be effective in the primary prevention of AF in patients with ESRD. Hence, renin-angiotensin system inhibition may be an emerging treatment target for the primary prevention of AF.

Atrial fibrillation and incident end-stage renal disease: The REasons for Geographic And Racial Differences in Stroke (REGARDS) study

INTRODUCTION

Atrial fibrillation (AF) is an independent risk factor for end-stage renal disease (ESRD) among persons with chronic kidney disease (CKD), however, the association between AF and incident ESRD has not been examined in the general United States population.

METHODS

A total of 24,953 participants (mean age 65 ± 9.0 years; 54% women; 40% blacks) from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study were included in this analysis. AF was identified at baseline (2003-2007) from electrocardiogram data and self-reported history. Incident cases of ESRD were identified through linkage with the United States Renal Data System. Cox proportional-hazards regression was used to compute hazard ratios (HR) and 95% confidence intervals (CI) for the association between AF and incident ESRD.

RESULTS

A total of 2,155 (8.6%) participants had AF at baseline. Over a median follow-up of 7.4 years, 295 (1.2%) persons developed ESRD. In a model adjusted for demographics and potential confounders, AF was associated with an increased risk of incident ESRD (HR=1.51, 95% CI=1.08, 2.11). The association between AF and ESRD became non-significant after further adjustment for CKD markers (eGFR <60 mL/min/1.73 m(2) and urine albumin-to-creatinine ratio ≥ 30 mg/dL) (HR=1.24, 95% CI=0.89, 1.73).

CONCLUSION

AF is associated with an increased risk of ESRD in the general United States population and this association potentially is explained by underlying CKD.

Relation of contrast induced nephropathy to new onset atrial fibrillation in acute coronary syndrome

Chronic renal failure has been described as a risk factor for the development of atrial fibrillation (AF). The aim of this study was to examine the association between contrast-induced nephropathy (CIN) and new-onset AF in patients with acute coronary syndromes. A total of 1,520 consecutive patients (mean age 67.1 ± 12.7 years) with acute coronary syndromes (34.4% with ST-segment elevation myocardial infarctions) who underwent coronary angiography were studied. CIN was defined as an increase in serum creatinine of 0.5 mg/dl within 72 hours of contrast exposure. The independent effect of AF history (chronic or paroxysmal AF before catheterization) on the development of CIN, as well as the independent effect of CIN on the development of new-onset AF (after catheterization, during the in-hospital phase), were tested by using different logistic regression models. One hundred thirty-nine patients (9.1%) had histories of AF before catheterization (60 with paroxysmal and 79 with chronic AF), and 56 (4.1%) developed new-onset AF after catheterization. Eighty-seven patients (5.7%) had CIN. AF history was a predictor of CIN in univariate analysis (odds ratio 2.19, 95% confidence interval 1.22 to 3.95, p = 0.007) but not in multivariate analysis, after adjusting for confounding variables (odds ratio 1.69, 95% confidence interval 0.89 to 3.22, p = 0.111). In contrast, those with CIN had an increased prevalence of new-onset AF (15.3% vs 3.4%, p <0.001). After adjusting for those variables associated with new-onset AF in the univariate analysis, CIN continued to show a significant association with new-onset AF, with a twofold increased risk (odds ratio 2.45, 95% confidence interval 1.07 to 5.64, p = 0.035). In conclusion, the development of CIN is an independent predictor of new-onset AF in the context of acute coronary syndromes.

Anemia and reduced kidney function as risk factors for new onset of atrial fibrillation (from the Ibaraki prefectural health study)

Chronic kidney disease (CKD) is a potential independent risk factor for atrial fibrillation (AF). It remains unclear whether anemia is synergistically associated with increased risk of AF onset in subjects with CKD. We evaluated the association of kidney function, hemoglobin (Hb), and their combination with new-onset AF in a population-based cohort study. We conducted a 15-year prospective cohort study of 132,250 Japanese subjects aged 40 to 79 years who participated in annual health checkups from 1993. Kaplan-Meier survival analysis was used to compare freedom from new-onset AF between groups classified by estimated glomerular filtration rate grade, Hb grade, and their combination. Cox proportional hazard model analysis was used to estimate hazard ratios (HRs) for new-onset AF. During a 13.8-year mean follow-up period, 1,232 (0.93%) subjects with new-onset AF were identified. Lower estimated glomerular filtration rate and lower Hb grades were significantly associated with a higher incidence of new-onset AF. Multivariate HRs and 95% confidence intervals (CIs) of new-onset AF were 1.38 (1.21 to 1.56) for mild CKD group, 2.56 (2.09 to 3.13) for CKD group, and 1.50 (1.24 to 1.83) for anemia group. Borderline Hb level was not significantly associated with increased risk for new-onset AF (HR 1.07, CI 0.91 to 1.25, p = 0.4284). In the model with interaction term between CKD and anemia, the risk was significantly higher (p = 0.0343 for the interaction) than that predicted by each factor independently. In conclusion, decreased kidney function and lower Hb level are associated with increased risk for new-onset AF, especially when both are present.