Prevalence of atrial fibrillation and associated factors in a population of long-term hemodialysis patients

The prevalence of and factors associated with chronic atrial fibrillation in Medicare/Medicaid-eligible dialysis patients

Atrial fibrillation is an important comorbidity with substantial therapeutic implications in dialysis patients but its prevalence varies in different studies. We used a database that includes patients in the United States on hemodialysis who were eligible for government assistance with prescription drugs. We then used ICD-9 codes from billing claims in this database to identify patients with chronic atrial fibrillation. Multivariable logistic regression was used to determine adjusted prevalence odds ratios for associated factors. Of 63,884 individuals, the prevalence of chronic atrial fibrillation was 7%. The factors of age over 60 years, male, Caucasian, body mass index over 25 kg/m(2), coronary artery disease, and heart failure were all significantly associated with chronic atrial fibrillation. Prevalence rates, particularly in younger patients, were far higher than those reported in an age group-matched nondialysis population. Thus, given its clinical impact, future efforts are needed to examine risk factors for adverse outcomes in chronic atrial fibrillation, and to identify appropriate management strategies for this disorder, as well as opportunities for quality improvement in this vulnerable population.

Effectiveness and safety of warfarin initiation in older hemodialysis patients with incident atrial fibrillation

BACKGROUND AND OBJECTIVES

Although generally recommended in atrial fibrillation (AF) patients, the effectiveness and safety of oral anticoagulation in dialysis patients with AF is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We assembled a cohort of older hemodialysis patients who initiated dialysis without prior record of AF and who had prescription drug benefits through three state-administered programs. The index event was a first hospitalization with diagnosed AF; patients with any recorded prior warfarin use were excluded. Eligible patients survived ≥30 days from discharge, and new warfarin use was recorded from prescription records during that 30-day window. Propensity-matched warfarin users and nonusers were compared using Cox regression. Outcomes included ischemic stroke, hemorrhagic stroke, and mortality.

RESULTS

Among 2313 patients with new AF who survived 30 days from discharge, 249 (10.8%) filled a prescription for warfarin. Comparing 237 warfarin users and 948 propensity-matched nonusers over 2287 person-years of follow-up, the occurrence of ischemic stroke was similar (HR = 0.92; 95% CI, 0.61 to 1.37), whereas warfarin users experienced twice the risk of hemorrhagic stroke (HR = 2.38; 95% CI, 1.15 to 4.96). The risks of stroke, gastrointestinal hemorrhage, and mortality did not differ between groups. As-treated analyses yielded similar findings, as did analyses restricted to patients with CHADS(2) scores ≥2.

CONCLUSIONS

Although we confirmed association between warfarin use and hemorrhagic stroke in dialysis patients with AF, we found no association between warfarin use and ischemic stroke. Adequately powered randomized trials are required to conclusively determine the risks and benefits of the studied warfarin indication in hemodialysis patients.

Recent mortality of Japanese patients with atrial fibrillation in an urban city of Tokyo

BACKGROUND

In Japan, the recent status of the mortality of atrial fibrillation (AF) patients is still unclear.

METHODS AND RESULTS

We used a single-hospital based cohort database in an urban city (Tokyo) in Japan, including all the new visitors from 2004 to 2009 (n=13,228). The non-adjusted death rates of AF patients for all-cause, stroke, and cardiovascular death were 1091, 97, and 727 per 100,000 patient-years, and the age-adjusted ones were 317 (95% CI, 316-318), 16 (95% CI, 16-16), and 238 (95% CI, 237-239), respectively. The age-adjusted relative risk of AF on all-cause mortality was 1.7 in the particular population.

CONCLUSIONS

The present study provides the most recent data about the characteristics and the mortality of AF patients in Tokyo, thus serving as the basic information for finding problems to solve regarding Japanese AF patients.

Marine n-3 fatty acids, atrial fibrillation and QT interval in haemodialysis patients

Patients treated with haemodialysis are at high risk of sudden cardiac death (SCD) often caused by arrhythmias. Atrial fibrillation (AF) is frequent among haemodialysis patients and is associated with increased mortality. Prolonged QTc is a risk marker of ventricular arrhythmia and is thereby associated with SCD. Studies have suggested that n-3 PUFA may have an antiarrhythmic effect, but the exact mechanism is not clear. The aim of this study was to examine whether AF was associated with n-3 PUFA in plasma phospholipids and whether supplementation with n-3 PUFA would shorten the QTc interval in haemodialysis patients compared to placebo. In a double-blinded randomised, placebo-controlled intervention trial 206 haemodialysis patients with CVD were treated with 1·7 g n-3 PUFA or placebo (olive oil) daily for 3 months. Blood samples and electrocardiogram evaluations were carried out at baseline and after 3 months. The QT interval, PQ interval and heart rate were measured in all patients with sinus rhythm (SR). At baseline 13 % of patients had AF. The content of the n-3 PUFA, DHA, was significantly lower (P < 0·05) in serum of patients with AF compared with patients with SR. Thus, the DHA content was independently negatively associated with AF. Supplementation with n-3 PUFA did not shorten the QT interval significantly compared to the placebo group (P = 0·42), although subgroup analysis within the n-3 PUFA group revealed a shortening effects on QTc (P = 0·01). In conclusion, an inverse association was found between the presence of AF and the plasma DHA in haemodialysis patients. Intervention with n-3 PUFA did not shorten the QTc interval compared to placebo.

Vitamin K, bone fractures, and vascular calcifications in chronic kidney disease: an important but poorly studied relationship

Vitamin K denotes a group of lipophilic vitamins determining post-translational modification of proteins. There are 2 main forms of vitamin K: vitamin K1 (phylloquinone, found in vegetables); vitamin K2 (menaquinone, produced by bacteria in the intestine and in fermented foods). Vitamin K stores are limited in humans, but it can be recycled. Vitamin K1 is principally transported to the liver, regulating the production of coagulation factors. Vitamin K2, instead, is also transported to extra-hepatic tissues, such as bone and arteries, regulating the activity of matrix Gla-protein (MGP) and osteocalcin [bone Gla-protein (BGP)]. In patients with chronic kidney disease (CKD), cardiovascular mortality is the first cause of death. Some pathogenetic mechanisms of vascular calcification (such as hyperparathyroidism, hyperphosphatemia, hypercalcemia, role of vitamin D) have been widely investigated, but the potential role of vitamin K is still uncertain. Vitamin K could play a key role, as it transforms glutamic acid residues into γ-carboxyglutamic acid, through a carboxylation process, makings both MGP (cMGP) and BGP (cBGP) biologically active. cMGP inhibits vascular calcifications (VC), while cBGP has an important role for a proper mineralization process. Uncarboxylated MGP and BGP (ucMGP and ucBGP) concentrations are indirect markers of vitamin K2 deficiency. The purpose of this review is to analyze the current literature to understand the relationship between vitamin K2 status, fragility fractures and VC in CKD patients. This analysis could be of help in planning investigations of Vitamin K status and its possible supplementation in CKD patients to avert fragility fractures and VC.

Atrial fibrillation linked to vascular access thrombosis in chronic hemodialysis patients

AIM

Atrial fibrillation (AF) is characterized by the development of thromboembolic events and is more prevalent among end-stage renal disease patients than in the general population. Vascular access thrombosis (VAT) is a major morbidity in chronic hemodialysis (HD) patients; however, the association between AF and VAT is unknown.

METHODS

We retrospectively reviewed chronic HD patients with functional vascular access between 1997 and 2006. The association between AF and the development of VAT was analyzed using Kaplan-Meier analysis and multivariate Cox proportional hazards regression.

RESULTS

A total of 568 chronic HD patients, including 55 (9.7%) patients with AF, were reviewed and 154 (27.1%) patients developed at least one episode of VAT. Patients with AF had worse VAT-free survival than patients without AF (p< 0.001). In Cox regression, age, type of vascular access, atrial fibrillation, diabetes, hypertension, and C-reactive protein were independently linked to the development of VAT ( p= 0.049, < 0.001, < 0.001, 0.001, 0.028 and 0.045). The hazard ratios were 2.1 (95% CI: 1.00-1.03) for arteriovenous graft, 2.47 (95% CI: 1.66-3.69) for AF, 1.72 (95% CI: 1.25-2.39) for diabetes and 1.09 (95% CI: 1.00-1.18) for serum C-reactive protein (every 1 mg/dL increase), respectively.

CONCLUSION

Atrial fibrillaiton is linked to the development of vascular access thrombosis in chronic hemodialysis patients and is independent of traditional VAT risk factors.

The increasing prevalence of atrial fibrillation among hemodialysis patients

A half million Americans have ESRD, which puts them at high risk for cardiovascular disease and poor outcomes. Little is known about the epidemiology of atrial fibrillation among patients with ESRD. We analyzed data from annual cohorts (1992 to 2006) of prevalent hemodialysis patients from the United States Renal Data System. In each cohort, we searched 1 year of medical claims for relevant diagnosis codes to determine the prevalence of atrial fibrillation. Among 2.5 million patient observations, 7.7% had atrial fibrillation, with the prevalence increasing 3-fold from 3.5% (1992) to 10.7% (2006). The number of affected patients increased from 3620 to 23,893 (6.6-fold) during this period. Older age, male gender, and several comorbid conditions were associated with increased risk for atrial fibrillation. Compared with otherwise similar Caucasians, the prevalence of atrial fibrillation rates was substantially lower for blacks, Asians, and Native Americans. One-year mortality was twice as high among hemodialysis patients with atrial fibrillation compared with those without (39% versus 19%), and this increased risk was constant during the 15 years of the study. In conclusion, the prevalence of diagnosed atrial fibrillation among patients receiving hemodialysis in the United States is increasing, varies by race, and remains associated with substantially increased mortality. Identifying potentially modifiable risk factors for incident atrial fibrillation requires further investigation.

Association of chronic kidney disease with atrial fibrillation among adults in the United States: REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

BACKGROUND

Atrial fibrillation (AF) is common among patients with end-stage renal disease, but few data are available on its prevalence among adults with chronic kidney disease (CKD) of lesser severity. methods and results: We evaluated the association of CKD with ECG-detected AF among 26 917 participants in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, a population-based cohort of African-American and white US adults ≥45 years of age. Estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Modification of Diet in Renal Disease study equation and albuminuria was defined as a urinary albumin to creatinine ratio ≥30 mg/g. Participants were categorized by renal function: no CKD (eGFR ≥60 mL/min/1.73 m(2) without albuminuria, n=21 081), stage 1 to 2 CKD (eGFR ≥60 mL/min/1.73 m(2) with albuminuria n=2938), stage 3 CKD (eGFR 30 to 59 mL/min/1.73 m(2), n=2683) and stage 4 to 5 CKD (eGFR <30 mL/min/1.73 m(2), n=215). The prevalence of AF among participants without CKD, and with stage 1 to 2, stage 3, and stage 4 to 5 CKD was 1.0%, 2.8%, 2.7% and 4.2%, respectively. Compared with participants without CKD, the age-, race-, and sex-adjusted odds ratios for prevalent AF were 2.67 (95% confidence interval, 2.04 to 3.48), 1.68 (95% confidence interval, 1.26 to 2.24) and 3.52 (95% confidence interval, 1.73 to 7.15) among those with stage 1 to 2, stage 3, and stage 4 to 5 CKD. The association between CKD and prevalent AF remained statistically significant after further multivariable adjustment and was consistent across numerous subgroups.

CONCLUSIONS

Regardless of severity, CKD is associated with an increased prevalence of AF among US adults.

Warfarin in haemodialysis patients with atrial fibrillation: what benefit?

Warfarin is commonly used to prevent stroke in patients with atrial fibrillation; however, patients on haemodialysis may not derive the same benefit from warfarin as the general population. There are no randomized controlled studies in dialysis patients which demonstrate the efficacy of warfarin in preventing stroke. In fact, warfarin places the dialysis patient at increased risk for haemorrhagic stroke and possibly ischaemic stroke. Additionally, warfarin increases the risk of major bleeding and has been associated with vascular calcification. Routine use of warfarin in dialysis for stroke prevention should be discouraged, and therapy should only be reserved for dialysis patients at high risk for thrombo-embolic stroke and carefully monitored if implemented.

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

BACKGROUND

The epidemiology of atrial fibrillation (AF) has been mainly investigated in patients with end-stage renal disease, with limited data on less advanced chronic kidney disease (CKD) stages.

METHODS

A total of 3,267 adult participants (50% non-Hispanic blacks, 46% women) with CKD from the Chronic Renal Insufficiency Cohort were included in this study. None of the study participants had been on dialysis. Those with self-identified race/ethnicity other than non-Hispanic black or white (n = 323) or those without electrocardiographic data (n = 22) were excluded. Atrial fibrillation was ascertained by a 12-lead electrocardiogram and self-report. Age-, sex-, and race/ethnicity-specific prevalence rates of AF were estimated and compared between subgroups. Cross-sectional associations and correlates with prevalent AF were examined using unadjusted and multivariable-adjusted logistic regression analysis.

RESULTS

The mean estimated glomerular filtration rate was 43.6 (+/-13.0) mL/(min 1.73 m(2)). Atrial fibrillation was present in 18% of the study population and in >25% of those > or =70 years old. In multivariable-adjusted models, 1-SD increase in age (11 years) (odds ratio 1.27, CI 95% 1.13-1.43, P < .0001), male [corrected] sex (0.80, 0.65-0.98, P = .0303), smoking (former vs never) (1.34, 1.08-1.66, P = .0081), history of heart failure (3.28, 2.47-4.36, P < .001), and history of cardiovascular disease (1.94, 1.56-2.43, P < .0001) were significantly associated with AF. Race/ethnicity, hypertension, diabetes, body mass index, physical activity, education, high-sensitivity C-reactive protein, total cholesterol, and alcohol intake were not significantly associated with AF. An estimated glomerular filtration rate <45 mL/(min 1.73 m(2)) was associated with AF in an unadjusted model (1.35, 1.13-1.62, P = .0010), but not after multivariable adjustment (1.12, 0.92-1.35, P = .2710).

CONCLUSIONS

Nearly 1 in 5 participants in Chronic Renal Insufficiency Cohort, a national study of CKD, had evidence of AF at study entry, a prevalence similar to that reported among patients with end-stage renal disease and 2 to 3 times of that reported in the general population. Risk factors for AF in this CKD population do not mirror those reported in the general population.

Alterations of atrial electrophysiology induced by electrolyte variations: combined computational and P-wave analysis

AIMS

Haemodialysis (HD) therapy represents a unique model to test in vivo, in humans, the effects of changes in plasma ionic concentrations. Episodes of paroxysmal atrial fibrillation (AF) often occur during the treatment. We investigated the effects of HD-induced electrolyte variations on atrial electrophysiology by analysing ECG P-wave duration (PWd), which reflects atrial conduction velocity (CV), and simulated atrial action potential (AP).

METHODS AND RESULTS

In 20 end-stage renal disease patients PWd (signal-averaged ECG), heart rate (HR), blood pressure, Na(+), K(+), Ca(2+), and Mg(2+) plasma concentrations were measured before and after HD session. The Courtemanche computational model of human atrial myocyte was used to simulate the atrial AP. AP upstroke duration (AP(ud)), AP duration and atrial cell effective refractory period (ERP) were computed. Extracellular electrolyte concentrations and HR were imposed to the average values measured in vivo. HD decreased K(+) (from 4.9 +/- 0.5 to 3.9 +/- 0.4 mmol/L, P < 0.001) and Mg(2+) (0.92 +/- 0.08 to 0.86 +/- 0.05 mmol/L, P < 0.05), and increased Na(+) (139.8 +/- 3.4 to 141.6 +/- 3.1 mmol/L, P < 0.05) and Ca(2+) (1.18 +/- 0.09 to 1.30 +/- 0.07 mmol/L, P < 0.001) plasma concentrations. PWd systematically increased in all the patients after HD (131 +/- 11 to 140 +/- 12 ms, P < 0.001), indicating an intra-atrial conduction slowing. PWd increments were inversely correlated with K(+) variations (R = 0.73, P < 0.01). Model-based analysis indicated an AP(ud) increase (from 2.58 to 2.94 ms) after HD, coherent with experimental observations on PWd, and a reduction of ERP by 12 ms.

CONCLUSION

Changes of plasma ionic concentrations may lead to modifications of atrial electrophysiology that can favour AF onset, namely a decrease of atrial CV and a decrease of atrial ERP.

Atrial fibrillation in hemodialysis patients: clinical features and associations with anticoagulant therapy

Using data from the international Dialysis Outcomes and Practice Patterns Study (DOPPS), we determined incidence, prevalence, and outcomes among hemodialysis patients with atrial fibrillation. Cox proportional hazards models, to identify associations with newly diagnosed atrial fibrillation and clinical outcomes, were stratified by country and study phase and adjusted for descriptive characteristics and comorbidities. Of 17,513 randomly sampled patients, 2188 had preexisting atrial fibrillation, with wide variation in prevalence across countries. Advanced age, non-black race, higher facility mean dialysate calcium, prosthetic heart valves, and valvular heart disease were associated with higher risk of new atrial fibrillation. Atrial fibrillation at study enrollment was positively associated with all-cause mortality and stroke. The CHADS2 score identified approximately equal-size groups of hemodialysis patients with atrial fibrillation with low (less than 2) and higher risk (more than 4) for subsequent strokes on a per 100 patient-year basis. Among patients with atrial fibrillation, warfarin use was associated with a significantly higher stroke risk, particularly in those over 75 years of age. Our study shows that atrial fibrillation is common and associated with elevated risk of adverse clinical outcomes, and this risk is even higher among elderly patients prescribed warfarin. The effectiveness and safety of warfarin in hemodialysis patients require additional investigation.

Prevalence of atrial fibrillation and its predictors in nondialysis patients with chronic kidney disease

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) increases systemic inflammation, which is implicated in development and maintenance of atrial fibrillation (AF); therefore, we hypothesized that the prevalence of AF would be increased among nondialysis patients with CKD. This study also reports independent predictors of the presence of AF in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective, cross-sectional analysis of 1010 consecutive nondialysis patients with CKD from two community-based hospitals was conducted. Estimated GFRs (eGFRs) were calculated using the Modification of Diet in Renal Disease (MDRD) equation. Multivariate logistic regression was used to determine independent predictors.

RESULTS

Of 1010 nondialysis patients with CKD, 214 (21.2%) had AF. Patients with AF were older than patients without AF (76 +/- 11 versus 63 +/- 15 yr). The prevalence of AF among white patients (42.7%) was higher than among black patients (12.7%) or other races (5.7%). In multivariate analyses, age, white race, increasing left atrial diameter, lower systolic BP, and congestive heart failure were identified as independent predictors of the presence of AF. Although serum high-sensitivity C-reactive protein levels were elevated in our population (5.2 +/- 7.4 mg/L), levels did not correlate with the presence of AF or with eGFR. Finally, eGFR did not correlate with the presence of AF in our population.

CONCLUSIONS

The prevalence of AF was increased in our population, and independent predictors were age, white race, increasing left atrial diameter, lower systolic BP, and congestive heart failure.

Relation of kidney function and albuminuria with atrial fibrillation (from the Heart and Soul Study)

Atrial fibrillation (AF) is common in end-stage renal disease, but the relation between more modest decrements in kidney function or albuminuria with AF is uncertain. Among 956 outpatients with coronary artery disease, kidney function was assessed using 3 methods (cystatin C-based estimated glomerular filtration rate [eGFR(cys)], creatinine-based eGFR [eGFR(Cr)], and the urinary albumin/creatinine ratio [ACR]) and prevalent AF using surface electrocardiography. Multivariate logistic regression was used to evaluated the association of each measure of kidney function with AF. The mean eGFR(cys) was 71 +/- 23 ml/min/1.73 m(2), and the median ACR was 10 mg/g (interquartile range 6 to 19). Forty subjects (4%) had prevalent AF. Compared to participants with eGFR(cys) in the highest tertile (eGFR(cys) >79), those with eGFR(cys) in the lowest tertile (eGFR(cys) <62) had more than threefold greater odds of AF (odds ratio [OR] 3.43, 95% confidence interval [CI] 1.18 to 9.97) after multivariate adjustment for traditional cardiovascular disease risk factors. This association remained significant with further adjustment for ACR (OR 3.37, 95% 1.02 to 11.14). Results were similar for eGFR(Cr) but did not reach statistical significance (OR 1.59, 95% CI 0.57 to 4.40). Participants with ACRs in the highest tertile (ACR >15 mg/g) had more than fourfold greater odds of AF compared to participants in the lowest ACR tertile (ACR <7 mg/g); an association that remained significant after adjustment for eGFR(cys) (OR 4.36, 95% CI 1.45 to 13.05) or eGFR(Cr) (OR 4.61, 95% CI 1.56 to 13.66). In conclusion, among outpatients with coronary artery disease, lower eGFR(cys) and higher ACR were associated with prevalent AF, independent of each other.

Incidence of thromboembolic stroke and of major bleeding in patients with atrial fibrillation and chronic kidney disease treated with and without warfarin

The objective was to investigate the incidence of thromboembolic stroke in patients with chronic kidney disease (CKD) and atrial fibrillation (AF) treated with and without warfarin. We investigated the incidence of thromboembolic stroke and of major bleeding in 399 unselected patients with CKD and AF treated with warfarin to maintain an international normalized ratio (INR) between 2.0 and 3.0 (N = 232) and without warfarin (N = 167). Of the 399 patients, 93 (23%) were receiving hemodialysis, and 132 (33%) had an estimated glomerular filtration rate (GFR) of <15 mL/min/1.73 m² At the 31-month follow-up of patients treated with warfarin and 23-month follow-up of patients not treated with warfarin, thromboembolic stroke developed in 21 of 232 patients (9%) treated with warfarin and in 43 of 167 patients (26%) not treated with warfarin (P < 0.001). Major bleeding occurred in 32 of 232 patients (14%) treated with warfarin and in 15 of 167 patients (9%) not treated with warfarin (P not significant). Stepwise Cox regression analysis showed that significant independent predictors of thromboembolic stroke were use of warfarin (odds ratio, 0.28; P < 0.0001) and prior stroke or transient ischemic attack (odds ratio, 2.9; P < 0.05). In conclusion, this observational study showed that CKD patients with AF treated with warfarin to maintain an INR between 2.0 and 3.0 had a significant reduction in thromboembolic stroke and an insignificant increase in major bleeding.

Close bidirectional relationship between chronic kidney disease and atrial fibrillation: the Niigata preventive medicine study

BACKGROUND

Atrial fibrillation (AF) and chronic kidney disease share risk factors and pathophysiologic mechanisms, suggesting that two conditions have close relationships.

METHODS

This is a prospective community-based observational cohort study including 235,818 subjects based upon a voluntary annual health check-up program in Japan. We studied the association of kidney dysfunction at entry with subsequent new-onset AF and the association of AF at entry with the development of kidney disease.

RESULTS

During a follow-up of 5.9 +/- 2.4 years, AF developed in 2947 subjects (1.3%). Baseline serum creatinine and estimated glomerular filtration rate (GFR) were associated with risk of subsequent AF. The HRs (95% CI) for AF were 1.32 (1.08-1.62) and 1.57 (0.89-2.77) for GFR 30 to 59 and <30 mL/min per 1.73 m(2), respectively. The effect of kidney disease on risk of new-onset AF remained significant in subjects without treated hypertension or diabetes. During the follow-up, 7791 subjects (3.3%) developed kidney dysfunction (GFR <60 mL/min per 1.73 m(2)), and 11 307 subjects (4.9%) developed proteinuria. Atrial fibrillation at entry was associated with development of kidney dysfunction (HRs [95% CI], 1.77 [1.50-2.10]) and proteinuria (HR [95% CI], 2.20 [1.92-2.52]). The association persisted in subjects without treated hypertension or diabetes.

CONCLUSIONS

Kidney dysfunction increased the risk of new onset of AF, and AF increased the risk of development of kidney disease. This finding supports the concept that the two conditions share common abnormal molecular signaling pathways contributing to their pathogenesis.

Sudden death and associated factors in a historical cohort of chronic haemodialysis patients

BACKGROUND

In haemodialysis patients, deaths due to cardiovascular causes constitute a large proportion of total mortality and sudden cardiac deaths account for approximately 22% of all deaths. The aim of this study was to evaluate the incidence of sudden cardiac death and associated risk factors in a cohort of haemodialysis patients.

METHODS AND RESULTS

The 3-year cumulative incidence of death in a cohort of 476 patients on chronic haemodialysis treatment was 34.3% (SE 2.3). Sudden death had a 6.9% (SE 1.2) cumulative incidence, with 32 events representing 19.2% of all deaths, while cardiovascular not sudden death and noncardiovascular death accounted for a 3-year cumulative incidence of 7.3% (SE 1.2) and 20.1% (SE 1.9), respectively. According to Cox multivariate analysis, significant risk factors for sudden death were the presence of atrial fibrillation, diabetes mellitus, predialytic hyperkalaemia, haemodialysis mode and C-reactive protein level, which were associated with a 2.9 (CI(95%) 1.3-6.4), 3.0 (CI(95%) 1.3-7.2), 2.7 (CI(95%) 1.3-5.8), 4.5 (CI(95%) 1.3-15.5) and 3.3 (CI(95%) 1.2-8.8)-fold increase in the risk of sudden death, respectively. Sudden death was significantly more frequent during the first 24 h of the first short interdialytic interval and during the last 24 h of the long interval, i.e. immediately before and immediately after the first weekly haemodialysis session (P = 0.02).

CONCLUSIONS

Our data show that the incidence of sudden death in haemodialysis patients is high and that atrial fibrillation, diabetes, hyperkalaemia, haemodialysis mode and C-reactive protein play an important role in developing fatal arrhythmia. Further studies will be necessary to define which interventions could be helpful in reducing this cause of mortality.

Relation of atrial fibrillation to glomerular filtration rate

Although both atrial fibrillation (AF) and decreasing glomerular filtration rate (GFR) are strongly related to advanced age and share common associated vascular risk factors, few studies have explored the relation between AF and GFR. From residents (age >or=40 years) in Kurashiki City, a total of 41,417 subjects (median age 72 years; 13,956 men) were enrolled in the Kurashiki City Annual Medical Survey from May to December 2006. The estimated overall prevalence of AF was 1.6% (2.8% in the low-GFR tertile, 1.2% in the middle tertile, and 0.9% in the high tertile, p <0.001). After all subjects were categorized into age tertiles (age thresholds 68 and 76 years), AF was identified in 0.9% in the low-GFR tertile, 0.6% in the middle tertile, and 0.5% in the high tertile in the low-age tertile (p = 0.018); 2.6% in the low-GFR tertile, 1.2% in the middle tertile, and 1.1% in the high tertile in the middle-age tertile (p <0.001); and 3.9% in the low-GFR tertile, 2.4% in the middle tertile, and 1.7% in the high tertile in the high-age tertile (p <0.001). The odds ratio for AF adjusted for age, gender, vascular risk factors, cardiac disease, and hemoglobin was 1.91 (95% confidence interval 1.54 to 2.38, p <0.001) for the low-GFR tertile versus the high tertile and 1.12 (95% confidence interval 0.88 to 1.42, p = 0.364) for the middle-GFR tertile versus the high tertile. The prevalence of AF gradually increased with decreasing GFR. In conclusion, AF appears to be associated with decreasing GFR.

New insights into stroke in chronic kidney disease

Patients with chronic kidney disease (CKD) are predisposed to stroke, especially as the estimated glomerular filtration rate decreases. This update reviews the pathologic mechanisms particular to this stroke population. The treatment for primary and secondary prevention of stroke is reviewed with respect to antiplatelet agents, anticoagulants, surgery, and carotid stenting. The control of chronic hypertension is particularly important in reducing stroke risk in CKD. In patients with prior stroke from atherosclerosis, antiplatelet agents are most beneficial in reducing secondary stroke risk. Those with atrial fibrillation and CKD may benefit from warfarin anticoagulation. Statins in CKD for stroke reduction in diabetics receiving dialysis are not useful, and the data are pending for their use in stroke reduction in the general CKD population. In carefully selected cases, carotid endarterectomy can be a treatment. The data on carotid stenting are conflicting.

Prevalence of atrial fibrillation in community-dwelling Japanese aged 40 years or older in Japan: analysis of 41,436 non-employee residents in Kurashiki-city

BACKGROUND

A community-based study was conducted to estimate the prevalence of atrial fibrillation (AF) in Japanese adults aged >or=40 years in Kurashiki-city and to examine associated risk factors.

METHODS AND RESULTS

Adult residents (>or=40-year-old) were examined in the Kurashiki-city Annual Medical Survey (KAMS) provided by the Kurashiki-city Public Health Center from May to December 2006. KAMS consisted of medical interviews, physical examination, blood testing and electrocardiography to assess the presence of AF. All participants were divided into AF and non-AF groups, their clinical characteristics compared, and the risk factors associated with AF investigated. Of 246,246 adult residents, 41,436 (age: 72.1+/-11.3 years; 13,963 men) underwent the KAMS. Estimated overall prevalence of AF was 1.6%. Multivariate analysis demonstrated that AF was independently associated with cardiac disease (odds ratio (OR), 9.00; 95% confidence interval (CI), 7.65-10.6; p<0.001), chronic kidney disease (OR, 1.76; 95%CI, 1.49-2.07; p<0.001), male sex (OR, 1.59; 95%CI, 1.34-1.85; p<0.001), and diabetes mellitus (OR, 1.46; 95%CI, 1.20-1.78; p<0.001). Hypercholesterolemia was highly associated with the absence of AF (OR, 0.54; 95%CI, 0.45-0.64, p<0.001).

CONCLUSIONS

Prevalence of AF in Japan is approximately 1.6%, lower than that in Western populations. Male sex, and cardiac and chronic kidney diseases are associated with the presence of AF.

Atrial fibrillation in chronic non-cardiac disease: where do we stand?

Atrial fibrillation is the most common arrhythmia, and is associated with increased risk of stroke and death. Most of present knowledge is derived from studies in patients with cardiac disease whilst limited information is available for patients with several chronic non-cardiac conditions like cancer, chronic obstructive pulmonary disease and chronic kidney disease. Although millions of patients are affected and are at risk of adverse prognosis due to co-existent atrial fibrillation, we are left with very limited guidance for management of atrial fibrillation itself and prevention of complications in those patients. In this paper, we review data on incidence, prognostic importance and treatment modalities of atrial fibrillation in patients with cancer, chronic obstructive pulmonary disease, and chronic kidney disease.

Atrial fibrillation and morbidity and mortality in a cohort of long-term hemodialysis patients

BACKGROUND

Atrial fibrillation is associated with increased mortality and hospitalization in the general population. Data about mortality, morbidity, and hospitalization in hemodialysis patients with atrial fibrillation are limited.

SETTING & PARTICIPANTS

All patients (n = 476) in 5 dialysis centers in Lombardia, Italy, as of June 2003 were enrolled and followed up until June 2006 (median age, 69 years; median hemodialysis duration, 45.2 months; and median follow-up, 36 months). 127 patients had atrial fibrillation at enrollment.

PREDICTORS & OUTCOME

A Cox model was used to relate: (1) atrial fibrillation, age, hemodialysis therapy duration, and comorbid conditions to all-cause and cardiovascular mortality; (2) angiotensin-converting enzyme (ACE)-inhibitor treatment and comorbid conditions to new onset of atrial fibrillation; and (3) atrial fibrillation and comorbid conditions on hospitalization.

RESULTS

There were 167 deaths (39.5% from cardiovascular disease). In multivariable models, atrial fibrillation was independently associated with increased mortality (hazard ratio [HR], 1.65; 95% confidence interval [CI], 1.18 to 2.31). This was more notable for cardiovascular (HR, 2.15; 95% CI, 1.27 to 3.64) than noncardiovascular mortality (HR, 1.39; 95% CI, 0.89 to 2.15). New-onset atrial fibrillation occurred in 35 of 349 individuals (4.1 events/100 person-years); the risk of incident atrial fibrillation was lower in those using ACE-inhibitor therapy (HR, 0.29; 95% CI, 0.10 to 0.82) and higher in those with left ventricular hypertrophy (HR, 2.55; 95% CI, 1.04 to 6.26). There were 539 hospitalizations during 3 years, with 114 hospitalizations in 162 patients with atrial fibrillation and 155 hospitalizations in 314 patients without atrial fibrillation (HR, 1.54; 95% CI, 1.18 to 2.01). Rates of stroke did not significantly differ by atrial fibrillation status (P = 0.4).

LIMITATIONS

Because of the observational nature of this study, results for treatment need confirmation in future trials.

CONCLUSIONS

Atrial fibrillation is associated with greater total and cardiovascular mortality. Patients with atrial fibrillation were hospitalized more frequently than patients without atrial fibrillation. ACE inhibitors may decrease the risk of new-onset atrial fibrillation.

Atrial fibrillation in end-stage renal disease

End-stage renal disease (ESRD) is associated with increased cardiovascular morbidity and mortality. Recent studies indicate that atrial fibrillation (AF) is prevalent among ESRD patients while it adversely affects the clinical outcome. Despite these considerations, AF management in this population is problematic. Notably, most ESRD patients with AF are deprived of the benefits of anticoagulation therapy because of the fear of hemorrhagic complications. This article provides a concise and critical overview of the complex pathophysiology, epidemiology, and discusses the clinical issues regarding the emerging association between ESRD and AF.

Stroke and its prevention in chronic kidney disease

This is a review of stroke mechanisms and management. The concept of stroke and transient ischemic attack and the recently proposed revision in definitions and controversies are discussed. We also discuss the use of antiplatelet and anticoagulant drugs for stroke due to carotid and cardiac disease.

Atrial fibrillation in haemodialysis patients: Do the guidelines for anticoagulation apply?

AIM

Atrial fibrillation (AF) is common in haemodialysis patients, but the risks and benefits of anticoagulation in this group are not well characterized. We investigated the prevalence of AF, its associated risk factors, and the incidence of stroke and haemorrhage in a cohort of haemodialysis patients.

METHODS

We retrospectively reviewed 155 patients undergoing maintenance haemodialysis on 1 April 2003 (age 56.9 +/- 13.5 years; men 62.6%; mean duration of haemodialysis 39.3 +/- 37.5 months). Patients with paroxysmal or permanent AF were identified, and baseline clinical and echocardiographic data were obtained. The incidence of cerebrovascular accidents, major haemorrhage and all-cause mortality was assessed during the 26 month average follow-up period.

RESULTS

AF was present in 25.8% of patients, paroxysmal in 18.1%, and permanent in 7.7%. Patients with AF were more likely to be older (64.2 +/- 9.4 vs 54.4 +/- 13.8 years; P < 0.005), have underlying ischaemic heart disease or congestive heart failure, and have a lower serum albumin (P < 0.05 for all). Only 12.5% of AF patients were anticoagulated, although 47.5% had contraindications to warfarin. Cerebrovascular events occurred in 5.2% of all patients (30.4 episodes/1000 patient-years), and major haemorrhage in 20.0% (106.4 episodes/1000 patient-years). All-cause mortality was 29.7%. The endpoints for the AF group did not significantly differ from the non-AF group.

CONCLUSION

AF is common in haemodialysis patients. The incidence of major haemorrhage was over three times that of cerebrovascular accidents. Guideline recommendations for anticoagulation in AF in the general population may not be appropriate for the haemodialysis population.

The Influence of Hemodialysis on P-Wave Signal-Averaged Electrocardiogram Findings

The role of P-wave signal-averaged electrocardiography (P-SAECG) in the prediction of atrial fibrillation (AF) attacks has been validated in various disease states. In the present study, we aimed to investigate the effect of hemodialysis (HD) on P-SAECG parameters and to determine the related risk factors that might affect those parameters. Ninety-one HD patients and 68 controls were included. Hemoglobin levels, serum electrolytes, arterial pH, and interdialytic weight changes were assessed. P-wave duration (PWD) and late potentials of P wave (root-mean-square voltage for the last 20 ms of the signal-averaged P wave [LP20]) were determined by P-SAECG. Pre- and postdialysis PWDs were significantly increased in HD patients than in controls (both P < 0.05), while the voltages of pre- and postdialysis LP20 were significantly reduced (both P < 0.05). A significant increase in PWD (P < 0.05) and a significant decrease in LP20 (P < 0.05) were observed following HD. Pre- and postdialysis PWDs and LP20 were correlated with age (all P < 0.05), dialysis duration (all P < 0.05), and left atrial diameters (LADs) (pre- and postdialysis) (all P < 0.05). Intradialytic changes in serum potassium levels were only correlated with postdialysis PWD and LP20 in HD patients (both P < 0.05). HD seems to increase PWD and to reduce LP20. Advanced age, duration of HD, intradialytic change in serum potassium levels, and LAD seem to be the important associates of P-SAECG parameters in HD patients.

La population âgée hémodialysée : évaluer et prendre en charge le risque de déclin cognitif

Epidemiological data suggest a large prevalence of cognitive impairment in elderly patients on haemodialysis. They are frequently exposed to pathologies that affect the brain, and hold a plurality of risk factors for neurodegenerative and vascular dementia. Cognitive dysfunctions, because of their medical and socio-economical consequences, may led to discuss the indication for haemodialysis and its profit for the elderly patient. These facts highlight the advantage of a regular assessment of cognitive functions in this population. They also suggest the need in the future of a multidisciplinary intervention for these patients, for a better evaluation of interventions aimed on primary and secondary prevention of cognitive decline in the elderly group.

The influence of the amount of ultrafiltration in chronic hemodialysis on P wave dispersion

OBJECTIVE

Paroxysmal atrial fibrillation (AF) observed in patients undergoing chronic hemodialysis program with higher rates is an important morbidity and mortality cause that negatively influences the hemodynamics and leads to thromboembolic complications. It is known that P wave dispersion (PWD) facilitating the development of paroxysmal atrial fibrillation is increasing during intradialytic process. This study researched the influence of various amounts of ultrafiltration that applied in the various hemodialysis sessions in the same patient cohort on PWD.

MATERIALS AND METHODS

25 patients in a chronic hemodialysis program undergoing four hours bicarbonate hemodialysis three times a week were included in the study. The patient cohort was divided into four groups regarding the amount of ultrafiltration (UF) performed during a four-hour standard hemodialysis session as following: UF up to 1 liter, UF of 1-2 liters, UF of 2-3 liters, and UF of 3-4 liters. Notes were kept until each patient had been included once into each group regarding the amount of ultrafiltration performed parallel to intradialytic weight gain in different hemodialysis session. A 12-lead ECG was taken from the patients immediately before the hemodialysis and within 20 minutes after completion of the session, and maximum P wave duration (Pmax), minimum P wave duration (Pmin) and PWD values (i.e., the difference between Pmax and Pmin) were measured. The inter-group data was assessed with a one-way ANOVA, and the within-group assessments were performed with paired samples test. Mann Whitney U test was used for the evaluations performed according to the presence of diabetes.

FINDINGS

The mean age of 25 patients (15 male and 10 female) was 62.7 +/- 20.2 (range: 21-89). PWD after UF was decreased significantly in group 1 (56.12 +/- 15.26 vs. 46.60 +/- 18.45 ms, p = 0.018) and were increased in groups with UF more than 1 liter: group 2 (39.68 +/- 21.26 vs. 47.12 +/- 21.20 ms, p = 0.020), group 3 (41.60 +/- 23.99 vs. 65.92 +/- 31.04 ms, p = 0.001), and group 4 (17.52 +/- 14.67 vs. 26.80 +/- 15.52 ms, p = 0.007). Furthermore, while PWD before UF was significantly higher in a diabetic group compared to a nondiabetic group (68.85 +/- 10.44 vs. 51.16 +/- 14.06 ms, p = 0.007), it was seen that PWD difference had disappeared after UF application (57.14 +/- 17.99 vs. 42.50 +/- 17.40 ms, p = 0.065).

CONCLUSION

UF application of more than 1 liter during hemodialysis session increases the PWD value significantly. Hypervolemia exceeding 1 liter between two dialysis sessions should be avoided in all patient groups, especially in diabetics, and an effective UF planning should be arranged because of a decrease in PWD values with UF observed in diabetics.