Risks of Death and Stroke in Patients Undergoing Hemodialysis With New-Onset Atrial Fibrillation: A Competing-Risk Analysis of a Nationwide Cohort

Anticoagulation for Patients with Atrial Fibrillation Receiving Dialysis: A Pilot Randomized Controlled Trial

Key Points

Is performing a large definitive trial to establish the optimal anticoagulation strategy in dialysis recipients with atrial fibrillation feasible? One hundred fifty-one patients at 28 dialysis centers were enrolled and randomized to apixaban (n =51), warfarin (n =52), or no oral anticoagulation (n =48). Despite coronavirus disease–related pauses, recruitment was completed in 30 months, with 83% of participants completing follow-up in their assigned treatment arm.

Background

Atrial fibrillation is common in individuals receiving dialysis. The role of oral anticoagulation in this population is uncertain given its exclusion from previous seminal clinical trials. Our objective was to determine the feasibility of performing a large definitive trial to establish the optimal anticoagulation strategy in individuals with atrial fibrillation receiving dialysis.

Methods

The Strategies for the Management of Atrial Fibrillation in Patients Receiving Dialysis trial was a parallel-group, open-label, allocation-concealed, pilot randomized control trial that took place at 28 centers in Canada and Australia. The trial included adults (18 years or older) undergoing dialysis with a history of nonvalvular atrial fibrillation who met the CHADS-65 criteria. Participants were randomized 1:1:1 to receive dose-adjusted warfarin, apixaban 5 mg twice daily, or no oral anticoagulation and followed for 26 weeks. The primary outcomes evaluated the following measures of feasibility: (1 ) recruitment of the target population within 2 years from the start of the trial and (2 ) adherence of >80% of randomized patients to the allocated treatment strategy at the conclusion of follow-up. Secondary outcomes included stroke and bleeding.

Results

From December 2019 to June 2022, 151 patients were enrolled and randomized to apixaban (n =51), warfarin (n =52), or no oral anticoagulation (n =48). Allowing for pauses related to the coronavirus disease pandemic, recruitment was completed in 30 months, and 123 (83%) of participants completed follow-up in their allocated treatment arm. There was one adjudicated stroke event. Eight participants had a major bleeding event (four warfarin, two apixaban, two no oral anticoagulation). Death occurred in 15 participants (nine warfarin, two apixaban, four no oral anticoagulation). Time in the therapeutic range for warfarin recipients was 58% (interquartile range, 47%–70%).

Conclusions

We have demonstrated the feasibility of recruitment and adherence in a trial that compared different anticoagulation strategies in patients with atrial fibrillation receiving dialysis.

Clinical Trial registry name and registration number:

Strategies for the Management of Atrial Fibrillation in Patients Receiving Dialysis (SAFE-D), NCT03987711 .

Podcast

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2025_04_09_ASN0000000000000495.mp3

Prediction models for ischemic stroke and bleeding in dialysis patients: a systematic review and meta-analysis

Background

Patients with kidney failure on maintenance dialysis have a high stroke and bleeding risk. Multivariable prediction models can be used to estimate the risk of ischemic stroke and bleeding. A systematic review and meta-analysis was performed to determine the performance of the existing models in patients on dialysis.

Methods

MEDLINE and Embase databases were searched, from inception through 12 January 2024, for studies of prediction models for stroke or bleeding, derived or validated in dialysis cohorts. Discrimination measures for models with c-statistic data from three or more cohorts were pooled by random effects meta-analysis and a 95% prediction interval (PI) was calculated. Risk of bias was assessed using PROBAST. The review was conducted according to the PRISMA statement and the CHARMS checklist.

Results

Eight studies were included in this systematic review. All the included studies validated pre-existing models that were derived in cohorts from the general population. None of the identified studies reported the development of a new dialysis specific prediction model for stroke, while dialysis specific risk scores for bleeding were proposed by two studies. In meta-analysis of c-statistics, the CHA2DS2-VASc, CHADS2, ATRIA, HEMORR(2)HAGES and HAS-BLED scores showed very poor discriminative ability in the dialysis population. Six of the eight included studies were at low or unclear risk of bias and certainty of evidence was moderate.

Conclusions

The existing prediction models for stroke and bleeding have very poor performance in the dialysis population. New dialysis-specific risk scores should be developed to guide clinical decision making in these patients.

Use of direct oral anticoagulants in patients on chronic hemodialysis: Contemporary appraisal on the role for patients with atrial fibrillation

Atrial fibrillation (AF) is common in patients with chronic kidney disease (CKD) undergoing hemodialysis and in this patient population, management in terms of oral anticoagulation (OAC) presents unique challenges due to the increased risk of both thromboembolic events and bleeding complications. The attributable risk of AF for stroke may differ from patients without CKD, raising the question if OAC is indicated at all. Historically, vitamin K antagonists (VKA) have been the standard treatment for anticoagulation in AF; however, direct oral anticoagulants (DOACs) have emerged as an alternative therapeutic option, whereby data from prospective randomised trials with hemodialysis patients is limited resulting in great variability of practice and guideline recommendations. This review summarizes existing data sources regarding the use and benefit of oral anticoagulation with VKA and DOAC in hemodialysis patients.

Oral Anticoagulation Use in Individuals With Atrial Fibrillation and Chronic Kidney Disease: A Review

Atrial fibrillation (AF) is highly prevalent in patients with chronic kidney disease (CKD). It is associated with an increased risk of stroke, which increases as kidney function declines. In the general population and in those with a moderate degree of CKD (creatinine clearance 30-50 mL/min), the use of oral anticoagulation to decrease the risk of stroke has been the standard of care based on a favorable risk-benefit profile that had been established in seminal randomized controlled trials. However, evidence regarding the use of oral anticoagulants for stroke prevention is less clear in patients with severe CKD (creatinine clearance <30 mL/min) and those receiving maintenance dialysis, as these individuals were excluded from such large randomized controlled trials. Nevertheless, the direct oral anticoagulants have invariably usurped vitamin K antagonists as the preferred choice for oral anticoagulation among patients with AF across all strata of CKD based on their well-defined safety and efficacy and multiple pharmacokinetic benefits (e.g., less drug-drug interactions). This review summarizes the current literature on the role of oral anticoagulation in the management of AF among patients with CKD and highlights current deficiencies in the evidence base and how to overcome them.

Effect of atherosclerosis on the relationship between atrial fibrillation and ischemic stroke incidence among patients on hemodialysis

In patients undergoing hemodialysis, the impact of atrial fibrillation (AF) through cardiac thromboembolism on the development of ischemic stroke may be influenced by the severity of atherosclerosis present. However, there are no large-scale reports confirming whether the severity of atherosclerosis influences the relationship between AF and stroke development in patients requiring hemodialysis. We aimed to investigate the effects of atherosclerotic disease on the relationship between AF and new-onset ischemic stroke. This nationwide longitudinal study based on dialysis facilities across Japan used data collected from the Japanese Renal Data Registry at the end of 2019 and 2020. The exposure was AF at the end of 2019, identified using a resting 12-lead electrocardiography. The primary outcome was the incidence of cerebral infarction (CI) after 1 year. To examine whether the number of atherosclerotic diseases modified the association between AF and the outcome, we estimated the odds ratios (ORs) using a logistic regression model and then assessed the presence of global interaction using Wald test. Following the study criteria, data from 151,350 patients (mean age, 69 years; men, 65.2%; diabetic patients, 48.7%) were included in the final analysis. A total of 9841 patients had AF (prevalence, 6.5%). Between 2019 and 2020, 4967 patients (3.2%) developed ischemic stroke. The adjusted OR of AF for new-onset CI was 1.5, which showed a decreasing trend with an increasing number of atherosclerotic diseases; the interaction was not significant (P = 0.34). While age, diabetes mellitus, smoking, systolic blood pressure, and serum C-reactive protein concentration were positively associated with CI, intradialytic weight gain, body mass index, and serum albumin level were negatively associated. While we demonstrated the association between AF and new-onset CI among Japanese patients on hemodialysis, we failed to demonstrate the evidence that the association was attenuated with an increasing numbers of atherosclerotic complications.

Long-term outcomes of left atrial appendage occlusion in patients with atrial fibrillation and end stage renal disease

OBJECTIVE

In patients with atrial fibrillation (AF) and end-stage renal disease (ESRD), oral anticoagulants are contraindicated, and left atrial appendage occlusion (LAAO) is an alternative treatment. However, the efficacy of thromboembolic prevention using LAAO in these patients has rarely been reported in Asian populations. To our knowledge, this is the first long-term LAAO study in patients with AF undergoing dialysis in Asia.

METHODS

In this study, 310 patients (179 men) with a mean age of 71.3 ± 9.6 years and mean CHA2DS2-VASc 4.2 ± 1.8 were consecutively enrolled at multiple centers in Taiwan. The outcomes of 29 patients with AF and ESRD undergoing dialysis who underwent LAAO were compared to those without ESRD. The primary composite outcomes were stroke, systemic embolization, or death.

RESULTS

No difference in mean CHADS-VASc score was noted between patients with versus without ESRD (4.1 ± 1.8 vs. 4.6 ± 1.9, p = 0.453). After a mean follow-up of 38 ± 16 months, the composite endpoint was significantly higher in patients with ESRD (hazard ratio, 5.12 [1.4-18.6]; p = 0.013) than in those without ESRD after LAAO therapy. Mortality was also higher in patients with ESRD (hazard ratio, 6.6 [1.1-39.7]; p = 0.038). The stroke rate was numerically higher in patients with versus without ESRD, but the difference was not statistically significant (hazard ratio, 3.2 [0.6-17.7]; p = 0.183). Additionally, ESRD was associated with device-related thrombosis (odds ratio, 6.15; p = 0.047).

CONCLUSION

Long-term outcomes of LAAO therapy may be less favorable in patients with AF undergoing dialysis, possibly because of the poor condition of patients with ESRD.

Nonvalvular atrial fibrillation in patients undergoing chronic hemodialysis. Should dialysis patients with atrial fibrillation receive oral anticoagulation?

Chronic kidney disease (CKD) is an independent risk factor for presenting atrial fibrillation (AF), which conditions an increased risk already present in CKD of suffering a thromboembolic event. And this risk is even higher in the hemodialysis (HD) population. On the other hand, in CKD patients and even more so in HD patients, the probability of suffering serious bleeding is also higher. Therefore, there is no consensus on whether or not to anticoagulate this population. Taking as a model what is advised for the general population, the most common attitude among nephrologists has been to opt for anticoagulation, even though there is no randomized studies to support it. Classically, anticoagulation has been done with vitamin K antagonists, at high cost for our patients: severe bleeding events, vascular calcification, and progression of nephropathy, among other complications. With the emergence of direct-acting anticoagulants, a hopeful outlook was opened in the field of anticoagulation, as they were postulated as more effective and safer drugs than antivitamin K. However, in clinical practice, this has not been the case. In this paper we review various aspects of AF and its anticoagulant treatment in the HD population.

Comprehensive comparison of stroke risk score performance: a systematic review and meta-analysis among 6 267 728 patients with atrial fibrillation

AIMS

Multiple risk scores to predict ischaemic stroke (IS) in patients with atrial fibrillation (AF) have been developed. This study aims to systematically review these scores, their validations and updates, assess their methodological quality, and calculate pooled estimates of the predictive performance.

METHODS AND RESULTS

We searched PubMed and Web of Science for studies developing, validating, or updating risk scores for IS in AF patients. Methodological quality was assessed using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). To assess discrimination, pooled c-statistics were calculated using random-effects meta-analysis. We identified 19 scores, which were validated and updated once or more in 70 and 40 studies, respectively, including 329 validations and 76 updates-nearly all on the CHA2DS2-VASc and CHADS2. Pooled c-statistics were calculated among 6 267 728 patients and 359 373 events of IS. For the CHA2DS2-VASc and CHADS2, pooled c-statistics were 0.644 [95% confidence interval (CI) 0.635-0.653] and 0.658 (0.644-0.672), respectively. Better discriminatory abilities were found in the newer risk scores, with the modified-CHADS2 demonstrating the best discrimination [c-statistic 0.715 (0.674-0.754)]. Updates were found for the CHA2DS2-VASc and CHADS2 only, showing improved discrimination. Calibration was reasonable but available for only 17 studies. The PROBAST indicated a risk of methodological bias in all studies.

CONCLUSION

Nineteen risk scores and 76 updates are available to predict IS in patients with AF. The guideline-endorsed CHA2DS2-VASc shows inferior discriminative abilities compared with newer scores. Additional external validations and data on calibration are required before considering the newer scores in clinical practice.

CLINICAL TRIAL REGISTRATION

ID CRD4202161247 (PROSPERO).

Insights into Concomitant Atrial Fibrillation and Chronic Kidney Disease

Chronic kidney disease (CKD) shows a high prevalence and is characterized by progressive and irreversible loss of renal function. It is also associated with a high risk of cardiovascular disease. The CKD population often suffers from atrial fibrillation (AF), which is associated with cardiovascular and all-cause mortality. There is a pernicious bidirectional relationship between CKD and AF: renal dysfunction can help promote AF initiation and maintenance, while unmanageable AF often accelerates kidney function deterioration. Therefore, it is necessary to determine the interactive mechanisms between CKD and AF for optimal management of patients. However, due to renal function impairment and changes in the pharmacokinetics of anticoagulants, it is still elusive to formulate a normative therapeutic schedule for the AF population concomitant with CKD especially those with end-stage kidney failure. This review describes the possible molecular mechanisms linking CKD to AF and existing therapeutic options.

Anticoagulation use and the risk of stroke and major bleeding in patients on hemodialysis: From the VIVALDI, a population-based prospective cohort study

BACKGROUND

Evidence supporting the use of anticoagulation for the prevention of stroke and thromboembolism in patients with kidney failure on hemodialysis (HD) and atrial fibrillation (AF) is limited. We prospectively assessed the incidences of stroke and major bleeding, as well as anticoagulation strategies in patients on HD with AF.

METHODS

We recruited 625 prevalent HD patients into a population-based observational cohort study. The primary prospective outcomes were thromboembolic events (stroke, transient ischemic attack, systemic embolism) and major bleeding. Secondary outcomes included a composite of thromboembolic events, major bleeding, and cardiovascular death to determine net clinical harm.

RESULTS

A total of 238 patients (38.1%) had AF, 165 (26.4%) already at baseline and 73 (15.9%) developed AF during a median follow up of 870 days. Forty (6.4%) thromboembolic events and 89 (14.2%) major bleedings occurred. Overall, 256 patients died (41.0%). In AF patients, use of vitamin K antagonists (VKAs) in 61 patients (25.6%) was not significantly associated with reduced risk of the primary thromboembolic outcome (subdistribution hazard ratio [SHR] 1.41 adjusted for age, sex, congestive heart failure, hypertension, stroke/transient ischemic attack/thromboembolism, vascular disease, and diabetes history score and antiplatelet co-medication (95% CI, 0.49-4.07), but with increased risk of major bleeding (SHR: 2.28; 95% CI, 1.09-4.79) compared with AF patients without anticoagulation (N = 139, 58.4%). Use of VKAs was associated with net clinical harm (adjusted SHR: 2.07; 95% CI, 1.25-3.42).

CONCLUSIONS

Although the nonrandomized nature of the study is prone to bias, anticoagulation with VKAs was not associated with decreased thromboembolic risk, but rather with increased risk of major bleeding and may be net harmful to patients with AF on HD.

Does CHA2DS2-VASc score predict mortality in chronic kidney disease?

Chronic kidney disease (CKD) is a leading cause of morbidity and mortality worldwide. Assessment of cardiovascular (CV) and all-cause mortality in CKD patients is of particular importance. CHA2DS2-VASc (congestive heart failure, hypertension, age ≥ 75 years, diabetes, prior stroke, vascular disease, age 65-74 years, and sex) score was originally formulated to predict the annual thromboembolic risk in patients with nonvalvular atrial fibrillation (AF). The calculation of R2CHADS2 and R2CHA2DS2VASc scores awarded an additional 2 points for CrCl < 60 mL/min and GFR < 60 mL/min/1.73 m2. Recent studies have investigated whether CHA2DS2-VASc and R2CHADS ± VASC scores could be used to predict CV or all-cause mortality in patients with CKD. CHA2DS2-VASc score was proven to be a significant predictor of CV and all-cause mortality in CKD patients, and a higher CHA2DS2-VASc score was associated with increased mortality. These findings are quite promising, and they may help physicians to identify high-risk groups in this population.

Statin Use and Influenza Vaccine Effectiveness in Persons >65 Years of Age, Taiwan

Influenza vaccine effectively reduced risks for in-hospital death or hospitalization, regardless of statin use.

Debates on whether statin use reduces the effectiveness of influenza vaccines against critical illness and death among persons >65 years of age continue. We conducted a study of 9,427,392 persons >65 years of age who did and did not receive influenza vaccinations during 12 consecutive influenza seasons, 2000–01 through 2011–12. Using data from Taiwan’s National Health Insurance Research Database, we performed propensity score-matching to compare vaccinated persons with unvaccinated controls. After propensity score-matching, the vaccinated group had lower risks for in-hospital death from influenza and pneumonia and for hospitalization for pneumonia and influenza, circulatory conditions, and critical illnesses compared with the unvaccinated group. We stratified the 2 groups by statin use and analyzed data by interaction analysis and saw no statistically significant difference. We found that influenza vaccine effectively reduced risks for hospitalization and death in persons >65 years of age, regardless of statin use.

Prior ischemic strokes are non-inferior for predicting future ischemic strokes than CHA2DS2-VASc score in hemodialysis patients with non-valvular atrial fibrillation

Background

We tested whether CHA₂DS₂-VASc and/or HAS-BLED scores better predict ischemic stroke and major bleeding, respectively, than their individual components in maintenance hemodialysis (MHD) patients with atrial fibrillation (AF).

Methods

A retrospective cohort study of a clinical database containing the medical records of 268 MHD patients with non-valvular AF (167 women, mean age 73.4 ± 10.2 years). During the median follow-up of 21.0 (interquartile range, 5.0–44.0) months, 46 (17.2%) ischemic strokes and 24 (9.0%) major bleeding events were reported.

Results

Although CHA₂DS₂-VASc predicted ischemic stroke risk in the study population (adjusted HR 1.74 with 95% CI 1.23–2.46 for each unit of increase in CHA₂DS₂-VASc score, and HR of 5.57 with 95% CI 1.88–16.49 for CHA₂DS₂-VASc score ≥ 6), prior ischemic strokes/transient ischemic attacks (TIAs) were non-inferior in both univariate and multivariate analyses (adjusted HR 8.65 with 95% CI 2.82–26.49). The ROC AUC was larger for the prior ischemic stroke/TIA than for CHA₂DS₂-VASc. Furthermore, the CHA₂DS₂-VASc score did not predict future ischemic stroke risks in study participants who did not previously experience ischemic strokes/TIAs (adjusted HR 1.41, 95% CI: 0.84–2.36). The HAS-BLED score and its components did not have predictive abilities in discriminating bleeding risk in the study population.

Conclusions

Previous ischemic strokes are non-inferior for predicting of future ischemic strokes than the complete CHA₂DS₂-VASc score in MHD patients. CHA₂DS₂VASc scores are less predictive in MHD patients without histories of CVA/TIA. HAS-BLED scores do not predict major bleeding in MHD patients. These findings should redesign approaches to ischemic stroke risk stratification in MHD patients if future large-scale epidemiological studies confirm them.

Chronic Kidney Disease is a Risk Factor for Stroke

Chronic kidney disease (CKD) is a sustained reduction in estimated glomerular filtration rate (eGFR), and/or presence of albuminuria. People with CKD have adverse cardiovascular outcomes including stroke. CKD and stroke share several risk factors, most notably older age, diabetes and hypertension, but CKD is also an independent risk factor for stroke. Relative burden of increased risk is worse for younger people and women, with <40 years with end stage CKD having more than 11 times the risk of their age-matched peers. Risk also varies by CKD treatment, with a risk peak for those starting dialysis, but dropping after the first month of treatment. Proposed mechanisms for increased risk are uraemia, cerebral blood flow dysregulation, vascular calcification, arterial stiffness, chronic inflammation, vascular access impacts, and for those on haemodialysis the use of anticoagulation to maintain dialysis circuits. Outcomes for people with CKD and stroke are poorer; functional outcomes may be impacted by reduced access to specialised stroke care. Stroke mortality is higher for those with CKD; with standardised mortality ratio more than three times higher than expected, but for some groups higher still (young women <40 years with a kidney transplant have 19 times the risk of stroke mortality than women without a transplant). Interventions to prevent and treat stroke lack the evidence base in CKD patients that is present for the general population.

Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Renal Dysfunction

Atrial fibrillation and renal dysfunction often coexist, each disorder may predispose to the other and contribute to worsening prognosis. Both atrial fibrillation and chronic kidney disease are associated with increased risk of stroke and thromboembolic complications. Oral anticoagulation for stroke prevention is therefore recommended in patients with atrial fibrillation and decreased renal function. Each direct oral anticoagulant has unique pharmacologic properties of which clinician should be aware to optimally manage patients. The doses of direct oral anticoagulants require adjustment for renal function. There is debate regarding which equation, the Chronic Kidney Disease Epidemiology (CKD-EPI) equation vs. the Cockcroft-Gault equation, should be used to estimate glomerular filtration rate in patients with atrial fibrillation treated with direct oral anticoagulants. Our review tries to find arguments for benefit of direct oral anticoagulants in patients with renal dysfunction.

Oral anticoagulation in chronic kidney disease with atrial fibrillation

Chronic kidney disease (CKD) and atrial fibrillation (AF) frequently coexist, amplifying the risk of cardiovascular events and mortality. In patients with CKD stage 3 and non-valvular AF, direct oral anticoagulants (DOACs) have shown, compared to vitamin K antagonists (VKA), equal or greater efficacy in the prevention of stroke and systemic embolism, and greater safety. There are no randomizedtrials of the efficacy and safety of DOACs and VKA in advanced CKD. On the other hand, observational studies suggest that DOACs, compared to warfarin, are associated with a lower risk of acute kidney damage and generation/progression of CKD. This paper reviews the epidemiological and pathophysiological aspects of the CKD and AF association, the evidence of the efficacy and safety of warfarin and ACODs in various stages of CKD with AF as well as the comparison between warfarin and ACODs in efficacy and anticoagulant safety, and in its renal effects.

Anticoagulation Management In Hemodialysis Patients With Atrial Fibrillation: Evidence And Opinion

In the absence of robust evidence to guide clinical decision making, the optimal approach to prevent stroke and systemic embolism in hemodialysis patients with atrial fibrillation (AF) remains moot. In this position paper, studies on oral anticoagulation in hemodialysis patients with AF are highlighted, followed by an evidence-based conclusion, a critical analysis to identify sources of bias, and practical opinion-based suggestions on how to manage anticoagulation in this specific population. It remains unclear whether AF is a true risk factor for embolic stroke in hemodialysis. The currently employed cutoff values for the CHA2DS2-VASc score do not adequately discriminate dialysis patients deriving a net benefit from those suffering a net harm from oral anticoagulation. Anticoagulation initiation should probably be more restrictive than currently advocated by official guidelines. Recent evidence reveals that the superior benefit-risk profile of direct oral anticoagulants (DOAC) versus vitamin K antagonists (VKA) observed in the general population and in moderate chronic kidney disease can be extended to the hemodialysis population. VKA may be especially harmful in dialysis patients and should therefore be avoided, in particular in patients with a high bleeding risk and labile international normalized ratio. Dose-finding studies of DOAC suggest that rivaroxaban 10 mg daily and apixaban 2.5 mg twice daily are appropriate choices in dialysis patients. Combined treatment of oral anticoagulants and antiplatelet agents should be reserved for strong indications and limited in time. Left atrial appendage occlusion is a potential attractive solution to reduce the risk of stroke without increasing bleeding propensity, but has not been properly studied in dialysis patients.

Risk of ischemic stroke in patients with end-stage renal disease receiving peritoneal dialysis with new-onset atrial fibrillation

BACKGROUND

The clinical effect of atrial fibrillation (AF)-related ischemic cardiovascular events in patients undergoing peritoneal dialysis (PD) remains uncertain. This study aimed to investigate the risk of ischemic events in patients undergoing PD with new-onset AF compared with that in patients without AF and ascertain the association between the CHA2DS2-VASc score and risk of ischemic stroke.

METHODS

This nationwide, population-based cohort study used data from Taiwan's National Health Insurance Research Database from 1998 to 2011 for patients receiving PD with or without new-onset AF. The clinical endpoints included ischemic stroke, all-cause death, and in-hospital cardiovascular death.

RESULTS

Patients undergoing PD with new-onset AF (N = 505) had significantly higher risks of ischemic stroke (adjusted hazard ratio [aHR], 1.98; 95% CI, 1.40-2.80), all-cause death (aHR, 1.61; 95% CI, 1.40-1.85), and in-hospital cardiovascular death (aHR, 1.82; 95% CI, 1.50.2.21) compared with those in patients undergoing PD without AF. After considering in-hospital death as a competing risk, AF remained associated with an increased risk of ischemic stroke (hazard ratio [HR], 1.67; 95% CI, 1.17-2.37). The CHA2DS2-VASc score was associated with the risk of ischemic stroke (HR, 1.28; 95% CI, 1.12-1.46).

CONCLUSION

The risks of ischemic stroke, all-cause death, and in-hospital cardiovascular death were significantly higher in patients undergoing PD with AF than those in patients without AF. The CHA2DS2-VASc score remained associated with the risk of ischemic stroke in patients undergoing PD with AF.

Impact of atrial fibrillation on the risk of ischemic stroke in patients on hemodialysis: BOREAS-HD3 Study

BACKGROUND

Atrial fibrillation (AF) is an established risk factor for ischemic stroke in a general population. However, its impact in patients on hemodialysis (HD), a group with a high risk for stroke, is still controversial. Here we examined this issue in a Japanese cohort.

METHODS

This study was designed as a multicenter cohort study. HD patients (n = 1,067) were enrolled from 22 institutes in January 2009 and followed up for 3 years. Patients with missing data (n = 196) or kidney transplantation (n = 4) were excluded, and 867 patients contributed to the analysis of the risk of new-onset of ischemic stroke.

RESULTS

At baseline, AF was observed in 123 patients (14.2%, AF group) and not in the others (n = 744: 85.8%, non-AF group). During a follow-up period of 31.3 months, the cumulative incidence rate for ischemic stroke was significantly higher in the AF group than in the non-AF group (6.5% vs. 2.9%, p < 0.05). In Cox regression analysis, AF was a significant independent risk factor for new-onset of ischemic stroke after adjustment for age, sex, prior history of ischemic stroke, use of warfarin, dialysis vintage, comorbidity of diabetic nephropathy, and interdialytic weight gain (hazard ratio 2.17-2.68).

CONCLUSION

Present analyses using comprehensive adjustment for multiple confounders, including prior history of ischemic stroke, indicated that AF independently increases the risk of new-onset of ischemic stroke by more than twofold in Japanese HD patients.

A systematic review and external validation of stroke prediction models demonstrates poor performance in dialysis patients

OBJECTIVES

The objective of this study was to systematically review and externally assess the predictive performance of models for ischemic stroke in incident dialysis patients.

STUDY DESIGN AND SETTING

Two reviewers systematically searched and selected ischemic stroke models. Risk of bias was assessed with the PROBAST. Predictive performance was evaluated within The Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD), a large prospective multicenter cohort of incident dialysis patients. For discrimination, c-statistics were calculated; calibration was assessed by plotting predicted and observed probabilities for stroke, and calibration-in-the-large.

RESULTS

Seventy-seven prediction models for stroke were identified, of which 15 were validated. Risk of bias was high, with all of these models scoring high risk in one or more domains. In NECOSAD, of the 1,955 patients, 127 (6.5%) suffered an ischemic stroke during the follow-up of 2.5 years. Compared with the original studies, most models performed worse with all models showing poor calibration and discriminative abilities (c-statistics ranging from 0.49 to 0.66). The Framingham showed reasonable calibration; however, with a c-statistic of 0.57 (95% CI 0.50-0.63), the discrimination was poor.

CONCLUSION

This external validation demonstrates the weak predictive performance of ischemic stroke models in incident dialysis patients. Instead of using these models in this fragile population, either existing models should be updated, or novel models should be developed and validated.

Cardiovascular Research Using the Korean National Health Information Database

The Korean National Health Information Database (NHID) contains nationwide claims data, including sociodemographic data, health care utilization, health screening data, and healthcare provider information. To compensate for the limitations of randomized clinical trials, real-world observational studies using claims data have emerged as a novel research tool. We summarized the structure of the Korean NHID and the recent researches conducted in the field of cardiovascular science. Epidemiological studies, prescription patterns, temporal trends, comparison of effectiveness and safety of treatments, variability index using laboratory data, and rare intractable disease constitute interesting topics of research in cardiovascular science using the NHID. The operational definition of covariates and clinical outcomes is important for researchers interested in using the NHID data as new tools to prove their hypothesis. A step-by-step approach adopted by a team of data scientists, epidemiologists, statisticians, and clinical researchers may be most effective while designing research studies. The ultimate direction of research using the NHID should aim to improve the welfare of the public by promoting public health, reducing medical costs, and guiding healthcare policies.

Association Between Use of Warfarin for Atrial Fibrillation and Outcomes Among Patients With End-Stage Renal Disease: A Systematic Review and Meta-analysis

IMPORTANCE

Several studies have examined the role of warfarin in preventing strokes in patients with atrial fibrillation and end-stage renal disease; however, the results remain inconclusive.

OBJECTIVE

To assess recently published studies to examine the outcomes of the use of warfarin among patients with atrial fibrillation and end-stage renal disease.

DATA SOURCES

A literature search was performed using the terms warfarin and atrial fibrillation and end-stage renal disease and warfarin and atrial fibrillation and dialysis in the MEDLINE, Embase, and Google Scholar databases from January 1, 2008, to February 28, 2019.

STUDY SELECTION

The studies included were those with patients with end-stage renal disease and atrial fibrillation who were receiving warfarin and with hazard ratios (HRs) of at least 1 primary outcome. The studies excluded were those with a lack of information on outcomes and unreliable 95% CIs of the results.

DATA EXTRACTION AND SYNTHESIS

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines were followed in selecting studies. Collected data were also scrutinized for reliable 95% CIs. Finally, studies were examined for perceived biases, their limitations, and the definitions of the outcomes.

MAIN OUTCOMES AND MEASURES

The HRs and 95% CIs were calculated for the incidence of ischemic stroke, hemorrhagic stroke, major bleeding, and mortality among patients receiving anticoagulants and those not receiving anticoagulants.

RESULTS

Study selection yielded 15 studies with a total of 47 480 patients with atrial fibrillation and end-stage renal disease. Of these patients, 10 445 (22.0%) were taking warfarin. With a mean (SD) follow-up period of 2.6 (1.4) years, warfarin use was associated with no significant change for the risk of ischemic stroke (HR, 0.96; 95% CI, 0.82-1.13), with a significantly higher risk of hemorrhagic stroke (HR, 1.49; 95% CI, 1.03-1.94), with no significant difference in the risk of major bleeding (HR, 1.20; 95% CI, 0.99-1.47), and with no change in overall mortality (HR, 0.95; 95% CI, 0.83-1.09).

CONCLUSIONS AND RELEVANCE

In the studies reviewed, warfarin use appears to have been associated with no change in the incidence of ischemic stroke in patients with atrial fibrillation and end-stage renal disease. However, from the studies reviewed, it does appear to be associated with a significantly higher risk of hemorrhagic stroke, with no significant difference in the risk of major bleeding, and with no change in mortality.

Systematic DOACs oral anticoagulation in patients with atrial fibrillation and chronic kidney disease: the nephrologist's perspective

Atrial fibrillation (AF) is highly prevalent among patients with chronic kidney disease (CKD), and also associated with unfavorable outcome. Anticoagulant therapy is the mainstep of management in such patients, aimed at reducing the high risk of systemic thromboembolism and especially of ischemic stroke, which is reportedly associated with increased mortality in CKD patients. Even though new direct oral anticoagulant agents (DOACs) proved to be effective in patients with non valvular chronic AF, and are therefore recommended by recent guidelines for their treatment, warfarin is currently used in more than one-half of subjects needing oral anticoagulation, and only 30% of them are converted from a vitamin K antagonist- to a DOAC-based regimen. The main reason for not prescribing DOACs is often a reduction in renal function, even if mild. Aim of this review was therefore to evaluate the impact of DOAC therapy in the setting of CKD, from a nephrological perspective, by comparing available evidence on the role of DOACs in patients with CKD and AF with that emerging from traditional warfarin-based therapy. Both the pathogenesis of AF in CKD, and available findings of renal, cardiovascular and bone effects of DOACs in CKD are discussed, leading to the conclusion that DOAC therapy should be considered as the first line therapy for non valvular AF in patients with mild and moderate reduction of renal function, and could also be adopted for patients with severe CKD not on hemodialysis treatment, whereas there is insufficient evidence for ESRD patients on dialysis.

Atrial fibrillation and associated outcomes in patients with peritoneal dialysis and hemodialysis: a 14-year nationwide population-based study

BACKGROUND

Patients with end-stage renal disease (ESRD) undergoing dialysis have increased risks of atrial fibrillation (AF).

OBJECTIVE

To investigate dialysis-related incident AF and associated outcomes.

METHODS

Patients with dialysis were retrieved using data from Taiwan National Health Insurance Research Database during 2001-2013. Patients were separated into peritoneal dialysis (PD) and hemodialysis (HD) according to their initial modality. Primary outcome was new-onset AF. Secondary outcomes were AF-associated ischemic stroke (IS)/systemic embolism (SE) and hemorrhagic stroke.

RESULTS

A total of 158,910 dialytic patients were retrieved. After exclusion criteria, a total of 117,023 patients with ESRD undergoing dialysis were separated into 12,659 patients on PD and 104,364 patients on HD. There were 458 PD patients with subsequent development of AF, and 6216 HD patients with subsequent development of AF. At end of follow-up, patients on PD and HD had AF incidence densities of 7.8 and 8.8 events per 1000 person-years, the SHR of PD versus HD was 0.83 (95% CI 0.73-0.94). The SHR of PD versus HD was 1.07 (95% CI 0.80-1.44) for IS/SE and the SHR of PD versus HD was 0.34 (95% CI 0.13-0.90) for hemorrhagic stroke.

CONCLUSION

In patients with ESRD undergoing dialysis, PD had lowered risks of new onset of AF compared to HD. Subsequently, these AF patients in PD group had comparable incidence of ischemic stroke but decreased incidence of hemorrhagic stroke compared to AF patients in HD group. PD could be the most suitable modality in patients at risk for the onset of AF.

Efficacy and Safety of Oral Anticoagulants in Patients With Atrial Fibrillation and Stages 4 or 5 Chronic Kidney Disease

PURPOSE

The aim of this study was to investigate whether oral anticoagulants can provide efficacy and safety profiles better than no anticoagulant in patients with stages 4 or 5 chronic kidney disease and atrial fibrillation.

METHODS

From 2001 to 2017, a cohort of patients with stages 4 or 5 chronic kidney disease and atrial fibrillation based on electronic medical records were selected from Chang Gung Memorial Hospital system in Taiwan. Patients were divided into nonvitamin K antagonist oral anticoagulants (NOACs), warfarin, and nonanticoagulated groups. They were followed from the index date to the occurrence of the study outcomes or for 5 years, whichever occurred first. The outcomes were admissions due to ischemic stroke or systemic embolism or major bleedings. Survival analyses were conducted to estimate the incidence rates of outcomes.

RESULTS

A total of 3771 patients with atrial fibrillation and estimated glomerular filtration rate less than 30 mL/min/1.73m² were enrolled, of whom 2971 were in the nonanticoagulated group, 280 in the NOAC group, and 520 in the warfarin group. About 25% of all subjects (940 patients) were on dialysis. The mean follow-up was 3.2 years. After adjusting for sex, age, comorbidities, and comedication, the warfarin group had a significantly higher risk of ischemic stroke or systemic embolism (adjusted hazard ratio [aHR] 3.1, 95% confidence interval [CI] 2.1-4.6) than the nonanticoagulated group. The NOAC group had a similar risk of ischemic stroke or systemic embolism (aHR 1.1; 95% CI 0.3-3.4) to that of the nonanticoagulated group. Both the warfarin and the NOAC groups had a significantly higher major bleeding risk than the noncoagulated group (aHR 2.8 [95% CI 2.0-3.8] for warfarin; aHR 3.1 [95% CI 1.9-5.2] for NOAC).

CONCLUSION

The use of NOACs or warfarin is not more effective than using no anticoagulants at all in reducing the risk of ischemic stroke or systemic embolism. Both NOACs and warfarin are associated with increased risk of major bleeding. Our results do not support the use of anticoagulants in patients with atrial fibrillation and stages 4-5 chronic kidney disease.

Atrial fibrillation in patients with end-stage renal disease on hemodialysis: Magnitude of the problem and new approach to oral anticoagulation

Atrial fibrillation (AF) is a frequent comorbid condition in patients with end-stage renal disease on hemodialysis (HD) with a prevalence of up to 27%. The incidence rate of stroke in AF patients on HD is approximately 5%. The AF-associated risk of stroke is a major clinical challenge because current evidence for anticoagulation in HD patients with AF is based on observational data. Results from these observational studies is largely contradictory because they do not show a clear benefit of vitamin K antagonists over no treatment in terms of stroke prevention, and they show an increased risk of hemorrhage associated with anticoagulation treatment in HD patients. HD patients were not included in randomized trials of the direct oral anticoagulants (DOACs), and therefore there is no evidence to support efficacy and safety of DOACs compared to vitamin K antagonists in HD patients. The pharmacological characteristics of DOACs are of particular interest in the HD setting. The factor Xa inhibitors rivaroxaban, apixaban, and edoxaban are not predominantly eliminated via the kidneys. The thrombin inhibitor dabigatran is 80% eliminated via the kidneys but is dialyzable due to its low protein binding. In this narrative review, we examine the current state of evidence regarding the prevalence of AF in patients on HD, the associated risk of stroke, and the efficacy and safety of anticoagulation for stroke prevention in the HD setting. Further, based on the pharmacokinetic properties of DOACs, we discuss their potential use in patients on HD and ongoing randomized trials.

The Association of Atrial Fibrillation and Ischemic Stroke in Patients on Hemodialysis: A Competing Risk Analysis

Background

Stroke is common in patients with end-stage renal disease (ESRD) treated with hemodialysis (HD) and associated with high mortality rate. In the general population, atrial fibrillation (AF) is a major risk factor for stroke and therapeutic anticoagulation is associated with risk reduction, whereas in ESRD the relationship is less clear.

Objective

The purpose of this study is to demonstrate the influence of AF on stroke rates and probability in those on HD following competing risk analyses.

Design

A national record linkage cohort study.

Setting

All renal and stroke units in Scotland, UK.

Patients

All patients with ESRD receiving HD within Scotland from 2005 to 2013 (follow-up to 2015).

Measurements

Demographic, clinical, and laboratory data were linked between the Scottish Renal Registry, Scottish Stroke Care Audit, and hospital discharge data. Stroke was defined as a fatal or nonfatal event and mortality derived from national records.

Methods

Associations for stroke were determined using competing risk models: the cause-specific hazards model and the Fine and Gray subdistribution hazards model accounting for the competing risk of death in models of all stroke, ischemic stroke, and first-ever stroke.

Results

Of 5502 patients treated with HD with 12 348.6-year follow-up, 363 (6.6%) experienced stroke. The stroke incidence rate was 26.7 per 1000 patient-years. Multivariable regression on the cause-specific hazard for stroke demonstrated age, hazard ratio (HR) (95% confidence interval [CI]) = 1.04 (1.03-1.05); AF, HR (95% CI) = 1.88 (1.25-2.83); prior stroke, HR (95% CI) = 2.29 (1.48-3.54), and diabetes, HR (95% CI) = 1.92 (1.45-2.53); serum phosphate, HR (95% CI) = 2.15 (1.56-2.99); lower body weight, HR (95% CI) = 0.99 (0.98-1.00); lower hemoglobin, HR (95% CI) = 0.88 (0.77-0.99); and systolic blood pressure (BP), HR (95% CI) = 1.01 (1.00-1.02), to be associated with an increased stroke rate. In contrast, the subdistribution HRs obtained following Fine and Gray regression demonstrated that AF, weight, and hemoglobin were not associated with stroke risk. In both models, AF was significantly associated with nonstroke death.

Limitations

Our analyses derive from retrospective data sets and thus can only describe association not causation. Data on anticoagulant use are not available.

Conclusions

The incidence of stroke in HD patients is high. The competing risk of "prestroke" mortality affects the relationship between AF and risk of future stroke. Trial designs for interventions to reduce stroke risk in HD patients, such as anticoagulation for AF, should take account of competing risks affecting associations between risk factors and outcomes.

Effects of Prevalent and Incident Atrial Fibrillation on Renal Outcome, Cardiovascular Events, and Mortality in Patients with Chronic Kidney Disease

BACKGROUND

Little is known about how incident atrial fibrillation (AF) affects the clinical outcomes in chronic kidney disease (CKD) patients and whether there is a different influence between pre-existing and incident AF.

METHODS

Incident CKD patients from 2000 to 2013 were retrieved from the National Health Insurance Research Database (NHIRD) of Taiwan and they were classified as non-AF (n = 15,251), prevalent AF (n = 612), and incident AF (n = 588). The outcomes of interest were end-stage renal disease (ESRD) requiring dialysis, all-cause mortality, cardiovascular (CV) mortality, acute myocardial infarction (AMI), stroke or systemic thromboembolism.

RESULTS

Compared with CKD patients without AF, those with prevalent or incident AF were associated with higher adjusted rates of ESRD (hazard ratio (HR), 1.40; 95% confidence interval (CI), 1.32-1.48; HR, 2.91; 95% CI, 2.74-3.09, respectively), stroke or systemic thromboembolism (HR, 1.89; 95% CI, 1.77-2.03; HR, 1.67; 95% CI, 1.54-1.81, respectively), AMI (HR, 1.24; 95% CI, 1.09-1.41; HR, 1.99; 95% CI, 1.75-2.27, respectively), all-cause mortality (HR, 1.64; 95% CI, 1.56-1.72; HR, 2.17; 95% CI, 2.06-2.29, respectively), and CV mortality (HR, 2.95; 95% CI, 2.62-3.32; HR, 4.61; 95% CI, 4.09-5.20, respectively). Intriguingly, CKD patients with prevalent AF were associated with lower adjusted rates of ESRD, AMI, all-cause mortality, and CV mortality compared with those with incident AF.

CONCLUSION

Both incident and prevalent AF were independently associated with greater risks of AMI, all-cause mortality, CV mortality, ESRD, and stroke or systemic thromboembolism. Our findings are novel in that, compared with prevalent AF, incident AF possessed an even higher risk of some clinical consequences, including ESRD, all-cause mortality, CV mortality, and AMI.

Association of a Family History of Atrial Fibrillation With Incidence and Outcomes of Atrial Fibrillation: A Population-Based Family Cohort Study

Importance

The heritability of atrial fibrillation (AF), the contribution of genetic and environmental factors, and the association of a family history of AF with prognosis are unclear.

Objectives

To measure genetic and environmental factors in the familial aggregation of AF and to estimate the association of a family history of AF with major adverse cardiovascular events (MACE).

Design, Setting, and Participants

In this Taiwanese nationwide population-based study among more than 23 million people, a custom data set was obtained using the data of all patients having a diagnosis of AF recorded between January 1996 and December 2013 in the Taiwan National Health Insurance Research Database. The study population comprised all 23 422 955 individuals registered with the database in 2013, of whom 177 770 had a diagnosis of AF and were included in the heritability estimation. From the latter, a subgroup of patients having newly diagnosed AF with a first-degree relative affected by AF between 2000 and 2010 were selected and matched 1:4 to controls without a family history for estimating MACE-free survival. The dates of analysis were January 2010 to December 2013.

Main Outcomes and Measures

The prevalence and relative risk of AF in relatives of patients with AF, as well as the relative contributions of heritability and shared and nonshared environmental factors to AF susceptibility. Also measured was MACE-free survival after AF was diagnosed.

Results

In total, 1510 patients (204 [13.5%] female; mean [SD] age, 57.9 [9.2] years) had newly diagnosed AF with a first-degree relative affected by AF. Individuals with a first-degree relative affected by AF had a relative risk of 1.92 (95% CI, 1.84-1.99) for AF. The accountability for the phenotypic variance of AF was 19.9% for genetic factors (heritability), 3.5% for shared environmental factors, and 76.6% for nonshared environmental factors. After matching for age, sex, hypertension, type 2 diabetes, previous stroke, and anticoagulation, incident AF patients with vs without an affected first-degree relative had similar MACE-free survival.

Conclusions and Relevance

Genetic and environmental factors were associated with AF, with nonshared environmental factors accounting for three-fourths of the phenotypic variance in Taiwan. Patients having AF with a first-degree relative affected by AF did not have more MACE. Therefore, family history may not be particularly informative in the diagnosis or management of AF.

Relation of Race, Apparent Disability, and Stroke Risk With Warfarin Prescribing for Atrial Fibrillation in Patients Receiving Maintenance Hemodialysis

Little is known about how warfarin is prescribed for stroke prevention in maintenance dialysis patients with chronic atrial fibrillation (AF). We examined patterns of warfarin use, and associated factors, after AF diagnosis. This retrospective cohort analysis studied US Medicare patients receiving maintenance dialysis January 1, 2008, to June 30, 2010. Demographics, co-morbidity, and a durable medical equipment claims-based disability proxy score predicted warfarin prescription after AF diagnosis. The analysis included 8,964 patients with nonvalvular AF. Compared with nonusers, warfarin users were younger (age 65.4 ± 12.1 vs 67.0 ± 12.9 years) and more likely to be men (54.3% vs 52.8%) and of white race (64.0% vs 59.6%). After adjustment for other factors, nonwhite, versus white, race was associated with significantly less warfarin use within 30 days: odds ratios (ORs), 95% confidence intervals (CIs), were 0.80, 0.71 to 91, for black patients; 0.57, 0.43 to 0.76, for Asians; and 0.74, 0.49 to 1.12, for members of other races. Percentages of patients receiving warfarin decreased as Hypertension Abnormal renal and liver function Stroke-Bleeding Labile INR Elderly Drugs or alcohol (HAS-BLED) bleeding risk score increased (OR 0.82, 95% CI 0.73 to 0.92, HAS-BLED score 3 to 4 versus 2; 0.38, 0.26 to 0.57, score ≥ 5 vs 2). However, as CHA2DS2-Vasc stroke-risk score increased, warfarin use tended to decrease (OR 0.90, 95% CI 0.78 to 1.03, p = 0.13, CHA2DS2-Vasc score 4 versus 1 to 3; 0.69, 0.61 to 0.78, p < 0.0001, score 5 vs 1 to 3). In conclusion, providers appear to weigh bleeding risk more heavily than stroke-prevention potential when prescribing warfarin for maintenance dialysis patients. Racial minorities received warfarin substantially less often than whites, even after accounting for other factors.

Dialysis Modality and Incident Atrial Fibrillation in Older Patients With ESRD

RATIONALE & OBJECTIVE

Atrial fibrillation (AF) is common in patients with kidney failure treated by maintenance dialysis. Whether the incidence of AF differs between patients receiving hemodialysis and peritoneal dialysis is uncertain.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Using the US Renal Data System, we identified older patients (≥67 years) with Medicare Parts A and B who initiated dialysis therapy (1996-2011) without a diagnosis of AF during the prior 2 years.

EXPOSURE

Dialysis modality at incident end-stage renal disease (ESRD) and maintained for at least 90 days.

OUTCOME

Patients were followed up for 36 months or less for a new diagnosis of AF.

ANALYTICAL APPROACH

Time-to-event analysis using multivariable Cox proportional hazards regression to estimate cause-specific HRs while censoring at modality switch, kidney transplantation, or death.

RESULTS

Overall, 271,722 older patients were eligible; 17,487 (6.9%) were treated with peritoneal dialysis, and 254,235 (93.1%), with hemodialysis, at the onset of ESRD. During 406,225 person-years of follow-up, 69,705 patients had AF newly diagnosed. Because the proportionality assumption was violated, we introduced an interaction term between time (first 90 days vs thereafter) and modality. The AF incidence during the first 90 days was 187/1,000 person-years on peritoneal dialysis therapy and 372/1,000 person-years on hemodialysis therapy. Patients on peritoneal dialysis therapy had an adjusted 39% (95% CI, 34%-43%) lower incidence of AF than those on hemodialysis therapy. From day 91 onward, AF incidence was ∼140/1,000 person-years with no major difference between modalities.

LIMITATIONS

Residual confounding from unobserved differences between exposure groups; ascertainment of AF from billing claims; study of first modality may not generalize to patients switching modalities; uncertain generalizability to younger patients.

CONCLUSIONS

Although patients initiating dialysis therapy using peritoneal dialysis had a lower AF incidence during the first 90 days of ESRD, there was no major difference in AF incidence thereafter. The value of interventions to reduce the early excess AF risk in patients receiving hemodialysis may warrant further study.

Cardiovascular Events after New-Onset Atrial Fibrillation in Adults with CKD: Results from the Chronic Renal Insufficiency Cohort (CRIC) Study

BACKGROUND

Atrial fibrillation (AF), the most common sustained arrhythmia in CKD, is associated with poor clinical outcomes in both patients without CKD and patients with dialysis-treated ESRD. However, less is known about AF-associated outcomes in patients with CKD who do not require dialysis.

METHODS

To prospectively examine the association of new-onset AF with subsequent risks of cardiovascular disease events and death among adults with CKD, we studied participants enrolled in the Chronic Renal Insufficiency Cohort Study who did not have AF at baseline. Outcomes included heart failure, myocardial infarction, stroke, and death occurring after diagnosis of AF. We used Cox regression models and marginal structural models to examine the association of incident AF with subsequent risk of cardiovascular disease events and death, adjusting for patient characteristics, laboratory values, and medication use.

RESULTS

Among 3080 participants, 323 (10.5%) developed incident AF during a mean 6.1 years of follow-up. Compared with participants who did not develop AF, those who did had higher adjusted rates of heart failure (hazard ratio [HR], 5.17; 95% confidence interval [95% CI], 3.89 to 6.87), myocardial infarction (HR, 3.64; 95% CI, 2.50 to 5.31), stroke (HR, 2.66; 95% CI, 1.50 to 4.74), and death (HR, 3.30; 95% CI, 2.65 to 4.12). These associations remained robust with additional adjustment for biomarkers of inflammation, cardiac stress, and mineral metabolism; left ventricular mass; ejection fraction; and left atrial diameter.

CONCLUSIONS

Incident AF is independently associated with two- to five-fold increased rates of developing subsequent heart failure, myocardial infarction, stroke, or death in adults with CKD. These findings have important implications for cardiovascular risk reduction.

Incident Atrial Fibrillation and the Risk of Stroke in Adults with Chronic Kidney Disease: The Stockholm CREAtinine Measurements (SCREAM) Project

BACKGROUND AND OBJECTIVES

Patients with CKD have a high risk of atrial fibrillation. Both CKD and atrial fibrillation are associated with higher risk of stroke and death. However, the effect of incident atrial fibrillation on stroke risk among patients with CKD is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our study included adults with CKD (eGFR<60 ml/min per 1.73 m2) without previously documented atrial fibrillation who had been in contact with health care in Stockholm, Sweden during 2006-2011. Incident atrial fibrillation was identified by administrative diagnostic codes in outpatient or inpatient care and treated as a time-updated exposure in the analysis of stroke and death risk. Stroke events and deaths were ascertained from regional and national registers with complete coverage. Covariates included demographics, comorbidities, therapeutic procedures, and medications. Multivariable Cox regression analysis and competing risk analysis (accounting for death) were used to estimate the association between incident atrial fibrillation and stroke.

RESULTS

Among 116,184 adults with CKD, 13,412 (12%) developed clinically recognized atrial fibrillation during a mean follow-up of 3.9 years (interquartile range, 2.3-5.7 years). Incidence of atrial fibrillation increased across lower eGFR strata: from 29.4 to 46.3 atrial fibrillations per 1000 person-years in subjects with eGFR=45-60 and <30 ml/min per 1.73 m2, respectively; 1388 (53.8 per 1000 person-years) cases of stroke and 5592 (205.1 per 1000 person-years) deaths occurred after incident atrial fibrillation compared with 6850 (16.6 per 1000 person-years) cases of stroke and 28,613 (67.5 per 1000 person-years) deaths during periods without atrial fibrillation. After adjustment, incident atrial fibrillation was associated with higher risk of stroke (hazard ratio, 2.00; 95% confidence interval, 1.88 to 2.14) and death (hazard ratio, 1.76; 95% confidence interval, 1.71 to 1.82). This was attributed to both ischemic stroke (hazard ratio, 2.11; 95% confidence interval, 1.96 to 2.28) and intracranial bleeds (hazard ratio, 1.64; 95% confidence interval, 1.42 to 1.90). Stroke risk was similar across all eGFR strata. In competing risk analyses accounting for death, the association between incident atrial fibrillation and stroke was attenuated but remained higher (subhazard ratio, 1.49; 95% confidence interval, 1.39 to 1.60).

CONCLUSIONS

Patients with CKD who develop atrial fibrillation are at higher risk of stroke and death.

Risk profiles for acute health events after incident atrial fibrillation in patients with end-stage renal disease on hemodialysis

Background

Little is known about the cardiovascular risks of incident atrial fibrillation/flutter (AF) in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD).

Methods

We studied older US patients who newly initiated HD for ESRD (2006-11) and who had not previously been diagnosed with AF, stroke, myocardial infarction (MI) or hip fracture. We used Cox regression with AF as a time-varying covariate, adjusted for socio-demographic characteristics and comorbidities to estimate hazard ratios [HRs (95% confidence intervals)] for the events of ischemic stroke, MI and death. Hip fracture served as a negative control outcome.

Results

We identified 85 377 older patients (mean age: 76.5 years) who initiated HD; of these, 14.3% were subsequently diagnosed with AF (14.9% thereof as primary diagnosis) and 49.8% died during follow-up. Incident AF was associated with nine times higher adjusted mortality during the first 30 days [9.2 (8.8-9.6)], 5-fold higher mortality between 31 and 90 days [4.6 (4.3-4.8)] and double the mortality beyond 90 days from first AF diagnosis [2.2 (2.1-2.3)]. Incident AF was similarly associated with higher adjusted risk of ischemic stroke: 2.1 (1.6-2.7) during the first 30 days, 2.5 (2.0-3.0) between 31 and 90 days and 1.5 (1.3-1.7) beyond 90 days. Similar findings were obtained for MI. However, the risk of hip fracture was only marginally increased following AF diagnosis [≤30 days: 1.1 (0.7-1.6); 31-90 days: 1.4 (1.0-1.8); >90 days: 1.2 (1.1-1.4)]. All associations were attenuated and the association with hip fracture was null when incident AF was defined by a primary diagnosis code.

Conclusions

AF was strongly associated with increased risks of ischemic stroke, MI and death, with risks highest soon after AF diagnosis but extending beyond 90 days.

Atrial Fibrillation Had Less Impact on the Risk of Ischemic Stroke in Non-anticoagulated Patients Undergoing Hemodialysis: Insight from the RAKUEN study

Objective The progress of non-anticoagulated patients with atrial fibrillation (AF) undergoing hemodialysis has not been determined. Using data from the RAKUEN (Registry of Atrial fibrillation in chronic Kidney disease Under hEmodialysis from Niigata) study, we examined the clinical characteristics and outcomes among hemodialysis patients with AF who were not receiving a vitamin K antagonist (VKA). Methods and Results Forty-three of 423 patients undergoing hemodialysis (-10%) were prescribed a VKA. The remaining 380 patients (age 64.8±12.8 years, male 70%) were enrolled in the present study. During a mean observation period of 36 months, AF (n=55) was independently associated with all-cause death (hazard ratio, 1.82; 95% confidence interval, 1.12-2.94; p=0.014), but was not associated with ischemic stroke (hazard ratio, 1.91; 95% confidence interval, 0.74-4.92; p=0.177) and major bleeding (hazard ratio, 1.80; 95% confidence interval, 0.80-4.08; p=0.150). The crude incidence rates of all-cause death and ischemic stroke in the AF patients were 15.75 (2.5-fold higher compared to the non-AF patients) and 3.63 (1.7-fold higher compared to the non-AF patients) per 100 person-years, respectively. Conclusion A great impact on death, but not ischemic stroke, was observed in non-anticoagulated hemodialysis patients with AF in comparison to those without AF from the analysis of the RAKUEN study.

Association between influenza vaccination and the reduced risk of acute kidney injury among older people: A nested case-control study

OBJECTIVE

The objective of this study is to determine whether vaccination against influenza is associated with a reduced risk of acute kidney injury (AKI) in a nationwide cohort of adults aged ≥65 years.

METHODS

We investigated a total of 13,270 patients aged ≥65 years who were hospitalized for AKI between 2000 and 2013 from Taiwan's National Health Insurance Research Database. Each AKI case was matched with one control subject according to duration of follow-up, age, sex, monthly income, urbanization level, and baseline comorbidities. Odds ratios (ORs) for AKI associated with exposure to the influenza vaccine in the previous year were calculated in a nested case-control analysis.

RESULTS

Influenza vaccination in the previous year was associated with a lower risk of AKI (adjusted OR 0.67, 95% confidence interval [CI] 0.63-0.72). Compared with a reference group of unvaccinated individuals with no influenza infection, vaccination with no influenza infection was associated with a lower risk of AKI (adjusted OR 0.68, 95% CI 0.64-0.73). Lack of vaccination and presence of influenza infection was associated with a higher risk of AKI (adjusted OR 1.78, 95% CI 1.57-2.01), whereas the risk of AKI was insignificant in vaccinated patients who developed influenza (adjusted OR 1.01, 95% CI 0.69-1.18).

CONCLUSIONS

The risk of AKI was 37% lower among older people who received vaccination against influenza in a real-world setting. Further work is required to clarify causality.

Contemporary approach to stroke prevention in atrial fibrillation: Risks, benefits, and new options

Atrial fibrillation is a common diagnosis affecting nearly 3 million adults in the United States. Morbidity and mortality in these patients is driven largely by the associated increased risk of thromboembolic complications, especially stroke. Atrial fibrillation is a stronger risk factor than hypertension, coronary disease, or heart failure and is associated with an approximately five-fold increased risk. Mitigating stroke risk can be challenging and requires accurate assessment of stroke risk factors and careful selection of appropriate therapy. Anticoagulation, including the more recently introduced direct oral anticoagulants, is the standard of care for most patients. In addition, emerging non-pharmacologic mechanical interventions are playing an expanding role in reducing stroke risk in select patients. In this review we highlight the current approach to stroke risk stratification in atrial fibrillation and discuss in detail the mechanism, risks, and benefits of current and evolving therapies.

Non-Vitamin K-Dependent Oral Anticoagulants for Nonvalvular Atrial Fibrillation in Patients With CKD: Pragmatic Considerations for the Clinician

Management of atrial fibrillation (AF) in patients with advanced chronic kidney disease (CKD) poses a complex conundrum because of higher risks for both thromboembolic and bleeding complications compared to the general population. This makes it particularly important for clinicians to carefully weigh the risks versus benefits of anticoagulation therapy to determine the individualized net clinical benefit for every patient. During the past few years, 4 non-vitamin K-dependent oral anticoagulant (NOAC) agents have supplemented warfarin in the therapeutic armamentarium for the prevention of systemic thromboembolism in nonvalvular AF. However, the use of NOACs in CKD specifically mandates a nuanced understanding due to their varying dependence on renal clearance, with resultant safety implications related to either underdosing (thromboembolism) or excessive drug exposure (bleeding). This pragmatic review highlights unique considerations pertaining to accurate estimation and temporal monitoring of kidney function in the context of NOAC use with specific clinical deliberations and variables when determining whether an NOAC is appropriate for a patient with CKD. The dependence of NOACs on renal clearance and several troubling safety signals in the published literature suggest that it is vital for nephrologists to be active members of a multidisciplinary team caring for these high-risk patients with CKD and AF.

Use of oral anticoagulants in patients with atrial fibrillation and renal dysfunction

Atrial fibrillation (AF) and chronic kidney disease (CKD) are increasingly prevalent in the general population and share common risk factors such as older age, hypertension and diabetes mellitus. The presence of CKD increases the risk of incident AF, and, likewise, AF increases the risk of CKD development and/or progression. Both conditions are associated with substantial thromboembolic risk, but patients with advanced CKD also exhibit a paradoxical increase in bleeding risk. In the landmark randomized clinical trials that compared non-vitamin K antagonist oral anticoagulants (NOACs) with warfarin for thromboprophylaxis in patients with AF, the efficacy and safety of NOACs in patients with mild-to-moderate CKD were similar to those in patients without CKD. Dose adjustment of NOACs as per the prescribing label is required in this population. Owing to limited trial data, evidence-based recommendations for the management of patients with AF and severe CKD or end-stage renal disease on dialysis are lacking. Observational cohort studies have reported conflicting results, and the management of these particularly vulnerable patients remains challenging and requires careful assessment of stroke and bleeding risk and, where appropriate, use of warfarin with good-quality anticoagulation control.

Is anticoagulating haemodialysis patients with non-valvular atrial fibrillation too risky?

There is an increasing understanding of the risks from atrial fibrillation (AF) in the current era. In patients with end-stage renal disease (ESRD) on dialysis, the prevalence of AF is significantly higher compared to the general population and those with earlier stages of CKD. Although anticoagulation of these patients may seem appropriate, there is a lack of conclusive evidence that it provides the same protection from thromboembolic complications as it does in patients not on dialysis. In addition, the increased risk of bleeding in patients requiring dialysis makes the use of anticoagulants less favourable. This article aims to discuss the problem of AF in dialysis patients, summarise the current evidence around the use of oral anticoagulants for AF in ESRD and provide some practical suggestions on management of AF in the haemodialysis population.

Treatment of atrial fibrillation with warfarin among older adults with end stage renal disease

BACKGROUND

There is increasing evidence questioning the use of warfarin for atrial fibrillation (AF) among older adults with end stage renal disease (ESRD). We assessed the patterns and determinants of warfarin utilization among these patients in the US.

METHODS

We assembled a cohort of older adults (age ≥65) undergoing dialysis with incident AF from July 2007 to November 2011 from the US Renal Data System (USRDS). We used descriptive statistics to characterize warfarin utilization within 30 days of AF discharge, and logistic regression to quantify patient characteristics associated with warfarin initiation.

RESULTS

Among 5730 older adults undergoing dialysis with incident AF, 15.5% initiated warfarin. Among 2906 patients with high risk of bleeding, 12.7% initiated warfarin; whereas 14.9% initiated warfarin among 4824 patients with high risk of stroke. After adjustment for patient characteristics, warfarin initiation was lower among patients who were older [odds ratio (OR) = 0.74 per 10-year increase, 95% confidence interval (CI) 0.66-0.83] and those with a history of diabetes (OR = 0.75, 95% CI 0.63-0.90), myocardial infarction (OR = 0.64, 95% CI 0.50-0.80), or bleeding (OR = 0.63, 95% CI 0.50-0.80). There was no association between sex, race, or dialysis modality and warfarin initiation. Among patients who initiated warfarin, 46.8% discontinued warfarin use after a median treatment length of 8.6 months.

CONCLUSION

Despite the unclear benefit and increased bleeding risk of warfarin treatment in patients with ESRD, 1 in 8 older adults undergoing dialysis with incident AF in the US who had high risk of bleeding used warfarin. Changes to warfarin therapy due to discontinuation were common after initiation.

Predicting in a predicament: Stroke and hemorrhage risk prediction in dialysis patients with atrial fibrillation

Whether to anticoagulate dialysis patients with atrial fibrillation is a common clinical dilemma with limited high-quality data to inform decision-making. While the efficacy and safety of anticoagulation for stroke prevention in dialysis patients with atrial fibrillation has long been debated and remains unclear, the more upstream issue of stroke risk assessment from atrial fibrillation has received relatively little attention. In the general population, a handful of risk scores to help predict stroke and hemorrhage risk in the setting of atrial fibrillation are widely validated and applied in clinical practice. But are they applicable to the dialysis population? The most commonly used stroke risk scores, CHADS2 and CHA2DS2-VASC, have limited validation in the dialysis population, and when validated, have shown poor performance (c-statistics <0.70). Stroke risk scores derived in the general atrial fibrillation population may perform poorly in dialysis patients for a number of reasons. Dialysis patients have unique stroke risk factors, such as chronic inflammation and vascular calcification, and a much higher competing risk of death, none of which are accounted for in current risk scores. Further complicating the dilemma of anticoagulation is hemorrhage risk, which is known to be exceedingly high in dialysis patients. Currently available hemorrhage risk scores, such as HAS-BLED, have not been validated in dialysis patients and will likely underestimate hemorrhage risk. Moving forward, risk tools specific to the dialysis population are needed to accurately assess and balance stroke and hemorrhage risks in dialysis patients with atrial fibrillation.