Warfarin Use in Hemodialysis Patients With Atrial Fibrillation: A Systematic Review of Stroke and Bleeding Outcomes

Potential Association of Holidays on Internationalized Normalized Ratio in Warfarin-Users at a Multidisciplinary Clinic

Background

Warfarin is approved by the United States Food and Drug Administration for numerous clinical indications. The effectiveness of warfarin is highly dependent on the time-in-therapeutic range based on the international normalized ratio (INR) goal, which may be altered by changes in diet, alcohol intake, concomitant drugs, and travel, all of which are prevalent during the holidays. At this time, there are no published studies assessing the impact of holidays on INR in warfarin-users.

Methods

A retrospective chart review was conducted on all adult patients taking warfarin and managed at a multidisciplinary clinic. Patients were included if they were taking warfarin at home regardless of indication for anticoagulation. The INR pre- and post-holiday was assessed.

Results

Of a total of 92 patients, the mean age was 71.5 ± 14.3 years, and most patients were on warfarin with an INR goal of 2 - 3 (89%). There were significant differences in INR before and after Independence Day (2.55 vs. 2.81, P = 0.043) and Columbus Day (2.39 vs. 2.82, P < 0.001). The remaining holidays showed no significant differences in INR before and after each respective holiday.

Conclusions

There may be factors related to Independence and Columbus Day that are increasing the level of anticoagulation in warfarin-users. Although the mean post-holiday INR values, in essence, maintained within the typical target of 2 - 3, our study underscores the specialized care that is warranted in higher risk patients to prevent a continued increase in INR and subsequent toxicities. We hope our results would be hypothesis-generating and aid in the development of larger, prospective evaluations to validate the findings of our present study.

The Next Evolution of HemoDialysis eXpanded: From a Delphi Questionnaire-Based Approach to the Real Life of Italian Dialysis Units

INTRODUCTION

Impact assessment of new technologies in chronic hemodialysis (HD) is challenging due to HD patient frailty, the complexity of HD clinical trials and practice variability among countries. Among the most recent HD innovations, medium cut-off (MCO) dialyzers present an optimized membrane geometry that provides enhanced clearances for middle and large molecular weight uremic toxins (UT). These toxins are poorly cleared by available HD techniques and largely contribute to patient morbidity and mortality. The aim of this paper is to assess the available clinical evidence about MCO membranes and to identify the next steps needed to generate conclusive data on their use in HD.

METHODS

With this purpose, we first reviewed and compared the current HD technologies aimed to improve the clearance of middle and large UT; subsequently, we used a Delphi questionnaire to identify and discuss the consensus about MCO efficacy within a large sample of the Italian Nephrology community.

RESULTS AND CONCLUSIONS

Our investigation gathered a significant degree of consensus on the beneficial role of MCO membrane and expanded HD. Finally, we used our results to propose future trial designs and clinical investigations aimed to improve evidence quality about the use of these membranes in the present clinical scenario of dialysis units.

Warfarin Use, Stroke, and Bleeding Risk among Pre-Existing Atrial Fibrillation US Veterans Transitioning to Dialysis

INTRODUCTION

Anticoagulation is commonly used for stroke prevention among patients with atrial fibrillation (AF); however, end-stage renal disease (ESRD) patients on hemodialysis are at higher risk of bleeding and stroke, even without anticoagulation. It is unclear if patients should be continued on anticoagulation at the time of transition to ESRD. In this study, we validated risk scores for stroke and bleeding in this population and assessed risk of stroke and bleeding among warfarin users compared to nonusers.

METHODS

We utilized a cohort of 28,620 pre-dialysis US veterans transitioning to hemodialysis between October 2007 and March 2015. Incident rates for the risks of stroke and bleeding were ascertained based upon CHA2DS2-VASc or HAS-BLED scores, respectively. A propensity score-based competing risk analysis was used to assess risk of stroke and bleeding.

FINDINGS

The mean age of our cohort was 77 ± 9 years, and the median CHA2DS2-VASc and HAS-BLED scores were 7 (5, 8) and 3 (3, 4), respectively. Increasing CHA2DS2-VASc and HAS-BLED scores were predictive of increasing stroke and bleeding rates, respectively. However, warfarin use did not appear to affect the risk of stroke and bleeding (p-interaction = 0.84 for stroke and 0.24 for bleeding). Warfarin use was associated with a higher risk of stroke (adjusted SHR 1.44, 95% CI: 1.23-1.69) and a higher risk of bleeding (adjusted SHR 1.38, 95% CI: 1.25-1.52) when accounting for the competing risk of death.

DISCUSSION

There was no difference in incidence rates of stroke or bleeding among warfarin users versus nonusers. Warfarin was associated with a higher risk of stroke and bleeding after considering mortality risk.

Warfarin is associated with the risk of vascular calcification in abdominal aorta in hemodialysis patients: a multicenter case-control study

BACKGROUND

Vascular calcifications (VCs), recognized risk factor for increased mortality, are highly prevalent in hemodialysis (HD) patients. We aimed to investigate the relation between VC and warfarin use with plain radiography.

METHODS

VCs were assessed using Adragao (radial and digital) and Kauppila (aortic) scores in 76 HD patients from six centers. Out of a total 711 HD patients, there were 32 (4.5%) who had been treated with warfarin for at least 1 year, and we included 44 control patients.

RESULTS

Of the patients, 47% were females, the mean age was 66 ± 9 years, 23% were diabetics, the mean dialysis vintage was 68 ± 38 months. In warfarin group, median Kauppila score was higher than in control group [11 vs 6.5, (25%-75% percentile, 5 vs. 15), p = 0.032] and the percentage of the patients with a Kauppila score of >6 was higher, as well (76.6% vs. 50%; p = 0.029). Median Adragao score was not significantly different between the two groups [7 vs. 6, (%25,%75 percentile 6 vs. 8), p = 0.17]. Logistic regression analysis revealed that warfarin treatment was independently associated with Kauppila scores of >6 (OR 3.60, 95% CI 1.18-10.9, p = 0.024).

DISCUSSION

In this study, we found that warfarin is associated to vascular calcifications, especially in aorta of HD patients.

Time in Therapeutic Range Using a Nomogram for Dose Adjustment of Warfarin in Patients on Hemodialysis With Atrial Fibrillation

Background:

Patients treated with hemodialysis and prescribed warfarin typically have lower time in therapeutic range (TTR) compared to the general population. This may result in less benefit or increased risk of over anticoagulation in these patients.

Objective:

To assess effectiveness of use of an electronic nomogram for the management of warfarin therapy in patients treated with hemodialysis.

Design:

Retrospective chart review.

Setting:

Adult patients treated with hemodialysis.

Patients:

Patients on hemodialysis receiving warfarin for the management of atrial fibrillation (AF) with therapy managed by nursing led electronic nomogram.

Measurements:

Time in therapeutic range (as fraction and Rosendaal).

Methods:

Retrospective chart review over 1 year of international normalized ratio (INR) results was completed, and TTR was calculated. Comparison of patients with TTR greater than 60% to those less than 60% was completed using chi-square analysis.

Results:

Of 43 patients with warfarin therapy managed by the nomogram, the mean TTR was 55.2% (calculated by fraction method) or 61.2% (calculated by Rosendaal method). More than half of the patients (63.5%) had moderate to good control, defined as TTR greater than 60%. Female sex, liver disease, or history of substance use and more medication holds were associated with lower TTR.

Limitations:

Small sample size and retrospective nature of review.

Conclusions:

The results of this review supports the use of an electronic, nursing-led nomogram for the maintenance management of warfarin therapy in stable patients treated with hemodialysis, as use results in TTR greater than 60% for more than half of patients.

A retrospective study of antithrombotic therapy use in an outpatient haemodialysis unit

WHAT IS KNOWN AND OBJECTIVE

Patients on haemodialysis (HD) are at increased risk of both bleeding and thrombotic events, due to comorbidities and nature of dialysis treatment. However, there is a lack of research on evidence-based treatment strategies and prescribing patterns for antithrombotic therapies (ATT) in this population. To characterize ATT use and its main indications in an outpatient HD unit.

METHODS

A single-centre retrospective chart review was conducted in a Toronto outpatient HD unit (n = 329). Medical histories, number of ATTs and corresponding indications were collected from adult patients prescribed at least one ATT from 1 October 2019 to 31 December 2019, inclusive.

RESULTS AND DISCUSSION

Of 329 patients in the unit, a total of 135 (41%) patients were on at least one ATT. Of these 135 patients, 80% were on monotherapy (55% antiplatelet, 25.1% anticoagulant), 12.6% were on dual antiplatelet therapy (DAPT), and 7.4% were on a antiplatelet and anticoagulant combination. Primary indications for ATT in our cohort were coronary artery disease (CAD; 55%), atrial fibrillation (18.5%) and venous thromboembolism (VTE; 17%). Described ATT use was in-line with current clinical guidelines. Monotherapy was primarily used in our HD cohort, whereas few patients were on dual therapy. Low-dose aspirin was the most common antiplatelet prescribed for secondary prevention of cardiovascular events. Warfarin monotherapy was primarily indicated for VTE, and DAPT aspirin/clopidogrel was the most commonly prescribed for CAD.

WHAT IS NEW AND CONCLUSION

Our characterization of ATT use in this HD cohort demonstrates that ATT is often prescribed for a number of different CVD reasons. Overlapping and confounding indications for prescribing ATTs, lack of randomized controlled trials and unclear clinical guidelines mean that individualized risk-benefit assessments for ATT use are still needed to provide care for these high-risk patients. More research to address the safety and efficacy of ATTs is warranted to develop more robust evidence-based treatment guidelines for the HD population.

Clinical Outcomes of Warfarin Initiation in Advanced Chronic Kidney Disease Patients With Incident Atrial Fibrillation

OBJECTIVES

The aim of this study was to examine the efficacy and safety of warfarin initiation following the diagnosis of atrial fibrillation (AF) in patients with late-stage chronic kidney disease (CKD) who transitioned to dialysis.

BACKGROUND

The clinical benefit of warfarin therapy for thromboprophylaxis after incident AF diagnosis in patients with late-stage CKD who are transitioning to dialysis is unknown.

METHODS

In this retrospective cohort analysis, the study population was a national cohort of 22,771 U.S. veterans with incident end-stage renal disease who developed incident AF before initiating renal replacement therapy. This study examined the association of warfarin therapy following the diagnosis of incident AF with ischemic cerebrovascular accidents (CVAs) (ischemic stroke or transient ischemic attack), ischemic CVA-related hospitalization, major bleeding events (gastrointestinal or intracranial bleeding), bleeding event-related hospitalizations, and post-dialysis, all-cause mortality in multivariable adjusted Cox regression analyses that adjusted for demographic characteristics and comorbidities.

RESULTS

The mean ± SD age of the cohort was 73.5 ± 8.8 years, 13% were African American, and the mean CHA₂DS₂-VASc score was 5.7 ± 2.1. Of the overall cohort, 6,682 (29.3%) patients were started on warfarin during the follow-up period. The hazard ratios (95% confidence intervals) for ischemic CVA, bleeding events, and death for those started on warfarin were 1.23 (1.16 to 1.30), 1.36 (1.29 to 1.44), and 0.94 (0.90 to 0.97), respectively, compared with those who received no anticoagulation. Warfarin exposure was associated with higher risk for ischemic CVA and bleeding event-related hospitalizations.

CONCLUSIONS

In patients with late-stage CKD who transitioned to dialysis, warfarin use was associated with higher risk of ischemic and bleeding events but a lower risk of mortality. Future studies such as those comparing warfarin with newer oral anticoagulant agents are needed to granularly define the net clinical benefit of anticoagulation therapy in patients with advanced CKD with incident AF.

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.

The influence of atrial fibrillation on the mortality of incident ESRD patients undergoing maintenance hemodialysis

Background

Atrial fibrillation (AF) is highly prevalent, occurring in 1%–2% of the adult population, increasing the risk of stroke, and resulting in considerable healthcare costs. While stroke is a major complication of AF, end-stage renal disease (ESRD) patients also have a high risk of stroke, suggesting that AF is a possible risk factor for mortality of ESRD patients. However, whether the existence of AF at the initiation of hemodialysis predicts higher mortality risk of incident ESRD patients remains to be defined.

Methods

This retrospective cohort study was performed at Wanfang Hospital from January 2004 to May 2018. The end points were mortality of patients or the end of the study. Incident ESRD patients who were on maintenance hemodialysis for more than 3 months were eligible for inclusion. Cox proportional regression and Kaplan–Meier survival curves were used to determine the association between predictors and mortality. The association between AF and echocardiographic parameters, causes of death were also investigated.

Results

Of the 393 incident ESRD patients at initiation of hemodialysis, 57 (14.5%) had AF and the median age was 71 years. Patients with AF were significantly older; showed significantly higher C-reactive protein levels, more heart failure, chronic obstructive pulmonary disease and mortality. Multivariate Cox regression showed that AF had a hazard ratio of 4.1 (95% confidence interval: 2.4–7.0) for mortality. Age-specific analysis showed that AF was significantly associated with mortality in all age groups. Echocardiography measurements including ejection fraction and left ventricular hypertrophy (LVH) were similar in AF and non-AF patients. Cause-specific analysis showed that AF significantly associated with overall cardiovascular death and death due to acute myocardial infarction/coronary artery disease and sepsis.

Conclusions

AF at the initiation of hemodialysis predicts higher mortality risk of incident ESRD patients regardless of age. The systolic function and degree of LVH were similar in AF and non-AF patients. The association between AF and sepsis-related death suggested the role of systemic inflammation on the pathogenesis of AF.