Impact of renal function on ischemic stroke and major bleeding rates in nonvalvular atrial fibrillation patients treated with warfarin or rivaroxaban: a retrospective cohort study using real-world evidence

Kidney function and the comparative effectiveness and safety of direct oral anticoagulants vs. warfarin in adults with atrial fibrillation: a multicenter observational study

AIMS

The aim of this study was to determine the comparative effectiveness and safety of direct oral anticoagulants (DOACs) and warfarin in adults with atrial fibrillation (AF) by level of kidney function.

METHODS AND RESULTS

We pooled findings from five retrospective cohorts (2011-18) across Australia and Canada of adults with; a new dispensation for a DOAC or warfarin, an AF diagnosis, and a measure of baseline estimated glomerular filtration rate (eGFR). The outcomes of interest, within 1 year from the cohort entry date, were: (1) the composite of all-cause death, first hospitalization for ischaemic stroke, or transient ischaemic attack (effectiveness), and (2) first hospitalization for major bleeding defined as an intracranial, upper or lower gastrointestinal, or other bleeding (safety). Cox models were used to examine the association of a DOAC vs. warfarin with outcomes, after 1:1 matching via a propensity score. Kidney function was categorized as eGFR ≥60, 45-59, 30-44, and <30 mL/min/1.73 m2. A total of 74 542 patients were included in the matched analysis. DOAC initiation was associated with greater or similar effectiveness compared with warfarin initiation across all eGFR categories [pooled HRs (95% CIs) for eGFR categories: 0.74(0.69-0.79), 0.76(0.54-1.07), 0.68(0.61-0.75) and 0.86(0.76-0.98)], respectively. DOAC initiation was associated with lower or similar risk of major bleeding than warfarin initiation [pooled HRs (95% CIs): 0.75(0.65-0.86), 0.81(0.65-1.01), 0.82(0.66-1.02), and 0.71(0.52-0.99), respectively). Associations between DOAC initiation, compared with warfarin initiation, and study outcomes were not modified by eGFR category.

CONCLUSION

DOAC use, compared with warfarin use, was associated with a lower or similar risk of all-cause death, ischaemic stroke, and transient ischaemic attack and also a lower or similar risk of major bleeding across all levels of kidney function.

Safety and Effectiveness of Rivaroxaban Versus Warfarin Across GFR Levels in Atrial Fibrillation: A Population-Based Study in Australia and Canada

Rationale & Objective

The benefit-risk profile of rivaroxaban versus warfarin for atrial fibrillation (AF) in patients with chronic kidney disease is uncertain. We compared rivaroxaban with warfarin across the range of kidney function in adults with AF.

Study Design

Multicenter retrospective cohort.

Setting & Participants

Adults with AF and a measure of estimated glomerular filtration rate (eGFR); using administrative data from 5 jurisdictions across Australia and Canada (2011-2018). Kidney function was categorized as eGFR ≥60, 45-59, 30-44, and <30 mL/min/1.73 m². Patients receiving dialysis and kidney transplant recipients were excluded.

Exposures

New dispensation of either rivaroxaban or warfarin.

Outcomes

Composite (1) effectiveness outcome (all-cause death, ischemic stroke, or transient ischemic attack) and (2) major bleeding events (intracranial, gastrointestinal, or other) at 1 year.

Analytical Approach

Cox proportional hazards models accounting for propensity score matching were performed independently in each jurisdiction and then pooled using random-effects meta-analysis.

Results

55,568 patients (27,784 rivaroxaban-warfarin user matched pairs; mean age 74 years, 46% female, 33.5% with eGFR <60 mL/min/1.73 m²) experienced a total of 4,733 (8.5%) effectiveness and 1,144 (2.0%) bleeding events. Compared to warfarin, rivaroxaban was associated with greater or similar effectiveness across a broad range of kidney function (pooled HRs of 0.72 [95% CI, 0.66-0.78], 0.78 [95% CI, 0.58-1.06], 0.70 [95% CI, 0.57-0.87], and 0.78 [95% CI, 0.62-0.99]) for eGFR ≥60, 45-59, 30-44, and <30 mL/min/1.73 m², respectively). Rivaroxaban was also associated with similar risk of major bleeding across all eGFR categories (pooled HRs of 0.75 [95% CI, 0.56-1.00], 1.01 [95% CI, 0.79-1.30], 0.87 [95% CI, 0.66-1.15], and 0.63 [95% CI, 0.37-1.09], respectively).

Limitations

Unmeasured treatment selection bias and residual confounding.

Conclusions

In adults with AF, rivaroxaban compared with warfarin was associated with lower or similar risk of all-cause death, ischemic stroke and transient ischemic attack and similar risk of bleeding across a broad range of kidney function.

Plain-Language Summary

This real-world study involved a large cohort of 55,568 adults with atrial fibrillation from 5 jurisdictions across Australia and Canada. It showed that the favorable safety (bleeding) and effectiveness (stroke or death) profile of rivaroxaban compared with warfarin was consistent across different levels of kidney function. This study adds important safety data on the use of rivaroxaban in patients with reduced kidney function, including those with estimated glomerular filtration rate <30 mL/min/1.73 m² in whom the risks and benefits of rivaroxaban use is most uncertain. Overall, the study supports the use of rivaroxaban as a safe and effective alternative to warfarin for atrial fibrillation across differing levels of kidney function.

The non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients with high-normal renal function - A systematic review

Non-vitamin K antagonist oral anticoagulants (NOACs) have revolutionized treatment of atrial fibrillation. Although benefits of anticoagulation therapy are clear, a minority of patients still experience treatment inefficacy or harm. All NOACs have varying degree of renal clearance, which may significantly affect plasma concentrations. Pivotal clinical trials have explored the effects of dose reduction in patients with chronic renal disease. None of these have, however, specifically addressed the need for a dose up-titration in patients with renal hyperfiltration, in whom lower drug plasma levels are to be expected. A signal for lower efficacy in this patient subset has recently emerged. We systematically assessed the peer-reviewed scientific literature on this topic, including a recently reported randomized pharmacokinetic study in renal hyperfiltrators also reporting on ischemic and bleeding events. We conclude that the reduction in NOAC plasma levels in AF patients with renal hyperfiltration is limited in extent and, does not translate into a clinically meaningful reduction in efficacy for NOACs as compared to vitamin K antagonists (VKAs) in such patients. At the current state of knowledge, NOAC current dosing should not be altered in patients with high-normal renal function.

Renal Function Protection as an Important Component of a Comprehensive Approach to the Management of Patients with Atrial Fibrillation

The increase in the life expectancy of the population  is accompanied by an increase in the prevalence of diseases for which old and senile age are risk factors. Atrial fibrillation (AF) and chronic kidney disease (CKD) are two diseases that can coexist in a patient. The risk of ac thromboembolic and hemorrhagic events in this case increases due to the mutual aggravating influence of these diseases. In addition,  these patients have a high incidence of coronary  events, and cardiovascular complications are the main cause of death in patients with AF and CKD. Consequently, such patients require an integrated  approach  to treatment,  and their management is a complex  clinical task. The direct oral anticoagulant rivaroxaban has been most studied in a population  of comorbid  AF and CKD  patients and has proven a high efficacy and safety profile in these patients in randomized controlled trials. In addition,  rivaroxaban has shown  a significant  reduction in the risk of myocardial  infarction  in various patients,  as well as the possibility of preserving renal function to a greater extent compared  with warfarin therapy, and a possible positive effect on reducing  the risk of cognitive impairment.  A single dosing  regimen  can improve adherence  to treatment,  which is one of the key conditions  for achieving  the above effects. Thus, these factors make it possible to achieve comprehensive protection of comorbid  patients with AF and CKD.

Non-valvular Atrial Fibrillation in CKD: Role of Vitamin K Antagonists and Direct Oral Anticoagulants. A Narrative Review

Atrial fibrillation (AF) is the most common arrhythmia in chronic kidney disease (CKD), with a close bidirectional relationship between the two entities. The presence of CKD in AF increases the risk of thromboembolic events, mortality and bleeding. Vitamin K antagonists (VKA) have been the mainstay of treatment for the prevention of thromboembolic events in AF until recently, with confirmed benefits in AF patients with stage 3 CKD. However, the risk-benefit profile of VKA in patients with AF and stages 4-5 CKD is controversial due to the lack of evidence from randomized controlled trials. Treatment with VKA in CKD patients has been associated with conditions such as poorer anticoagulation quality, increased risk of bleeding, faster progression of vascular/valvular calcification and higher risk of calciphylaxis. Direct oral anticoagulants (DOACs) have shown equal or greater efficacy in stroke/systemic embolism prevention, and a better safety profile than VKA in post-hoc analysis of the pivotal randomized controlled trials in patients with non-valvular AF and stage 3 CKD, yet evidence of its risk-benefit profile in more advanced stages of CKD is scarce. Observational studies associate DOACs with a good safety/effectiveness profile compared to VKA in non-dialysis CKD patients. Further, DOACs have been associated with a lower risk of acute kidney injury and CKD development/progression than VKA. This narrative review summarizes the evidence of the efficacy and safety of warfarin and DOACs in patients with AF at different CKD stages, as well as their effects on renal function, vascular/valvular calcification and bone health.

Real-world comparison of direct-acting oral anticoagulants and vitamin K antagonists in chronic kidney disease: a systematic review and meta-analysis

Background: No clear clinical guidelines exist on anticoagulant use for chronic kidney disease (CKD) patients. We compared the efficacy and safety of direct-acting oral anticoagulants (DOACs) vs. vitamin K antagonists (VKA) in patients with CKD by pooling data from real-world observational studies.Research design & methods: This systematic review searched PubMed, Embase, and CENTRAL databases and pooled multivariable-adjusted hazard ratios (HR) of outcomes.Results: Fifteen studies were included. Our results indicated a small but significant reduction in the risk of all-cause mortality (p = 0.01), stroke or systemic embolism (p = 0.03), and major bleeding (p = 0.01) with DOAC as compared to VKA. In subgroup analysis based on the severity of CKD, no difference in the risk of stroke or systemic embolism was noted in any subgroups. The risk of mortality was reduced only in patients with moderate-severe or severe CKD and the risk of major bleeding was reduced only in patients with moderate-severe or moderate CKD.Conclusion: DOACs are associated with only a modest reduction in stroke or systemic embolism, major bleeding, and mortality when compared to VKA in CKD patients. Reduction in mortality and major bleeding with DOAC may only be seen in moderate-to-severe CKD patients.

Oral Anticoagulant Agents in Patients With Atrial Fibrillation and CKD: A Systematic Review and Pairwise Network Meta-analysis

OBJECTIVE

To evaluate the relative efficacy and safety of different oral anticoagulant agents (OACs) for patients with atrial fibrillation (AF) and chronic kidney disease (CKD).

STUDY DESIGN

Systematic review and pairwise and Bayesian network meta-analysis.

SETTING & STUDY POPULATIONS

Adult patients with AF and CKD stages 3-5D who received OACs.

SELECTION CRITERIA FOR STUDIES

Randomized controlled trials (RCTs) and observational studies that reported the efficacy and safety outcomes of subgroups with a glomerular filtration rate (GFR)<60mL/min.

DATA EXTRACTION

Two reviewers independently abstracted data, assessed study quality, and rated the strength of evidence (SOE).

ANALYTICAL APPROACH

Random-effects models using restricted maximum-likelihood methods were fit for the pairwise meta-analyses as well as a network meta-analysis within a Bayesian framework.

RESULTS

Pairwise meta-analysis including 8 RCTs and 46 observational studies showed that direct OACs (DOACs) were superior to warfarin in preventing thromboembolic events (hazard ratio [HR], 0.86 [95% CI, 0.78-0.95]), without heterogeneity (I²=10.5%), and in reducing the risk of bleeding events (HR, 0.81 [95% CI, 0.66-0.99]), with substantial heterogeneity (I²=69.8%), in patients with AF and a GFR of 15-60mL/min. Bayesian network meta-analysis including 8 RCTs showed that dose-adjusted apixaban and a 15-mg dose of edoxaban were superior to the other OAC regimens in reducing bleeding events. Dose-adjusted apixaban was more effective than edoxaban in preventing thromboembolic events for patients with AF and GFR in the range of 25-50 or 30-50mL/min. In dialysis recipients with AF, the use of OACs increased the risk of bleeding events by 28% (HR, 1.28 [95% CI, 1.03-1.60]) without significant beneficial effects versus not using anticoagulants.

LIMITATIONS

Low SOE and heterogeneity in most comparisons.

CONCLUSIONS

This study suggests that DOACs are superior to warfarin for the prevention of thromboembolic events and reduction in bleeding risk in patients with AF and mild to moderate kidney disease. However, the low SOE limits the conclusions that can be drawn about the preferred DOAC. Notably, the use of OACs may increase bleeding risk without significant benefits in dialysis recipients with AF.

REGISTRATION

Registered at PROSPERO with identification number CRD42018090896.

Thromboembolic and bleeding events with rivaroxaban in clinical practice in Spain: impact of inappropriate doses (the EMIR study)

Aim: To analyze the frequency and variables related to inappropriate rivaroxaban dosage in clinical practice and its impact on outcomes after 2 years. Materials & methods: Postauthorization, observational, multicenter study, in which atrial fibrillation patients, treated with rivaroxaban ≥6 months were included. Results: A total of 1421 patients (74.2 ± 9.7 years, CHA₂DS₂-VASc 3.5 ± 1.6) were included. Overall, 22.9% received rivaroxaban 15 mg. The proper dose of rivaroxaban was taken by 83.3% (9.7% underdosed, 7.0% overdosed). Older age and renal insufficiency were associated with inadequate rivaroxaban dosage. There was a trend toward higher all-cause mortality among underdosed patients (adjusted hazard ratio 1.39; 95% CI 0.75-2.58), and more bleedings in overdosed patients (2.29 vs 0.80 events/100 patient-years; p = 0.14). Conclusion: In clinical practice, rivaroxaban is properly dosed in most patients.

The Pharmacology, Efficacy, and Safety of Rivaroxaban in Renally Impaired Patient Populations

Rivaroxaban is a factor Xa inhibitor oral anticoagulant first approved for use in the United States in 2011. Under the drug class commonly termed direct oral anticoagulants, rivaroxaban is approved for the most indications within its class, 7 indications, which are: (1) reduction of risk of stroke and systemic embolism (SE) in nonvalvular atrial fibrillation, (2) treatment of deep vein thrombosis (DVT), (3) treatment of pulmonary embolism (PE), (4) reduction in the risk of recurrence of DVT and/or PE, (5) prophylaxis of DVT following hip or knee replacement surgery, (6) prophylaxis of venous thromboembolism in acutely ill medical patients at risk for thromboembolic complications not at high risk of bleeding, and (7) reduction of risk of major cardiovascular events in patients with chronic coronary artery disease or peripheral artery disease. Considering the relationship between cardiovascular disease, renal impairment, and the use of oral anticoagulants, the following targeted review was created. This review reports the results of the primary pharmacology, pharmacokinetic modeling, clinical safety and efficacy, and real-world postmarketing effectiveness and safety of rivaroxaban in patients with various degrees of renal impairment. Based on these data, rivaroxaban is a viable option for when anticoagulation is needed in patients who have both cardiovascular disease and renal impairment. However, as with any therapy, the benefits and risks of intervention should be carefully assessed and balanced. Patients treated with rivaroxaban for several of its approved indications should have their kidney function assessed prior to and during continued therapy to ensure consistency with the drug label.

Direct Oral Anticoagulants in the Treatment of Venous Thromboembolism: Use in Patients with Advanced Renal Impairment, Obesity, or Other Weight-Related Special Populations

There are currently more than 7 million patients taking a direct oral anticoagulant (DOAC), with more new prescriptions per year than warfarin. Despite impressive efficacy and safety data for the treatment of venous thromboembolism, patients with obesity or advanced renal impairment represented a small portion of the patients enrolled in the phase 3 clinical trials. Therefore, to evaluate the potential use of DOACs in these special populations, clinicians need to have an understanding of the pharmacokinetics and pharmacodynamics of these agents in these settings. Since data from randomized controlled trials are limited, data from observational trials are helpful in gaining comfort with the use of DOACs in these special populations. Selecting the appropriate dose for each agent is imperative in achieving optimal patient outcomes. We provide an extensive review of the pharmacokinetics, pharmacodynamics, phase 3 clinical trials, and observational studies on the use of DOACs in patients with advanced renal impairment, obesity, or other weight-related special populations to provide clinicians with a comprehensive understanding of the data for optimal drug and dose selection.

Use of Non-vitamin K Antagonist Oral Anticoagulants for Stroke Prevention across the Stroke Spectrum: Progress and Prospects

Multiple randomized controlled trials and many real-world evidence studies have consistently shown that non-vitamin K antagonist oral anticoagulants (NOACs) are preferable to vitamin K antagonists for thromboembolic stroke prevention in the majority of patients with atrial fibrillation (AF). However, their role in the management of patients with AF and comorbidities, as well as in other patient populations with a high risk of stroke, such as patients with prior embolic stroke of undetermined source (ESUS) and those with atherosclerosis, is less clear. There is now increasing evidence suggesting that NOACs have a beneficial effect in the prevention of stroke in patients with AF and comorbidities, such as renal impairment and diabetes. In addition, while studies investigating the efficacy and safety of NOACs for the prevention of secondary stroke in patients with a history of ESUS demonstrated neutral results, subanalyses suggested potential benefits in certain subgroups of patients with ESUS. One NOAC, rivaroxaban, has also recently been found to be effective in reducing the risk of stroke in patients with chronic cardiovascular disease including coronary artery disease and peripheral artery disease, further broadening the patient groups that may benefit from NOACs. In this article, we will review recent evidence for the use of NOACs across the stroke spectrum in detail, and discuss the progress and future prospects in the different stroke areas.

Rivaroxaban versus warfarin in patients with nonvalvular atrial fibrillation and stage IV-V chronic kidney disease

BACKGROUND

There is limited evidence on the effectiveness and safety of direct-acting oral anticoagulants in patients with nonvalvular atrial fibrillation (NVAF) and advanced chronic kidney disease (CKD). This study compared the risks of ischemic stroke/systemic embolism (ISSE) and major bleeding in patients with NVAF and stage IV-V CKD treated with rivaroxaban or warfarin.

METHODS

Patients with NVAF and stage IV-V CKD who initiated rivaroxaban or warfarin treatment between November 2011 and June 2018 were selected from the Optum® Deidentified Electronic Health Record Database. Propensity score matching was used to balance rivaroxaban and warfarin patients on 112 measured baseline covariates. ISSE and major bleeding events over 2 years following treatment initiation were ascertained with validated end point definitions. Outcomes were analyzed as time-to-event data using Kaplan-Meier survival estimators and Cox regression.

RESULTS

A total of 781 eligible rivaroxaban-treated patients were propensity score-matched to 1,536 warfarin-treated patients; baseline covariates were well balanced after matching (absolute standardized differences <0.1). The average patient age was 80 years; 60.5% were female; 81.3% and 18.7% had CKD stage IV and V, respectively. Hazard ratios for rivaroxaban compared to warfarin were 0.93 (95% CI 0.46-1.90, P = .85) for the risk of ISSE and 0.91 (95% CI 0.65-1.28, P = .60) for major bleeding.

CONCLUSIONS

No statistically significant difference in the risk of ISSE or major bleeding was found between rivaroxaban- and warfarin-treated patients. Although further study is needed, rivaroxaban appears to be a reasonable alternative to warfarin for ISSE prevention in the setting of NVAF and stage IV-V CKD.

Risk of Major Gastrointestinal Bleeding With New vs Conventional Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over whether use of non-vitamin K antagonist oral anticoagulants (NOACs) associates with increased risk of major gastrointestinal bleeding (GIB) compared with conventional therapies (such as vitamin K antagonists or anti-platelet agents). We performed a systematic review and meta-analysis of data from randomized controlled trials and high-quality real-world studies.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov Website databases (through Oct 12, 2018) for randomized controlled trials and high-quality real-world studies that reported major GIB events in patients given NOACs or conventional therapy. Relative risks (RRs) for randomized controlled trials and adjusted hazard ratios (aHRs) for real-world studies were calculated separately using random-effects models.

RESULTS

We analyzed data from 43 randomized controlled trials (183,752 patients) and 41 real-world studies (1,879,428 patients). The pooled major rates of GIB for patients on NOACs (1.19%) vs conventional treatment (0.92%) did not differ significantly (RR from randomized controlled trials, 1.09; 95% CI, 0.91-1.31 and aHR from real-world studies, 1.02; 95% CI, 0.94-1.10; P_interaction=.52). Rivaroxaban, but not other NOACs, was associated with an increased risk for major GIB (RR from randomized controlled trials, 1.39; 95% CI, 1.17-1.65 and aHR from real-world studies, 1.14; 95% CI, 1.04-1.23; P_interaction = .06). Analyses of subgroups, such as patients with different indications, dosage, or follow-up time, did not significantly affect results. Meta-regression analysis failed to detect any potential confounding to impact the primacy outcome.

CONCLUSIONS

In a systematic review and meta-analysis of data from randomized controlled trials and real-world studies, we confirmed that there is no significant difference in risk of major GIB between patients receiving NOACs vs conventional treatment. Rivaroxaban users had a 39% increase in risk for major GIB.

Recent evidence for direct oral anticoagulants in chronic kidney disease

PURPOSE OF REVIEW

The direct oral anticoagulants (DOACs) have emerged as an effective and safe alternative to vitamin K antagonists (VKAs) for stroke and venous thromboembolism (VTE) prevention. However, patients with chronic kidney disease (CKD) experience an increase in the risk of both thromboembolism and bleeding, and the risk-benefit profile of DOACs, particularly in advanced CKD remains a source of ongoing debate. This review summarizes the recent evidence on the effects of DOACs in CKD across a range of clinical indications including newly emerging indications.

RECENT FINDINGS

Data on early-to-moderate stage CKD derived from pivotal randomized controlled trials in broader atrial fibrillation and VTE populations support the favorable risk-benefit ratio of DOACs compared with VKAs in patients in these groups. However, safety data from observational studies comparing DOACs with VKAs in patients with atrial fibrillation and CKD (moderate to advanced) have been conflicting. Recent trials have evaluated the efficacy of low-dose DOACs on major cardiovascular outcomes, showing promising risk-benefit ratios in high-risk populations with concurrent CKD.

SUMMARY

Current data on patients with CKD derived from trials in the broader population suggest that DOACs are an effective alternative to VKAs in patients with early-to-moderate stage CKD. However, studies on patients with advanced CKD are lacking. Further randomized controlled trials, particularly those evaluating the risk of any clinically relevant bleeding as part of a more accurate assessment of the risk-benefit profile of DOACs in people with CKD, are needed.

Impact of direct oral anticoagulant off-label doses on clinical outcomes of atrial fibrillation patients: A systematic review

AIMS

Worldwide observational studies are evidencing discordance between guidelines and real-world practice regarding direct oral anticoagulant drug (DOAC) doses. This systematic review summarizes and evaluate DOACs use in real-world practice.

METHODS

This review was performed following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines searching PubMed (MEDLINE) and Medscape databases.

RESULTS

Data from 75 studies showed that most of the patients treated with DOACs for stroke prevention in atrial fibrillation received doses in accordance to the guidelines. However, a significant number of patients received off-label doses (25-50% in most of the studies evaluated). DOAC overdosing was associated with increased all-cause mortality and worse bleeding events while underdosing was associated with increased cardiovascular hospitalization and, particularly for apixaban, with a nearly 5-fold increased risk of stroke.

CONCLUSION

Patients prescribed with off-label DOAC doses did not receive the full benefit of anticoagulation and presented an increased risk of stroke, bleeding and/or adverse effects.

Urinary dysfunction in acute brain injury: A narrative review

The frontal lobe urinary control center is an important regulator of urinary function. Neurologic injury often causes damage or temporary dysfunction of this center and other related urinary control pathways. Little has been reported about this topic in the literature although a majority of neurologic injury patients suffer from some type of urinary dysfunction. In this review, we highlight what is known about urinary dysfunction based on injury type (traumatic brain injury, hemorrhagic stroke, ischemic stroke, subarachnoid hemorrhage, subdural hematoma, and epilepsy). We discuss both clinical and pre-clinical data and pinpoint areas warranting further investigation. In the final section, we provide proposed practice suggestions for managing these patients clinically with the intended goal for refinement in these approaches following further clinical trials.

Warfarin Dosing and Outcomes in Chronic Kidney Disease: A Closer Look at Warfarin Disposition

BACKGROUND

Chronic Kidney Disease (CKD) is a prevalent worldwide health problem. Patients with CKD are more prone to developing cardiovascular complications such as atrial fibrillation and stroke. This warrants the use of oral anticoagulants, such as warfarin, in this population. While the efficacy and safety of warfarin in this setting remain controversial, a growing body of evidence emphasizes that warfarin use in CKD can be problematic. This review discusses 1) warfarin use, dosing and outcomes in CKD patients; and 2) possible pharmacokinetic mechanisms for altered warfarin dosing and response in CKD.

METHODS

Structured search and review of literature articles evaluating warfarin dosing and outcomes in CKD. Data and information about warfarin metabolism, transport, and pharmacokinetics in CKD were also analyzed and summarized.

RESULTS

The literature data suggest that changes in warfarin pharmacokinetics such as protein binding, nonrenal clearance, the disposition of warfarin metabolites may partially contribute to altered warfarin dosing and response in CKD.

CONCLUSION

Although the evidence to support warfarin use in advanced CKD is still unclear, this synthesis of previous findings may help in improving optimized warfarin therapy in CKD settings.

[The Nephrological Aspects of the Use of Rivaroxaban and Other Direct Peroral Anticoagulants in Non-Valvular Atrial Fibrillation]

Chronic kidney disease (CKD) is a powerful cardiovascular risk factor, its presence is accompanied by an increased risk of hospitalization for exacerbation of chronic heart failure (CHF), adverse outcomes in myocardial infarction, and cardiovascular mortality. Among the adverse events, an increased risk of atrial fibrillation (AF) should be noted. This article contains discussion of current approaches to the treatment of AF in patients with different stages of CKD, data on benefits of certain direct oral anticoagulants, as well as comparative characteristics of therapy with direct oral anticoagulants and warfarin. Pharmacokinetics and pharmacodynamics of direct oral anticoagulants, which determine the features of therapy in CKD, are also considered.

Novel oral anticoagulants in chronic kidney disease: ready for prime time?

PURPOSE OF REVIEW

Patients with chronic kidney disease (CKD) are at increased risk of atrial fibrillation, stroke, and bleeding posing unique clinical challenges. Novel oral anticoagulants (NOACs) including dabigatran, rivaroxaban, and apixaban have become recognized as alternative therapy to Vitamin K Antagonists (VKA) regarding the prevention of venous thromboembolism (VTE) and reduce the risk of stroke in atrial fibrillation. However, the understanding of NOACs in CKD is still underdeveloped. This review summarizes recent literature on the efficacy and safety of NOACs in patients with CKD.

RECENT FINDINGS

Studies focusing on patients with moderate kidney disease were drawn from post hoc analyses from three major NOAC trials, meta-analyses, and postmarketing surveillance studies. Cumulatively, these studies continue to demonstrate NOACs as equivalent if not superior therapies to VKAs in regards to both efficacy and safety. These studies are limited by small sample sizes as well as a lack of direct comparison between NOACs.

SUMMARY

The role of NOACs in managing VTE and atrial fibrillation is increasing. Current research suggests that NOACs are at least as efficacious and well tolerated as VKAs. More research is required to elucidate which NOAC is preferable in the clinical setting.

Comparative effectiveness of novel oral anticoagulants in UK patients with non-valvular atrial fibrillation and chronic kidney disease: a matched cohort study

OBJECTIVES

To evaluate the effectiveness and safety of novel oral anticoagulants (NOACs) compared with vitamin K antagonists (VKAs) among patients with non-valvular atrial fibrillation (NVAF), particularly those with chronic kidney disease (CKD).

DESIGN

Population-based matched cohort study.

SETTING

Over 670 primary care practices in the UK, contributing to the Clinical Practice Research Datalink.

PARTICIPANTS

Up to 6818 adult patients newly treated with NOACs between 2011 and 2016, matched 1:1 to new users of VKAs on age, sex and high-dimensional propensity score.

INTERVENTIONS

Current exposure to NOACs compared with current exposure to VKAs.

MAIN OUTCOME MEASURES

HRs of ischaemic stroke and systemic embolism (SE), major bleeding, gastrointestinal (GI) bleeding, intracranial bleeding, myocardial infarction and all-cause mortality.

RESULTS

In as-treated analyses, the rates of ischaemic stroke/SE were similar between NOACs and VKAs (HR 0.94; 95% CI 0.62 to 1.42), as were the rates of major bleeding (HR 0.86; 95% CI 0.56 to 1.33). NOACs also significantly increased the risk of GI bleeding (HR 1.78; 95% CI 1.27 to 2.48). In patients with NVAF and CKD, NOACs and VKAs remained comparable with respect to the risk of ischaemic stroke/SE (HR 0.79; 95% CI 0.40 to 1.58) and major bleeding (HR 0.88; 95% CI 0.47 to 1.62), with no difference in the risk of GI bleeding (HR 0.99; 95% CI 0.63 to 1.55). Similar results were obtained in on-treatment analyses using a time-dependent exposure definition.

CONCLUSIONS

Our results suggest that in the UK primary care, NOACs are overall effective and safe alternatives to VKAs, among patients with NVAF altogether, as well as in patients with NVAF and CKD.