Decreased risk of renal impairment in atrial fibrillation patients receiving non-vitamin K antagonist oral anticoagulants: A pooled analysis of randomized controlled trials and real-world studies

Adverse events of direct factor Xa inhibitors: a disproportionality analysis of the FAERS database

OBJECTIVES

Direct factor Xa inhibitors rivaroxaban, apixaban, and edoxaban, commonly used direct oral anticoagulant (DOAC), are widely used to prevent and treat stroke and venous thromboembolic events in patients with atrial fibrillation (AF). This study aimed to assess and compare reports of adverse events associated with rivaroxaban, apixaban, and edoxaban, including hemorrhagic and non-hemorrhagic events.

METHODS

Reporting odds ratio (ROR), proportional reporting ratio (PRR), Medications and Health Care Products Regulatory Agency (MHRA), and the information component (IC) were used to perform a risk assessment of adverse event reports in the FDA Adverse Event Reporting System (FAERS) database for the years 2018-2022.

RESULTS

Combined with disproportionality analysis in different backgrounds, the salient risks of the three-factor Xa inhibitors varied. Rivaroxaban had the most significant risk of hemorrhage, apixaban had a higher incidence and risk of death, cardiac and cerebral adverse events, and edoxaban showed a more prominent risk in the kidneys and urinary system.

CONCLUSION

Hemorrhage is a common risk with factor Xa inhibitors, with rivaroxaban being the most significant. Apixaban and edoxaban also showed significant association with non-hemorrhagic adverse events, and increased attention to non-hemorrhagic adverse events is needed in clinical use.

Comparative effectiveness of factor Xa non-vitamin K antagonist oral anticoagulants versus phenprocoumon in patients with non-valvular atrial fibrillation

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) have largely supplanted vitamin K antagonists (VKAs) for oral anticoagulation in non-valvular atrial fibrillation (NVAF). However, data on the real-world effectiveness of NOACs vs. phenprocoumon, a VKA widely used in Germany, are limited. The RELOADED study aimed to compare effectiveness of factor Xa NOACs and phenprocoumon in NVAF in clinical practice.

METHODS

Patients who started on a factor Xa NOAC or phenprocoumon for NVAF during the study period were enrolled from the Institute for Applied Healthcare Research Berlin. Patients were followed from first prescription until the end of exposure or available data. Primary outcomes were analyzed by Cox proportional hazard regression models and included ischemic stroke and systemic embolism for effectiveness, and intracranial hemorrhage (ICH) for safety. Subgroups of interest were patients with diabetes and patients with renal impairment.

RESULTS

The total study population was 64,920; 36.3% of patients initiated phenprocoumon, 34.4% initiated rivaroxaban, 25.0% apixaban, and 4.4% edoxaban. Treatment with phenprocoumon is associated with a similar risk of ischemic stroke/systemic embolism as treatment with rivaroxaban or apixaban; while rivaroxaban (adjusted hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.43-0.75) and apixaban (adjusted HR 0.43, 95% CI 0.31-0.6) were associated with a lower risk of ICH compared to phenprocoumon in NVAF patients. The use of rivaroxaban and apixaban was associated with a lower risk of developing kidney failure in patients with diabetes or renal impairment in comparison to those treated with phenprocoumon.

CONCLUSION

The factor Xa NOACs rivaroxaban and apixaban demonstrated similar effectiveness and lower rates of ICH compared with phenprocoumon in this study.

Prescription of DOACs in Patients with Atrial Fibrillation at Different Stages of Renal Insufficiency

Atrial fibrillation (AF) and renal insufficiency often coexist and are increasingly prevalent with advancing age. Both the risk of thromboembolic events and bleeding propensity are higher in patients with AF and impaired renal function versus those with good renal health. Direct oral anticoagulants (DOACs) are being increasingly preferred over vitamin K antagonists (VKAs) in the treatment of patients with AF and impaired renal function as VKAs may accelerate progression of chronic kidney disease. DOACs, however, are eliminated by the kidneys to varying degrees, and their dosages must be adapted in accordance with renal function. Since creatinine clearance (CrCl) monitoring is recommended in patients with AF receiving DOAC therapy, CrCl must be routinely monitored in patients at the start and during the course of anticoagulation to avoid deviation from Summary of Product Characteristics dosage specifications. This review article provides an overview of current knowledge on the selection and dose of DOACs including apixaban, dabigatran, edoxaban and rivaroxaban in AF patients at different stages of renal insufficiency, with a special focus on elderly patients with comorbidities and receiving multiple medications. The groups discussed in this review include patients with varying levels of CrCl including hyperfiltration or CrCl > 90 ml/min, CrCl < 90-50 ml/min, CrCl < 50-30 ml/min, CrCl < 30-15 ml/min and end-stage renal disease or on dialysis.

Vascular protection with rivaroxaban in the comprehensive management of atrial fibrillation

INTRODUCTION

In addition to an increased risk of thromboembolic complications, patients with atrial fibrillation (AF) are at risk for vascular events. Consequently, complete vascular protection is warranted in these patients.

AREAS COVERED

A narrative search was conducted on PubMed (MEDLINE), using the MeSH terms [Rivaroxaban] + [Atrial fibrillation] + [Cardiovascular] + [Vascular] + [Treatment]. Original data from clinical trials, prospective and retrospective studies, useful reviews and experimental studies, were selected.

EXPERT OPINION

The ROCKET-AF trial showed that rivaroxaban is effective in reducing the risk of stroke, with a lower risk of fatal and intracranial bleeding compared to warfarin. Remarkably, experimental data have provided a number of pathogenic mechanisms through which rivaroxaban could provide beneficial vascular properties beyond its antithrombotic activity. Moreover, in the AF population, additional to its ability to reduce the risk of thromboembolic complications, rivaroxaban is associated with a lower risk of myocardial infarction, major adverse cardiac and limb events, and vascular mortality in patients with diabetes, also attenuating renal impairment during follow-up. These findings suggest that rivaroxaban may provide a comprehensive vascular protection in patients with AF.

Use of rivaroxaban attenuates renal function impairment in patients with atrial fibrillation: insights of the EMIR study

BACKGROUND

In atrial fibrillation (AF) patients on vitamin K antagonists, a progressive deterioration of renal function is common but there is limited evidence with long-term use of rivaroxaban. Herein, we investigated the change in renal function in AF patients after 2 years of rivaroxaban treatment.

METHODS

The EMIR registry is an observational and multicentre study including AF patients treated with rivaroxaban for at least 6 months prior to inclusion. Changes in analytical parameters were recorded during 2 years of follow-up. Renal function was estimated using the Cockroft-Gault equation.

RESULTS

1433 patients (638, 44.5% women, mean age of 74.2 ± 9.7 years) were included. Creatinine clearance (CrCl) was available at baseline and at 2 years in 1085 patients. At inclusion, 33.2% of patients had impaired renal function (CrCl <60 ml/min). At 2 years, we were not able to find changes in the proportion of patients with impaired renal function, which increased to 34.6% (p = 0.290). However, the baseline mean CrCl was 76.0 ± 30.5 ml/min and slightly improved at 2 years (77.0 ± 31.8 ml/min; p = 0.014). Overall, the proportion of patients with CrCl <60 ml/min at baseline that had CrCl ≥60 ml/min at 2 years was significantly higher compared to that of patients with CrCl ≥60 ml/min at baseline and CrCl <60 ml/min after (22.2% vs. 13.1%; p < 0.001) CONCLUSIONS: In AF patients on long-term rivaroxaban therapy, a decrease in renal function was not observed. We even observed a slight improvement in the patients with renal impairment. These results reinforce the idea that rivaroxaban may be a safe option even in patients with renal impairment.

Vitamin K1 inhibits ferroptosis and counteracts a detrimental effect of phenprocoumon in experimental acute kidney injury

Ferroptosis, a type of iron-dependent programmed cell death distinct from apoptosis, necroptosis, and other types of cell death, is characterized by lipid peroxidation, reactive oxygen species production, and mitochondrial dysfunction. Accumulating evidence has highlighted vital roles for ferroptosis in multiple diseases, including acute kidney injury. Therefore, ferroptosis has become a major focus for translational research. However, despite its involvement in pathological conditions, there are no pharmacologic inhibitors of ferroptosis in clinical use. In the context of drug repurposing, a strategy for identifying new uses for approved drugs outside the original medical application, we discovered that vitamin K1 is an efficient inhibitor of ferroptosis. Our findings are strengthened by the fact that the vitamin K antagonist phenprocoumon significantly exacerbated ferroptotic cell death in vitro and also massively worsened the course of acute kidney injury in vivo, which is of utmost clinical importance. We therefore assign vitamin K1 a novel role in preventing ferroptotic cell death in acute tubular necrosis during acute kidney injury. Since the safety, tolerability, pharmacokinetics, and pharmacodynamics of vitamin K1 formulations are well documented, this drug is primed for clinical application, and provides a new strategy for pharmacological control of ferroptosis and diseases associated with this mode of cell death.

Direct Oral Anticoagulants vs. Warfarin in Hemodialysis Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background

The use of Direct Oral Anticoagulants (DOACs) in patients who have both atrial fibrillation (AF) and end-stage renal disease (ESRD) requiring hemodialysis remains controversial, with warfarin remaining the mainstay of the treatment. As hemodialysis patients were excluded from most clinical DOACs trials, the evidence of their efficacy and safety is lacking in this cohort of patients.

Aim

To review the current evidence investigating safety profile and the efficacy of DOACs in comparison with warfarin in patients with AF and end-stage renal disease (ESRD) requiring hemodialysis.

Methods and Results

We included five studies with a total of 34,516 patients in our meta-analysis. The outcomes were major bleeding, ischemic stroke, systemic embolization, hemorrhagic stroke, gastrointestinal bleeding, minor bleeding, and death. Of these patients, 31,472 (92.14%) received warfarin and 3,044 patients received DOACs (8.91%). No significant differences in the incidence of hemorrhagic stroke, major bleeding, hemodialysis access site bleeding, ischemic stroke, and GI bleeding were found between DOACs and warfarin. However, there were higher rates of systemic embolization, minor bleeding, and death events in patients who received DOACs than in the warfarin group (3.39% vs. 1.97%, P-value = 0.02), (6.78% vs. 2.2%, P-value 0.02), and (11.38% vs. 5.12%, P-value < 0.006) respectively.

Conclusion

In patients on dialysis who require anticoagulation for AF, warfarin could be associated with a significant reduction in minor bleeding, systemic embolization, and death compared to DOACs. These findings need to be validated by further prospective studies to address the best strategy to deal with the increased thrombotic and bleeding risks in such patients.

Oral anticoagulants and relative risk of acute kidney injury in patients with atrial fibrillation: A systematic review and network meta-analysis

Study objective

Oral anticoagulants (direct oral anticoagulants [DOACs] or warfarin) prevent stroke in patients with atrial fibrillation (AF), but their use may be associated with acute kidney injury (AKI). We aimed to compare AKI risk across individual oral anticoagulants in patients with AF.

Design

Systematic review and network meta-analysis.

Setting

Randomized trials and population-based studies.

Participants

Patients with AF.

Interventions

Oral anticoagulants.

Main outcome measures

AKI.

Results

A systematic literature search in Medline and Embase databases performed on December 17, 2021 identified ten randomized trials and eight population-based longitudinal studies based on prespecified inclusion criteria for systematic review. Clinical trials had short follow-ups and reported only low event rates of serious AKI. Retrospective longitudinal studies were assessed to be at higher risk for bias from confounding and outcome ascertainment, but follow-up was longer (1.5 to 8 years), with AKI incidence ranging from 2 to 29/100 person-years. Eight longitudinal studies that met transitivity assumption were included in a random-effects network meta-analysis within a Bayesian framework. All DOACs were associated with significantly lower risk of AKI compared to warfarin. Dabigatran was associated with lower risk of AKI compared to apixaban (hazard ratio [HR] = 0.82; 95% confidence interval [CI]: 0.68-0.99), rivaroxaban (HR = 0.84; 95%CI: 0.72-0.98), and warfarin (HR = 0.68; 95%CI: 0.59-0.77). Effect size estimates varied by chronic kidney disease status and study geographic locations.

Conclusion

Apixaban, rivaroxaban, and dabigatran were associated with lower long-term risk of AKI compared to warfarin among patients with AF, with dabigatran potentially associated with the lowest risk.

Comparative effectiveness and safety of pharmaceuticals assessed in observational studies compared with randomized controlled trials

BACKGROUND

There have been ongoing efforts to understand when and how data from observational studies can be applied to clinical and regulatory decision making. The objective of this review was to assess the comparability of relative treatment effects of pharmaceuticals from observational studies and randomized controlled trials (RCTs).

METHODS

We searched PubMed and Embase for systematic literature reviews published between January 1, 1990, and January 31, 2020, that reported relative treatment effects of pharmaceuticals from both observational studies and RCTs. We extracted pooled relative effect estimates from observational studies and RCTs for each outcome, intervention-comparator, or indication assessed in the reviews. We calculated the ratio of the relative effect estimate from observational studies over that from RCTs, along with the corresponding 95% confidence interval (CI) for each pair of pooled RCT and observational study estimates, and we evaluated the consistency in relative treatment effects.

RESULTS

Thirty systematic reviews across 7 therapeutic areas were identified from the literature. We analyzed 74 pairs of pooled relative effect estimates from RCTs and observational studies from 29 reviews. There was no statistically significant difference (based on the 95% CI) in relative effect estimates between RCTs and observational studies in 79.7% of pairs. There was an extreme difference (ratio < 0.7 or > 1.43) in 43.2% of pairs, and, in 17.6% of pairs, there was a significant difference and the estimates pointed in opposite directions.

CONCLUSIONS

Overall, our review shows that while there is no significant difference in the relative risk ratios between the majority of RCTs and observational studies compared, there is significant variation in about 20% of comparisons. The source of this variation should be the subject of further inquiry to elucidate how much of the variation is due to differences in patient populations versus biased estimates arising from issues with study design or analytical/statistical methods.

Non-Vitamin K Antagonist Oral Anticoagulants Provide Less Adverse Renal Outcomes Than Warfarin In Non-Valvular Atrial Fibrillation: A Systematic Review and MetaAnalysis

Background

Non‐vitamin K antagonist oral anticoagulants (NOACs) have better pharmacologic properties than warfarin and are recommended in preference to warfarin in most patients with non‐valvular atrial fibrillation. Besides lower bleeding complications, other advantages of NOACs over warfarin particularly renal outcomes remain inconclusive.

Methods and Results

Electronic searches were conducted through Medline, Scopus, Cochrane Library databases, and ClinicalTrial.gov. Randomized controlled trials and observational cohort studies reporting incidence rates and hazard ratio (HR) of renal outcomes (including acute kidney injury, worsening renal function, doubling serum creatinine, and end‐stage renal disease) were selected. The random‐effects model was used to calculate pooled incidence and HR with 95% CI. Eighteen studies were included. A total of 285 201 patients were enrolled, 118 863 patients with warfarin and 166 338 patients with NOACs. The NOACs group yielded lower incidence rates of all renal outcomes when compared with the warfarin group. Patients treated with NOACs showed significantly lower HR of risk of acute kidney injury (HR, 0.70, 95% CI, 0.64–0.76; P<0.001), worsening renal function (HR, 0.83; 95% CI, 0.73–0.95; P=0.006), doubling serum creatinine (HR, 0.58; 95% CI, 0.41–0.82; P=0.002), and end‐stage renal disease (HR, 0.82; 95% CI, 0.78–0.86; P<0.001).

Conclusions

In non‐valvular atrial fibrillation, patients treated with NOACs have a lower risk of both acute kidney injury and end‐stage renal disease when compared with warfarin.

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.

Idarucizumab for the treatment of dabigatran-related nephropathy

Anticoagulant-related nephropathy (ARN) is a clinical syndrome of acute kidney injury in patients taking vitamin K antagonists or direct oral anticoagulants. It is associated with increased mortality and there is no specific treatment. We report the case of a 78-year-old man on dabigatran who developed macroscopic haematuria and acute kidney injury 2 weeks after mitral valve repair, reaching a peak creatinine of 415 µmol/L from a normal baseline, which was successfully treated with one course of idarucizumab. This case illustrates the efficacy of an anticoagulant reversal agent for the treatment of ARN.

Cost-effectiveness analysis of dabigatran, rivaroxaban and warfarin in the prevention of stroke in patients with atrial fibrillation in China

BACKGROUND AND OBJECTIVE

To evaluate the cost-effectiveness of new anticoagulants and warfarin in the prevention of stroke in Chinese patients with atrial fibrillation (AF).

METHODS

The Markov model was constructed to compare patients' quality-adjusted life-years (QALYs) using drug cost, the cost of the examination after taking a drug, and the incremental cost of other treatments. Both dabigatran (110 and 150 mg, twice a day) and rivaroxaban (20 mg, once a day) were compared with warfarin (3-6 mg, once a day). Willingness to pay, three times the 2018 China GDP per capita (9481.88 $), was the cost-effect threshold in our study.

RESULTS

The total cost were was 5317.31$, 29673.33$, 23615.49$, and 34324.91$ for warfarin, rivaroxaban, dabigatran 110 mg bid, and dabigatran 150 mg bid, respectively. The QALYs for each of the four interventions were 11.07 years, 15.46 years, 12.4 years, and 15 years, respectively. The cost-effectiveness analysis of the three new oral anticoagulants and warfarin showed that the incremental cost-effectiveness ratio (ICER) was 5548.07$/QALY when rivaroxaban was compared with warfarin. Rivaroxaban was the most cost-effective choice and warfarin was the least.

CONCLUSIONS

In Chinese patients with AF, although warfarin is cheaper, rivaroxaban has a better cost-effectiveness advantage from an economic point of view.

No inexplicable disagreements between real-world data-based nonrandomized controlled studies and randomized controlled trials were found

OBJECTIVES

We assessed disagreements between nonrandomized controlled studies based on real-world data (NRCS-RWDs) and randomized controlled trials (RCTs).

STUDY DESIGN AND SETTING

We systematically searched for studies that compared treatment effect estimates from NRCS-RWDs and RCTs on the same clinical question. We assessed the potential difference between NRCS-RWDs and RCTs related to internal and external validity. We calculated various meta-epidemiological measures to assess agreement. In case of disagreements, we tried to identify the probable causes of disagreements.

RESULTS

We included 12 studies comparing 15 treatment effect estimates of NRCS-RWDs and RCTs. There were many potential causes of disagreement. Ninety-five percent confidence intervals overlapped for 12 of 15 treatment effect estimates. Our analysis on predicted vs. observed overlap showed that there were no more disagreements than expected by chance. We observed only two substantial differences between the 15 treatment effect estimates. In both cases, we identified risk of bias in the NRCS-RWDs as the most probable cause of disagreement.

CONCLUSION

Our findings suggest that there are clinical questions where the difference in risk of bias between a well-conducted NRCS-RWD and an RCT is negligible. In our analysis, threats to external validity appeared to have no or only a weak impact on the disagreements of treatment effect estimates.

Thromboembolic and Bleeding Risk in Atrial Fibrillation Patients with Chronic Kidney Disease: Role of Anticoagulation Therapy

Atrial fibrillation (AF) and chronic kidney disease (CKD) are strictly related; several independent risk factors of AF are often frequent in CKD patients. AF prevalence is very common among these patients, ranging between 15% and 20% in advanced stages of CKD. Moreover, the results of several studies showed that AF patients with end stage renal disease (ESRD) have a higher mortality rate than patients with preserved renal function due to an increased incidence of stroke and an unpredicted elevated hemorrhagic risk. Direct oral anticoagulants (DOACs) are currently contraindicated in patients with ESRD and vitamin K antagonists (VKAs), remaining the only drugs allowed, although they show numerous critical issues such as a narrow therapeutic window, increased tissue calcification and an unfavorable risk/benefit ratio with low stroke prevention effect and augmented risk of major bleeding. The purpose of this review is to shed light on the applications of DOAC therapy in CKD patients, especially in ESRD patients.

Position paper on the safety/efficacy profile of direct oral anticoagulants in patients with chronic kidney disease. Consensus document from the SIN, FCSA and SISET

Direct oral anticoagulants (DOAC) are mostly prescribed to prevent cardioembolic stroke in patients with non-valvular atrial fibrillation (AF). An increasing number of guidelines recommend DOAC in AF patients with preserved renal function for the prevention of thromboembolism, and an increased use of DOAC in daily practice has been recorded also in elderly patients. Ageing is associated with a reduction in glomerular filtration rate, and impaired renal function, regardless of the cause, increases the risk of bleeding. Multiple medication use (polypharmacy) for treating superimposed co-morbidities is common in both elderly and chronic kidney disease (CKD) patients and drug-drug interaction may cause accumulation of DOAC, thereby increasing the risk of bleeding. The safety profile of DOAC in patients with CKD has not been defined with any certainty, particularly in those with severely impaired renal function or end stage renal disease. This has been due to the heterogeneity of studies and the relative paucity of data. This document reports the position of three Italian scientific societies engaged in the management of patients with atrial fibrillation who are treated with DOAC and present with CKD.

Position paper on the safety/efficacy profile of Direct Oral Anticoagulants in patients with Chronic Kidney Disease: Consensus document of Società Italiana di Nefrologia (SIN), Federazione Centri per la diagnosi della trombosi e la Sorveglianza delle terapie Antitrombotiche (FCSA) and Società Italiana per lo Studio dell'Emostasi e della Trombosi (SISET)

Direct oral anticoagulants (DOAC) are mostly prescribed to prevent cardioembolic stroke in patients with non-valvular atrial fibrillation (AF). An increasing number of guidelines recommend DOAC in AF patients with preserved renal function for the prevention of thromboembolism and an increased use of DOAC in daily practice is recorded also in elderly patients. Aging is associated with a reduction of glomerular filtration rate and impaired renal function, regardless of the cause, increases the risk of bleeding. Multiple medication use (polypharmacy) for treating superimposed co-morbidities is common in both elderly and chronic kidney disease (CKD) patients and drug-drug interaction may cause accumulation of DOAC, thereby increasing the risk of bleeding. There is uncertainty on the safety profile of DOAC in patients with CKD, particularly in those with severely impaired renal function or end stage renal disease, due to the heterogeneity of studies and the relative paucity of data. This document reports the position of three Italian scientific societies engaged in the management of patients with atrial fibrillation who are treated with DOAC and present with CKD.

The Impairment in Kidney Function in the Oral Anticoagulation Era. A Pathophysiological Insight

The need for anticoagulation in patients with atrial fibrillation (AF) is fundamental to prevent thromboembolic events. Direct oral anticoagulants (DOACs) recently demonstrated to be superior, or at least equal, to Warfarin in reducing the risk for stroke/systemic embolism and preventing major bleeding and intracranial hemorrhages. The AF population often suffers from chronic kidney disease (CKD). Indeed, the relationship between AF and renal function is bidirectional: AF can trigger kidney failure, while kidney impairment can promote alterations able to enhance AF. Therefore, there are concerns regarding prescriptions of anticoagulants to patients with AF and CKD. The worsening in kidney function can be effectively due to anticoagulants administration. Warfarin has been recognized to promote acute kidney injury in case of excessive anticoagulation levels. Nevertheless, further mechanisms can induce the chronic worsening of renal function, thus leading to terminal kidney failure as observed in post-hoc analysis from registration trials and dedicated observational studies. By contrast, DOACs seem to protect kidneys from injuries more efficiently than Warfarin, although they still continue to play a role in promoting some kidney lesions. However, the exact mechanisms remain unknown. This narrative review aimed to discuss the influence of oral anticoagulants on renal impairment as well as to overview potential pathophysiological mechanisms related to this clinical complication.

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.

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.