Incidence of chronic kidney disease in patients with atrial fibrillation and its relevance for prescribing new oral antithrombotic drugs

Non-Vitamin K Oral Anticoagulants Assessment in High Risk of Bleeding Patients with Non-Valvular Atrial Fibrillation

Atrial fibrillation (AF) is commonly associated with advanced age and the presence of multiple, concomitant acute and chronic health conditions, placing this population at high risk for serious therapeutic side effects. Nonvitamin K antagonist oral anticoagulants (NOACs) are increasingly used for stroke prevention in patients with atrial fibrillation. The purpose of this study was to investigate the effectiveness and safety of NOAC in a group at high risk of bleeding complications, in a real-world setting. We conducted a retrospective analysis of a high-risk cohort of 418 patients (pts) followed-up in our anticoagulation unit; data on patient characteristics, anticoagulation treatment, and bleeding and thrombotic complications were evaluated. The population had a median age of 77.8 ± 10.3 years and the mean CHA₂DS₂-VASc score was 3.85 (SD ± 1.4). Overall, 289 (69.1%) were ≥75 years old. During a mean follow-up time of 51.2 ± 35.7 months, we observed a rate of any bleeding of 7, a clinically relevant non-major bleeding rate of 4.8, a major bleeding rate of 2.2, a stroke rate of 1.6, and a rate of thrombotic events of 0.28 per 100 patient-years. There were 59 hospitalizations due to any cause (14.1%) and 36 (8.6%) deaths (one due to ischemic stroke). A structured follow-up, with judicious prescribing and drug compliance, may contribute to preventing potential complications.

Anticoagulation Prescription and Outcomes in Relation to Renal Function in Patients with Atrial Fibrillation: Results from GLORIA-AF

Objective  Anticoagulation management in patients with atrial fibrillation (AF) and impaired renal function is challenging. This study aimed to evaluate anticoagulation prescription patterns in relation to renal function and to describe 2-year clinical outcomes among dabigatran users. Methods  Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF) is an international, prospective, and observational study program involving patients with newly diagnosed AF at risk for stroke. Prescription patterns were assessed by creatinine clearance (CrCl) at enrollment. Dabigatran users were followed for 2 years. Clinical outcomes were standardized for stroke and bleeding risk, based on CHA ₂ DS ₂ -VASc and HAS-BLED scores, with missing values imputed. Results  Baseline CrCl values were available for 12,056 of 15,308 eligible patients (79%). With declining renal function, prescriptions increased for vitamin K antagonists (VKAs) and decreased for dabigatran (30-47% and 34-12%, respectively). The prescription of other non-vitamin K antagonists remained similar across CrCl groups (14-19%). In 4,873 dabigatran users, standardized stroke rates were low across all CrCl groups; 0.58/100 patient-years (95% confidence interval [CI]: 0.30-0.90) in CrCl ≥80 mL/min, 0.85 (95% CI: 0.48-1.21) in CrCl 50 to 79 mL/min, and 0.33 (95% CI: 0.06-1.11) in CrCl 30 to 49 mL/min. Similarly, major bleeding rates were low and numerically increased with declining renal function (0.68/100 patient-years, 95% CI: 0.39-1.03; 0.92, 95% CI: 0.58-1.32; and 1.26, 95% CI: 0.66-1.97, respectively). Conclusion  In patients with AF, VKA prescriptions increased and dabigatran prescriptions decreased with declining renal function. Rates of stroke and major bleeding in dabigatran patients remained low across the categories of renal impairment.

Approaches for the identification of chronic kidney disease in CPRD-HES-linked studies

Aim: There are different methods to identify chronic kidney disease (CKD) in Clinical Practice Research Datalink (CPRD)-Hospital Episode Statistics (HES). Methods: Using CPRD-HES, nonvalvular atrial fibrillation patients were classified according to CKD category. Results: Using glomerular filtration rate/estimated glomerular filtration rate tests only to identify patients with CKD resulted in 3.5% stage 2, 2.7% stage 3, 0.3% stage 4 and 0.03% stage 5. Using data from diagnostic codes to identify patients with CKD resulted in 1.4% stage 3, 0.4% stage 4 and 0.3% stage 5. Using test records and codes resulted in 3.5% stage 2, 4.0% stage 3, 0.6% stage 4 and 0.4% stage 5. Conclusion: To identify CKD status in CPRD-HES, a combination of test records and codes should be used. Using diagnostic codes only significantly underestimates CKD prevalence.

The use of anticoagulants in chronic kidney disease: Common point of view of cardiologists and nephrologists

In patients diagnosed with chronic kidney disease (CKD), atrial fibrillation (AF) is associated with an increased risk of thromboembolism and stroke. Moreover, patients with CKD - especially those in end-stage renal disease - also present an increased risk of bleeding. Oral anticoagulation is the most effective form of thromboprophylaxis in patients with AF and an increased risk of stroke. However, the underuse of these drugs was observed, mainly due to safety reasons and restricted evidence on efficacy. Much evidence suggests that non-vitamin K-dependent oral anticoagulant agents significantly reduce the risk of stroke, intracranial hemorrhage, and mortality, with lower to similar major bleeding rates compared with vitamin K antagonists, such as warfarin, in normal renal function subjects. Thus, they are currently recommended for that group of patients. However, their metabolism is largely dependent on the kidneys for elimination, and current knowledge in this area is limited due to patients with a decreased glomerular filtration rate are usually excluded from clinical trials. The present review article focuses on currently available data on oral anticoagulants in patients with moderate to advanced chronic kidney disease and those with end stage renal disease.

Influence of Renal Function on the Pharmacokinetics, Pharmacodynamics, Efficacy, and Safety of Non-Vitamin K Antagonist Oral Anticoagulants

With the growing integration of non-vitamin K antagonist oral anticoagulants (NOACs) into clinical practice, questions have arisen regarding their use in special populations, including groups that may have been underrepresented in clinical trials. Patients with renal impairment, particularly in the lower echelons of renal function, are one such group. In an effort to elucidate the current evidence regarding the use of NOACs in patients with renal impairment, a systematic assessment of the literature was performed. The MEDLINE database was interrogated for studies and analyses evaluating the influence of renal function on the pharmacokinetics, pharmacodynamics, efficacy, and safety of NOACs published from January 1, 2000, through August 2, 2017. The 82 relevant publications retrieved highlight the diversity in the NOAC class regarding the impact of renal function on drug clearance, drug exposures, and clinical trial outcomes. In several large clinical trials, subgroup analyses revealed no significant differences when patients were stratified by creatinine clearance as a measure of renal function. Efficacy findings, in particular, were largely aligned with the overall population in the included studies. However, relative risks of bleeding were shown to vary, sometimes driven by changes in bleeding event rates in the comparator arm (eg, warfarin, enoxaparin). With few exceptions, minimal influence of mild renal impairment was observed on the relative efficacy and safety of NOACs. Taken together, the evidence suggests that the presence of renal impairment merits careful consideration of anticoagulant choice but should not deter physicians from appropriate use of NOACs.

Anticoagulation for Stroke Prevention in Older Adults with Atrial Fibrillation and Comorbidity: Current Evidence and Treatment Challenges

The burden of atrial fibrillation (AF) is projected to increase substantially over the next decade in parallel with the aging of the population. The increasing age, level of comorbidity, and polypharmacy will complicate the treatment of older adults with AF. For instance, advanced age and chronic kidney disease have been shown to increase the risk of both thromboembolism and bleeding in patients with AF. Frailty, recurrent falls and polypharmacy, while very common among elderly patients with AF, are often overlooked in the clinical decision making despite their significant interaction with oral anticoagulant (OAC) and profound impact on the patient's clinical outcomes. Such factors should be recognized, evaluated and considered in a comprehensive decision-making process. The introduction of non-vitamin K oral anticoagulants has radically changed the management of AF allowing for a more individualized selection of OAC. An understanding of the available data regarding the performance of each of the available OAC in a variety of at risk patient populations is paramount for the safe and effective management of this patient population. The aim of this review is to appraise the current evidence, point out the gaps in knowledge, and provide recommendations regarding stroke prevention in older adults with AF and comorbid conditions.

[Anticoagulation in geriatric patients with atrial fibrillation : With what and for whom no more?]

Based on established risk scores, such as the CHA₂DS₂-VASc score, the indications for oral anticoagulation are given for patients over 65 years old with atrial fibrillation and even more so for patients over 75 years old. Before beginning anticoagulation a geriatric assessment for evaluation of the cognitive ability, the activities of daily living and the risk of falling should be made because of the known complications of anticoagulation. Geriatric patients with non-valvular atrial fibrillation (AF) are increasingly being treated with non-vitamin K antagonist oral anticoagulants (NOAC) to prevent ischemic stroke. The European Society for Cardiology (ESC) guidelines for the management of AF recommended NOACs as the preferred treatment and vitamin K antagonists (VKA) only as an alternative option. Meanwhile, apixaban, rivaroxaban, and edoxaban as factor Xa inhibitors and dabigatran as a thrombin inhibitor, are more commonly used in clinical practice in patients with AF. Although, these drugs have pharmacodynamics and pharmacokinetic similarities and are often grouped together, it is important to recognize that the pharmacology and dose regimens differ between compounds. Especially in elderly patients the new drugs have interesting advantages compared to VKA, i. e., less drug-drug interactions with concomitant medication and a more favorable risk-benefit ratio mostly driven by the reduction of bleeding. Treatment of anticoagulation in elderly patients requires weighing the serious risk of stroke with an equally high risk of major bleeding and pharmacoeconomic considerations. The easier practicality of NOACs in routine practice must be emphasized as no international normalized ratio (INR) monitoring is necessary and the interruption of treatment for planned interventions is uncomplicated. A regular monitoring of the indications for NOACs is indispensable (as for all other medications). Especially elderly patients have the greatest benefit from NOAC along with a low renal elimination rate and they should certainly not be withheld from elderly patients who have a clear need for oral anticoagulation.

Real-world stroke prevention strategies in nonvalvular atrial fibrillation in patients with renal impairment

BACKGROUND

The data regarding stroke prevention strategies in nonvalvular atrial fibrillation (NVAF) are limited especially in patients with renal impairment (RI). We sought to evaluate management dilemmas in patients with concurrent NVAF and RI in RAMSES (ReAl-life Multicenter Survey Evaluating Stroke Prevention Strategies inTurkey) study.

METHODS

We conducted a prospective, multicenter, nation-wide registry in NVAF patients in outpatient cardiology clinics. All consecutive patients with NVAF were enrolled in RAMSES study (ClinicalTrials.gov identifier NCT02344901). The baseline data were collected. Glomerular filtration rate (GFR) was estimated by Cockcroft-Gault equation.

RESULTS

A total number of 6273 patients from 29 provinces of Turkey with the contribution of 83 investigators were enrolled to the study. Of the study population, 1964(33%) patients had RI which was defined as GFR < 60 mL/min. Patients with RI had significantly higher CHA₂ DS₂ VASc and HAS-BLED scores compared to those without RI (3·9 ± 1·5 vs. 2·9 ± 1·5, and 2·0 ± 1 vs. 1·4 ± 1; P < 0·001). Prior history of major bleeding (6·9% vs. 4·1%, P < 0·001) and stroke (16·2% vs. 11·8%, P < 0·001) was significantly higher among individuals with concomitant RI and NVAF. Although RI patients had a higher risk for thromboembolism, number of the patients who did not receive any anticoagulant therapy was higher in patients with RI than without RI (30·1 vs. 26·4%, P = 0·003).

CONCLUSION

RAMSES study showed that one-third of the patients with NVAF had RI in the real-world setting. Although it is mandatory in most of the patients with concomitant NVAF and RI, nearly one-third of these patients did not receive any anticoagulant therapy.

Estimated glomerular filtration rate calculated using different creatinine and cystatin based formulas in prediction of trough plasma Dabigtran concentration

BACKGROUND

In this paper we evaluated the relationship between trough DAB concentration with eGFR calculated using CRE and CYS based formulas.

MATERIALS AND METHODS

We considered 100 patients. eGFR was calculated using CKD-EPIcreat, CG, MDRD, CKD-EPIcys and CKD-EPIcombined equations. DAB dosage was selected on the basis of CKD-EPIcreat and relationship between trough DAB concentration and eGFRs was evaluated.

RESULTS

Trough DAB concentration roughly correlates with eGFR calculated using various formulas. CKD-EPIcreat eGFR was higher than CKD-EPIcys. In patients receiving a DAB dosage considered adequate using CKD-EPIcreat eGFR but considered excessive using CKD-EPIcys, we observed higher DAB trough concentration and an increased prevalence of subjects with drug concentration >200ng/mL.

CONCLUSION

These results suggest that eGFR alone was unable to fully explain trough DAB plasma concentration. Therefore a drug's prescription schedule based on eGFR only should be inadequate. We observed a better correlation between trough DAB concentration and CKD-EPIcys rather than CKD-EPIcreat eGFR. Thus, in patients chronically treated with DAB for thromboprophylaxis in nonvalvular atrial fibrillation evaluation of eGFR using a cystatin base formula should be considered.

Oxidized Low-Density Lipoprotein Predicts the Development of Renal Dysfunction in Atrial Fibrillation

BACKGROUND/AIM

To investigate the role of oxidative stress (OS) in the development of chronic kidney disease (CKD) in atrial fibrillation (AF).

METHODS

We compared OS burden, determined at study inclusion as plasma concentrations of oxidized low-density lipoprotein (oxLDL), between stable AF patients (n = 256, mean age: 62.8 ± 9.3 years; 60.9% males) with preserved renal function, defined as an estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m2, and a matched control group in sinus rhythm (n = 138, mean age: 61.5 ± 11.2 years; 60.9% males). During the prospective follow-up of AF patients, we investigated the association and prognostic validity of oxLDL for CKD development, diagnosed as a sustained decline in eGFR to <60 ml/min/1.73 m2.

RESULTS

AF patients had a higher mean oxLDL (76.2 ± 21.7 U/l) compared to sinus rhythm controls (61.6 ± 13.1 U/l; p < 0.001). AF presence independently predicted increased oxLDL levels in the study cohort [β = 14.7; 95% confidence interval (CI), 10.7-18.7; p < 0.001]. Over a median 4-year follow-up, 19.9% of AF patients developed CKD. Adjusting for all clinical covariates, oxLDL (per tertile) was associated with a hazard ratio of 2.17 for CKD occurrence (95% CI, 1.40-3.35; p < 0.001). AF patients in the upper oxLDL tertile (≥88.7 U/l) had a 3.70-fold (95% CI, 1.55-8.81) higher risk for CKD compared to the lower oxLDL tertile (<67.0 U/l) patients (p < 0.001). oxLDL improved discriminative validity (c-statistic increment: 0.041, 95% CI, 0.007-0.075, p = 0.017), and increased the net reclassification and integrated discrimination for CKD risk by 12.4 and 6.0%, respectively (both p < 0.001).

CONCLUSIONS

oxLDL is increased in AF patients compared to sinus rhythm controls. oxLDL has an independent association and an incremental predictive value that might complement clinical CKD risk assessment in AF patients following further research.

Overcoming global challenges in stroke prophylaxis in atrial fibrillation: The role of non-vitamin K antagonist oral anticoagulants

Atrial fibrillation is the world's most common sustained cardiac arrhythmia and is associated with a significantly increased risk of stroke. The global burden of atrial fibrillation is rising, commensurate with the ageing population. Well-controlled vitamin K antagonist-based anticoagulation has been shown to reduce the risk of stroke secondary to atrial fibrillation by two-thirds. However, patients with atrial fibrillation have frequently been denied anticoagulation because of a variety of perceived risks related to bleeding, falls, chronological age, and poor compliance. Even when vitamin K antagonists are used, maximum benefit and safety are only delivered when high quality control of therapy (TTR > 70%) is achieved, which has proven remarkably difficult in many health-care systems and amongst many patient groups. The non-vitamin K antagonist oral anticoagulants (NOACs) offer solutions to many of the challenges of achieving widespread, safe, and effective anticoagulation for stroke prophylaxis in atrial fibrillation, yet their uptake into routine clinical practice remains variable. The evidence supporting their more widespread use to overcome the challenges of stroke prophylaxis for atrial fibrillation is reviewed in this article.

Individualising Anticoagulant Therapy in Atrial Fibrillation Patients

Non-vitamin K antagonist (VKA) oral anticoagulants (NOACs) have emerged as alternatives to VKAs for the prevention of stroke in patients with non-valvular atrial fibrillation. Four NOACS: dabigatran, apixaban, rivaroxaban and edoxaban, have received regulatory approval in Europe from the European Medicines Agency. Numerous factors can influence the decision to prescribe a NOAC, the most important of which are assessment of stroke and bleeding risks. Given the variation in design of the pivotal phase III clinical trials investigating the efficacy and safety of NOACs, and in the absence of head-to-head comparative data, it is impossible to recommend one NOAC over the other. However, NOACS offer the opportunity for individualised therapy based on factors such as renal function, age or patient/doctor preference for once- or twice-daily dosing regimens. Dose reduction of some NOACS should be considered in at-risk patient populations.

Individualized approaches to thromboprophylaxis in atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide. The prevalence of AF in persons older than 55 years is at least 33.5 million globally and is predicted to more than double in the next half-century. Anticoagulation, heart rate control, and heart rhythm control comprise the 3 main treatment strategies in AF. Anticoagulation is aimed at preventing debilitating stroke, systemic embolism, and associated mortality. Historically, anticoagulation in AF was achieved with a vitamin K antagonist such as warfarin, which is supported by evidence demonstrating reduced incident stroke and all-cause mortality. However, warfarin has unpredictable pharmacokinetics with many drug-drug interactions that require regular monitoring to ensure patients remain in the therapeutic anticoagulant range. Non-vitamin K antagonist oral anticoagulants including dabigatran, rivaroxaban, apixaban, and edoxaban provide a possible solution to these issues with their more predictable pharmacokinetics, rapid onset of action, and greater specificity. Results from large randomized, controlled trials indicate that these agents are at least noninferior to warfarin in prevention of stroke. These trials also demonstrate a consistently lower incidence of intracranial hemorrhage, almost always all life-threatening bleeds, and many forms of major bleeds with the possible exception of gastrointestinal and some other forms of mucosal bleeding, compared with warfarin. Patients with AF are a heterogeneous population with diverse risk of stroke and bleeding, and different subgroups respond differently to anticoagulation. Important clinical questions have arisen regarding optimal anticoagulation drug selection in distinct populations such as those with renal impairment, older age, coronary artery disease, and heart failure as well as those at particularly high risk for bleeding or thromboembolism. In this review, treatment strategies in AF management are discussed in the context of different individual subgroups of patients.

Renal function assessment in atrial fibrillation: Usefulness of chronic kidney disease epidemiology collaboration vs re-expressed 4 variable modification of diet in renal disease

AIM: To compare the performance of the re-expressed Modification of Diet in Renal Disease equation vs the new Chronic Kidney Disease Epidemiology Collaboration equation in patients with non-valvular atrial fibrillation.

METHODS: We studied 911 consecutive patients with non-valvular atrial fibrillation on vitamin-K antagonist. The performance of the re-expressed Modification of Diet in Renal Disease equation vs the new Chronic Kidney Disease Epidemiology Collaboration equation in patients with non-valvular atrial fibrillation with respect to either a composite endpoint of major bleeding, thromboembolic events and all-cause mortality or each individual component of the composite endpoint was assessed using continuous and categorical ≥ 60, 59-30, and < 30 mL/min per 1.73 m² estimated glomerular filtration rate.

RESULTS: During 10 ± 3 mo, the composite endpoint occurred in 98 (10.8%) patients: 30 patients developed major bleeding, 18 had thromboembolic events, and 60 died. The new equation provided lower prevalence of renal dysfunction < 60 mL/min per 1.73 m² (32.9%), compared with the re-expressed equation (34.1%). Estimated glomerular filtration rate from both equations was independent predictor of composite endpoint (HR = 0.98 and 0.97 for the re-expressed and the new equation, respectively; P < 0.0001) and all-cause mortality (HR = 0.98 for both equations, P < 0.01). Strong association with thromboembolic events was observed only when estimated glomerular filtration rate was < 30 mL/min per 1.73 m²: HR is 5.1 for the re-expressed equation, and HR = 5.0 for the new equation. No significant association with major bleeding was observed for both equations.

CONCLUSION: The new equation reduced the prevalence of renal dysfunction. Both equations performed similarly in predicting major adverse outcomes.

Choosing the right drug to fit the patient when selecting oral anticoagulation for stroke prevention in atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and is a growing health problem that is associated with a significantly increased risk of stroke and thromboembolism. Oral anticoagulant (OAC) therapy reduces the risk of stroke and all-cause mortality in patients with AF. OAC therapy is commonly given as a well-controlled vitamin K antagonist (VKA; e.g. warfarin) and can reduce the risk of stroke in AF patients by almost two-thirds. However, the widespread use of VKAs has been hampered by the unpredictable pharmacokinetic and pharmacodynamic properties of the drugs and justifiable concerns about the consequent risk of haemorrhage. The non-VKA OACs (NOACs) have revolutionized thromboprophylaxis in AF by providing therapeutic options with predictable pharmacodynamic and pharmacokinetic properties that are as efficacious as warfarin in the prevention of stroke and thromboembolism but are more convenient to use. In this review, we provide a patient-centred framework to assist clinicians in recommending the right OAC therapy to fit the individual patient with AF, including methods for stratifying the risk of stroke and haemorrhage and the chances of achieving tight control of VKA anticoagulation, and we discuss the properties of the NOACs that favour their use in particular patient cohorts.

Risk of Ischemic Stroke and Stroke Prevention in Patients with Atrial Fibrillation and Renal Dysfunction

Chronic kidney disease (CKD) has been identified as an important risk factor for new-onset atrial fibrillation (AF) and would significantly increase the risk of AF-related strokes. Stroke prevention in AF patients with CKD is a big challenge, especially for patients with end-stage renal disease (ESRD) undergoing long-term dialysis. In addition to an increase risk of stroke, renal dysfunction was also associated with a higher risk of hemorrhage due to dysregulation of coagulation and uremia-mediated platelet dysfunction. Therefore, the net clinical benefit balancing stroke risk reduction and increased risk of bleeding should be weighed carefully before initiating oral anti-coagulants for ESRD patients. Several studies investigating whether warfarin should be used for stroke prevention in AF patients with ESRD have been published and showed inconsistent results. Since none of these studies was a prospective and randomized trial, the best strategy for stroke prevention in AF patients with ESRD undergoing dialysis remained unknown and more data are necessary to answer this issue.

Anticoagulants and acute kidney injury: clinical and pathology considerations

We have recently identified a new clinical syndrome in patients receiving warfarin for anticoagulation therapy. This syndrome has been named warfarin-related nephropathy (WRN), and patients with chronic kidney disease (CKD) appear to be particularly susceptible. WRN is defined as an acute increase in international normalized ratio (INR) to >3.0, followed by evidence of acute kidney injury (AKI) within 1 week of the INR increase. AKI was defined as a sustained increase in serum creatinine of greater than or equal to 0.3 mg/dL. The AKI cannot be explained by any other factors, and the kidney biopsy demonstrates extensive glomerular hemorrhage with tubular obstruction by red blood cells (RBCs). Beyond AKI, WRN is a significant risk factor for mortality within the first 2 months of diagnosis and it accelerates the progression of CKD. We demonstrated that 5/6 nephrectomy in rats is a suitable experimental model to study WRN. Animals treated with warfarin showed an increase in serum creatinine and morphologic findings in the kidney similar to those in humans with WRN. Our recent evidence suggests that novel oral anticoagulants may induce AKI. Diagnosis of WRN may be challenging for a renal pathologist. A few cases with suspected WRN and pathologic considerations are described.

Efficacy and safety of vitamin K-antagonists (VKA) for atrial fibrillation in non-dialysis dependent chronic kidney disease

Background

Essential information regarding efficacy and safety of vitamin K-antagonists (VKA) treatment for atrial fibrillation (AF) in non-dialysis dependent chronic kidney disease (CKD) is still lacking in current literature. The aim of our study was to compare the risks of stroke or transient ischemic attack (TIA) and major bleeds between patients without CKD (eGFR >60 ml/min), and those with moderate (eGFR 30–60 ml/min), or severe non-dialysis dependent CKD (eGFR <30 ml/min).

Methods

We included 300 patients without CKD, 294 with moderate, and 130 with severe non-dialysis dependent CKD, who were matched for age and sex. Uni- and multivariate Cox regression analyses were performed reporting hazard ratios (HRs) for the endpoint of stroke or TIA and the endpoint of major bleeds as crude values and adjusted for comorbidity and platelet-inhibitor use.

Results

Overall, 6.2% (45/724, 1.7/100 patient years) of patients developed stroke or TIA and 15.6% (113/724, 4.8/100 patient years) a major bleeding event. Patients with severe CKD were at high risk of stroke or TIA and major bleeds during VKA treatment compared with those without renal impairment, HR 2.75 (95%CI 1.25–6.05) and 1.66 (95%CI 0.97–2.86), or with moderate CKD, HR 3.93(1.71–9.00) and 1.86 (95%CI 1.08–3.21), respectively. These risks were similar for patients without and with moderate CKD. Importantly, both less time spent within therapeutic range and high INR-variability were associated with increased risks of stroke or TIA and major bleeds in severe CKD patients.

Conclusions

VKA treatment for AF in patients with severe CKD has a poor safety and efficacy profile, likely related to suboptimal anticoagulation control. Our study findings stress the need for better tailored individualised anticoagulant treatment approaches for patients with AF and severe CKD.

Renal impairment in a "real-life" cohort of anticoagulated patients with atrial fibrillation (implications for thromboembolism and bleeding)

Renal dysfunction is highly prevalent among patients with atrial fibrillation (AF) and confers an increased risk of thrombotic and bleeding complications. We evaluated the effect of renal function on prognosis in anticoagulated patients with AF and assessed the changes in renal function during a long-term follow-up period. We recruited 978 consecutive stable anticoagulated patients with AF from our outpatient anticoagulation clinic (international normalized ratio 2.0 to 3.0 within the previous 6 months). The estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease equation at inclusion and 2 years of follow-up. Adverse events were recorded during follow-up (thrombotic/vascular events, major bleeding episodes, and mortality). Longitudinal changes in renal function were analyzed in 886 patients (90.6%). At baseline, the median eGFR using the Modification of Diet in Renal Disease equation was 70.24 ml/min/1.73 m(2) (interquartile range 46.79 to 72.52). During follow-up, a low eGFR was associated with thrombotic/vascular events, with every 30 ml/min/1.73 m(2) eGFR decrease (hazard ratio 1.42, 95% confidence interval [CI] 1.11 to 1.83, p = 0.006), bleeding (hazard ratio 1.44, 95% CI 1.08 to 1.94, p = 0.015), and mortality (hazard ratio 1.47, 95% CI 1.13 to 1.91, p = 0.004). After excluding patients with a baseline eGFR <30 ml/min/1.73 m(2), the mean eGFR in our cohort decreased >10 ml/min/1.73 m(2) in 181 patients (21%) during the follow-up period. The variables associated with severe renal impairment during follow-up were heart failure (odds ratio 3.58, 95% CI 1.36 to 9.42, p = 0.010), basal eGFR (odds ratio 6.34, 95% CI 2.44 to 16.50, p <0.001), and CHADS2 (Congestive heart failure, Hypertension, Age >75 years, Diabetes mellitus, and previous Stroke or transient ischemic attack [doubled]) score (odds ratio 1.63, 95% CI 1.19 to 2.23, p = 0.003). In conclusion, the presence of impaired renal function was closely related to thrombotic/vascular events, bleeding, and mortality in anticoagulated patients with AF. During follow-up, 1/5 of the patients had significant impairment in renal function. Importantly, normal or mild renal dysfunction at baseline did not exclude the subsequent development of severe renal dysfunction during the follow-up period.

New oral anticoagulants in atrial fibrillation: a reappraisal of trial results looking at absolute figures

Three new oral anticoagulant agents were tested versus warfarin in separate, large phase III randomized clinical trials for prevention of any stroke and systemic embolism in atrial fibrillation. Dabigatran, a direct thrombin inhibitor, is at 110 mg bid non-inferior and at 150 mg bid superior to warfarin; rivaroxaban, a factor X inhibitor, is also non-inferior, and apixaban, also a factor X inhibitor, is superior to warfarin on the same efficacy end point. Statistical analysis of subgroups does not suggest, for any of the tested drugs, major differences in relation to different risk levels and history of previous stroke/TIA. This re-appraisal of data was undertaken in search for possible additional information, by considering the absolute differences in efficacy and safety events versus warfarin and the corresponding efficiency and number needed to treat, also with regard to secondary versus primary prevention. By this approach, it appears that for all drugs, equivalence or advantage versus warfarin on the efficacy end point is largely driven by a reduction in hemorrhagic rather than ischemic strokes. Dabigatran shows a balanced effect on ischemic and hemorrhagic strokes, and apixaban is most effective in sparing intracranial bleeding versus warfarin. In secondary prevention, better efficiency is shown by dabigatran 150 and apixaban, versus rivaroxaban, despite the higher proportion of post-stroke/TIA patients (55 %) in the ROCKET AF trial of rivaroxaban seemed to favor better results of this drug in secondary prevention. These and other results of our approach should not be directly translated into clinical practice. They may supply useful suggestions to be subsequently tested in specific trials, although head-to-head comparative studies of the three drugs remain unlikely.