Performance of bleeding risk scores in dialysis patients

The Safety and Effectiveness of Apixaban in Patients with End-Stage Kidney Disease on Dialysis: A Retrospective Observational Study

Background: Apixaban has been increasingly utilized for various FDA-approved indications, including stroke prevention and venous thromboembolism (VTE) treatment in patients with end stage kidney disease (ESKD) on hemodialysis. However, the safety and efficacy of its use in this population is not well established. Hence, the purpose of this study is to evaluate the safety and effectiveness of apixaban by examining outcomes in this population. Methods: This was a retrospective observational study that involved adults with ESKD who were on hemodialysis and prescribed apixaban from our hospital's outpatient pharmacy between 1 May 2015, and 31 March 2022. Demographics, apixaban indications, dose appropriateness, concomitant antiplatelet use, and comorbidities data were collected. Bleeding and thromboembolic events were also collected. Results: Sixty-six patients fulfilled the inclusion criteria, 50% of them males. Median age was 71 (63.5-82) years, and the median BMI 28.2 (59.5-86.25) kg/m2. The median follow-up time was 5 (1.9-12.3) months. Concomitant antiplatelet use (39.4%) and high medication adherence (84.8%) were observed. During follow-up, major bleeding events occurred in 15.2% of cases, with minor bleeding being more common (36.4%), and VTE and stroke events occurred in 4.5% of cases; appropriate dosing was prevalent (62.1%), and there was an overall all-cause mortality rate of 34.8%. Most patients received a 2.5 mg BID apixaban dose (56.1%), including both NVAF and VTE groups. Notably, the multivariate logistic regression analysis indicated that weight, and daily dose were insignificant predictors of bleeding events (p = 0.104, 0.591), however, the BMI was the main independent risk factor for bleeding in this population [OR = 0.9, 95% CI: 0.8-0.99; p = 0.023]. Conclusions: Our analysis of apixaban-treated ESKD patients highlights that the risk of bleeding is significant, and BMI was the main independent risk factor. A larger prospective study is needed to confirm our findings.

Cardiovascular Events and Mortality in Patients on Hemodialysis: The Prognostic Value of the CHA2DS2-VASc Score

Background and Objectives: Cardiovascular events are the major cause of morbidity and mortality in patients on hemodialysis (HD). Identifying risk factors can help in the effort to reduce cardiovascular risk and improve life expectancy. The objective of this study was to evaluate the ability of the CHA2DS2-VASc score-the risk index of stroke in atrial fibrillation (AF)-to predict strokes, major cardiovascular events, and mortality in patients with end-stage kidney disease. Materials and Methods: The CHA2DS2-VASc and HAS-BLED scores (the bleeding risk from the use of anticoagulation in AF) were calculated in 237 HD patients, 99 women with a median age of 76 (15) years, at the time they commenced HD. The scores' ability to predict long term cardiovascular morbidity and mortality was estimated, both in those with and without AF. Among the exclusion criteria were the change of dialysis method or loss of follow-up, HD due to acute renal failure, and incompliance with medical instructions, thus the sample is not representative of a broader population. Results: The CHA2DS2-VASc score was higher in AF (n = 69) compared to non-AF (n = 168) patients, 5 (2.5) vs. 4 (2), p < 0.0001, respectively. An increased CHA2DS2-VASc score was correlated with cardiovascular events, namely, heart failure (p = 0.007, p = 0.024), stroke (p < 0.0001, p < 0.0001), and risk of all-cause mortality (p < 0.0001, p < 0.0001) in AF and non-AF groups, respectively. The C statistics indicated that the referred score showed modest discrimination in AF and non-AF patients on HD for heart failure, stroke, and all-cause mortality, however for cardiovascular mortality this was found only in the AF group. Conclusions: An increased CHA2DS2-VASc score at the time of HD initiation can predict strokes, heart failure, and all-cause mortality in HD patients independent of the presence of AF. The risk of cardiovascular mortality could only be predicted in patients with AF.

Development and Validation of a Risk-Prediction Nomogram for Preoperative Blood Type and Antibody Testing in Spinal Fusion Surgery

OBJECTIVE

With advancements in minimally invasive techniques, the use of spinal fusion surgery is rapidly increasing and transfusion rates are decreasing. Routine preoperative ABO/Rh blood type and antibody screening (T&S) laboratory tests may not be appropriate for all spinal fusion patients. Herein, we constructed a nomogram to assess patient transfusion risk based on various risk factors in patients undergoing spinal fusion surgery, so that preoperative T&S testing can be selectively scheduled in appropriate patients to reduce healthcare and patient costs.

METHODS

Patients who underwent spinal fusion surgery between 01/2020 and 03/2023 were retrospectively examined and classified into the training (n = 3533, 70%) and validation (n = 1515, 30%) datasets. LASSO and multivariable logistic regression were used to analyze risk factors for blood transfusion. Nomogram predictive model was built according to the independent predictors and mode predictive power was validated using consistency index (C-index), Hosmer-Lemeshow (HL) test, calibration curve analysis and area under the curve (AUC) for receiver operating characteristic (ROC) curve. Bootstrap resampling was used for internal validation. Decision curve analysis (DCA) was applied to evaluate the model's performance in the clinic.

RESULTS

Being female, age, BMI, admission route, critical patient, operative time, heart failure, end-stage renal disease or chronic kidney disease (ESRD or CKD), anemia, and coagulation defect were predictors of blood transfusion for spinal fusion. A prediction nomogram was developed according to a multivariate model with good discriminatory power (C-index = 0.887); Bootstrap resampling internal validation C-index was 0.883. Calibration curves showed strong matching between the predicted and actual probabilities of the training and validation sets. HL tests for the training and validation sets had p-values of 0.327 and 0.179, respectively, indicating good calibration. When applied to the training set, the following parameters were found: AUC: 0.895, 95% CI: 0.871-0.919, sensitivity 78.2%, specificity 86.7%, positive predictive value 29.4% and negative predictive value 98.2%. If the model were applied in the training set, 2911 T&S tests (82.4%) would be eliminated, equaling a RMB349,320 cost reduction. The AUC in the internal validation was: 0.879, 95% CI: 0.839-0.927, sensitivity 75.2%, specificity 88.8%, positive predictive value 34.3%, negative predictive value 97.9%, would eliminate 1276 T&S tests (84.2%), saving RMB 153,120. The DCA curve indicated good clinical application value.

CONCLUSION

The nomogram based on 10 independent factors can help healthcare professionals predict the risk of transfusion for patients undergoing spinal fusion surgery to target preoperative T&S testing to appropriate patients and reduce healthcare costs.

Bleeding Risk in Hemodialysis Patients

Cardiovascular diseases are highly prevalent among patients on dialysis. For these diseases, antiplatelets and antithrombotic therapies including heparin, vitamin K antagonists, and direct oral anticoagulants, are being used. However, the benefit-risk balance of these therapies could differ for dialysis patients compared with the general population. This review article focuses on the bleeding risk associated with the use of heparin, antiplatelets, vitamin K antagonists, and direct oral anticoagulants in patients receiving hemodialysis.

Sex differences in associations between creatinine and cystatin C-based kidney function measures with stroke and major bleeding

PURPOSE

We sought to explore whether adding kidney function biomarkers based on creatinine (eGFRCr), cystatin C (eGFRCys) or a combination of the two (eGFRCr-Cys) could improve risk stratification for stroke and major bleeding, and whether there were sex differences in any additive value of kidney function biomarkers.

METHOD

We included participants from the UK Biobank who had not had a previous ischaemic or haemorrhagic stroke or major bleeding episode, and who had kidney function measures available at baseline. Cause-specific Cox proportional hazards models tested associations between eGFRCr, eGFRCys and eGFRCr-Cys (mL/min/1.73 m2) with ischaemic and haemorrhagic stroke, major bleeding (gastrointestinal or intracranial, including haemorrhagic stroke) and all-cause mortality.

FINDINGS

Among 452,879 eligible participants, 246,244 (54.4%) were women. Over 11.5 (IQR 10.8-12.2) years, there were 3706 ischaemic strokes, 795 haemorrhagic strokes, 26,025 major bleeding events and 28,851 deaths. eGFRCys was more strongly associated with ischaemic stroke than eGFRCr: an effect that was more pronounced in women (men - HR: 1.16, 95% CI: 1.12-1.19; female to male comparison - HR: 1.11, 95% CI: 1.05-1.16, per 10 mL/min/1.73 m2 decline in eGFRCys). This interaction effect was also demonstrated for eGFRCr-Cys, but not eGFRCr. eGFRCys and eGFRCr-Cys were more strongly associated with major bleeding and all-cause mortality than eGFRCr in both men and women. Event numbers were small for haemorrhagic stroke.

DISCUSSION

To a greater degree than is seen in men, eGFRCr underestimates risk of ischaemic stroke and major bleeding in women compared to eGFRCys. The difference between measures is likely explained by non-GFR biology of creatinine and cystatin C.

CONCLUSION

Enhanced measurement of cystatin C may improve risk stratification for ischaemic stroke and major bleeding and clinical treatment decisions in a general population setting, particularly for women.

Growth differentiation factor-15 predicts major bleeding, major adverse cardiac events and mortality in patients with end-stage kidney disease on haemodialysis: findings from the VIVALDI study

BACKGROUND

Patients with end-stage kidney disease (ESKD) are at high risk of cardiovascular events and bleeding. Optimizing risk assessment of ESKD patients regarding the risk of thromboembolism and bleeding complications in comorbid conditions, including atrial fibrillation and coronary heart disease, is challenging. To improve risk prediction we investigated growth differentiation factor-15 (GDF-15), a promising cardiovascular biomarker, and its relation to adverse outcomes.

METHODS

In this prospective, multicentre, population-based cohort study, GDF-15 was measured in 594 ESKD patients on haemodialysis (median age 66 years, 38% female), who were followed up for a median of 3.5 years. The association of GDF-15 with major bleeding, arterial thromboembolism, major adverse cardiac events (MACE) and death was analysed within a competing risk framework. Further, we evaluated the additive predictive value of GDF-15 to cardiovascular and death risk assessment.

RESULTS

GDF-15 levels were in median 5475 ng/l (25th-75th percentile 3964-7533) and independently associated with major bleeding {subdistribution hazard ratio [SHR] 1.31 per double increase [95% confidence interval (CI) 1.00-1.71]}, MACE [SHR 1.47 (95% CI 1.11-1.94)] and all-cause mortality [SHR 1.58 (95% CI 1.28-1.95)] but not arterial thromboembolism [SHR 0.91 (95% CI 0.61-1.36)]. The addition of GDF-15 to the HAS-BLED score significantly improved discrimination and calibration for predicting major bleeding [C-statistics increased from 0.61 (95% CI 0.52-0.70) to 0.68 (95% CI 0.61-0.78)]. Furthermore, we established an additive predictive value of GDF-15 beyond current risk models for predicting MACE and death.

CONCLUSION

GDF-15 predicts the risk of major bleeding, cardiovascular events and death in ESKD patients on haemodialysis and might be a valuable marker to guide treatment decisions in this challenging patient population.

Development and Validation of a Predictive Risk Algorithm for Bleeding in Individuals on Long-term Hemodialysis: An International Prospective Cohort Study (BLEED-HD)

Background

Individuals with kidney disease are at a high risk of bleeding and as such tools that identify those at highest risk may aid mitigation strategies.

Objective

We set out to develop and validate a prediction equation (BLEED-HD) to identify patients on maintenance hemodialysis at high risk of bleeding.

Design

International prospective cohort study (development); retrospective cohort study (validation).

Settings

Development: 15 countries (Dialysis Outcomes and Practice Patterns Study [DOPPS] phase 2-6 from 2002 to 2018); Validation: Ontario, Canada.

Patients

Development: 53 147 patients; Validation: 19 318 patients.

Measurements

Hospitalization for a bleeding event.

Methods

Cox proportional hazards models.

Results

Among the DOPPS cohort (mean age, 63.7 years; female, 39.7%), a bleeding event occurred in 2773 patients (5.2%, event rate 32 per 1000 person-years), with a median follow-up of 1.6 (interquartile range [IQR], 0.9-2.1) years. BLEED-HD included 6 variables: age, sex, country, previous gastrointestinal bleeding, prosthetic heart valve, and vitamin K antagonist use. The observed 3-year probability of bleeding by deciles of risk ranged from 2.2% to 10.8%. Model discrimination was low to moderate (c-statistic = 0.65) with excellent calibration (Brier score range = 0.036-0.095). Discrimination and calibration of BLEED-HD were similar in an external validation of 19 318 patients from Ontario, Canada. Compared to existing bleeding scores, BLEED-HD demonstrated better discrimination and calibration (c-statistic: HEMORRHAGE = 0.59, HAS-BLED = 0.59, and ATRIA = 0.57, c-stat difference, net reclassification index [NRI], and integrated discrimination index [IDI] all P value <.0001).

Limitations

Dialysis procedure anticoagulation was not available; validation cohort was considerably older than the development cohort.

Conclusion

In patients on maintenance hemodialysis, BLEED-HD is a simple risk equation that may be more applicable than existing risk tools in predicting the risk of bleeding in this high-risk population.

UK prescribing practice of anticoagulants in patients with chronic kidney disease: a nephrology and haematology-based survey

A survey to gain insight into anticoagulant prescribing practice in the setting of chronic kidney disease (CKD) across the UK was disseminated via renal and haematology networks. Areas of anticoagulant use included patients with venous thromboembolism (VTE), requiring thromboprophylaxis for VTE, Atrial Fibrillation (AF) and nephrotic syndrome.An online-survey was disseminated via British Haematology Society, UK Kidney Association, and Renal Pharmacy Group over a five month period. All responses were voluntary and anonymous.Among 117 responses there were 49 nephrology doctors, 47 renal pharmacists and 20 haematology clinicians. A specialist multidisciplinary team to discuss the specific anticoagulant management of these patients was only available to 3% (4/117) respondents. Renal function estimate used for anticoagulant dosing was mainly Cockcroft-Gault for pharmacists and haematology but lab-based estimates were used by nephrology doctors. Therapeutic dose of Low Molecular Weight Heparin was mostly likely to be reduced by one-third when used for VTE treatment, with the majority of units undertaking anti-Xa monitoring in CKD stage 5 and dialysis. Direct-acting Oral Anticoagulants are being used in patients with nephrotic syndrome, those with CKD stage 5 and on dialysis for VTE and AF in the absence of license in these indications.This survey highlighted the significant differences between anticoagulant prescribing in CKD between two professional specialties and marked variation between centres in anticoagulant management strategies employed for these patients. With gaps still existing in the evidence base and answers to these not expected within the next few years, development of a best-practice guideline would be warranted to support clinicians in this field.

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

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

Bleeding Risk Assessment in End-Stage Kidney Disease: Validation of Existing Risk Scores and Evaluation of a Machine Learning-Based Approach

BACKGROUND

 Patients with end-stage kidney disease (ESKD) on hemodialysis (HD) are at increased risk for bleeding. However, despite relevant clinical implications regarding dialysis modalities or anticoagulation, no bleeding risk assessment strategy has been established in this challenging population.

METHODS

 Analyses on bleeding risk assessment models were performed in the population-based Vienna InVestigation of Atrial fibrillation and thromboemboLism in patients on hemoDialysIs (VIVALDI) study including 625 patients. In this cohort study, patients were prospectively followed for a median observation period of 3.5 years for the occurrence of major bleeding. First, performances of existing bleeding risk scores (i.e., HAS-BLED, HEMORR2HAGES, ATRIA, and four others) were evaluated in terms of discrimination and calibration. Second, four machine learning-based prediction models that included clinical, dialysis-specific, and laboratory parameters were developed and tested using Monte Carlo cross-validation.

RESULTS

 Of 625 patients (median age: 66 years, 37% women), 89 (14.2%) developed major bleeding, with a 1-year, 2-year, and 3-year cumulative incidence of 6.1% (95% confidence interval [CI]: 4.2-8.0), 10.3% (95% CI: 8.0-12.8), and 13.5% (95% CI: 10.8-16.2), respectively. C-statistics of the seven contemporary bleeding risk scores ranged between 0.54 and 0.59 indicating poor discriminatory performance. The HAS-BLED score showed the highest C-statistic of 0.59 (95% CI: 0.53-0.66). Similarly, all four machine learning-based predictions models performed poorly in internal validation (C-statistics ranging from 0.49 to 0.55).

CONCLUSION

 Existing bleeding risk scores and a machine learning approach including common clinical parameters fail to assist in bleeding risk prediction of patients on HD. Therefore, new approaches, including novel biomarkers, to improve bleeding risk prediction in patients on HD are needed.

External validation of risk scores to predict in-hospital mortality in patients hospitalized due to coronavirus disease 2019

BACKGROUND

The coronavirus disease 2019 (COVID-19) presents an urgent threat to global health. Prediction models that accurately estimate mortality risk in hospitalized patients could assist medical staff in treatment and allocating limited resources.

AIMS

To externally validate two promising previously published risk scores that predict in-hospital mortality among hospitalized COVID-19 patients.

METHODS

Two prospective cohorts were available; a cohort of 1028 patients admitted to one of nine hospitals in Lombardy, Italy (the Lombardy cohort) and a cohort of 432 patients admitted to a hospital in Leiden, the Netherlands (the Leiden cohort). The endpoint was in-hospital mortality. All patients were adult and tested COVID-19 PCR-positive. Model discrimination and calibration were assessed.

RESULTS

The C-statistic of the 4C mortality score was good in the Lombardy cohort (0.85, 95CI: 0.82-0.89) and in the Leiden cohort (0.87, 95CI: 0.80-0.94). Model calibration was acceptable in the Lombardy cohort but poor in the Leiden cohort due to the model systematically overpredicting the mortality risk for all patients. The C-statistic of the CURB-65 score was good in the Lombardy cohort (0.80, 95CI: 0.75-0.85) and in the Leiden cohort (0.82, 95CI: 0.76-0.88). The mortality rate in the CURB-65 development cohort was much lower than the mortality rate in the Lombardy cohort. A similar but less pronounced trend was found for patients in the Leiden cohort.

CONCLUSION

Although performances did not differ greatly, the 4C mortality score showed the best performance. However, because of quickly changing circumstances, model recalibration may be necessary before using the 4C mortality score.

Age Modifies Intracranial and Gastrointestinal Bleeding Risk from P2Y12 Inhibitors in Patients Receiving Dialysis

Background

Individuals aged ≥75 years are the fastest-growing population starting dialysis for end-stage kidney disease (ESKD) due to living longer with coronary artery disease. ESKD alone can increase bleeding risk, but P2Y₁₂ inhibitor (P2Y12-I) antiplatelet medications prescribed for cardiovascular treatment can exacerbate this risk in patients with ESKD. The age-specific rates of bleeding complications in dialysis patients with ESKD on P2Y12-I remain unclear, as does how age modifies the bleeding risk from P2Y12-I use in these patients.

Methods

In a retrospective cohort study, we collected data on 40,972 patients receiving maintenance hemo- or peritoneal dialysis who were newly prescribed P2Y12-I therapy between 2011 and 2015 from the USRDS registry. We analyzed the effect of age on the time to first bleed and the interactions between age and P2Y12-I type on modifying the effects of a bleed.

Results

Twenty percent of the cohort were aged ≥75 years. There were 3096 (8%) gastrointestinal (GI) and 1298 (3%) intracranial (IC) bleeding events during a median follow-up of 1 year. Annual incidence rates for IC bleeds were 2% in those aged <55 years and 3% in those aged ≥75 years. Rates for GI bleeds were 4% in those aged <55 years and 9% in those aged ≥75 years. On clopidogrel, prasugrel, and ticagrelor, for every decade increase in age of the cohort members, the risk of IC bleed increased by 9%, 55%, and 59%, and the risk of GI bleed increased by 21%, 28%, and 39%, respectively. At age ≥75 years, prasugrel was associated with a greater risk of IC bleed than clopidogrel. At age ≥60 years, ticagrelor was associated with a greater risk of GI bleed than clopidogrel.

Conclusions

More potent P2Y12-Is (prasugrel and ticagrelor) were associated with a disproportionately higher risk of IC bleed with increasing age compared with that of clopidogrel-prasugrel was much worse than clopidogrel at age ≥75 years. All three drugs were associated with only modest increase in the risk of GI bleed with every decade increase in age-ticagrelor was much worse than clopidogrel at ≥60 years of age. These results highlight the need for head-to-head clinical trials for the use of P2Y12-Is in patients with ESKD to determine age cutoffs where the risk of bleeding outweighs the benefits of thrombosis prevention.

Chronic kidney disease and atrial fibrillation: A dangerous combination

Background

Chronic kidney disease (CKD) and atrial fibrillation (AF) are both risk factors for bleeding, stroke and mortality. The aim of our study was to investigate the interaction between CKD and atrial fibrillation and outcomes.

Methods

We included 12,394 subjects referred to the University Medical Center Utrecht (the Netherlands) from September 1996 to February 2018 for an out-patient visit (Utrecht Cardiovascular Cohort Second Manifestation of Arterial disease cohort). Hazard ratios (HRs) with 95% confidence intervals (CIs) for bleeding, ischemic stroke or mortality were calculated with Cox proportional hazard analyses. Presence of interaction between AF and CKD was examined by calculating the relative excess risk due to interaction (RERI), the attributable proportion (AP) due to interaction and the synergy index (S).

Results

Of the 12,394 patients, 699 patients had AF, 2,752 patients had CKD and 325 patients had both AF and CKD. Patients with both CKD and AF had a 3.0-fold (95% CI 2.0–4.4) increased risk for bleeding, a 4.2-fold (95% CI 3.0–6.0) increased ischemic stroke risk and a 2.2-fold (95% CI 1.9–2.6) increased mortality risk after adjustment as compared with subjects without atrial fibrillation and CKD. We did not find interaction between AF and CKD for bleeding and mortality. However, we found interaction between AF and CKD for ischemic stroke risk (RERI 1.88 (95% CI 0.31–3.46), AP 0.45 (95% CI 0.17–0.72) and S 2.40 (95% CI 1.08–5.32)).

Conclusion

AF and CKD are both associated with bleeding, ischemic stroke and mortality. There is a positive interaction between AF and CKD for ischemic stroke risk, but not for bleeding or mortality.

Platelet thrombus formation in patients with end-stage renal disease before and after hemodialysis as measured by the total thrombus-formation analysis system

Background

Patients with end-stage renal disease (ESRD) receiving hemodialysis (HD) often experience bleeding. However, mechanisms behind this bleeding tendency are incompletely understood but may involve platelet dysfunction. We, therefore, studied platelet-dependent thrombus formation in flowing whole blood inside a microchip coated with collagen, and its association with circulating von Willebrand factor (VWF).

Methods

Blood samples were obtained in 22 patients before and after HD. The area under the 10 min flow pressure curve in a microchip (AUC10) reflecting total platelet thrombogenicity was measured, using the Total Thrombus-formation Analysis System (T-TAS01). AUC10 < 260 indicates platelet dysfunction. VWF activity and antigen in plasma were also assayed.

Results

VWF levels were moderately elevated and increased further after HD (P < 0.01 or lower). In contrast, AUC10 before and after HD was < 260 in 17/22 patients and < 130 in 15/22 patients, with no statistically significant difference in pre- vs post-HD measurements, indicating reduced platelet thrombogenicity, but with some variability as 5/22 patients showed normal platelet responsiveness. AUC10 and VWF activity or antigen levels in plasma were not correlated, either before or after HD.

Conclusions

Most ESRD patients display moderate-to-severe platelet dysfunction as assessed by shear-induced platelet-dependent thrombus formation with T-TAS01. HD does not influence platelet function despite HD-induced elevations in VWF. T-TAS01 should be further evaluated as a tool in the assessment of bleeding risk in patients on HD.

Graphical abstract

Platelet Abnormalities in CKD and Their Implications for Antiplatelet Therapy

Patients with CKD display a significantly higher risk of cardiovascular and thromboembolic complications, with around half of patients with advanced CKD ultimately dying of cardiovascular disease. Paradoxically, these patients also have a higher risk of hemorrhages, greatly complicating patient therapy. Platelets are central to hemostasis, and altered platelet function resulting in either platelet hyper- or hyporeactivity may contribute to thrombotic or hemorrhagic complications. Different molecular changes have been identified that may underlie altered platelet activity and hemostasis in CKD. In this study, we summarize the knowledge on CKD-induced aberrations in hemostasis, with a special focus on platelet abnormalities. We also discuss how prominent alterations in vascular integrity, coagulation, and red blood cell count in CKD may contribute to altered hemostasis in these patients who are high risk. Furthermore, with patients with CKD commonly receiving antiplatelet therapy to prevent secondary atherothrombotic complications, we discuss antiplatelet treatment strategies and their risk versus benefit in terms of thrombosis prevention, bleeding, and clinical outcome depending on CKD stage. This reveals a careful consideration of benefits versus risks of antiplatelet therapy in patients with CKD, balancing thrombotic versus bleeding risk. Nonetheless, despite antiplatelet therapy, patients with CKD remain at high cardiovascular risk. Thus, deep insights into altered platelet activity in CKD and underlying mechanisms are important for the optimization and development of current and novel antiplatelet treatment strategies, specifically tailored to these patients who are high risk. Ultimately, this review underlines the importance of a closer investigation of altered platelet function, hemostasis, and antiplatelet therapy in patients with CKD.

Survival Benefit of Anticoagulation Therapy in End Stage Kidney Disease Patients with Atrial Fibrillation: A Single Center Retrospective Study

Background and Objectives: Although the need for anticoagulation to prevent thromboembolism is increasing and non-vitamin K antagonist oral anticoagulants (NOACs) have been tried, there is still controversy about the efficacy of anticoagulation in patients with dialysis. Materials and Methods: We retrospectively analyzed the risk and benefit of anticoagulation in dialysis patients with atrial fibrillation (AF). We retrospectively analyzed all data of 89 patients who received dialysis therapy and were diagnosed with AF. Among them, 27 received anticoagulation (11 warfarin and 16 apixaban 2.5 mg twice a day), while 62 received no anticoagulation. Results: In multivariate Cox regression analysis, compared to no anticoagulation treatment, anticoagulation treatment was associated with a low incidence of all-cause mortality (hazard ratios (HR) 0.36; 95% confidence interval (CI) 0.15–0.88). Compared to no anticoagulation treatment, more anticoagulation treatment patients experienced severe bleeding (HR 4.67; 95% CI 1.26–17.25) and any bleeding (HR 2.79; 95% CI 1.01–7.74). Compared to no anticoagulation, warfarin treatment patients were associated with a low incidence of all-cause mortality (HR 0.26; 95% CI 0.09–0.81) and a high incidence of severe bleeding (HR 4.85; 95% CI 1.12–21.10). All-cause mortality and bleeding were not significantly different between no anticoagulation and apixaban treatment patients. Conclusions: In dialysis patients with AF, anticoagulation therapy is associated with an increased incidence of severe bleeding, but anticoagulation therapy is associated with a low incidence of all-cause mortality. Individualized anticoagulation therapy with careful bleeding monitoring is needed in dialysis patients with AF.

Validation of risk scores for ischaemic stroke in atrial fibrillation across the spectrum of kidney function

Aims 

The increasing prevalence of ischaemic stroke (IS) can partly be explained by the likewise growing number of patients with chronic kidney disease (CKD). Risk scores have been developed to identify high-risk patients, allowing for personalized anticoagulation therapy. However, predictive performance in CKD is unclear. The aim of this study is to validate six commonly used risk scores for IS in atrial fibrillation (AF) patients across the spectrum of kidney function.

Methods and results 

Overall, 36 004 subjects with newly diagnosed AF from SCREAM (Stockholm CREAtinine Measurements), a healthcare utilization cohort of Stockholm residents, were included. Predictive performance of the AFI, CHADS₂, Modified CHADS₂, CHA₂DS₂-VASc, ATRIA, and GARFIELD-AF risk scores was evaluated across three strata of kidney function: normal kidney function [estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m²], mild CKD (eGFR 30–60 mL/min/1.73 m²), and advanced CKD (eGFR <30 mL/min/1.73 m²). Predictive performance was assessed by discrimination and calibration. During 1.9 years, 3069 (8.5%) patients suffered an IS. Discrimination was dependent on eGFR: the median c-statistic in normal eGFR was 0.75 (range 0.68–0.78), but decreased to 0.68 (0.58–0.73) and 0.68 (0.55–0.74) for mild and advanced CKD, respectively. Calibration was reasonable and largely independent of eGFR. The Modified CHADS₂ score showed good performance across kidney function strata, both for discrimination [c-statistic: 0.78 (95% confidence interval 0.77–0.79), 0.73 (0.71–0.74) and 0.74 (0.69–0.79), respectively] and calibration.

Conclusion 

In the most clinically relevant stages of CKD, predictive performance of the majority of risk scores was poor, increasing the risk of misclassification and thus of over- or undertreatment. The Modified CHADS₂ score performed good and consistently across all kidney function strata, and should therefore be preferred for risk estimation in AF patients.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

OBJECTIVES

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

STUDY DESIGN AND SETTING

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

RESULTS

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

CONCLUSION

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

Anticoagulation in Concomitant Chronic Kidney Disease and Atrial Fibrillation: JACC Review Topic of the Week

Atrial fibrillation (AF) and chronic kidney disease (CKD) often coexist as they share multiple risk factors, including hypertension, diabetes mellitus, and coronary artery disease. Although there is irrefutable evidence supporting anticoagulation in AF in the general population, these data may not be transferable to the setting of advanced CKD, where the decision to commence anticoagulation poses a conundrum. In this cohort, there is a progressively increased risk of both ischemic stroke and hemorrhage as renal function declines, complicating the decision to initiate anticoagulation. No definitive clinical guidelines derived from randomized controlled trials exist to aid clinical decision-making, and the findings from observational studies are conflicting. In this review, the authors outline the pathophysiological mechanisms at play and summarize the limited existing data related to anticoagulation in those with concomitant CKD and AF. Finally, the authors suggest how to approach the decision of whether and how to use oral anticoagulation in these patients.

Anticoagulant strategies for the patient with chronic kidney disease

Chronic kidney disease (CKD) is a global health problem affecting up to 14% of the adult population in developed countries. On the basis of current guidelines, patients with CKD will often fulfil criteria for both short-term and long-term anticoagulation. Paradoxically, patients with CKD are not only at a higher risk of thrombosis, they are also at increased risk of bleeding. Furthermore, the pharmacokinetics and pharmacodynamics of many anticoagulant therapies are significantly affected by renal dysfunction. In addition, patients with advanced CKD are often systematically excluded from major clinical trials. As such, the decision on whether to anticoagulate or not, and if so with what agent, poses significant challenges. A solid understanding of the condition in question and the available treatments is required to make an informed judgement call. An in-depth appreciation of the advantages and disadvantages of the currently available anticoagulants is a key element in the decision-making process.

Anticoagulation in Patients With Advanced Chronic Kidney Disease: Walking the Fine Line Between Benefit and Harm

Chronic kidney disease affects more than 3 million Canadians and is highly associated with cardiovascular diseases that require anticoagulation, such as atrial fibrillation and venous thromboembolism. Patients with chronic kidney disease are at a problematic crossroads; they are at high risk of thrombotic conditions requiring anticoagulation and bleeding complications due to anticoagulation. The limited high-quality clinical evidence to guide decision-making in this area further compounds the dilemma. In this review, we discuss the physiology and epidemiology of bleeding and thrombosis in patients with kidney disease. We specifically focus on patients with advanced kidney disease (estimated glomerular filtration rate ≤ 30 mL/min) or who are receiving dialysis and focus on the nephrologist perspective regarding these issues. We summarize the existing evidence for anticoagulation use in the prevention of stroke with atrial fibrillation and provide practical clinical recommendations for considering anticoagulation use in this population. Last, we examine specific scenarios such as the use of a glomerular filtration rate estimating equation and dosing, the use of existing prediction tools for stroke and hemorrhage risk, current patterns of anticoagulation use (including during the dialysis procedure), and vascular calcification with vitamin K antagonist use in patients with chronic kidney disease.