The Predictive Ability of the CHADS2 and CHA2DS2-VASc Scores for Bleeding Risk in Atrial Fibrillation: The MAQI2 Experience

Influence of thrombocytopenia on bleeding and vascular events in atrial fibrillation

Whether thrombocytopenia substantively increases the risk of hemorrhage associated with anticoagulation in patients with atrial fibrillation (AF) is not established. The purpose of this study was to compare rates of bleeding in patients with AF and thrombocytopenia (platelet count < 100 000/μL) to patients with AF and normal platelet counts (>150 000/μL). We performed a propensity score-matched, retrospective cohort study of adults (n = 1070) with a new diagnosis of AF who received a prescription for an oral anticoagulant between 2015 and 2020. The thrombocytopenia cohort was defined as having at least 2 platelet counts <100 000/μL on separate days in the period spanning the 12 weeks preceding the initiation of anticoagulation to 6 weeks after the initiation of anticoagulation. The primary end point was the 1-year cumulative incidence of major bleeding; secondary end points included clinically relevant bleeding, arterial and venous thrombotic events, and all-cause mortality. Patients with AF and thrombocytopenia experienced a higher 1-year cumulative incidence of major bleeding (13.3% vs 5.7%; P < .0001) and clinically relevant bleeding (24.5% vs 16.7%; P = .005) than the controls. Thrombocytopenia was identified as an independent risk factor for major bleeding (hazard ratio, 2.20; confidence interval, 1.36-3.58; P = .001), with increasing risk based on the severity of thrombocytopenia. The cumulative incidence of arterial thrombosis at 1 year was 3.6% in the group with thrombocytopenia and 1.5% in controls (Gray test, P = .08). These findings suggest that baseline platelet counts are an important biomarker for hemorrhagic outcomes in AF and that the degree of thrombocytopenia is an important factor in determining the level of risk.

Prediction of bleeding in patients being considered for venous thromboembolism prophylaxis

BACKGROUND

Venous thromboembolism (pulmonary embolism and deep vein thrombosis) is an important preventable cause of in-hospital death. Prophylaxis with low doses of anticoagulants reduces the incidence of venous thromboembolism but can also cause bleeding. It is, therefore, important to stratify the risk of bleeding for hospitalized patients when considering pharmacologic prophylaxis. The IMPROVE (international medical prevention registry on venous thromboembolism) and Consensus risk assessment models (RAMs) are the two tools available for such patients. Few studies have evaluated their ability to predict bleeding in a large, unselected cohort of patients. We assessed the ability of the IMPROVE and Consensus bleeding RAMs to predict bleeding within 90 days of hospitalization in a comprehensive analysis encompassing all hospitalized patients, regardless of surgical vs nonsurgical status.

METHODS

We analyzed consecutive first hospital admissions of 1,228,448 unique surgical and nonsurgical patients to 1298 Veterans Affairs facilities nationwide between January 2016 and December 2021. IMPROVE and Consensus scores were generated using data from a repository of their common electronic medical records. We assessed the ability of the two RAMs to predict bleeding within 90 days of admission. We used area under the receiver operating characteristic curves to determine the prediction of bleeding by each RAM.

RESULTS

Of 1,228,448 hospitalized patients, 324,959 (26.5%) were surgical and 903,489 (73.5%) were nonsurgical. Of these patients, 68,372 (5.6%) had a bleeding event within 90 days of admission. The Consensus RAM scores ranged from -5.60 to -1.21 (median, -4.93; interquartile range, -5.60 to -4.93). The IMPROVE RAM scores ranged from 0 to 22 (median, 3.5; interquartile range, 2.5-5). Both showed good calibration, with higher scores associated with higher bleeding rates. The ability of both RAMs to predict 90-day bleeding was low (area under the receiver operating characteristic curve 0.61 for the IMPROVE RAM and 0.59 for the Consensus RAM). The predictive ability was also low at 30 and 60 days for surgical and nonsurgical patients, patients receiving prophylactic, therapeutic, or no anticoagulation, and patients hospitalized for ≥72 hours. Prediction was also low across different bleeding outcomes (ie, any bleeding, gastrointestinal bleeding, nongastrointestinal bleeding, and bleeding or death).

CONCLUSIONS

In this large, unselected, nationwide cohort of surgical and nonsurgical hospital admissions, increasing IMPROVE and Consensus bleeding RAM scores were associated with increasing bleeding rates. However, both RAMs had low ability to predict bleeding at 0 to 90 days after admission. Thus, the currently available RAMs require modification and rigorous reevaluation before they can be applied universally.

[Comparison of Various Regimens of Antithrombotic Therapy in Patients With Valvular Heart Disease and Coronary Artery Disease After Surgical and Interventional Interventions]

AIM

To evaluate the postoperative incidence of bleeding, incidence of thromboembolic complications, and all-cause mortality in patients with valvular heart disease and ischemic heart disease (IHD) associated with various regimens of the antithrombotic treatment during one year after surgery.

MATERIAL AND METHODS

This study included 271 patients with valvular heart disease and IHD after heart valve replacement and myocardial revascularization from 2009 through 2018. However, during the follow-up period (12 months), contact with 12 patients was lost, and therefore these patients were excluded from the study. Further analysis included 259 patients. Coronary artery bypass grafting (CABG) in combination with heart valve intervention was performed in 217 (83.8 %) patients, and percutaneous coronary interventions (PCIs) were performed in 42 (16.2 %) patients. There were 197 (72.7 %) male participants; median age was 64.0 [58.0; 67.5] years. The patients were divided into two groups. Group 1 consisted of 113 patients who received postoperative dual antithrombotic therapy (DAT) with acetylsalicylic acid (ASA)/clopidogrel+vitamin K antagonist (VKA). Group 2 included 146 patients receiving postoperative triple antithrombotic therapy (TAT) with ASA+clopidogrel+VKA. Follow-up duration was 12 months after surgery. Due to significant intergroup differences in major clinical anamnestic data, the data were adjusted using pseudo-randomization (Propensity Score Matching, PSM). In result, 109 patients were selected for each group.

RESULTS

The incidence of adverse hemorrhagic outcomes was significantly higher in the group treated with TAT than with DAT. Minor bleedings were observed in 19 (17.4 %) vs. 8 (7.3 %) cases; moderate, clinically significant bleedings in 16 (14.7 %) vs. 6 (5.5 %) cases; and the total number of bleedings was 35 (32.1 %) vs. 14 (12.8 %; p=0.02, p=0.02, and р=0.001, respectively). Comparing the incidence of major bleedings did not show and significant intergroup differences (p=1.000). The incidence rate of any bleeding during the follow-up period was 32.1 % in patients treated with TAT (n=109) and 12.8 % in patients treated with DAT (n=109; p=0.005). The incidence of no bleeding during one year after surgery was 87 % in the DAT treatment group and 67 % in the TAT treatment group (p=0.005). The incidence of secondary endpoints, including ischemic stroke, myocardial infarction, prosthetic valve thrombosis, and death, was statistically non-significant.

CONCLUSION

Administration of DAT vs. TAT after heart valve replacement and myocardial revascularization significantly decreases the incidence of any bleedings in the absence of significant differences in the incidence of thromboembolic events and mortality.

Oral Anticoagulation in Patients With Advanced Chronic Kidney Disease and Atrial Fibrillation: Beyond Anticoagulation

The optimal approach to prevent stroke and systemic embolism in patients with advanced chronic kidney disease (CKD) and atrial fibrillation remains unresolved. We conducted a narrative review to explore areas of uncertainty and opportunities for future research. First, the relationship between atrial fibrillation and stroke is more complex in patients with advanced CKD than in the general population. The currently employed risk stratification tools do not adequately discriminate between patients deriving a net benefit and those suffering a net harm from oral anticoagulation. Anticoagulation initiation should probably be more restrictive than is currently advocated by official guidelines. Recent evidence reveals that the superior benefit-risk profile of non-vitamin K antagonist oral anticoagulants (NOACs) vs vitamin K antagonists (VKAs) observed in the general population and in moderate CKD can be extended to advanced CKD. The NOACs yield better protection against stroke, cause less major bleeding, are associated with less acute kidney injury and a slower decline of CKD, and are associated with a lower incidence of cardiovascular events than VKAs. The VKAs may be harmful in CKD patients, in particular in patients with a high bleeding risk and labile international normalized ratio. The better safety and efficacy of NOACs as opposed to VKAs may be particularly evident in advanced CKD as a result of better on-target anticoagulation with NOACs, harmful off-target vascular effects of VKAs, and beneficial off-target vascular effects of NOACs. The intrinsic vasculoprotective effects of NOACs are supported by animal experimental evidence as well as by findings of large clinical trials and may result in use of NOACs beyond their anticoagulant properties.

Comparison of Patient Outcomes Before and After Switching From Warfarin to a Direct Oral Anticoagulant Based on Time in Therapeutic Range Guideline Recommendations

This cohort study evaluates stroke and major bleeding rates before and after switching from warfarin to a direct oral anticoagulant (DOAC) in patients grouped by pre-switch time-in-therapeutic range guideline thresholds.

Barriers to prescribing oral anticoagulants to inpatients aged 80 years and older with nonvalvular atrial fibrillation: a cross-sectional study

Background

To investigate the temporal trend of the prevalence of underprescription of anticoagulation treatment and explore the factors associated with underprescription of oral anticoagulants (OACs) among inpatients aged ≥ 80 years with nonvalvular atrial fibrillation (NVAF).

Methods

We retrospectively reviewed the medical records of inpatients with a discharge diagnosis of NVAF from a medical database. We used the Pearson chi-square or Fisher’s exact test to compare categorical variables between patients with and without OAC prescriptions during hospitalization. Logistic regression analysis was used to assess the association between risk factors and underprescription of OACs.

Results

A total of 4375 patients aged ≥ 80 years with AF were assessed in the largest academic hospital in China from August 1, 2016, to July 31, 2020, and 3165 NVAF patients were included. The prevalence of underprescription of OACs was 79.1% in 2017, 71.3% in 2018, 64.4% in 2019, and 56.1% in 2020. Of all participants, 2138 (67.6%) were not prescribed OACs; 66.3% and 68.2% of patients with and without prior stroke did not receive OACs, respectively. Age (85–89 vs 80–84, OR = 1.48, 95% CI (1.25–1.74); 90 + vs 80–84, OR = 2.66, 95% CI: 2.09–3.42), clinical department where patients were discharged (Reference = Cardiology, Geriatrics: OR = 2.97, 95% CI: 2.45- 3.61; neurology: OR = 1.25, 95% CI: 0.96, 1.63; others: OR = 4.23, 95% CI: 3.43- 5.24), use of antiplatelets (OR = 1.69, 95% CI: 1.45- 1.97), and history of stroke (OR = 0.83, 95% CI: 0.71- 0.98 adjusted age), and dementia (OR = 2.16, 95% CI: 1.60- 2.96) were significantly associated with not prescribing OACs.

Conclusions

The prevalence of underprescription of OACs has decreased over the past several years. The rate of underprescription of OACs was higher among NVAF patients who were older, prescribed antiplatelets, discharged from nondepartmental cardiology, and suffered from comorbidities. This study found iatrogenic factors affecting the underprescription of OACs in inpatients aged ≥ 80 years, providing clues and a basis for the standardized use of OACs in inpatients.

Anticoagulation Changes Following Major and Clinically Relevant Nonmajor Bleeding Events in Non-valvular Atrial Fibrillation Patients

BACKGROUND

Bleeding events are common complications of oral anticoagulant drugs, including both warfarin and the direct oral anticoagulants (DOACs). Some patients have their anticoagulant changed or discontinued after experiencing a bleeding event, while others continue the same treatment. Differences in anticoagulation management between warfarin- and DOAC-treated patients following a bleeding event are unknown.

METHODS

Patients with non-valvular atrial fibrillation from six anticoagulation clinics taking warfarin or DOAC therapy who experienced an International Society of Thrombosis and Haemostasis (ISTH)-defined major or clinically relevant non-major (CRNM) bleeding event were identified between 2016 and 2020. The primary outcome was management of the anticoagulant following bleeding (discontinuation, change in drug class, and restarting of same drug class). DOAC- and warfarin-treated patients were propensity matched based on the individual elements of the CHA2DS2-VASc and HAS-BLED scores as well as the severity of the bleeding event.

RESULTS

Of the 509 patients on warfarin therapy and 246 on DOAC therapy who experienced a major or CRNM bleeding event, the majority of patients continued anticoagulation therapy. The majority of warfarin (231, 62.6%) and DOAC patients (201, 81.7%) restarted their previous anticoagulation.

CONCLUSION

Following a bleeding event, most patients restarted anticoagulation therapy, most often with the same type of anticoagulant that they previously had been taking.

Diagnostic Accuracy of the HAS-BLED Bleeding Score in VKA- or DOAC-Treated Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background: Several bleeding risk assessment models have been developed in atrial fibrillation (AF) patients with oral anticoagulants, but the most appropriate tool for predicting bleeding remains uncertain. Therefore, we aimed to assess the diagnostic accuracy of the Hypertension, Abnormal liver/renal function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly, Drugs/alcohol concomitantly (HAS-BLED) score compared with other risk scores in anticoagulated patients with AF.

Methods: We comprehensively searched the PubMed and Embase databases until July 2021 to identify relevant pieces of literature. The predictive abilities of risk scores were fully assessed by the C-statistic, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) values, calibration data, and decision curve analyses.

Results: A total of 39 studies met the inclusion criteria. The C-statistic of the HAS-BLED score for predicting major bleeding was 0.63 (0.61–0.65) in anticoagulated patients regardless of vitamin k antagonists [0.63 (0.61–0.65)] and direct oral anticoagulants [0.63 (0.59–0.67)]. The HAS-BLED had the similar C-statistic to the Hepatic or renal disease, Ethanol abuse, Malignancy, Older, Reduced platelet count or function, Re-bleeding risk, Hypertension (uncontrolled), Anemia, Genetic factors, Excessive fall risk, Stroke (HEMORR₂HAGES), the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA), the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT), the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF), or the Age, Biomarkers, Clinical History (ABC) scores, but significantly higher C-statistic than the Congestive heart failure, Hypertension, Age ≥75 years, Diabetes mellitus, Stroke/transient ischemic attack history (CHADS₂) or the Congestive heart failure/left ventricular ejection fraction ≤ 40%, Hypertension, Age ≥75 years, Diabetes mellitus, Stroke/transient ischemic attack/thromboembolism history, Vascular disease, Age 65–74 years, Sex (female) (CHA₂DS₂-VASc) scores. NRI and IDI values suggested that the HAS-BLED score performed better than the CHADS₂ or the CHA₂DS₂-VASc scores and had similar or superior predictive ability compared with the HEMORR₂HAGES, the ATRIA, the ORBIT, or the GARFIELD-AF scores. Calibration and decision curve analyses of the HAS-BLED score compared with other scores required further assessment due to the limited evidence.

Conclusion: The HAS-BLED score has moderate predictive abilities for bleeding risks in patients with AF regardless of type of oral anticoagulants. Current evidence support that the HAS-BLED score is at least non-inferior to the HEMORR₂HAGES, the ATRIA, the ORBIT, the GARFIELD-AF, the CHADS₂, the CHA₂DS₂-VASc, or the ABC scores.

Performance of bleeding risk scores in dialysis patients

BACKGROUND

Bleeding risk scores have been created to identify patients with an increased bleeding risk, which could also be useful in dialysis patients. However, the predictive performances of these bleeding risk scores in dialysis patients are unknown. Therefore, the aim of this study was to validate existing bleeding risk scores in dialysis patients.

METHODS

A cohort of 1745 incident dialysis patients was prospectively followed for 3 years during which bleeding events were registered. We evaluated the discriminative performance of the Hypertension, Abnormal kidney and liver function, Stroke, Bleeding, Labile INR, Elderly and Drugs or alcohol (HASBLED), the AnTicoagulation and Risk factors In Atrial fibrillation (ATRIA), the Hepatic or kidney disease, Ethanol abuse, Malignancy, Older age, Reduced platelet count or Reduced platelet function, Hypertension, Anaemia, Genetic factors, Excessive fall risk and Stroke (HEMORR2HAGES) and the Outcomes Registry for Better Informed Treatment (ORBIT) bleeding risk scores by calculating C-statistics with 95% confidence intervals (CI). In addition, calibration was evaluated by comparing predicted and observed risks.

RESULTS

Of the 1745 dialysis patients, 183 patients had a bleeding event, corresponding to an incidence rate of 5.23/100 person-years. The HASBLED [C-statistic of 0.58 (95% CI 0.54-0.62)], ATRIA [C-statistic of 0.55 (95% CI 0.51-0.60)], HEMORR2HAGES [C-statistic of 0.56 (95% CI 0.52-0.61)] and ORBIT [C-statistic of 0.56 (95% CI 0.52-0.61)] risk scores had poor discriminative performances in dialysis patients. Furthermore, the calibration analyses showed that patients with a low risk of bleeding according to the HASBLED, ATRIA, HEMORR2HAGES and ORBIT bleeding risk scores had higher incidence rates for bleeding in our cohort than predicted.

CONCLUSIONS

The HASBLED, ATRIA, HEMORR2HAGES and ORBIT bleeding risk scores had poor predictive abilities in dialysis patients. Therefore, these bleeding risk scores may not be useful in this population.

Cost-Effectiveness of Bridging Anticoagulation Among Patients with Nonvalvular Atrial Fibrillation

BACKGROUND

Bridging anticoagulation is commonly prescribed to patients with atrial fibrillation during initiation and interruption of warfarin. Guidelines recommend bridging patients at high risk of stroke, while a recent randomized trial demonstrated overall harm in a population at comparatively low risk of ischemic stroke. Theory suggests that patients at high risk of stroke and low risk of hemorrhage may benefit from bridging, but data informing patient selection are scant.

OBJECTIVE

To estimate the utility and cost-effectiveness of bridging anticoagulation among patients with nonvalvular atrial fibrillation, stratified by thromboembolic and hemorrhagic risk DESIGN: Cost-effectiveness analysis with lifelong time horizon, from the perspective of a third-party payer MAIN MEASURES: Quality-adjusted life years (QALYs) per bridged patient; US dollars per QALY gained KEY RESULTS: Unselected patients with nonvalvular atrial fibrillation may be harmed by bridging anticoagulation. Hospital admission for bridging is almost never cost-effective, and generally harmful. Among patients carefully selected by both thromboembolic and hemorrhagic risks, outpatient bridging can be beneficial and cost-effective. Results were sensitive to how effectively heparin products reduce stroke risk.

CONCLUSIONS

Outpatient bridging anticoagulation can be beneficial and cost-effective for a subset of patients with nonvalvular atrial fibrillation during interruption or initiation of warfarin. Admission for bridging should be avoided.

Risk factors for thromboembolic and bleeding events in anticoagulated patients with atrial fibrillation: the prospective, multicentre observational PREvention oF thromboembolic events - European Registry in Atrial Fibrillation (PREFER in AF)

OBJECTIVES

We identified factors associated with thromboembolic and bleeding events in two contemporary cohorts of anticoagulated patients with atrial fibrillation (AF), treated with either vitamin K antagonists (VKA) or non-VKA oral anticoagulants (NOACs).

DESIGN

Prospective, multicentre observational study.

SETTING

461 centres in seven European countries.

PARTICIPANTS

5310 patients receiving a VKA (PREvention oF thromboembolic events - European Registry in Atrial Fibrillation (PREFER in AF), derivation cohort) and 3156 patients receiving a NOAC (PREFER in AF Prolongation, validation cohort) for stroke prevention in AF.

OUTCOME MEASURES

Risk factors for thromboembolic events (ischaemic stroke, systemic embolism) and major bleeding (gastrointestinal bleeding, intracerebral haemorrhage and other life-threatening bleeding).

RESULTS

The mean age of patients enrolled in the PREFER in AF registry was 72±10 years, 40% were female and the mean CHA₂DS₂-VASc Score was 3.5±1.7. The incidence of thromboembolic and major bleeding events was 2.34% (95% CI 1.93% to 2.74%) and 2.84% (95% CI 2.41% to 3.33%) after 1-year of follow-up, respectively.Abnormal liver function, prior stroke or transient ischaemic attack, labile international normalised ratio (INR), concomitant therapy with antiplatelet or non-steroidal anti-inflammatory drugs, heart failure and older age (≥75 years) were independently associated with both thromboembolic and major bleeding events.With the exception of unstable INR values, these risk factors were validated in patients treated with NOACs (PREFER in AF Prolongation Study, 72±9 years, 40% female, CHA₂DS₂-VASc 3.3±1.6). For each single point decrease on a modifiable bleeding risk scale we observed a 30% lower risk for major bleeding events (OR 0.70, 95% CI 0.64 to 0.76, p<0.01) and a 28% lower rate of thromboembolic events (OR 0.72, 95% CI 0.66 to 0.82, p<0.01).

CONCLUSION

Attending to modifiable risk factors is an important treatment target in anticoagulated AF patients to reduce thromboembolic and bleeding events. Initiation of anticoagulation in those at risk of stroke should not be prevented by elevated bleeding risk scores.

Predicting Thromboembolic and Bleeding Event Risk in Patients with Non-Valvular Atrial Fibrillation: A Systematic Review

BACKGROUND

 Atrial fibrillation (AF) is a common cardiac arrhythmia that increases the risk of stroke. Medical therapy for decreasing stroke risk involves anticoagulation, which may increase bleeding risk for certain patients. In determining the optimal therapy for stroke prevention for patients with AF, clinicians use tools with various clinical, imaging and patient characteristics to weigh stroke risk against therapy-associated bleeding risk.

AIM

 This article reviews published literature and summarizes available risk stratification tools for stroke and bleeding prediction in patients with AF.

METHODS

 We searched for English-language studies in PubMed, Embase and the Cochrane Database of Systematic Reviews published between 1 January 2000 and 14 February 2018. Two reviewers screened citations for studies that examined tools for predicting thromboembolic and bleeding risks in patients with AF. Data regarding study design, patient characteristics, interventions, outcomes, quality, and applicability were extracted.

RESULTS

 Sixty-one studies were relevant to predicting thromboembolic risk and 38 to predicting bleeding risk. Data suggest that CHADS₂, CHA₂DS₂-VASc and the age, biomarkers, and clinical history (ABC) risk scores have the best evidence for predicting thromboembolic risk (moderate strength of evidence for limited prediction ability of each score) and that HAS-BLED has the best evidence for predicting bleeding risk (moderate strength of evidence).

LIMITATIONS

 Studies were heterogeneous in methodology and populations of interest, setting, interventions and outcomes analysed.

CONCLUSION

 CHADS₂, CHA₂DS₂-VASc and ABC scores have the best prediction for stroke events, and HAS-BLED provides the best prediction for bleeding risk. Future studies should define the role of imaging tools and biomarkers in enhancing the accuracy of risk prediction tools.

PRIMARY FUNDING SOURCE

 Patient-Centered Outcomes Research Institute (PROSPERO #CRD42017069999).

Structure and function of anticoagulation clinics in the United States: an AC forum membership survey

Many anticoagulation clinics have adapted their services to provide care for patients taking direct oral anticoagulants (DOAC) in addition to traditional warfarin management. Anticoagulation clinic scope of service and operations in this transitional environment have not been well described in the literature. A survey was conducted of United States-based Anticoagulation Forum members to inquire about anticoagulation clinic structure, function, and services provided. Survey responses are reported using summary or non-parametric statistics, when appropriate. Unique clinic survey responses were received from 159 anticoagulation clinics. Clinic structure and staffing are highly variable, with approximately half of clinics (52%) providing DOAC-focused care in addition to traditional warfarin-focused care. Of those clinics managing DOAC patients, this accounts for only 10% of their clinic volume. These clinics commonly have a DOAC follow up protocol (75%). Clinics assign a median of 190.5 (interquartile range 50-300) patients per staff full-time-equivalent, with more patients assigned in phone-based care clinics than in face-to-face based care clinics. Most clinics (68.5%) report receiving reimbursement, which occur either through a combination of patient and insurance provider billing (78.2%), insurance reimbursement only (19.5%) or patient reimbursement only (2.3%). There is wide heterogeneity in anticoagulation clinic structure, function, and services provided. Half of all survey-responding anticoagulation clinics provide care for DOAC-treated patients. Understanding how changes in healthcare policy and reimbursement have impacted these clinics remains to be explored.

Comparison of Clinical Outcomes Among Patients With Atrial Fibrillation or Atrial Flutter Stratified by CHA2DS2-VASc Score

Importance

Current guidelines support treating atrial fibrillation (AF) and atrial flutter (AFL) as equivalent risk factors for ischemic stroke stratified by CHA2DS2-VASc scores, recommending anticoagulation therapy for patients with a CHA2DS2-VASc score of 2 or higher, but some studies found differences in clinical outcomes.

Objective

To investigate differences in clinical outcomes among AF, AFL, and matched control cohorts.

Design, Setting, and Participants

This nationwide cohort study analyzed data from the Taiwan National Health Insurance Research Database from January 1, 2001, through December 31, 2012. Follow-up and data analysis ended December 31, 2012. A total of 219 416 age- and sex-matched individuals participated in the study. Clinical outcomes were compared after stratification by CHA2DS2-VASc score (possible score range, 0-9; higher scores indicate greater risk of ischemic stroke).

Main Outcomes and Measures

Ischemic stroke, heart failure hospitalization, and all-cause mortality among the AF, AFL, and matched control cohorts were analyzed using Cox proportional hazards regression.

Results

This study comprised 188 811 patients in the AF cohort (mean [SD] age, 73.8 [13.4] years; 104 703 [55.5%] male), 6121 patients in the AFL cohort (mean [SD] age, 67.7 [15.8] years; 3735 [61.0%] male), and 24 484 patients in the matched control cohort (mean [SD] age, 67.3 [15.6] years; 14 940 [61.0%] male). The patients with AF were older, were more predominantly female, and had higher CHA2DS2-VASc scores than the patients with AFL and the control participants. After stratification by CHA2DS2-VASc score, the incidence densities (IDs; events per 100 person-years) of ischemic stroke (AF cohort: ID, 3.08; 95% CI, 3.03-3.13; AFL cohort: ID, 1.45; 95% CI, 1.28-1.62; controls: ID, 0.97; 95% CI, 0.92-1.03), heart failure hospitalization (AF cohort: ID, 3.39; 95% CI, 3.34-3.44; AFL cohort: ID, 1.57; 95% CI, 1.39-1.74; controls: ID, 0.32; 95% CI, 0.29-0.35), and all-cause mortality (AF cohort: ID, 17.8; 95% CI, 17.7-17.9; AFL cohort: ID, 13.9; 95% CI, 13.4-14.4; controls: ID, 4.2; 95% CI, 4.1-4.4) were significantly higher in the AF cohort than in the matched control cohort. For the AFL cohort vs the matched control cohort, the incidences of heart failure hospitalization and all-cause mortality were significantly higher across all levels, but the incidence of ischemic stroke was only significantly higher at CHA2DS2-VASc scores of 5 to 9. For the AF cohort vs the AFL cohort, the incidences of ischemic stroke and heart failure hospitalization were significantly higher at a CHA2DS2-VASc score of 1 or higher, but the incidence of all-cause mortality was significantly higher only at CHA2DS2-VASc scores of 1 to 3.

Conclusions and Relevance

This study found different clinical outcomes between patients with AFL and AF and those without AF and AFL. The current recommended level of the CHA2DS2-VASc score in preventing ischemic stroke in patients with AFL should be reevaluated.

Extended International Normalized Ratio testing intervals for warfarin-treated patients

Essentials Warfarin typically requires International Normalized Ratio (INR) testing at least every 4 weeks. We implemented extended INR testing for stable warfarin patients in six anticoagulation clinics. Use of extended INR testing increased from 41.8% to 69.3% over the 3 year study. Use of extended INR testing appeared safe and effective.

SUMMARY

Background A previous single-center randomized trial suggested that patients with stable International Normalized Ratio (INR) values could safely receive INR testing as infrequently as every 12 weeks. Objective To test the success of implementation of an extended INR testing interval for stable warfarin patients in a practice-based, multicenter collaborative of anticoagulation clinics. Methods At six anticoagulation clinics, patients were identified as being eligible for extended INR testing on the basis of prior INR value stability and minimal warfarin dose changes between 2014 and 2016. We assessed the frequency with which anticoagulation clinic providers recommended an extended INR testing interval (> 5 weeks) to eligible patients. We also explored safety outcomes for eligible patients, including next INR values, bleeding events, and emergency department visits. Results At least one eligible period for extended INR testing was identified in 890 of 3362 (26.5%) warfarin-treated patients. Overall, the use of extended INR testing in eligible patients increased from 41.8% in the first quarter of 2014 to 69.3% in the fourth quarter of 2016. The number of subsequent out-of-range next INR values were similar between eligible patients who did and did not have an extended INR testing interval (27.3% versus 28.4%, respectively). The numbers of major bleeding events were not different between the two groups, but rates of clinically relevant non-major bleeding (0.02 per 100 patient-years versus 0.09 per 100 patient-years) and emergency department visits (0.07 per 100 patient-years versus 0.19 per 100 patient-years) were lower for eligible patients with extended INR testing intervals than for those with non-extended INR testing intervals. Conclusions Extended INR testing for stable warfarin patients can be successfully and safely implemented in diverse, practice-based anticoagulation clinic settings.

Multiple spontaneous hemorrhages after commencing warfarin therapy

A 94 year-old Japanese woman with renal dysfunction was admitted to our hospital for congestive heart failure caused by atrial fibrillation with rapid ventricular response. Considering the risk of stroke, warfarin was commenced. However, she developed shock following brachial and retroperitoneal hemorrhage 4 days after starting warfarin despite not being over-anticoagulated. She recovered after receiving blood transfusion and intravenous vitamin K2. Bleeding during warfarin administration occurs more frequently in older individuals with lower glomerular filtration rates, especially within the first 30 days of warfarin treatment. Physicians should therefore check for unexpected bleeding after commencing warfarin and be prepared to reverse anticoagulation.

Underuse of Oral Anticoagulants and Inappropriate Prescription of Antiplatelet Therapy in Older Inpatients with Atrial Fibrillation

BACKGROUND

Several studies have shown that the prescription of antiplatelet therapy (APT) is associated with an increased risk of oral anticoagulant (OAC) underuse in patients aged 75 years and over with atrial fibrillation (AF). An associated atheromatous disease may be the underlying reason for APT prescription. The objective of the study was to determine whether the association between underuse of OAC and APT prescription was explained by the presence of an atheromatous disease.

METHODS AND RESULTS

We performed a retrospective, observational, single-centre study between 2009 and 2013 based on administrative data. Patients aged 75 years and over with non-valvular AF were identified in a database of 72,090 hospital stays. Prescriptions of anti-thrombotic medications and their association with the presence of atheromatous disease were evaluated by the mean of a logistic regression. A total of 2034 hospital stays were included (mean age 84.3 ± 5.2 years). The overall prevalence of known atheromatous disease was 25.9%. OAC underuse was observed in 58.5% of the stays. In multivariable analysis, the prescription of an APT was associated with an increased risk of OAC underuse [odds ratio (OR) 6.85; 95% confidence interval (CI) 5.50-8.58], independently of the presence of a concomitant known atheromatous disease (OR 0.78; 95% CI 0.60-1.01). Among the 692 stays with APT monotherapy (34.0%), 232 (33.5%) displayed an atheromatous disease.

CONCLUSIONS

The underuse of OAC is associated with the prescription of APT in older patients with AF, regardless of the presence or absence of known atheromatous disease. Our results suggest that APT is often inappropriately prescribed instead of OAC.

Personalizing Bridging Anticoagulation in Patients with Nonvalvular Atrial Fibrillation-a Microsimulation Analysis

BACKGROUND

Bridging anticoagulation is commonly prescribed to patients with atrial fibrillation who are initiating warfarin or require interruption of anticoagulation. Current guidelines recommend bridging for patients at high risk of stroke. Among patients with atrial fibrillation and one or more risk factors for ischemic stroke, the recently published BRIDGE trial found forgoing bridging during interruption to be, on average, noninferior to bridging with respect to ischemic complications, with significantly fewer hemorrhagic complications.

OBJECTIVE

We sought to examine the benefits and harms of bridging anticoagulation across the spectrum of ischemic and hemorrhagic stroke risk and thereby enable more nuanced, risk-stratified decision-making when bridging is considered during initiation or interruption of vitamin K antagonists.

DESIGN

A Monte Carlo simulation, using a combination of literature-derived estimates, registry data, and trial data.

MAIN MEASURES

Net clinical benefit, weighting for ischemic strokes, intracranial hemorrhages, and extracranial major hemorrhages.

KEY RESULTS

The benefits and harms of bridging anticoagulation vary according to underlying patient risk profiles for both thromboembolic stroke and major intracranial bleeding. Patients at high risk of ischemic stroke and low risk of hemorrhage derive benefit from bridging during initiation or interruption of warfarin therapy. Patients at similarly high or low risk of both outcomes may receive benefit from bridging during initiation and bridging during interruption, but this was sensitive to underlying assumptions. The need for stratification along both axes of risk was robust to a wide range of parameters.

CONCLUSIONS

Bridging anticoagulation may provide benefit to patients at high risk of ischemic stroke and low risk of intracranial hemorrhage who are initiating or interrupting warfarin therapy, while patients at high or low risk of both complications may be harmed. The use of bridging anticoagulation in patients with non-valvular atrial fibrillation should be considered only after stratification by risk of ischemic and hemorrhagic complications.

The HAS-BLED Score for Predicting Major Bleeding Risk in Anticoagulated Patients With Atrial Fibrillation: A Systematic Review and Meta-analysis

Our objective was to compare the diagnostic accuracy between the HAS-BLED score and any of HEMORR2 HAGES, ATRIA, CHADS2 , or CHA2 DS2 -VASc scores in anticoagulated patients with atrial fibrillation. We systematically searched the Cochrane Library, MEDLINE, PubMed, and Embase databases for relevant studies. Data were extracted and analyzed according to predefined clinical endpoints. Eleven studies were identified. Discrimination analysis demonstrates that HAS-BLED has no significant C-statistic differences for bleeding risk prediction compared with ATRIA or HEMORR2 HAGES, but it has significant differences compared with CHADS2 or CHA2 DS2 -VASc. The significant positive net reclassification improvement and integrated discrimination improvement values also show that HAS-BLED is superior to that of any of HEMORR2 HAGES, ATRIA, CHADS2 , or CHA2 DS2 -VASc scores. According to calibration analysis of HAS-BLED, it overpredicts the risk of bleeding in the low (risk ratio [RR]: 1.16, 95% confidence interval [CI]: 0.63-2.13, P = 0.64) risk stratification but underpredicts that in the moderate (RR: 0.66, 95% CI: 0.51-0.86, P = 0.002) and high (RR: 0.88, 95% CI: 0.70-1.10, P = 0.27) risk stratifications. The HAS-BLED score not only performs better than the HEMORR2 HAGES and ATRIA bleeding scores, but it also is superior to the CHADS2 and CHA2 DS2 -VASc stroke scores for bleeding prediction. The HAS-BLED score should be the optimal choice to assess major bleeding risk in clinical practice.

The changing characteristics of atrial fibrillation patients treated with warfarin

It has been suggested that direct oral anticoagulants are being preferentially used in low risk atrial fibrillation (AF) patients. Understanding the changing risk profile of new AF patients treated with warfarin is important for interpreting the quality of warfarin delivery through an anticoagulation clinic. Six anticoagulation clinics participating in the Michigan Anticoagulation Quality Improvement Initiative enrolled 1293 AF patients between 2010 and 2014 as an inception cohort. Abstracted data included demographics, comorbidities, medication use and all INR values. Risk scores including CHADS2, CHA2DS2-VASc, HAS-BLED, SAMe-TT2R2, and Charlson comorbidity index (CCI) were calculated for each patient at the time of warfarin initiation. The quality of anticoagulation was assessed using the Rosendaal time in the therapeutic range (TTR) during the first 6 months of treatment. Between 2010 and 2014, patients initiating warfarin therapy for AF had an increasing mean CHADS2 (2.0 ± 1.1 to 2.2 ± 1.4, p = 0.02) and CCI (4.7 ± 1.8 to 5.1 ± 2.0, p = 0.03), and a trend towards increasing mean CHA2DS2-VASc, HAS-BLED, and SAMe-TT2R2 scores. The actual TTR remained unchanged over the study period (62.6 ± 18.2 to 62.7 ± 17.0, p = 0.98), and the number of INR checks did not change (18.9 ± 5.2 to 18.5 ± 5.1, p = 0.06). Between 2010 and 2014, AF patients newly starting warfarin had mild increases in risk for stroke and death with sustained quality of warfarin therapy.

Predictive ability of HAS-BLED, HEMORR2HAGES, and ATRIA bleeding risk scores in patients with atrial fibrillation. A French nationwide cross-sectional study

OBJECTIVE

The HAS-BLED, ATRIA, and HEMORR2HAGES risk scores were created to evaluate individual bleeding risk in atrial fibrillation (AF). We sought to estimate and compare the predictive ability of these scores for major hemorrhage in AF, including elderly (≥80years) and non-elderly (<80years) patients.

METHODS

This cross-sectional study is based on the French National Hospital Database (PMSI), which covers the entire French population. Data from all patients with an AF diagnosis in 2012 were extracted. Demographic and comorbidity data were used to calculate the three bleeding risk scores for each patient. Patients hospitalized with a principal diagnosis of major bleeding were identified.

RESULTS

Of the 533,044 AF patients identified, 53.2% were ≥80years; 7013 patients (1.3%) were hospitalized for a bleeding event (1785 for intracranial hemorrhage). Bleeding occurred more frequently in patients with higher HAS-BLED, HEMORR2HAGES, and ATRIA scores. In patients ≥80years, the c-statistics did not differ (p=0.27) between HAS-BLED (0.54; 95% confidence interval [CI]: 0.53-0.54), HEMORR2HAGES (0.53; 95% CI: 0.53-0.54), and ATRIA (0.53; 95% CI: 0.52-0.54). In patients <80years, HAS-BLED (0.59; 95% CI: 0.58-0.60) had a slightly higher c-statistic than HEMORR2HAGES (0.56; 95% CI: 0.55-0.57) and ATRIA (0.55, 95% CI: 0.55-0.56) (p<0.0001).

CONCLUSIONS

Given its simplicity and similar performance, HAS-BLED may be an attractive alternative to HEMORR2HAGES for estimation of bleeding risk in AF patients <80years. However, accurate determination of bleeding risk among the elderly is difficult with existing risk-prediction scores, indicating a clear need for improvement in their clinical utility.

International Validity of the HOSPITAL Score to Predict 30-Day Potentially Avoidable Hospital Readmissions

IMPORTANCE

Identification of patients at a high risk of potentially avoidable readmission allows hospitals to efficiently direct additional care transitions services to the patients most likely to benefit.

OBJECTIVE

To externally validate the HOSPITAL score in an international multicenter study to assess its generalizability.

DESIGN, SETTING, AND PARTICIPANTS

International retrospective cohort study of 117 065 adult patients consecutively discharged alive from the medical department of 9 large hospitals across 4 different countries between January 2011 and December 2011. Patients transferred to another acute care facility were excluded.

EXPOSURES

The HOSPITAL score includes the following predictors at discharge: hemoglobin, discharge from an oncology service, sodium level, procedure during the index admission, index type of admission (urgent), number of admissions during the last 12 months, and length of stay.

MAIN OUTCOMES AND MEASURES

30-day potentially avoidable readmission to the index hospital using the SQLape algorithm.

RESULTS

Overall, 117 065 adults consecutively discharged alive from a medical department between January 2011 and December 2011 were studied. Of all medical discharges, 16 992 of 117 065 (14.5%) were followed by a 30-day readmission, and 11 307 (9.7%) were followed by a 30-day potentially avoidable readmission. The discriminatory power of the HOSPITAL score to predict potentially avoidable readmission was good, with a C statistic of 0.72 (95% CI, 0.72-0.72). As in the derivation study, patients were classified into 3 risk categories: low (n = 73 031 [62.4%]), intermediate (n = 27 612 [23.6%]), and high risk (n = 16 422 [14.0%]). The estimated proportions of potentially avoidable readmission for each risk category matched the observed proportion, resulting in an excellent calibration (Pearson χ2 test P = .89).

CONCLUSIONS AND RELEVANCE

The HOSPITAL score identified patients at high risk of 30-day potentially avoidable readmission with moderately high discrimination and excellent calibration when applied to a large international multicenter cohort of medical patients. This score has the potential to easily identify patients in need of more intensive transitional care interventions to prevent avoidable hospital readmissions.

Predicting Atrial Fibrillation and Its Complications

Atrial fibrillation (AF) is a common cardiac arrhythmia associated with an increased risk of stroke and other complications. Identifying individuals at higher risk of developing AF in the community is now possible using validated predictive models that take into account clinical variables and circulating biomarkers. These models have shown adequate performance in racially and ethnically diverse populations. Similarly, risk stratification schemes predict incidence of ischemic stroke in persons with AF, assisting clinicians and patients in decisions regarding oral anticoagulation use. Complementary schemes have been developed to predict the risk of bleeding in AF patients taking vitamin K antagonists. However, major gaps exist in our ability to predict AF and its complications. Additional research should refine models for AF prediction and determine their value to improve population health and clinical outcomes, advance our ability to predict stroke and other complications in AF patients, and develop predictive models for bleeding events and other adverse effects in patients using non-vitamin K oral anticoagulants. (Circ J 2016; 80: 1061-1066).

Direct Oral Anticoagulants for the Prevention of Stroke in Patients with Nonvalvular Atrial Fibrillation: Understanding Differences and Similarities

The presence of atrial fibrillation (AF), the most common sustained cardiac arrhythmia, significantly increases the risk for stroke. Current guidelines recommend that the vitamin K antagonist warfarin or direct oral anticoagulants (DOACs), such as the approved direct thrombin inhibitor dabigatran and the approved direct factor Xa inhibitors apixaban, rivaroxaban, and edoxaban, should be used for thromboprophylaxis in patients with nonvalvular AF at risk for stroke or systemic embolic events (SEE). Warfarin, the mainstay of stroke prevention in AF, increases the risk of major bleeding. Furthermore, warfarin therapy comes with several limitations including frequent monitoring and the need for dose adjustments, unpredictable pharmacokinetics and pharmacodynamics, and the potential for significant drug-drug and food-drug interactions. The DOACs were developed to overcome these limitations while maintaining or surpassing warfarin's efficacy and safety profiles. All four DOACs have similar or better efficacy and safety compared with warfarin and are therefore valuable alternatives for the prevention of stroke and SEE in patients with nonvalvular AF. Understanding the subtle differences in the DOACs' pharmacology, phase 3 study designs, and trial outcomes will allow for a more tailored approach in selecting the right oral anticoagulant for each patient.