Antithrombotic treatment for stroke prevention in atrial fibrillation: The Asian agenda

Direct Anticoagulants Versus Vitamin K Antagonists in Patients Aged 80 Years or Older With Atrial Fibrillation in a "Real-world" Nationwide Registry: Insights From the FANTASIIA Study

OBJECTIVE

To describe major events at follow up in octogenarian patients with atrial fibrillation (AF) according to anticoagulant treatment: direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs).

METHODS

A total of 578 anticoagulated patients aged ≥80 years with AF were included in a prospective, observational, multicenter study. Basal features, embolic events (stroke and systemic embolism), severe bleedings, and all-cause mortality at follow up were investigated according to the anticoagulant treatment received.

RESULTS

Mean age was 84.0 ± 3.4 years, 56% were women. Direct oral anticoagulants were prescribed to 123 (21.3%) patients. Compared with 455 (78.7%) patients treated with VKAs, those treated with DOACs presented a lower frequency of permanent AF (52.9% vs 61.6%, P = .01), cancer history (4.9% vs 10.9%, P = .046), renal failure (21.1% vs 32.2%, P = .02), and left ventricular dysfunction (2.4% vs 8.0%, P = .03); and higher frequency of previous stroke (26.0% vs 16.6%, P = .02) and previous major bleeding (8.1% vs 3.6%, P = .03). There were no significant differences in Charlson, CHA2DS2VASc, nor HAS-BLED scores. At 3-year follow up, rates of embolic events, severe bleedings, and all-cause death (per 100 patients-year) were similar in both groups (DOACs vs VKAs): 0.34 vs 1.35 (P = .15), 3.45 vs 4.41 (P = .48), and 8.2 vs 11.0 (P = .18), respectively, without significant differences after multivariate analysis (hazard ratio [HR]: 0.25, 95% confidence interval [CI]: 0.03-1.93, P = .19; HR: 0.88, 95% CI: 0.44-1.76, P = .72 and HR: 0.84, 95% CI: 0.53-1.33, P = .46, respectively).

CONCLUSION

In this "real-world" registry, the differences in major events rates in octogenarians with AF were not statistically significant in those treated with DOACs versus VKAs.

Temporal Trends and Patient Characteristics Associated With Drug Utilisation After First-Ever Stroke: Insights From Chronic Disease Registry Data in Singapore

Introduction: Data on drug utilisation among stroke patients of Asian ethnicities are lacking. The objectives of the study were to examine the temporal trends and patient characteristics associated with prescription of thrombolytic, antithrombotic and statin medications among patients with first-ever stroke. Materials and Methods: First-ever ischaemic and haemorrhagic stroke patients admitted to 2 Singapore tertiary hospitals between 2010‒2014 were included. Data were extracted from the National Healthcare Group Chronic Disease Management System. Association between drug utilisation and admission year, as well as characteristics associated with drug use, were explored using multivariable logistic regression. Results: There was an increasing trend in the combined use of all 3 guideline medications in ischaemic stroke patients (P<0.001) ―specifically thrombolytic agents (P <0.001), oral antithrombotics (P = 0.002) and statins (P = 0.003) at discharge. Among antithrombotics, the use of clopidogrel (P <0.001) and aspirinclopidogrel (P <0.001) had increased, whereas prescription of dipyridamole (P <0.001) and aspirin-dipyridamole (P <0.001) had declined. For statins, the increase in atorvastatin prescription (P <0.001) was accompanied by decreasing use of simvastatin (P <0.001). Age, ethnicity and certain comorbidities (hyperlipidaemia, atrial fibrillation and chronic kidney disease) were associated with the combined use of all 3 guideline medications (P <0.05). In haemorrhagic stroke, prescription of statins at discharge were comparatively lower. Conclusion: This study reveals changes in prescription behaviour over time in a multiethnic Asian population with first-ever stroke. Patient characteristics including younger age, Malay ethnicity and certain comorbidities (i.e. hyperlipidaemia, atrial fibrillation) were associated with the combined use of all 3 guideline medications among ischaemic stroke patients. Key words: Antithrombotics, Asian, Statins, Thrombolytic agents

Using non-vitamin K oral anticoagulants in specific patient populations: a study of Korean cases

Non-vitamin K oral anticoagulants (NOACs) are increasingly used as alternatives to conventional therapies and have considerable accumulated real-world clinical data in patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE). However, it is not easy to make a complete changeover to NOACs in real-world clinical practice because NOACs still have challenges in specific patient populations (eg, Asian patients, NVAF patients presenting with acute coronary syndrome [ACS], dialysis patients with NVAF, patients with cancer-associated VTE, etc.). Clinical data on the optimal dose of NOACs in Asian patients with NVAF are not sufficient. The intensity of NOAC and antiplatelet treatment and the duration of antiplatelet treatment should be adjusted according to the bleeding and thrombotic risk profiles of the individual NVAF patient presenting with ACS. Increased bleeding risk and unclear efficacy of NOACs in dialysis patients with NVAF should be considered when making decisions on whether to give NOACs for these patients. If dialysis patients with NVAF require anticoagulant for stroke prevention, then apixaban could be considered while awaiting more clinical efficacy and safety data. Additional studies are needed to determine the utility of continuing treatment with reduced-dose NOACs for long-term therapy after VTE. We have enough experiences in using NOACs in cancer patients showing the benefit of antithrombotic treatment counterbalanced the bleeding risk; however, some challenges of cancer-associated VTE management exist due to differences in cancer types or chemotherapy regimens and comorbidities. Different dosing regimens among NOACs may impact on medication adherence; thus, individual patient preference should be considered in choosing a particular NOAC. A significant proportion of patients remain on warfarin because of the high price of NOACs and variability in reimbursement coverage. To compensate clinical-evidence and achieve optimal use of NOACs, we should pay attention to the outcomes of ongoing studies and evaluate more real-world data.

Antithrombotic Treatment May Reduce Mortality Among New-Onset Atrial Fibrillation Patients with Gray-Zone Risk of Stroke

In clinical practice, some atrial fibrillation (AF) patients were classified as having low and moderate stroke risk by the CHADS₂ score (≤ 1) in 2001 but in 2012 they were not truly classified as low risk of stroke according to the CHA₂DS₂-VASc score (≥ 2) (defined gray zone). Therefore, a treatment gap exists in gray zone AF patients. This study aimed to evaluate whether gray zone AF patients could benefit from reduced all-cause mortality under antithrombotic treatment. This was a longitudinal cohort study performed using data from claim forms submitted to the Taiwan Bureau of National Health Insurance from January 2000 to December 2011. The new-onset AF patients consisted of a gray zone cohort with a total of 1237 patients being enrolled. The primary outcome was all-cause mortality between 2001 and 2011. Patients in the gray zone receiving antithrombotic treatment had a significant reduction in all-cause mortality [hazard ratio (HR): 0.21; 95% confidence interval (CI): 0.16-0.28] compared with the no treatment group [warfarin only: HR, 0.28 (95% CI, 0.15-0.52); warfarin + Aspirin: HR, 0.21 (95% CI, 0.15-0.30); and Aspirin only: HR, 0.22 (95% CI, 0.16-0.29) ]. All-cause mortality was notably increased when any of the following risk factors were present: age 65-74 years, age ≥ 75 years, chronic kidney disease, and vascular disease. We concluded that AF patients in the gray zone must receive either anticoagulant and/or antiplatelet treatment and there is a lower mortality in these groups during long-term follow-up. Further investigation is needed to observe whether the antithrombotic drugs have benefits for patients with AF with a CHA₂DS₂-VASc score < 2.

Racial and ethnic differences in the prevalence, management, and outcomes in patients with atrial fibrillation: A systematic review

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the United States and is associated with increased morbidity, mortality, and health care expenditures. In this review, our aim was to assess the racial and ethnic differences in the epidemiology, management, and outcomes of patients with AF. A search of relevant studies from January 1, 2007, to December 30, 2017, was conducted in PubMed, EMBASE, and Web of Science and supplemented by manual searches of the bibliographies of retrieved articles. We identified 152 studies of which 64 were subsequently included. We found that underrepresented racial and ethnic groups have a higher prevalence of established risk factors associated with the development of AF but an overall lower incidence and prevalence of AF as compared with non-Hispanic whites. Moreover, racial and ethnic differences exist in detection, awareness, and AF-associated symptoms. Nonwhite populations also experience decreased use of rhythm control modalities and anticoagulation for stroke prevention. Lastly, among those with AF, underrepresented racial and ethnic groups had increased morbidity and mortality relative to white groups. Racial and ethnic differences exist in the prevalence, quality of life, management, and outcomes of individuals with AF; however, the mechanisms for these differences have yet to be fully elucidated. Racial and ethnic differences in AF warrant further analysis to understand the factors contributing to the differences in prevalence and management to ensure the delivery of high quality care that prevents stroke, reduces deaths, and decreases expenses associated with caring for underrepresented populations with AF.

Survey of Antithrombotic Treatment in Rural Patients (>60 years) with Atrial Fibrillation in East China

The prevalence and antithrombotic treatment of atrial fibrillation (AF) in Chinese rural population is not well known. The aim of this study was to investigate the extent to which antithrombotic treatment was prescribed for rural AF patients >60 years. We identified 828 AF patients from 36734 rural residents >60 years in Shanghai China. Our data indicated the overall prevalence rate of AF was 2.3% in rural population >60 years in East China and 38.9% of AF patients underwent antithrombotic therapy, including warfarin (5.9%), aspirin (29.6%), clopidogrel (2.9%) and aspirin combined with clopidogrel (0.5%). Of enrolled subjects, 98.4% had CHA₂DS₂-VASc score ≥1, 72.0% had HAS-BLED score <3 and 59.2% had CHA₂DS₂-VASc score ≥2 with HAS-BLED score <3. Missing early detection (34.9%), delay in seeking treatment for asymptomatic AF (25.5%) and doctors’s incomplete inform of AF-related risk of stroke to patients (21.7%) were three dominant causes for failing anticoagulant usage. In conclusion, most AF patients were with a high risk of thrombosis and a low risk of bleeding in China, but a large majority of them failed to take anticoagulants mainly for missing an early screening of AF and lack of awareness on AF for both patients and primary care physicians.

Long-Term Statin Administration Does Not Affect Warfarin Time in Therapeutic Range in Australia or Singapore

BACKGROUND

Warfarin requires ongoing monitoring of the International Normalised Ratio (INR). This is because numerous factors influence the response, including drug interactions with commonly-prescribed medications, such as statins. The administration of statins with warfarin may change INR; however, there is limited information regarding the effects on warfarin control as measured by time in therapeutic range (TTR). Statins may also alter bleeds with warfarin, but there are conflicting reports demonstrating both increased and decreased bleeds, and limited data on diverse ethnic populations. Therefore, the aim of this study was to determine the effect of statin administration on warfarin control and bleeds in patients in Australia and Singapore.

METHODS

Retrospective data were collected for patients on warfarin between January and June 2014 in Australia and Singapore. Patient data were used to calculate TTR and bleed events. Concurrent statin therapy was assessed and comparisons of TTR and bleed incidence were made across patient subgroups.

RESULTS

Warfarin control in Australia and Singapore was not significantly affected by statins, as measured by TTR (83% and 58%, respectively), frequency of testing, and warfarin doses. In Australia, statin use did not significantly affect bleeds, whilst in Singapore the bleed incidence was significantly lower for patients on statins.

CONCLUSIONS

Chronic concurrent administration of statins with warfarin does not adversely affect warfarin TTR in Australia or Singapore. In Singapore, patients on statins, compared to no statins, had a lower bleed incidence and this requires further investigation, especially given the potential genetic influences of ethnicity on both statin and warfarin metabolism.

High Incidence of Occult Atrial Fibrillation in Asian Patients with Cryptogenic Stroke

BACKGROUND

Occult atrial fibrillation (AF) is not uncommon in patients with stroke. In western cohorts, insertable loop recorders (ILRs) have been shown to be the gold-standard and are cost-effective for AF detection. Anticoagulation for secondary stroke prevention is indicated if AF is detected. The incidence of occult AF among Asian patients with cryptogenic stroke is unclear.

METHODS

Patients with cryptogenic stroke referred between August 2014 and February 2017 had ILRs implanted. Episodes of AF >2 minutes duration were recorded using proprietary algorithms within the ILRs, whereupon clinicians and patients were alerted via remote monitoring. All AF episodes were adjudicated using recorded electrograms. Once AF was detected, patients were counseled for anticoagulation.

RESULTS

Seventy-one patients with cryptogenic stroke, (age 61.9 ± 13.5 years, 77.5% male, mean CHA₂DS₂VASc score of 4.2 ± 1.3) had ILRs implanted. Time from stroke to the ILR implant was a median of 66 days. Duration of ILR monitoring was 345 ± 229 days. The primary endpoint of AF detection at 6 months was 12.9%; and at 12 months it was 15.2%. Median time to detection of AF was 50 days. The AF episodes were all asymptomatic and lasted a mean of 77 minutes (± 118.9). Anticoagulation was initiated in all but 1 patient found to have AF.

CONCLUSIONS

The incidence of occult AF is high in Asian patients with cryptogenic stroke and comparable to western cohorts. The combination of ILR and remote monitoring is a highly automated, technologically driven, and clinically effective technique to screen for AF.

Antithrombotic Therapy Underutilization in Patients With Atrial Flutter

BACKGROUND

Patients with atrial fibrillation not being adequately treated with oral anticoagulant (OAC) therapy, with therapy underutilization or premature termination, have been commonly reported. However, studies on the utilization pattern of OAC therapy for patients with atrial flutter (AFL) are few. The aim of this study was to investigate the utilization of OAC therapy, and its influencing factors for patients with AFL in South Korea, as well as the types and percentages of anticoagulants used.

METHODS

We analyzed Aged Population Sample data compiled by the Health Insurance Review & Assessment Service from 2011 to 2015. We identified patients with AFL having the KCD-6 code I48.1. Patients at high risk of stroke with a congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke (or transient ischemic attack), vascular disease, sex score of ≥2 and at low risk of bleeding with an anticoagulation and risk factors in atrial fibrillation score of ≤4 were included in the study. Oral anticoagulant therapy underutilization was estimated in these patients using anticoagulant underutilization (ACU) scales. Demographic and clinical factors associated with OAC therapy underutilization were investigated using a logistic regression model.

RESULTS

The mean ACU value was calculated as 67.4% between 2011 and 2015. Positive risk factors for ACU were identified as follows: female sex, aspirin utilization, and limited anticoagulant options. Negative risk factors included comorbidities, such as congestive heart failure and valvular heart disease, and a history of stroke or transient ischemic attack.

CONCLUSIONS

Our study demonstrates that two-third of patients with AFL in South Korea failed to obtain adequate stroke prevention treatment, even in the era of direct OAC availability. This tendency was more profound in women or those on aspirin therapy.

Prescription of secondary preventive drugs after ischemic stroke: results from the Malaysian National Stroke Registry

BACKGROUND

Evaluation of secondary stroke prevention in low and middle-income countries remains limited. This study assessed the prescription of secondary preventive drugs among ischemic stroke patients upon hospital discharge in Malaysia and identified factors related to the prescribing decisions.

METHODS

From Malaysian National Stroke Registry, we included patients with non-fatal ischemic stroke. Prescriptions of antiplatelet, anticoagulants, antihypertensive drugs and lipid-lowering drugs were assessed. Multi-level logistic regressions were performed to determine the relation between potential factors and drug prescriptions.

RESULTS

Of 5292 patients, 48% received antihypertensive drugs, 88.9% antiplatelet and 88.7% lipid-lowering drugs upon discharge. Thirty-three percent of patients with an indication for anticoagulants (n = 391) received it. Compared to patients <=50 years, patients above 70 years were less likely to receive antiplatelet (OR: 0.72, 95% CI: 0.50-1.03), lipid-lowering drugs (OR: 0.66, 95% CI: 0.45-0.95) and anticoagulants (OR: 0.27, 95% CI: 0.09-0.83). Patients with moderate to severe disability upon discharge had less odds of receiving secondary preventive drugs; an odds ratio of 0.57 (95% CI: 0.45-0.71) for antiplatelet, 0.86 (95% CI: 0.75-0.98) for antihypertensive drugs and 0.78 (95% CI: 0.63-0.97) for lipid-lowering drugs in comparison to those with minor disability. Having prior specific comorbidities and drug prescriptions significantly increased the odds of receiving these drugs. No differences were found between sexes and ethnicities.

CONCLUSIONS

Prescription of antihypertensive drugs and anticoagulants among ischemic stroke patients in Malaysia were suboptimal. Efforts to initiate regular clinical audits to evaluate the uptake and effectiveness of secondary preventive strategies are timely in low and middle-income settings.

Bleeding risk of apixaban, dabigatran, and low-dose rivaroxaban compared with warfarin in Japanese patients with non-valvular atrial fibrillation: a propensity matched analysis of administrative claims data

OBJECTIVES

There is scarce evidence comparing novel oral anticoagulants (NOACs) with warfarin in real-world settings in Japan. This study compared the risk of bleeding events among patients with non-valvular atrial fibrillation (NVAF) initiating treatment with NOACs versus warfarin.

METHODS

A retrospective cohort study was conducted using a de-identified electronic health record based database of health claims and Diagnosis Procedure Combination data from 275 consenting hospitals in Japan. NVAF patients newly initiated on oral anticoagulants were eligible. Based on the first prescription, patients were assigned to 5/2.5 mg BID apixaban, 150/110 mg BID dabigatran, 15/10 mg QD rivaroxaban (approved dose lower in Japan compared to Western countries [20/15 mg QD]) or warfarin groups. One-to-one propensity score matching (PSM) was used to balance patient characteristics between warfarin and each NOAC. Patients were followed up to 1 year post-first prescription.

RESULTS

Among 38,662 eligible patients, a total of 5977, 5090, and 6726 matched pairs were identified for warfarin versus apixaban, warfarin versus dabigatran, and warfarin versus rivaroxaban, respectively after PSM. Compared to warfarin, apixaban (hazard ratio [HR] 0.586; 95% CI 0.421-0.815), dabigatran (HR 0.617; 0.425-0.895) and rivaroxaban (HR 0.693; 0.514-0.933) were associated with a significantly lower risk of major bleeding. The risk of any bleeding was significantly lower for apixaban (HR 0.782; 0.682-0.896), but not for dabigatran (HR 0.988; 0.860-1.135) or rivaroxaban (HR 0.938; 0.832-1.057) when comparing to warfarin.

CONCLUSIONS

Among Japanese patients with NVAF, treatment with apixaban 5/2.5 mg BID was associated with a significantly lower risk of major bleeding and any bleeding when compared to warfarin. Treatment with dabigatran 150/110 mg BID or rivaroxaban 15/10 mg QD was associated with a significantly lower risk of major bleeding, but not any bleeding, than warfarin. The potential benefit of individual NOACs in real-world practice needs to be assessed further.

Factors influencing warfarin control in Australia and Singapore

INTRODUCTION

Warfarin is widely used for patients with non-valvular atrial fibrillation (NVAF). Variations in warfarin control, as measured by time in therapeutic range (TTR), have been reported across different regions and ethnicities, particularly between Western and Asian countries. However, there is limited data on comparative factors influencing warfarin control in Caucasian and Asian patients. Therefore, the aim of this study was to determine warfarin control and potential factors influencing this in patients with NVAF in Australia and Singapore.

METHODS

Retrospective data was collected for patients receiving warfarin for January to June 2014 in Australia and Singapore. TTR was calculated for individuals with mean patient TTR used for analysis. Possible influential factors on TTR were analysed including age, gender, concurrent co-morbidities, and concurrent medication.

RESULTS

The mean TTR was significantly higher in Australia (82%) than Singapore (58%). At both sites, chronic kidney disease significantly lowered this TTR. Further factors influencing control were anaemia and age<60years in Australia, and vascular disease, CHA₂DS₂-VASc score of 6, and concurrent platelet inhibitor therapy in Singapore.

DISCUSSION

Warfarin control was significantly higher in Australia compared to Singapore, however chronic kidney disease reduced control at both sites. The different levels of control in these two countries, together with patient factors further reducing control may impact on anticoagulant choice in these countries with better outcomes from warfarin in Australia compared to Singapore.

A High HASBLED Score Identifies Poor Warfarin Control in Patients Treated for Non-Valvular Atrial Fibrillation in Australia and Singapore

Warfarin reduces stroke risk in atrial fibrillation (AF) patients. The quality of warfarin control, measured by time in therapeutic range (TTR), impacts outcome and adverse events. One tool evaluating risk of adverse events and potential warfarin control would simplify risk-benefit assessment of warfarin. Recently, HASBLED was demonstrated effective for this purpose, but this was in well-controlled patients with deep vein thrombosis. HASBLED as a predictor of warfarin control has not been validated in other populations including differing indications, warfarin control levels and ethnicities. The aim of this study was to determine whether HASBLED can predict warfarin control in patients with AF in Australia and Singapore. Retrospective data were collected for patients receiving warfarin between January and June 2014 in Australia and Singapore. Patient data were used to calculate HASBLED at the start and end of the study period. TTR was calculated for each patient, and mean TTR used for analysis to stratified HASBLED scores. Of the 4370 patients, there were 3199 in Australia and 1171 in Singapore with mean TTRs of 82% and 58%, respectively. At the start of the study, a HASBLED score ≥3 predicted significantly lower TTR in Singapore, whilst at the end of the study, this score identified patients with poor control in both Australia and Singapore. A HASBLED score ≥3 in patients treated with warfarin can differentiate significantly lower TTRs in Australian and Singapore patients with AF. HASBLED may assess bleed risk and warfarin control, identifying patients at high risk of poor warfarin outcome requiring additional INR monitoring or alternative anticoagulation.

Vitamin K antagonists: relative strengths and weaknesses vs. direct oral anticoagulants for stroke prevention in patients with atrial fibrillation

Vitamin K antagonists (VKAs) have been the mainstay of anticoagulation therapy for more than 50 years. VKAs are mainly used for the prevention of stroke in patients with atrial fibrillation (AF) and the treatment and secondary prevention of venous thromboembolism. In the past 5 years, four new agents-the direct factor Xa inhibitors apixaban, edoxaban and rivaroxaban and the direct thrombin inhibitor dabigatran [collectively known as direct oral anticoagulants (DOACs) or non-VKA oral anticoagulants]-have been approved for these and other indications. Despite these new treatment options, the VKA warfarin currently remains the most frequently prescribed oral anticoagulant. The availability of DOACs provides an alternative management option for patients with AF, especially when the treating physician is hesitant to prescribe a VKA owing to associated limitations, such as food and drug interactions, and concerns about bleeding complications. Currently available real-world evidence shows that DOACs have similar or improved effectiveness and safety outcomes compared with warfarin. Treatment decisions on which DOAC is best suited for which patient to maximize safety and effectiveness should take into account not only clinically relevant patient characteristics but also patient preference. This article reviews and highlights real and perceived implications of VKAs for the prevention of stroke in patients with non-valvular AF, with specific reference to their strengths and weaknesses compared with DOACs.

Dual pathway therapy in acute coronary syndrome

In 10 % of patients, who suffer an acute coronary syndrome (ACS), a major cardiovascular event occurs despite optimal therapy. The occlusion of the vessel is driven by atherothrombosis, which arises from platelet activation and activation of the coagulation cascade. In the last decade the secondary prevention continuously improved by development of dual anti-platelet therapy with new P2Y12-inhibitors such as clopidogrel, prasugrel, and ticagrelor. Until recently, the coagulation cascade was not targeted in secondary prevention. The coagulation factor Xa plays a crucial role in thrombosis and is elevated in patients after acute coronary syndrome, therefore representing an attractive target for novel therapies in ACS. Former studies with vitamin K antagonists showed reduction of cardiovascular events but increased major bleedings. Two phase-3 trials investigated the role of novel oral anticoagulant agents on top of aspirin and clopidogrel in patients with ACS. The APPRAISE-2 study, which tested the oral factor Xa inhibitor apixaban was prematurely terminated because of an increase of major bleedings in the absence of an effect on cardiovascular events. In contrast, the ATLAS ACS2 TIMI-51 trial interrogating the oral factor Xa inhibitor rivaroxaban in a low dose regimen showed significant reduction of cardiovascular events as well as total mortality. Thus, add-on treatment with low dose rivaroxaban emerged as a new option for patients with ACS. This review illustrates recent advances in the development of antithrombotic therapy in acute coronary syndromes, provides guidance on which patients should receive which therapy for secondary prevention of events, and points out potentially fruitful new strategies for the future of antithrombotic treatment in ACS.

The Sex, Age, Medical History, Treatment, Tobacco Use, Race Risk (SAMe TT2R2) Score Predicts Warfarin Control in a Singaporean Population

BACKGROUND

Warfarin reduces stroke risk in atrial fibrillation (AF) patients but requires ongoing monitoring. Time in therapeutic range (TTR) is used as a measure of warfarin control, with a TTR less than 60% associated with adverse patient outcomes. The Sex, Age, Medical history, Treatment, Tobacco use, Race (SAMe-TT₂R₂) score has been identified as a model able to predict warfarin control, but this has been tested in mainly Caucasian populations. Therefore, the aim of this study was to determine the ability of the SAMe-TT₂R₂ score to predict warfarin control in a Singaporean population consisting of Chinese, Malay, and Indian race.

METHODS

Retrospective data were collected from the National Heart Centre Singapore for AF patients receiving warfarin between January and June 2014. The TTR and the SAMe-TT₂R₂ score were calculated for each patient.

RESULTS

The 1137 non-valvular AF patients had a mean TTR of 58.0 ± 34.3% and a median SAMe-TT₂R₂ score of 3. The categorized SAMe-TT₂R₂ scores (2 versus >2) showed a significant reduction in mean TTR for the entire population (63.2% versus 55.8%, P = .0004) and also when categorized according to race for Chinese (62.7% versus 56.9%, P = .0075) and Malay (68.4% versus 50.6%, P = .0131) populations.

CONCLUSION

The SAMe-TT₂R₂ tool is effective in predicting warfarin control in a Singaporean population as patients with a score greater than 2 had poor control. The minimum score for non-Caucasian patients is 2; thus, in these patients, the presence of any additional risk factors identified in the SAMe-TT₂R₂ tool categorizes them as unlikely to achieve adequate warfarin control and possible candidates for alternative anticoagulants.

Assessing bleeding risk in 4824 Asian patients with atrial fibrillation: The Beijing PLA Hospital Atrial Fibrillation Project

The risks of major bleeding and intracranial hemorrhage (ICH) are higher in Asian patients with atrial fibrillation (AF) compared to non-Asians. We aimed to investigate risk factors for bleeding, and validate the predictive value of available bleeding risk scores (mOBRI, HEMORR2HAGES, Shireman, HAS-BLED, ATRIA and ORBIT) in a large cohort of Chinese inpatients with AF. Using hospital electronic medical databases, we identified 4824 AF patients (mean age 67 years; 34.9% female) from January 1, 1995 to May 30, 2015, with median (interquartile) in-hospital days of 10 (7-16) days. On multivariate analysis, prior bleeds, vascular disease, anemia, prior stroke, and liver dysfunction were independent risk factors of major bleeding (all p < 0.05). C-statistics (95%CI) of the HAS-BLED score were 0.72 (0.65-0.79) for major bleeding events and 0.83 (0.75-0.91) for ICH (all p < 0.001). Compared to other risk scores, the HAS-BLED score was significantly better in predicting major bleeding events (Delong test, all P < 0.05, apart from mOBRI, HEMORR2HAGES) and ICH (all p < 0.05), and additionally, resulted in a net reclassification improvement (NRI) of 17.1-65.5% in predicting major bleeding events and 29.5-67.3% in predicting ICH (all p < 0.05). We conclude that the HAS-BLED score had the best predictive and discriminatory ability for major bleeding and ICH in an Asian/Chinese AF population.

Relation of Nonvalvular Atrial Fibrillation to Body Mass Index (from the SPORTIF Trials)

Obesity is well-established as a major cardiovascular (CV) risk factor. Obesity confers a greater risk for developing atrial fibrillation (AF), but the relation between obesity and established nonvalvular AF for stroke and all-cause death is still unclear. To ascertain the prevalence of overweight and obesity in patients with nonvalvular AF, their influence on adverse events, and the relation with anticoagulation control, we performed this post hoc analysis of the pooled Stroke Prevention using an Oral Thrombin Inhibitor in patients with atrial Fibrillation (SPORTIF) III and V data sets. For this study, we analyzed all patients assigned to the warfarin arm with data on body mass index (BMI). Time in therapeutic range was used as an index of the quality of anticoagulation control. The 3,630 patients eligible for this analysis were categorized as follows: (1) BMI 18.5 to 24.9 ("normal weight") in 24.1%; (2) BMI 25.0 to 29.9 ("overweight") in 39.8%; and BMI ≥30 ("obese") in 36.1%. Both overweight (hazard ratio [HR] 0.70) and obese (HR 0.59) categories were inversely associated with the composite outcome of stroke/all-cause death. A similar inverse association was seen for the end point of stroke (HR 0.61 and 0.47, respectively). Good anticoagulation control also attenuated the association between BMI categories and outcomes. In patients with time in therapeutic range >70%, BMI category was not significantly associated with the composite outcome of stroke/death and stroke. Stroke and all-cause death progressively reduced in overweight and obese anticoagulated patients with AF. The inverse relation of BMI categories to the risk of stroke and all-cause death was mitigated by good anticoagulation control.

Geographic variations in the PARADIGM-HF heart failure trial

Aims

The globalization of clinical trials has highlighted geographic variations in patient characteristics, event rates, and treatment effects. We investigated these further in PARADIGM-HF, the largest and most globally representative trial in heart failure (HF) to date.

Methods and results

We looked at five regions: North America (NA) 602 (8%), Western Europe (WE) 1680 (20%), Central/Eastern Europe/Russia (CEER) 2762 (33%), Latin America (LA) 1433 (17%), and Asia-Pacific (AP) 1487 (18%). Notable differences included: WE patients (mean age 68 years) and NA (65 years) were older than AP (58 years) and LA (63 years) and had more coronary disease; NA and CEER patients had the worst signs, symptoms, and functional status. North American patients were the most likely to have a defibrillating-device (54 vs. 2% AP) and least likely prescribed a mineralocorticoid receptor antagonist (36 vs. 65% LA). Other evidence-based therapies were used most frequently in NA and WE. Rates of the primary composite outcome of cardiovascular (CV) death or HF hospitalization (per 100 patient-years) varied among regions: NA 13.6 (95% CI 11.7–15.7) WE 9.6 (8.6–10.6), CEER 12.3 (11.4–13.2), LA 11.2 (10.0–12.5), and AP 12.5 (11.3–13.8). After adjustment for prognostic variables, relative to NA, the risk of CV death was higher in LA and AP and the risk of HF hospitalization lower in WE. The benefit of sacubitril/valsartan was consistent across regions.

Conclusion

There were many regional differences in PARADIGM-HF, including in age, symptoms, comorbidity, background therapy, and event-rates, although these did not modify the benefit of sacubitril/valsartan.

Clinical trial registration URL

http://www.clinicaltrials.gov. Unique identifier: NCT01035255.

Atrial Fibrillation is Associated With Morphine Treatment in Female Breast Cancer Patients: A Retrospective Population-Based Time-Dependent Cohort Study

We investigated the relationship between morphine treatment and the risk of atrial fibrillation (AF) in female patients with breast cancer. We identified a malignancy cohort of 73,917 female breast cancer patients without an AF history before the date of breast cancer diagnosis between 2000 and 2010 by using the Longitudinal Health Insurance Database for Catastrophic Illness Patients in Taiwan. This malignancy cohort was divided into morphine and comparison cohorts comprising 18,671 and 55,246 patients, respectively, and the incidences of newly diagnosed AF were calculated. We used the Cox proportional hazard model with time-dependent exposure covariates to estimate the risk of AF. The effect of morphine was assessed through multivariable Cox proportional hazard regression controlling for age, the Charlson comorbidity index (CCI) score, and the use of bisphosphonates and paclitaxel. Compared with nonmorphine users, patients who received morphine exhibited a 4.37-fold (95% CI = 3.56-5.36) increase in the risk of developing AF. The risk of AF increased as the CCI score increased, but decreased in patients with tamoxifen treatment. This risk is especially significant in current morphine users of all ages and with low CCI score. AF risk increased as the duration of morphine use lengthened (P for trend <0.0001). The incidence of AF in female breast cancer patients in Taiwan is associated with morphine, but prevented by tamoxifen treatment.

Factor Xa Inhibitor Suppresses the Release of Phosphorylated HSP27 from Collagen-Stimulated Human Platelets: Inhibition of HSP27 Phosphorylation via p44/p42 MAP Kinase

Selective inhibitors of factor Xa (FXa) are widely recognized as useful therapeutic tools for stroke prevention in non-valvular atrial fibrillation or venous thrombosis. Thrombin, which is rapidly generated from pro-thrombin through the activation of factor X to FXa, acts as a potent activator of human platelets. Thus, the reduction of thrombin generation by FXa inhibitor eventually causes a suppressive effect on platelet aggregation. However, little is known whether FXa inhibitors directly affect the function of human platelets. We have previously reported that collagen induces the phosphorylation of heat shock protein 27 (HSP27), a low-molecular weight heat shock protein via Rac-dependent activation of p44/p42 mitogen-activated protein (MAP) kinase in human platelets, eventually resulting in the release of HSP27. In the present study, we investigated the direct effect of FXa inhibitor on the collagen-induced human platelet activation. Rivaroxaban as well as edoxaban significantly reduced the collagen-induced phosphorylation of both HSP27 and p44/p42 MAP kinase without affecting the platelet aggregation. Rivaroxaban significantly inhibited the release of phosphorylated HSP27 from collagen-stimulated platelets but not the secretion of platelet derived growth factor-AB. In patients administrated with rivaroxaban, the collagen-induced levels of phosphorylated HSP27 were markedly diminished after 2 days of administration, which failed to affect the platelet aggregation. These results strongly suggest that FXa inhibitor reduces the collagen-stimulated release of phosphorylated HSP27 from human platelets due to the inhibition of HSP27 phosphorylation via p44/p42 MAP kinase.