Quality of Anticoagulation with Warfarin in Korean Patients with Atrial Fibrillation and Prior Stroke: A Multicenter Retrospective Observational Study

Outcomes of non-vitamin K oral anticoagulants for secondary prevention in ischemic stroke with atrial fibrillation

Previous studies have rarely investigated the role of non-vitamin K oral anticoagulants (NOAC) and warfarin in the secondary prevention of ischemic stroke patients with nonvalvular atrial fibrillation (NVAF). In this study, we compared the effectiveness and safety of NOAC and warfarin for secondary prevention in Korean ischemic stroke patients with NVAF. Based on the Korean National Health Insurance Service Database, this study included 21,064 oral anticoagulants-naïve acute ischemic stroke patients with NVAF between July 2015 and June 2019. The main study outcomes included ischemic stroke, systemic embolism, major bleeding, and death. During the observational periods, NOAC users had a significantly decreased risk of ischemic stroke + systemic embolism (adjusted hazard ratio [aHR] 0.86; 95% confidence interval [CI] 0.78-0.95), ischemic stroke (aHR 0.89; 95% CI 0.81-0.99), major bleeding (aHR 0.78; 95% CI 0.68-0.89), and all-cause death (aHR 0.87; 95% CI 0.81-0.93). Standard-dose NOAC users had a lower risk of ischemic stroke, systemic embolism, and major bleeding events than warfarin users. In contrast, low-dose NOAC users did not differ in risk from warfarin users for all outcomes. In conclusion, NOACs were associated with a lower risk of secondary thromboembolic events and bleeding complications in Korean ischemic stroke patients with NVAF than warfarin.

Use of Direct-Acting Oral Anticoagulants in Patients With Atrial Fibrillation and Significant Tricuspid Regurgitation

BACKGROUND

There are limited data on the efficacy and safety of direct oral anticoagulants (DOACs) in patients with atrial fibrillation with significant tricuspid regurgitation (TR), which can lead to hepatic dysfunction and intestinal malabsorption. We aimed to compare the efficacy and safety of DOACs and warfarin for patients with atrial fibrillation with significant (moderate to severe) TR.

METHODS AND RESULTS

A total of 1215 patients with significant TR and atrial fibrillation who were treated with warfarin (N=491) or DOACs (N=724) were retrospectively analyzed. The primary outcomes were ischemic stroke, systemic embolic events, and hospitalization for major bleeding. The secondary outcomes were intracranial hemorrhage, hospitalization for gastrointestinal bleeding, all-cause mortality, and a composite outcome. The median follow-up duration was 2.4 years. In the inverse probability treatment weighting-adjusted cohort, DOACs and warfarin had a similar risk for ischemic stroke and systemic embolic events (adjusted hazard ratio [aHR], 0.95 [95% CI, 0.67-1.36]; P=0.79) and major bleeding (aHR, 0.78 [95% CI, 0.57-1.06]; P=0.11). For the secondary outcomes, relative to warfarin, DOACs had a lower risk of intracranial hemorrhage and the composite outcome, and a comparable risk for gastrointestinal bleeding and all-cause mortality. In the subgroup analysis, the effects of DOACs on ischemic stroke and systemic embolic events were comparable to the effects of warfarin, even in patients with inferior vena cava plethora (increased right atrial pressure) or severe TR.

CONCLUSIONS

In this study, relative to warfarin, DOACs demonstrated comparable efficacy for ischemic stroke and systemic embolic events and major bleeding, with a lower intracranial hemorrhage risk in patients with significant TR and atrial fibrillation, indicating their effectiveness and safety.

Effectiveness and safety of secondary prevention of non-vitamin K oral anticoagulants use by drug type in Asian patients

BACKGROUND

Although widely used in clinical fields, real-world data on the role of warfarin and non-vitamin K oral anticoagulants (NOACs) for the secondary prevention of thromboembolic complications in ischemic stroke patients with nonvalvular atrial fibrillation (NVAF) are scarce.

AIMS

This retrospective cohort study compared the effectiveness and safety of secondary prevention of NOAC and warfarin in ischemic stroke patients with NVAF.

METHODS

From the Korean National Health Insurance Service Database, we included 16,762 oral anticoagulants-naive acute ischemic stroke patients with NVAF between July 2016 and June 2019. The main outcomes included ischemic stroke, systemic embolism, major bleeding, and all-cause of death.

RESULTS

In total, 1717 warfarin and 15,025 NOAC users were included in the analysis. After 1:8 propensity score matching, during the observation period, all types of NOACs had a significantly lower risk of ischemic stroke and systemic embolism than warfarin (edoxaban: adjusted hazard ratio [aHR], 0.80; 95% confidence interval [CI], 0.68-0.93, rivaroxaban: aHR, 0.82; 95% CI, 0.70-0.96, apixaban: aHR, 0.79; 95% CI, 0.69-0.91, and dabigatran: aHR, 0.82; 95% CI, 0.69-0.97). Edoxaban (aHR, 0.77; 95% CI, 0.62-0.96), apixaban (aHR, 0.73; 95% CI, 0.60-0.90), and dabigatran (aHR, 0.66; 95% CI, 0.51-0.86) had lower risks of major bleeding and all-cause of death.

CONCLUSIONS

All NOACs were more effective than warfarin in the secondary prevention of thromboembolic complications in ischemic stroke patients with NVAF. Except for rivaroxaban, most NOACs demonstrated a lower risk of major bleeding and all-cause of death than warfarin.

Assessment of the relationship between the level of patient knowledge on warfarin therapy and the quality of oral anticoagulation: A systematic review and meta-analysis

The present study aimed to investigate the relationship between the level of patient knowledge on warfarin therapy and the quality of oral anticoagulation. This is a systematic review and meta-analysis written on the basis of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Searches at MEDLINE, EMBASE, Scopus and LILACS electronic databases were carried out on February 13, 2023, using the descriptors "Patient Medication Knowledge", "Patient Education as Topic", "Health Education", "Patient Education" and Warfarin. The steps of selection, data extraction and quality analysis of articles were performed independently by two reviewers. The analysis was performed considering patient knowledge as a possible modifier of time in therapeutic range (TTR). The meta-analysis included studies that reported the correlation coefficient (Pearson or Spearman) between patient knowledge and TTR. A subgroup analysis was performed according to questionnaires employed to measure patient knowledge. Twelve studies were selected with an overall sample size of 7634 participants and mean age 58.2 (standard deviation (SD)±12,8) years. Eleven (92.0%) cross-sectional studies. The mean TTR was 57.8% (SD±11,3%) and the average level of knowledge was 60.4%. The meta-analysis indicated that patient level of knowledge on warfarin therapy was moderately associated with TTR (rs = 0.435; 95% confidence interval (CI) = 0.163-0.645; I2 = 96%). Subgroup analysis indicated association between knowledge level and TTR in studies employing the OAK test (rs = 0.617; 95% CI = 0.192-0.847; I2 = 97%) and the AKA (rs = 0.269; 95% CI = 0.002 to 0.501; I2 = 94%). However, the subgroup analysis presented no significant difference between them (p = 0.14). The meta-regression showed a non-significant negative effect of age on the correlation (estimate = -0.028, 95% CI = -0.073 to 0.016, p = 0.207). No publication bias was noted (p = 0.881). To our knowledge, this is the first systematic review and meta-analysis gathering evidence about the relationship between the level of patient knowledge on oral anticoagulation with warfarin and TTR. The implementation of structured and patient-centered educational interventions is essential to effectively increase the level of patient knowledge and, thus, to improve the quality and safety of warfarin therapy. Systematic review registration number: PROSPERO CRD42023398030.

Renal outcomes of rivaroxaban compared with warfarin in Asian patients with nonvalvular atrial fibrillation: A nationwide population-based cohort study

Background

Further studies are needed to expand the evidence for the association of rivaroxaban with a lower risk of adverse renal outcomes in patients with atrial fibrillation (AF) as compared with warfarin, especially in Asians.

Objectives

To determine whether there are differences in adverse renal outcomes between rivaroxaban and warfarin-treated AF patients.

Methods

Using the Korean nationwide claims database partly linked to laboratory results, patients with AF who initiated warfarin or rivaroxaban from 1 January 2014 to 31 December 2017 were identified. Inverse probability of treatment weighting (IPTW) was used to balance the baseline characteristics of the two groups. The primary outcome (kidney failure) was defined as the need for maintenance dialysis or having kidney transplantation. For the exploratory analysis in a subset of patients with baseline and follow-up laboratory results, the composite of renal outcomes, including estimated glomerular filtration rate (eGFR) lower than 15 ml/min/1.73 m2 at follow-up measurement, starting dialysis, or having kidney transplantation, ≥ 30% decline in eGFR, doubling of serum creatinine level, and acute kidney injury (AKI) were evaluated. The two groups were compared using Cox proportional hazards regression in the weighted population.

Results

We identified 30,933 warfarin users and 17,013 rivaroxaban users (51% of low dose rivaroxaban). After IPTW, the mean age was 70 years, and the mean CHA2DS2-VASc score was 3.9 in both groups. During a median follow-up of 0.93 (interquartile ranges 0.23-2.10) years, weighted incidence rates of kidney failure for warfarin and rivaroxaban were 0.83 and 0.32 per 100 person-years, respectively. Compared with the warfarin group, the rivaroxaban group was associated with a lower risk of kidney failure (hazard ratio [HR] 0.389, 95% confidence interval [CI] 0.300-0.499, p < 0.001). In patients with preexisting chronic kidney disease or eGFR ≤ 60 ml/min/1.73 m2, rivaroxaban was more beneficial than warfarin in reducing the risk of kidney failure. For the composite of five renal outcomes in the exploratory analysis, the rivaroxaban group showed a lower risk than warfarin (HR 0.798, 95% CI 0.713-0.892, p < 0.001).

Conclusion

Rivaroxaban was associated with lower risks of renal adverse outcomes than warfarin in Korean patients with AF.

The effect of antithrombotic treatment on the fecal immunochemical test for colorectal cancer screening: a nationwide cross-sectional study

BACKGROUND : Screening for colorectal cancer (CRC) using the fecal immunochemical test (FIT) has been widely adopted. The use of antithrombotic treatment is increasing in the Western world. This study aimed to assess the effects of antithrombotic treatment on the FIT-based Danish national screening program for CRC. METHODS : This was a cross-sectional study of all individuals returning a FIT from 2014 until 2016. The effect of antithrombotic treatment on FIT positivity and the positive predictive value (PPV) were assessed using proportions and multivariable Poisson regression. RESULTS : Of 884 036 invited individuals, we identified 551 570 participants. A positive FIT was observed in 9052 of 77 007 individuals (11.8 %) receiving antithrombotic treatment compared with 28 387 of 474 587 individuals (6.0 %) receiving no treatment. The adjusted relative risk (RR) for a positive FIT was 1.59 (95 %CI 1.56-1.63) for any treatment. Nonvitamin K oral anticoagulants (NOACs) were associated with the largest increase in FIT positivity (adjusted RR 2.40, 95 %CI 2.48-2.54). The proportion of CRC detected at colonoscopy was slightly lower among patients on antithrombotic treatment (6.0 %, 95 %CI 5.5 %-6.6 %) than among treatment-naïve patients (6.4 %, 95 %CI 6.1 %-6.7 %). The PPV for CRC or high risk adenomas was decreased nearly twofold in patients treated with NOAC (adjusted RR 0.58, 95 %CI 0.51-0.66]). CONCLUSION : Antithrombotic treatment was associated with a decreased PPV in FIT-based CRC screening.

Rosendaal linear interpolation method appraising of time in therapeutic range in patients with 12-week follow-up interval after mechanical heart valve replacement

Background

The objective of this study was to evaluate the quality of anticoagulation by the time in therapeutic range (TTR) for patients with 12-week INR follow-up interval.

Materials and methods

From January 2018 to December 2020, a selective group of patients who underwent mechanical valve replacement and followed up at our anticoagulation clinic for adjustment of warfarin dose were enrolled. The incidences of complications of anticoagulation therapy were reported by linearized rates. TTR was calculated by the Rosendaal linear interpolation method.

Results

Two hundred and seventy-four patients were eligible for this study. The mean age of these patients was 52.8 ± 12.7 years, and 65.7% (180 cases) of them were females. The mean duration of warfarin therapy was 16.7 ± 28.1 months. A total of 1309 INR values were collected, representing 66789 patient days. In this study, the mean TTR was 63.7% ± 18.6%, weekly doses of warfarin were 20.6 ± 6.0 mg/weekly, and the mean monitoring interval for the patient was 53.6 ± 27.1 days. There were 153 cases in good TTR group (TTR ≥ 60%) and 121 cases in poor TTR group (TTR < 60%). The calculated mean TTR in both groups was 42.6% ± 22.1% and 74.8% ± 10.4%, respectively. Compared with the TTR ≥ 60% group, the TTR < 60% group exhibited a more prevalence of female gender (p = 0.001), atrial fibrillation (p < 0.001), NYHA ≥ III (p < 0.001), and lower preoperative left ventricular ejection fraction (LVEF, p = 0.032). In multivariate analysis, female gender (p = 0.023) and atrial fibrillation (p = 0.011) were associated with TTR < 60%. The incidence of major bleeding and thromboembolic events was 2.7% and 1.1% patient-years, respectively. There was one death which resulted from cerebral hemorrhage. The incidence of death was 0.5% patient-years. The difference in anticoagulation-related complications between the TTR < 60% group and the TTR ≥ 60% group was not statistically significant.

Conclusion

For patients with stable international normalized ratio monitoring results who are follow-up at anticoagulation clinics, a 12-week monitoring interval has an acceptable quality of anticoagulation. The female gender and atrial fibrillation were associated with TTR < 60%.

Acute Stroke and Atrial Fibrillation: Risk of Incorrect NOAC Dosage When Estimating Renal Function From Plasma Creatinine Only

Background

Cardioembolic stroke (CS) due to atrial fibrillation (AF) bears a high risk of unfavorable outcome. Treatment with a non-vitamin K antagonist oral anticoagulant (NOAC) reduces this risk. NOAC dosage occurs on a thin line during the acute phase of the stroke unit when the patient is threatened by both recurrent CS and a hemorrhagic stroke. It is often adapted to renal function—usually glomerular filtration rate (GFR)—to prevent both under- and overdosing. This study investigates the hypothetical risk of incorrect NOAC dosage after acute stroke when relying on plasma creatinine alone in comparison to a more exact renal function assessment including urine collection.

Methods

In a cohort study on consecutive 481 patients treated in a stroke unit with acute stroke and AF, the GFR estimated from plasma creatinine (eGFR) was compared to concurrent creatinine clearance measurement (CrCl) from urine collection regarding the hypothetically derived NOAC dosage.

Results

The risk of incorrect dosage (mean, 95% confidence interval) was 6.9% (4.8–9.5), 26% (23–31), 38% (33–42), and 20% (16–23) for apixaban, dabigatran, edoxaban, and rivaroxaban, respectively. The overall risk for incorrect dosage of any NOAC was 23% (21–25). Thresholds for age and admission eGFR were optimized to achieve an overall risk below 5% by additional CrCl measurements in selected patients (apixaban <36 ml/min and any age, dabigatran <75 ml/min and >70 y, edoxaban >36 ml/min and >58 y, rivaroxaban <76 ml/min and >75 y, any NOAC <81 ml/min and >54 y). The resulting portion of patients requiring an additional CrCl measurement was 10, 60, 80, 55, and 65% for apixaban, dabigatran, edoxaban, rivaroxaban, and any NOAC, respectively.

Conclusions

There is a considerable risk of incorrect NOAC dosage in patients with acute CS treated in a stroke unit that can be lowered by targeted CrCl measurements in selected patients.

Comparison of early clinical outcomes between dual antiplatelet therapy and triple antithrombotic therapy in patients with atrial fibrillation undergoing percutaneous coronary intervention

Background and objective

Most Asian patients with atrial fibrillation (AF) who undergo percutaneous coronary intervention (PCI) receive only dual antiplatelet therapy (DAPT) without oral anticoagulants (vitamin K antagonists [VKA] or non-VKA oral anticoagulants [NOAC]). However, it has not been fully investigated whether the DAPT results in better clinical outcomes in the early period after PCI than the standard triple therapy with VKA or NOAC.

Methods

We analyzed the claims records of 11,039 Korean AF population who had PCI between 2013 and 2018. Patients were categorized according to the post-PCI antithrombotic therapy as VKA-based triple therapy (VKA-TT), NOAC-based triple therapy (NOAC-TT), and DAPT groups. After baseline adjustment using inverse probability weighting, we compared the risks of ischemic endpoints (ischemic stroke, myocardial infarction, and all-cause mortality) and major bleeding at 3 months post-PCI.

Results

Ischemic stroke, MI, and all-cause mortality occurred in 105, 423, and 379 patients, respectively, and 138 patients experienced major bleeding. The DAPT group was associated with a lower risk of ischemic stroke and major bleeding (hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.37–0.84) compared to the VKA-TT group, despite no significant differences in the risks of MI and all-cause mortality. In contrast, the DAPT group demonstrated no significant difference in the risks for ischemic endpoints compared to the NOAC-TT group. Additionally, the DAPT group had a numerically lower risk of major bleeding than the NOAC-TT group but this was not statistically significant (HR 0.69, 95% CI 0.45–1.07).

Conclusions

An outcome benefit of DAPT was observed in the early period after PCI compared to the VKA-TT, but not against NOAC-TT users among the Asian AF population. Given the potential long-term benefits of NOACs, greater efforts should be made to increase compliance in clinical practice with proper combination therapy with NOAC after PCI.

Patients’ time in therapeutic range on warfarin among atrial fibrillation patients in Warfarin Medication Therapy Adherence Clinic

BACKGROUND

The quality of warfarin therapy can be determined by the time in the therapeutic range (TTR) of international normalized ratio (INR). The estimated minimum TTR needed to achieve a benefit from warfarin therapy is ≥ 60%.

AIM

To determine TTR and the predictors of poor TTR among atrial fibrillation patients who receive warfarin therapy.

METHODS

A retrospective observational study was conducted at a cardiology referral center in Selangor, Malaysia. A total of 420 patients with atrial fibrillation and under follow-up at the pharmacist led Warfarin Medication Therapeutic Adherence Clinic between January 2014 and December 2018 were included. Patients’ clinical data, information related to warfarin therapy, and INR readings were traced through electronic Hospital Information system. A data collection form was used for data collection. The percentage of days when INR was within range was calculated using the Rosendaal method. The poor INR control category was defined as a TTR < 60%. Predictors for poor TTR were further determined by using logistic regression.

RESULTS

A total of 420 patients [54.0% male; mean age 65.7 (10.9) years] were included. The calculated mean and median TTR were 60.6% ± 20.6% and 64% (interquartile range 48%-75%), respectively. Of the included patients, 57.6% (n = 242) were in the good control category and 42.4% (n = 178) were in the poor control category. The annual calculated mean TTR between the year 2014 and 2018 ranged from 59.7% and 67.3%. A high HAS-BLED score of ≥ 3 was associated with poor TTR (adjusted odds ratio, 2.525; 95% confidence interval: 1.6-3.9, P < 0.001).

CONCLUSION

In our population, a high HAS-BLED score was associated with poor TTR. This could provide an important insight when initiating an oral anticoagulant for these patients. Patients with a high HAS-BLED score may obtain less benefit from warfarin therapy and should be considered for other available oral anticoagulants for maximum benefit.

Real-world oral anticoagulants for Asian patients with non-valvular atrial fibrillation: A PRISMA-compliant article

BACKGROUND AND PURPOSE

This study aimed to evaluate the comparative efficacy and safety of 4 non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin in Asians with non-valvular atrial fibrillation in real-world practice through a network meta-analysis of observational studies.

METHODS

We searched multiple comprehensive databases (PubMed, Embase, and Cochrane library) for studies published until August 2020. Hazard ratios and 95% confidence intervals were used for the pooled estimates. Efficacy outcomes included ischemic stroke (IS), stroke/systemic embolism (SSE), myocardial infarction (MI), and all-cause mortality, and safety outcomes included major bleeding, gastrointestinal (GI) bleeding, and intracerebral hemorrhage (ICH). The P score was calculated for ranking probabilities. Subgroup analyses were separately performed in accordance with the dosage range of NOACs ("standard-" and "low-dose").

RESULTS

A total of 11, 6, and 8 studies were allocated to the total population, standard-dose group, and low-dose group, respectively. In the total study population, edoxaban ranked the best in terms of IS and ICH prevention and apixaban ranked the best for SSE, major bleeding, and GI bleeding. In the standard-dose regimen, apixaban ranked the best in terms of IS and SSE prevention. For major bleeding, GI bleeding, and ICH, edoxaban ranked the best. In the low-dose regimen, edoxaban ranked the best for IS, SSE, GI bleeding, and ICH prevention. For major bleeding prevention, apixaban ranked best.

CONCLUSIONS

All 4 NOACs had different efficacy and safety outcomes according to their type and dosage. Apixaban and edoxaban might be relatively better and more well-balanced treatment for Asian patients with non-valvular atrial fibrillation.

Physician-Pharmacist Collaborative Clinic Model to Improve Anticoagulation Quality in Atrial Fibrillation Patients Receiving Warfarin: An Analysis of Time in Therapeutic Range and a Nomogram Development

Background: Poor time in therapeutic range (TTR) control is associated with an increased risk of stroke and bleeding in atrial fibrillation (AF) patients receiving warfarin. This study aimed to determine whether the physician-pharmacist collaborative clinic (PPCC) model could improve the anticoagulation quality as well as to create a nomogram for predicting anticoagulation quality in AF patients. Methods: This retrospective observational study enrolled AF patients who either initially received warfarin or returned to warfarin after withdrawal between January 1, 2016 and January 1, 2021, at our institution. The primary outcome was dynamic changes in TTRs (a TTR of ≥60% considered high anticoagulation quality). The secondary outcomes were thromboembolic and bleeding events during follow-up. We compared the dynamic changes in TTRs between the general clinic (GC) and PPCC groups in both the original and propensity score matching (PSM) cohorts. In addition, we explored the potential predictors of high anticoagulation quality and subsequently formulated a nomogram to predict anticoagulation quality. Results: A total of 265 patients with AF were included, comprising 57 patients in the PPCC group and 208 patients in the GC group. During a median follow-up period of 203 days, the PPCC group had a shorter time (76 vs. 199 days, p < 0.001) and more patients achieved a TTR ≥60% (73.7 vs. 47.1%, p = 0.002 by log-rank test) than the GC group. The results from the PSM cohort confirmed this finding. No significant differences in the incidences of thromboembolic events (5.3 vs. 5.3%, p = 1.000) and bleeding events (4.3 vs. 3.5%, p = 1.000) were observed between the two groups. Four variables were explored as predictors related to high anticoagulation quality: treatment within a PPCC, history of bleeding, history of bleeding, and the presence of more than four comorbidities. The nomogram revealed a moderate predictive ability (c-index: 0.718, 95% confidence interval (95%CI): 0.669-0.767) and a moderately fitted calibration curve. Conclusion: The PPCC model contributed to improved anticoagulation quality in AF patients receiving warfarin. The nomogram might be an effective tool to predict anticoagulation quality and could aid physicians and pharmacists in the selection of patients who will likely benefit from sustained and active intervention.

Factors associated with the dosing of edoxaban for stroke prevention in patients with atrial fibrillation from South Korea and Taiwan: 1-year data from the Global ETNA-AF Program

BACKGROUND

Direct oral anticoagulants (DOACs) have replaced vitamin K antagonists as the standard of care for stroke prevention in patients with atrial fibrillation (AF). However, DOAC prescriptions at dosages that do not adhere to labeling are common in daily practice. This analysis from the observational Global Edoxaban Treatment in routiNe clinical prActice (ETNA)-AF program focuses on edoxaban-treated patients from South Korea and Taiwan to identify patient baseline characteristics that may be associated with non-recommended dosing.

METHODS

We report baseline data from ETNA-AF, including patient demographics, clinical characteristics, and bleeding/stroke history of patients receiving recommended or non-recommended edoxaban dosing.

RESULTS

A total of 2677 patients were enrolled. Among 1543 patients who did not meet dose-reduction criteria, 1033 (66.9%) were prescribed the recommended 60-mg dose, and 510 (33.1%) were prescribed the non-recommended 30-mg dose. Among 1134 patients meeting ≥1 of the dose-reduction criteria, 863 (76.1%) were prescribed the recommended 30-mg dose; 271 (23.9%) were prescribed the nonrecommended 60-mg dose. Compared with the recommended 60-mg group, the nonrecommended 30-mg group had a higher proportion of patients aged ≥75 years, higher stroke and bleeding risks, and a history of major bleeding. The non-recommended 60-mg group had a lower proportion of patients aged ≥75 years, a higher history of stroke, and lower history of bleeding compared with the recommended 30-mg group.

CONCLUSION

The baseline data from ETNA-AF indicate that physicians take patient clinical characteristics (e.g., bleeding risks) into consideration when deviating from the dosing recommendation per label.

Anticoagulation Quality of Warfarin and the Role of Physician-Pharmacist Collaborative Clinics in the Treatment of Patients Receiving Warfarin: A Retrospective, Observational, Single-Center Study

Background: The management of patients receiving warfarin is complicated. This study evaluated the anticoagulation quality of warfarin, explored potential predictors associated with poor anticoagulation quality, and elucidated the role of clinical pharmacists in the management of warfarin treatment. Methods: We retrospectively collected data on patients who either initially received warfarin or returned to warfarin after withdrawal between January 1, 2015 and January 1, 2020. The primary outcome was time in therapeutic range (TTR), and a TTR of ≥60% was considered as good anticoagulation quality. The secondary outcomes included thromboembolic and bleeding events during the follow-up. We assessed the TTR of each participant and investigated the potential predictors of poor anticoagulation quality (TTR < 60%) using logistic regression analysis. Additionally, we compared the warfarin anticoagulant quality and the incidence of clinical adverse events between atrial fibrillation patients in physician-pharmacist collaborative clinics (PPCCs) and general clinics. Results: Totally, 378 patients were included. The mean TTR of patients was 42.6 ± 29.8%, with only 32% of patients having achieved good anticoagulation quality. During a mean follow-up period of 192 ± 92 days, we found no significant differences in the incidences of thromboembolic events (5.0% vs. 5.1%, p = 0.967) and bleeding events (1.7% vs. 4.7%, p = 0.241) between patients with good and those with poor anticoagulation quality. The presence of PPCCs (odds ratio [OR]: 0.47, 95% confidence interval [CI]: 0.25-0.90, p = 0.022) was an independent protective factor of poor anticoagulation quality, while the presence of more than four comorbidities (OR: 1.98, 95% CI: 1.22-3.24, p = 0.006) and an average interval of international normalized ratio monitoring of >30 days (OR: 1.74, 95% CI: 1.10-2.76, p = 0.019) were independent risk factors of poor anticoagulation quality. Compared with atrial fibrillation patients in general clinics, patients in PPCCs were found to have a significantly increased mean TTR level (48.4% ± 25.7% vs. 38.0% ± 27.6%, p = 0.014). Conclusion: The anticoagulation quality of warfarin was relatively low at our institution. The presence of more than four comorbidities and an average interval of international normalized ratio monitoring of >30 days independently contributed to poor anticoagulation quality. Meanwhile, the use of PPCC model improved the anticoagulation quality of warfarin.

Non-Vitamin K Antagonist Oral Anticoagulants in Patients With Atrial Fibrillation and Prior Gastrointestinal Bleeding

BACKGROUND AND PURPOSE

Limited data support the benefits of non-vitamin K oral anticoagulants (NOACs) among atrial fibrillation patients with prior gastrointestinal bleeding (GIB). We aimed to evaluate the effectiveness and safety of NOACs compared with those of warfarin among atrial fibrillation patients with prior GIB.

METHODS

Oral anticoagulant-naive individuals with atrial fibrillation and prior GIB between January 2010 and April 2018 were identified from the Korean claims database. NOAC users were compared with warfarin users by balancing covariates using the inverse probability of treatment weighting method. The primary outcomes were ischemic stroke, major bleeding, and the composite outcome (combined ischemic stroke and major bleeding). Fatal events from each outcome were evaluated as secondary outcomes.

RESULTS

A total of 42 048 patients were included (24 781 in the NOAC group and 17 267 in the warfarin group). The mean time from prior GIB to the initiation of oral anticoagulant was 3.1±2.6 years. After inverse probability of treatment weighting, baseline characteristics were balanced between the two groups (mean age, 72 years; men, 56.8%; and mean CHA₂DS₂-VASc score, 3.7). Lower risks of ischemic stroke, major bleeding, and the composite outcome were associated with NOAC use than with warfarin use (weighted hazard ratio, 0.608 [95% CI, 0.543-0.680]; hazard ratio, 0.731 [95% CI, 0.642-0.832]; and hazard ratio, 0.661 [95% CI, 0.606-0.721], respectively). For all secondary outcomes, NOACs showed greater risk reductions compared with warfarin.

CONCLUSIONS

NOACs were associated with lower risks of ischemic stroke and major bleeding than warfarin among atrial fibrillation patients with prior GIB.

The risk of stroke/systemic embolism and major bleeding in Asian patients with non-valvular atrial fibrillation treated with non-vitamin K oral anticoagulants compared to warfarin: Results from a real-world data analysis

BACKGROUND

Although randomized trials provide a high level of evidence regarding the efficacy of non-vitamin K oral anticoagulants (NOACs), the results of such trials may differ from those observed in day-to-day clinical practice.

AIMS

To compare the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) between NOAC and warfarin in clinical practice.

METHODS

Patients with non-valvular atrial fibrillation (NVAF) who started warfarin/NOACs between January 2015 and November 2016 were retrospectively identified from Korea's nationwide health insurance claims database. Using inpatient diagnosis and imaging records, the Cox models with inverse probability of treatment weighting using propensity scores were used to estimate hazard ratios (HRs) for NOACs relative to warfarin.

RESULTS

Of the 48,389 patients, 10,548, 11,414, 17,779 and 8,648 were administered apixaban, dabigatran, rivaroxaban and warfarin, respectively. Many patients had suffered prior strokes (36.7%, 37.7%, 31.4%, and 32.2% in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively), exhibited high CHA2DS2-VASc (4.8, 4.6, 4.6, and 4.1 in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively) and HAS-BLED (3.7, 3.6, 3.6, and 3.3 in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively) scores, had received antiplatelet therapy (75.4%, 75.7%, 76.8%, and 70.1% in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively), or were administered reduced doses of NOACs (49.8%, 52.9%, and 42.8% in apixaban, dabigatran, and rivaroxaban group, respectively). Apixaban, dabigatran and rivaroxaban showed a significantly lower S/SE risk [HR, 95% confidence intervals (CI): 0.62, 0.54-0.71; 0.60, 0.53-0.69; and 0.71, 0.56-0.88, respectively] than warfarin. Apixaban and dabigatran (HR, 95% CI: 0.58, 0.51-0.66 and 0.75, 0.60-0.95, respectively), but not rivaroxaban (HR, 95% CI: 0.84, 0.69-1.04), showed a significantly lower MB risk than warfarin.

CONCLUSIONS

Among Asian patients who were associated with higher bleeding risk, low adherence, and receiving reduced NOAC dose than that provided in randomised controlled trials, all NOACs were associated with a significantly lower S/SE risk and apixaban and dabigatran with a significantly lower MB risk than warfarin.

Non-vitamin K antagonist oral anticoagulants in very elderly east Asians with atrial fibrillation: A nationwide population-based study

BACKGROUND

The evidence of effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (NOACs) among elderly East Asians is limited.

OBJECTIVES

We aimed to describe the effectiveness and safety outcomes associated with NOACs and warfarin among elderly Koreans aged ≥80 years.

METHODS

Using the Korean Health Insurance Review and Assessment service database, patients with atrial fibrillation (AF) who were naïve to index oral anticoagulant between 2015 and 2017 were included in this study (20,573 for NOACs and 4086 for warfarin). Two treatment groups were balanced using the inverse probability of treatment weighting (IPTW) method. The clinical outcomes including ischemic stroke, major bleeding including intracranial hemorrhage (ICH) and gastrointestinal bleeding (GIB), and a composite of these outcomes were evaluated.

RESULTS

Compared to warfarin, NOACs were associated with lower risks of ischemic stroke (hazard ratio 0.74 [95% confidence interval 0.62-0.89]), and composite outcome (0.78 [0.69-0.90]). NOACs showed nonsignificant trends towards to lower risks of GIB and major bleeding than warfarin. The risk of ICH of NOAC group was comparable with the warfarin group. Among NOACs, apixaban and edoxaban showed better composite outcomes than warfarin. Among the clinical outcomes, only ischemic stroke and the composite outcome had a significant interaction with age subgroups (80-89 years and ≥90 years, P-for-interaction = .097 and .040, respectively).

CONCLUSION

NOACs were associated with lower risks of ischemic stroke and the composite outcome (ischemic stroke and major bleeding) compared to warfarin in elderly East Asians. Physicians should be more confident in prescribing NOACs to elderly East Asians with AF.

Effectiveness and Safety of Direct Oral Anticoagulants in Relation to Temporal Changes in Their Use

Background:

Since the direct oral anticoagulants (DOAC) were introduced, oral anticoagulant (OAC) prescription patterns have rapidly changed in patients with atrial fibrillation (AF). We aimed to evaluate the evolving trends of OAC use in a large nationwide cohort and specifically examine the changes in patient profiles treated with warfarin or DOAC and whether the time trends in OAC use affected clinical outcomes.

Methods and Results:

Using the Korean Health Insurance Review and Assessment database, we divided OAC naive patients with AF into 3 groups according to the enrollment period between January 2015 and December 2017 (n=35 353 in cohort 1, n=36 631 in cohort 2, and n=44 819 in cohort 3). DOAC use increased from 59% to 89%, whereas warfarin use has decreased from 41% to 11% during the study period. Patients treated with warfarin were increasingly younger from cohort 1 to cohort 3 (mean age 68–65 years, P <0.001) with lower mean CHA 2 DS 2 -VASc scores (3.3–2.9, P <0.001), whereas those with DOAC did not show a significant difference in clinical characteristics over the study period. Warfarin group had improved clinical outcomes over time, reflecting dynamic changes in patient characteristics. Compared with warfarin group, unadjusted hazard ratios of composite outcome for DOAC group have changed over time (hazard ratio 0.77 [95% CI, 0.69–0.85] in cohort 1, hazard ratio 0.84 [95% CI, 0.73–0.97] in cohort 2, and hazard ratio 1.00 [95% CI, 0.78–1.25] in cohort 3). After propensity score weighting between warfarin and DOAC groups in each cohort, DOAC showed consistently lower risks of the composite outcome by approximately 23% to 25% compared with warfarin across 3 different periods.

Conclusions:

In contemporary clinical practice, OAC prescription patterns and characteristics of patients treated warfarin or DOAC have dynamically changed. Despite these changes, DOAC showed a consistent better net clinical benefit compared with warfarin across different periods.

Ten-year trends in the incidence, treatment and outcomes of patients with mitral stenosis in Korea

Objective

Mitral stenosis increases the risk of atrial fibrillation (AF) and stroke. Large data underlying the trend in incidence, treatment and outcomes of mitral stenosis are lacking.

Methods

Based on the Health Insurance Review and Assessment Service database in Republic of Korea, patients who were diagnosed with mitral stenosis between 2007 and 2016 were enrolled. Trends in the incidence rate and changing patterns of treatment and outcome for stroke and systemic embolism and intracranial haemorrhage (ICH) were analysed.

Results

A total of 42 075 patients (mean age 60.7±13.5 years, 13 303 (31.6%) male) were included in the present study. The number included 27 824 (66.1%) patients with mitral stenosis and comorbid AF. The age-standardised annual incidence rate per 100 000 of mitral stenosis in Korea decreased remarkably from 10.3 to 3.6 over 10 years. The use of anticoagulation therapy increased consistently. The annual incidence of stroke and systemic embolism showed signs of plateau, while the incidence of ICH increased.

Conclusions

The overall incidence rate of mitral stenosis in Korean population has decreased remarkably. As increasing the use of vitamin K antagonist, the annual incidence rate of ICH was increased but the rate of stroke incidence reached a plateau. Alternative effective anticoagulation strategy should be investigated.

Direct Oral Anticoagulants in Patients With Nonvalvular Atrial Fibrillation and Low Body Weight

BACKGROUND

It is unclear whether the overall effectiveness and safety of direct oral anticoagulants (DOACs) are consistent in patients with nonvalvular atrial fibrillation (AF) and extremely low body weight (<50 kg).

OBJECTIVES

This study compared DOACs with warfarin in AF patients with low body weight.

METHODS

Using data from the Korean National Health Insurance Service database from January 2014 to December 2016, AF patients with body weight ≤60 kg and who were treated with oral anticoagulants (n = 14,013 taking DOACs and n = 7,576 taking warfarin) were included and examined for ischemic stroke, intracranial hemorrhage (ICH), gastrointestinal bleeding, major bleeding, all-cause death, and composite outcome. The propensity score weighting was used to balance the 2 groups.

RESULTS

Baseline characteristics were well balanced between the 2 groups (mean age 73 years, mean CHA₂DS₂-VASc score 4, and 28% of patients weighed <50 kg). DOACs were associated with lower risks of ischemic stroke (hazard ratio [HR]: 0.591; 95% confidence interval [CI]: 0.510 to 0.686) and major bleeding (HR: 0.705; 95%: CI 0.601 to 0.825), which were caused by a reduction in ICH (HR: 0.554; 95% CI: 0.429 to 0.713) compared with warfarin. DOAC improved the net clinical benefit compared with warfarin (HR for composite outcome: 0.660; 95% CI: 0.606 to 0.717), and this was consistent in patients who weighed <50 kg (HR for composite outcome: 0.665; 95% CI: 0.581 to 0.762).

CONCLUSIONS

In this real-world Asian AF population with low body weight, DOACs showed better effectiveness and safety than warfarin. These results were consistent in patients with extremely low body weight. Regular dosages of DOACs showed comparable results as reduced dosages of DOACs in both effectiveness and safety.

Time in therapeutic range and risk of thromboembolism and bleeding in patients with a mechanical heart valve prosthesis

OBJECTIVE

Oral anticoagulation with vitamin K antagonists is recommended after mechanical heart valve replacement. However, data regarding the association between the quality of vitamin K antagonist treatment and the risk of complications are sparse.

METHODS

Patients undergoing mechanical heart valve replacement (1997-2012) with available data on international normalized ratio values were identified in Danish registries. The quality of vitamin K antagonist treatment between discharge after valve replacement and 6 months postdischarge (ie, index) was assessed as time in therapeutic range (TTR) ≥70% or <70% reflecting the percentage of time in therapeutic international normalized ratio interval. Patients were followed from index until occurrence of an outcome of interest (ie, thromboembolism and bleeding), death, or end of study (December 31, 2012), whichever came first. The risk of outcomes according to quality of vitamin K antagonist treatment was estimated with multivariable Cox regression.

RESULTS

In total, 659 patients undergoing mechanical heart valve replacement were included in the study. Median number of international normalized ratio measurements in the 6-month period after surgery was 13 (interquartile range, 8-19). Median TTR was 54.9% (interquartile range, 39.0%-72.9%) and 29.1% of patients had a TTR ≥70%. Median follow-up was 6.1 years. The risk of thromboembolism was significantly lower in the group with TTR ≥70% compared with TTR <70% (hazard ratio, 0.44; 95% confidence interval, 0.22-0.85), whereas no significant difference concerning risk of bleeding among groups was found (hazard ratio, 0.63; 95% confidence interval 0.36-1.08).

CONCLUSIONS

In patients undergoing mechanical heart valve replacement, TTR <70% in the 6-month period after surgery was associated with an increased risk of thromboembolic events but not bleeding compared with TTR ≥70%.

Effectiveness and Safety of Direct Oral Anticoagulant for Secondary Prevention in Asians with Atrial Fibrillation

We investigated the effectiveness and safety of direct oral anticoagulants (DOACs) for secondary prevention in patients with atrial fibrillation (AF), particularly focusing on subgroups of patients with severe, disabling, and recent stroke. Using the Korean National Health Insurance Service claims database between January 2010 and April 2018, we selected OAC-naïve patients with non-valvular AF and a history of stroke. Cumulative risks for recurrent stroke, major bleeding, composite outcome (recurrent stroke + major bleeding), and mortality were compared between DOAC and warfarin groups. Among 61,568 patients, 28,839 and 32,729 received warfarin and DOACs, respectively. Compared with warfarin, DOACs were associated with lower risks of recurrent stroke (hazard ratio (HR) 0.67, 95% confidence interval (CI) 0.62-0.72), major bleeding (HR 0.73, 95% CI 0.66-0.80), composite outcome (HR 0.69, 95% CI 0.65-0.73), and mortality. DOAC use resulted in a consistent trend of improved outcomes in the subgroups of patients with severe, disabling, and recent stroke. In conclusion, DOACs were associated with lower risks of recurrent stroke, major bleeding, composite clinical outcomes, and mortality in patients with AF and a history of stroke. These results were consistent across all types of DOACs and subgroups of patients with severe, disabling, and recent stroke.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulants in octogenarian patients with non-valvular atrial fibrillation

BACKGROUND AND OBJECTIVE

Elderly patients with atrial fibrillation (AF) are known to have a high risk of stroke and bleeding. We investigated the effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) in octogenarian patients with non-valvular AF compared with warfarin.

METHODS

A total of 687 octogenarian patients with AF who were administered NOACs (n = 403) or warfarin (n = 284) for stroke prevention between 2012 and 2016 were included. Thromboembolic (TE) events (stroke or systemic embolism), major bleeding events, and all-cause death were analyzed.

RESULTS

The NOACs group (age 83.4±3.2 years, women 52.4%, CHA2DS2-VASc score 5.0±1.8) comprised 141 dabigatran, 158 rivaroxaban, and 104 apixaban users. Most patients from the NOACs group had been prescribed a reduced dose of medication (85.6%). During 14±18 months of follow-up periods, there were 19 TE events and 18 major bleeding events. Patients with NOAC showed a lower risk of TE (1.84 vs. 2.71 per 100 person-years, hazard ration [HR] 0.134, 95% confidence interval [CI] 0.038-0.479, P = 0.002), major bleeding (1.48 vs. 2.72 per 100 person-years, HR 0.110, 95% CI 0.024-0.493, P = 0.001), and all-cause death (2.57 vs. 3.50 per 100 person-years, HR 0.298, 95% CI 0.108-0.824, P = 0.020).

CONCLUSION

In octogenarian Asian patients with AF, NOACs might be associated with lower risks of thromboembolic events, major bleeding, and all-cause death than warfarin. Although most patients had received reduced doses, on-label use of NOACs was effective and safe.

Outcomes After Use of Standard- and Low-Dose Non-Vitamin K Oral Anticoagulants in Asian Patients With Atrial Fibrillation

Background and Purpose- Limited data are available describing the relative effectiveness, safety, and optimal dosing of non-vitamin K antagonist oral anticoagulants (NOACs) for treatment of nonvalvular atrial fibrillation in East Asian patients. We tried to compare effectiveness and safety outcomes of standard- and low-dose NOACs and warfarin in this population. Methods- Using nationwide administrative claims-based datasets from the Korean National Health Insurance Service Database (July 1, 2015, to December 31, 2016), this study comprised 56 504 anticoagulation-naive nonvalvular atrial fibrillation patients with high thromboembolic risk (CHA2DS2-VASc score, ≥2) treated with oral anticoagulants. Main study outcomes included thromboembolic events (ischemic stroke or systemic embolism), major bleeding, and mortality. Results- Among the study patients, 10 409 (18.4%) received warfarin and 46 095 (81.6%) were treated with NOACs: dabigatran (n=12 593; 22.3%), rivaroxaban (n=21 000; 37.2%), and apixaban (n=12 502; 22.1%). Low-dose NOAC (75.1% dabigatran, 59.7% rivaroxaban, and 62.7% apixaban) was more frequently used than standard-dose NOAC. During median follow-up of 15.0 months, each NOAC was associated with significantly lower risk of thromboembolic events (hazard ratio [HR], 0.76; 95% CI, 0.75-0.81 for dabigatran; HR, 0.74; 95% CI, 0.65-0.83 for rivaroxaban; and HR, 0.68; 95% CI, 0.59-0.78 for apixaban). Regarding safety outcomes, dabigatran (HR, 0.81; CI, 0.69-0.95) and apixaban (HR, 0.67; CI, 0.56-0.79) were associated with lower risk of major bleeding but not with rivaroxaban (HR, 0.96; CI, 0.84-1.11). Among adults <75 years of age without chronic kidney disease, use of low-dose apixaban did not demonstrate clinical benefit over warfarin with respect to thromboembolic events (HR, 0.99; CI, 0.76-1.28) and mortality (HR, 0.85; CI, 0.62-1.16). Conclusions- In this cohort of East Asian patients with nonvalvular atrial fibrillation, NOACs were associated with better effectiveness and safety outcomes versus warfarin. Lower NOAC doses were more often used, but an unjustified underdosing of apixaban seems to result in lower clinical benefit.

Stroke Prevention in Atrial Fibrillation: Focus on Asian Patients

Atrial fibrillation (AF) is the most common arrhythmia conferring a fivefold increased risk of stroke. Stroke prevention is the cornerstone of management of patients with AF. Asians have a generally higher incidence of AF-related risks of stroke and bleeding (particularly intracranial bleeding), compared with non-Asians. Despite the well-documented efficacy and relative safety of oral anticoagulation for stroke prevention among Asians, the suboptimal use of oral anticoagulation remains common. The current narrative review aims to provide a summary of the available evidence on stroke prevention among patients with AF focused on the Asia region, regarding stroke and bleeding risk evaluation, the performance of oral anticoagulation, and current use of thromboprophylaxis.