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

The use of reduced DOAC doses in atrial fibrillation patients does not always lead to good anticoagulation levels and avoid adverse events

BACKGROUND

The MAS study (Blood Advances 2024) showed that a high proportion of Italian AF patients treated with direct oral anticoagulants (DOACs) receive reduced doses. This sub-analysis of MAS data aimed to analyze the effects of reduced (appropriate or not)- or standard-dose use on DOAC activity assessed at baseline and the occurrence of thrombotic or bleeding complications during follow-up.

METHODS

The MAS study design, the methods for DOAC measurement, the results, and the adverse events during follow-up, are described in detail elsewhere.

RESULTS

Seven hundred AF patients (42 % of the total 1657) received a reduced dose (considered inappropriate in 140 [20 %]). They were older, more frequently women, with lower body mass index (BMI), hemoglobin levels, and creatinine clearance. They more often had cerebral or cardiovascular diseases, were taking more medications, with higher scores for thrombotic or bleeding risk. Despite the use of low doses, 133 (19.0 %) patients had high standardized C-trough DOAC levels and experienced a high proportion of bleeding events (8.3 % per year). Conversely, some patients (4.7 %) had very low levels, resulting in a high incidence of thrombotic events (6.7 % per year). No difference was detected if the reduced dose was appropriate or not.

CONCLUSION

The unpredictable, highly variable inter-individual anticoagulant effect of DOACs may lead to either too low or too high anticoagulant levels, increasing the risk of thrombotic or bleeding events. This is particularly relevant for patients with high-risk conditions, such as those chosen for reduced-dose treatment. Further studies are needed to investigate this important clinical issue.

More early bleeds associated with high baseline direct oral anticoagulant levels in atrial fibrillation: the MAS study

ABSTRACT

Treatment with direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) is effective and safe. However, bleeding complications still occur. Whether DOAC level measurement may further improve treatment efficacy and safety is still an open issue. In the "Measure and See" study, venous blood was collected 15-30 days after DOAC initiation in patients with AF who were then followed up for 1 year to record the occurrence of major and clinically relevant nonmajor bleeding. DOAC plasma levels were measured in 1 laboratory, and results were kept blind to patients and treating doctors. Trough DOAC levels were assessed in 1657 patients (957 [57.7%] and 700 patients treated with standard and low-dose, respectively). Fifty bleeding events were recorded during 1606 years of follow-up (3.11% pt/yrs). Fifteen bleeding events (4.97% pt/yrs) occurred in patients with C-trough standardized values in the highest activity class (>0.50), whereas 35 events (2.69% pt/yrs) occurred in those with values in the 2 lower classes (≤0.50, P = .0401). Increasing DOAC levels and low-dose DOAC use were associated with increased bleeding risk in the first 3 months of treatment. Overall, 19% of patients receiving low doses had standardized values in the highest class. More bleeding occurred in patients on low (4.3% pt/yrs) vs standard (2.2% pt/yrs; P = .0160) dose DOAC. Early measurement of DOAC levels in patients with AF identified many individuals with high levels despite the low doses use and had more bleeding risk during the first 3 months of treatment. This trial was registered at www.ClinicalTrials.gov as #NCT03803579.

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

It remains unclear whether non-vitamin K antagonist oral anticoagulants (NOACs) are more effective and safer than warfarin in low-weight patients with atrial fibrillation (AF). Here, we retrospectively compared the effectiveness and safety of NOACs with those of warfarin in low-weight patients with AF. We extracted the July 2011-September 2022 data of patients with AF treated with a NOAC (dabigatran, rivaroxaban, apixaban, or edoxaban) or warfarin at a tertiary hospital. The patients were divided into low-weight (body weight ≤ 60 kg) and non-low-weight (body weight = 60-100 kg) groups. The primary outcomes were hospitalization for ischemic stroke (IS) or systemic embolism (SE) and major bleeding, whereas the secondary outcomes were any ischemic and bleeding events. We used the inverse probability of treatment weighting to balance the baseline characteristics between the groups. In total, 5,044 patients (mean age = 73.7 years, mean CHA2DS2-VASc score = 3.0, mean HAS-BLED score = 2.3) were enrolled and divided into low-weight and non-low-weight groups-containing 1,666 (1,406 NOAC users, 260 warfarin users) and 3,378 (2,978 NOAC users, 400 warfarin users) patients, respectively. NOACs were associated with a lower risk of any bleeding event in the low-weight group (adjusted hazard ratio = 0.61, 95% confidence interval = 0.51-0.73). The between-group differences in the risks of IS/SE, any ischemic event, major bleeding, and any bleeding event were nonsignificant. Thus, the use of NOACs (specifically dabigatran or edoxaban) is associated with a lower risk of any bleeding event than warfarin use in low-weight patients with AF.

Clinical characteristics of apixaban prescription in AF patients with single dose-reduction criterion: the ASPIRE (efficAcy and safety of aPixaban in rEal-world practice in Korean frail patients with atrial fibrillation) study

Background

Data on off-label reduced dose risk among patients with atrial fibrillation (AF) who qualify for a single-dose reduction of apixaban is scarce.

Objectives

We prospectively assessed apixaban dosing and clinical characteristics in AF patients meeting a dose reduction criterion.

Methods

The multicentre, prospective cohort study, the efficAcy and Safety of aPixaban In REal-world practice in Korean frail patients with AF (ASPIRE), encompasses patients with AF who met the criteria for a single-dose reduction of apixaban and were given varying doses of apixaban, either the on-label standard dose or the off-label reduced dose.

Results

Of 2,000 patients (mean age 74.3 ± 7.9 years, 55.8% women), 29.7% were ≥80 years, 62.6% weighed ≤60 kg, and 7.8% had serum creatinine ≥1.5 mg/dL. Of these, 51.3% were prescribed an off-label reduced dose of apixaban. The off-label group was characterized with older age, more comorbidities, and antiplatelet agents, while the on-label group had more prior strokes. Physicians preferred off-label reduced dose in the "marginal zone," defined as age 75-80 years, weight 60-65 kg, and creatinine levels 1.2-1.5 mg/dL.

Conclusions

In real-world clinical setting of the Korean population, off-label reduced dose apixaban was administered to nearly half of the patients who qualified for a single dose reduction. This reduced dosage was more commonly prescribed to patients with frail characteristics, while patients with a history of stroke were more often given the standard dose as per the label. A future study is planned to contrast the safety and effectiveness of the standard dose against the reduced dose of apixaban in this population.

Perioperative Management in Patients with Atrial Fibrillation Treated with Non-Vitamin K Antagonist Oral Anticoagulants Undergoing Minor Bleeding Risk Procedure: Rationale and Protocol for the PERIXa Study

Background

While treatment interruption of non-vitamin K antagonist oral anticoagulants (NOACs) for elective surgery or procedures among patients with atrial fibrillation (AF) is becoming more prevalent, there remains insufficient evidence regarding the optimal perioperative management of NOACs, particularly procedures with minor bleeding risks.

Objective

This study aims to evaluate the safety and effectiveness of a simplified, standardized protocol for perioperative management of direct factor Xa inhibitors in patients, with AF undergoing procedures associated with minor bleeding risk.

Methods

This multicenter, prospective single-arm registry study plans to enroll patients undergoing procedures with minor bleeding risk who were prescribed direct factor Xa inhibitors for AF. The procedures with minor bleeding risk will include gastrointestinal endoscopy for diagnostic purposes, selected dental procedures, and ocular surgery for cataracts or glaucoma. For apixaban, patients will withhold the last evening dose and resume either from the evening dose of the procedure day or the following morning, depending on the bleeding risk of the patient. For edoxaban or rivaroxaban, patients will withhold only a single dose on the procedure day. The primary outcome is the occurrence of major bleeding events within 30 days. Secondary outcomes include systemic thromboembolism, all-cause mortality, and a composite of major and clinically relevant non-major bleeding events.

Conclusion

This study has the potential to generate evidence regarding the safety of perioperative management for patients, with AF undergoing procedures associated with minor bleeding risk.

Trial Registration

Clinicaltrials.gov: NCT05801068.

Reduction of Upper Gastrointestinal Bleeding Risk With Proton Pump Inhibitor Therapy in Asian Patients With Atrial Fibrillation Receiving Direct Oral Anticoagulant: A Nationwide Population-based Cohort Study

BACKGROUND & AIMS

In patients with atrial fibrillation (AF) receiving direct oral anticoagulant (DOAC), upper gastrointestinal bleeding (UGIB) is a serious complication. There are limited data on the benefit of preventive proton pump inhibitor (PPI) use to reduce the risk of UGIB in DOAC users.

METHODS

We included patients with AF receiving DOAC from 2015 to 2020 based on the Korean Health Insurance Review and Assessment database. The propensity score (PS) weighting method was used to compare patients with PPI use and those without PPI use. The primary outcome was hospitalization for UGIB. Weighted hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were evaluated using the Cox proportional hazards regression model.

RESULTS

A total of 165,624 patients were included (mean age: 72.2 ± 10.8 years; mean CHA2DS2-VASc score: 4.3 ± 1.8; mean HAS-BLED score: 3.3 ± 1.2). Among them, 99,868 and 65,756 were in the non-PPI group and PPI group, respectively. During a median follow-up of 1.5 years, the PPI group was associated with lower risks of hospitalization for UGIB and UGIB requiring red blood cell transfusion than non-PPI group (weighted HR, 0.825; 95% CI, 0.761-0.894 and 0.798; 95% CI, 0.717-0.887, respectively, both P < .001). The benefits of PPI on the risk of hospitalization for UGIB were greater in those with older age (≥75 years), higher HAS-BLED score (≥3), prior GIB history, and concomitant use of antiplatelet agent (all P-for-interaction < .1). Low-dose PPI was consistently associated with a lower risk of significant UGIB by 43.6-49.3% (P < .001).

CONCLUSIONS

In this large Asian cohort of patients with AF on DOAC, PPI co-therapy is beneficial for reducing the risk of hospitalization for UGIB, particularly in high-risk patients.

Thrombotic events associated with low baseline direct oral anticoagulant levels in atrial fibrillation: the MAS study

ABSTRACT

Although effective and safe, treatment with direct oral anticoagulants (DOAC) in atrial fibrillation (AF) is still associated with thrombotic complications. Whether the measurement of DOAC levels may improve treatment efficacy is an open issue. We carried out the observational, prospective, multicenter Measure and See (MAS) study. Blood was collected 15 to 30 days after starting DOAC treatment in patients with AF who were followed-up for 1 year. Plasma samples were centralized for DOAC level measurement. Patients' DOAC levels were converted into drug/dosage standardized values to allow a pooled analysis in a time-dependent, competitive-risk model. The measured values were transformed into standardized values (representing the distance of each value from the overall mean) by subtracting the DOAC-specific mean value from the original values and dividing by the standard deviation. Trough and peak DOAC levels were assessed in 1657 and 1303 patients, respectively. In total, 21 thrombotic complications were recorded during 1606 years of follow-up (incidence of 1.31% of patients per year). Of 21 thrombotic events, 17 occurred in patients whose standardized activity levels were below the mean of each DOAC (0); the incidence was the highest (4.82% of patients per year) in patients whose standardized values were in the lowest class (-1.00 or less). Early measurement of DOAC levels in patients with AF allowed us to identify most of the patients who, having low baseline DOAC levels, subsequently developed thrombotic complications. Further studies are warranted to assess whether thrombotic complications may be reduced by measuring baseline DOAC levels and modifying treatment when indicated. This trial was registered at www.ClinicalTrials.gov as #NCT03803579.

The Danish Atrial Fibrillation Registry: A Multidisciplinary National Pragmatic Initiative for Monitoring and Supporting Quality of Care Based on Data Retrieved from Administrative Registries

Aim

The Danish Atrial Fibrillation (AF) Registry monitors and supports improvement of quality of care for all AF patients in Denmark. This report describes the registry's administrative and organizational structure, data sources, data flow, data analyses, annual reporting, and feedback between the registry, clinicians, and the administrative system. We also report the selection process of the quality indicators and the temporal trends in results from 2017-2021.

Methods and Results

The Danish AF Registry aims for complete registration and monitoring of care for all patients diagnosed with AF in Denmark. Administrative registries provide data on contacts to general practice, contacts to private cardiology practice, hospital contacts, medication prescriptions, updated vital status information, and biochemical test results. The Danish Stroke Registry provides information on stroke events. From 2017 to 2021, the proportion with a reported echocardiography among incident AF patients increased from 39.9% (95% CI: 39.3-40.6) to 82.6% (95% CI: 82.1-83.1). The initiation of oral anticoagulant therapy among patients with incident AF and a CHA2DS2-VASc score of ≥1 in men and ≥2 in women increased from 85.3% (95% CI: 84.6-85.9) to 90.4% (95% CI: 89.9-91.0). The 1-year and 2-year persistence increased from 85.2% (95% CI: 84.5-85.9) to 88.7% (95% CI: 88.0-89.3), and from 85.4% (95% CI: 84.7-86.2) to 88.2% (95% CI: 87.5-88.8), respectively. The 1-year risk of ischemic stroke among prevalent patients with AF decreased from 0.88% (95% CI: 0.83-0.93) to 0.71% (95% CI: 0.66-0.75). Variation in clinical performance between the five administrative Danish regions was reduced.

Conclusion

Continuous nationwide monitoring of quality indicators for AF originating from administrative registries is feasible and supportive of improvements of quality of care.

Effectiveness and safety of oral anticoagulants for non-valvular atrial fibrillation: a population-based cohort study in primary healthcare in Catalonia

Objectives: Our objective was to analyse effectiveness and safety of oral anticoagulants (OAC) for stroke prevention in non-valvular atrial fibrillation. Material and methods: Population-based cohort study including adults initiating oral anticoagulants, either direct oral anticoagulants (DOAC) or vitamin K antagonists (VKA), during 2011-2020. Data source: SIDIAP, capturing information from the electronic health records of Primary Health Care in Catalonia, Spain. Study outcomes: stroke, cerebral and gastrointestinal (GI) haemorrhage, assessed by patients' subgroups according to different clinical characteristics. Results: We included 90,773 patients. Male sex, older than 75, previous event, peripheral artery disease, deep vein thrombosis, or receiving antiplatelets, antidiabetics or proton pump inhibitors (PPI) was associated with higher stroke risk. For DOAC-treated, treatment switch increased stroke risk, while being adherent had a protective effect. Men, antidiabetic treatment or a previous event increased the risk of cerebral bleeding. Receiving direct oral anticoagulants had a protective effect in comparison to vitamin K antagonists. For DOAC-treated, treatment switch increased, and adherence decreased the bleeding risk. Men, people with chronic kidney disease or a previous event posed an increased risk of gastrointestinal bleeding, whereas receiving PPI had a protective effect. For DOAC-treated, switch was associated with a higher bleeding risk. Conclusion: Being men, a previous event and DOAC-switch posed a higher risk for all study outcomes. direct oral anticoagulants had a protective effect against cerebral bleeding in comparison to vitamin K antagonists. Adherence to direct oral anticoagulants resulted in lower risk of stroke and cerebral bleeding. We found no differences in the risk of stroke and gastrointestinal bleeding when we compared direct oral anticoagulants vs. vitamin K antagonists.

Clinical outcomes and predictors of a gap in direct-acting oral anticoagulant therapy in the elderly: A time-varying analysis of a nationwide cohort study

INTRODUCTION

As direct-acting oral anticoagulants (DOACs) have short half-lives of around 12 h, even a short gap in DOAC therapy may diminish anticoagulation effects, increasing risks of adverse clinical outcomes. We aimed to evaluate clinical consequences of a gap in DOAC therapy with atrial fibrillation (AF) and to identify its potential predictors.

MATERIALS AND METHODS

In this retrospective cohort study, we included DOAC users aged over 65 years with AF from the 2018 Korean nationwide claims database. We defined a gap in DOAC therapy as no claim for a DOAC one or more days after the due date of a refill prescription. We used a time-varying-analysis method. The primary outcome was a composite of death and thrombotic events including ischemic stroke/transient ischemic attack or systemic embolism. Potential predictors of a gap included sociodemographic and clinical factors.

RESULTS AND CONCLUSIONS

Among 11,042 DOAC users, 4857 (44.0 %) patients had at least one gap. Standard national health insurance, non-metropolitan locations of medical institutions, history of liver disease, chronic obstructive pulmonary disease, cancer, or dementia, and use of diuretics or non-oral agents were associated with increased risks of a gap. In contrast, history of hypertension, ischemic heart disease, or dyslipidemia were associated with a decreased risk of a gap. A short gap in DOAC therapy was significantly associated with a higher risk of the primary outcome compared to no gap (hazard ratio 4.04, 95 % confidence interval 2.95-5.52). The predictors could be utilized to identify at-risk patients to provide additional support to prevent a gap.

Geographical Variation in the Use of Oral Anticoagulation and Clinical Outcomes among Patients with Atrial Fibrillation in Denmark, Sweden, and Finland

Background  Geographical mapping of variations in the treatment and outcomes of a disease is a valuable tool for identifying inequity. We examined international and intranational variations in initiating oral anticoagulation (OAC) therapy and clinical outcomes among patients with atrial fibrillation (AF) in Nordic countries. We also tracked real-world trends in initiating OAC and the clinical outcomes. Methods  We conducted a registry-based multinational cohort study of OAC-naive patients with an incident hospital diagnosis of AF in Denmark ( N  = 61,345), Sweden ( N  = 124,120), and Finland ( N  = 59,855) and a CHA ₂ DS ₂ -VASc score of ≥1 in men and ≥2 in women between 2012 and 2017. Initiation of OAC therapy was defined as dispensing at least one prescription between 90 days before and 90 days after the AF diagnosis. Clinical outcomes included ischemic stroke, intracerebral hemorrhage, intracranial bleeding, other major bleeding, and all-cause mortality. Results  The proportion of patients initiating OAC therapy ranged from 67.7% (95% CI: 67.5-68.0) in Sweden to 69.6% (95% CI: 69.2-70.0) in Finland, with intranational variation. The 1-year risk of stroke varied from 1.9% (95% CI: 1.8-2.0) in Sweden and Finland to 2.3% (95% CI: 2.2-2.4) in Denmark, with intranational variation. The initiation of OAC therapy increased with a preference for direct oral anticoagulants over warfarin. The risk of ischemic stroke decreased with no increase in intracranial and intracerebral bleeding. Conclusion  We documented inter- and intranational variation in initiating OAC therapy and clinical outcomes across Nordic countries. Adherence to structured care of patients with AF could reduce future variation.

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.

Clinical Complexity Domains, Anticoagulation, and Outcomes in Patients with Atrial Fibrillation: A Report from the GLORIA-AF Registry Phase II and III

BACKGROUND

 Clinical complexity is common in atrial fibrillation (AF) patients. We assessed the impact of clinical complexity on oral anticoagulant (OAC) treatment patterns and major adverse outcomes in a contemporary cohort of AF patients.

METHODS

 The GLORIA-AF Phase II and III Registry enrolled newly diagnosed AF patients with at least one stroke risk factor. Among patients with CHA₂DS₂-VASc score ≥2, we defined four domains of perceived clinical complexity: frail elderly (age ≥75 years and body mass index <23 kg/m²), chronic kidney disease (CKD, creatinine clearance <60 mL/min), history of bleeding, and those with ≥2 of the above conditions. We evaluated the associations between clinical complexity domains and antithrombotic treatment prescription, risk of OAC discontinuation, and major adverse outcomes.

RESULTS

 Among the 29,625 patients included (mean age 69.6 ± 10.7 years, 44.2% females), 9,504 (32.1%) presented with at least one complexity criterion. Clinical complexity was associated with lower OAC prescription, with stronger associations in frail elderly (odds ratio [OR]: 0.47, 95% confidence interval [CI]: 0.36-0.62) and those with ≥2 complexity domains (OR: 0.50, 95% CI: 0.44-0.57). Risk of OAC discontinuation was higher among frail elderly (hazard ratio [HR]: 1.30, 95% CI: 1.00-1.69), CKD (HR: 1.10, 95% CI: 1.02-1.20), and those with ≥2 complexity domains (HR: 1.39, 95% CI: 1.23-1.57). Clinical complexity was associated with higher risk of the primary outcome of all-cause death, thromboembolism, and major bleeding, with the highest magnitude in those with ≥2 criteria (HR: 1.63, 95% CI: 1.43-1.86).

CONCLUSION

 In AF patients, clinical complexity influences OAC treatment management, and increases the risk of poor clinical outcomes. These patients require additional efforts, such as integrated care approach, to improve their management and prognosis.

Protective effect of proton pump inhibitor against gastrointestinal bleeding in patients receiving oral anticoagulants: A systematic review and meta-analysis

AIM

The evidence of a protective effect of proton pump inhibitor (PPI) in oral anticoagulant (OAC) treated patients against gastrointestinal bleeding (GIB) is still lacking. We conducted a meta-analysis to estimate the risk of GIB in patients with OAC and PPI co-therapy.

METHODS

A systematic search of PubMed, EMBASE, Cochrane, and Scopus databases was performed for studies reporting GIB risk in OAC and PPI co-therapy. Primary outcomes were total GIB and major GIB events. Pooled estimates of GIB risk were calculated by a random-effect meta-analysis and reported as odds ratios (OR) and 95% confidence interval (CI).

RESULTS

A total of 10 studies and 1,970,931 patients were included. OAC and PPI co-therapy were associated with a lower odds of total and major GIB; OR (95% CI) was 0.67 (0.62-0.74) for total and 0.68 (0.63-0.75) for major GIB, respectively. No differences in the GIB of PPI co-therapy were observed between Asians and non-Asians (p-for-difference, total GIB=0.70, major GIB=0.75, respectively). For all kinds of OAC except for edoxaban, PPI cotreatment was related to a lower odds of GIB by 24-44%. The protective effect of PPI on total GIB was more significant in concurrent antiplatelets or non-steroidal anti-inflammatory drug users and those with high bleeding risks: patients with previous GIB history, HAS-BLED ≥3, or underlying gastrointestinal diseases.

CONCLUSION

In patients who receive OAC, PPI co-therapy is associated with a lower total and major GIB irrespective of ethnic group and OAC type, except for edoxaban. PPI co-therapy can be considered particularly in high GIB risk patients.

Comparing Warfarin and 4 Direct Oral Anticoagulants for the Risk of Dementia in Patients With Atrial Fibrillation

Background and Purpose

Atrial fibrillation is a risk factor for dementia, and oral anticoagulant use is associated with a decreased risk of dementia in patients with atrial fibrillation. We aimed to investigate whether the risk of dementia would be different between patients treated with direct oral anticoagulants (DOACs) compared with those with warfarin.

Methods

Using the Korean nationwide claims database from January 2014 to December 2017, we identified oral anticoagulant–naive nonvalvular atrial fibrillation patients aged ≥40 years. For the comparisons, warfarin and DOAC groups were balanced using the inverse probability of treatment weighting method. The primary outcome was incident dementia.

Results

Among 72 846 of total study patients, 25 948 were treated with warfarin, and 46 898 were treated with DOAC (17 193 with rivaroxaban, 9882 with dabigatran, 11 992 with apixaban, and 7831 with edoxaban). During mean 1.3±1.1 years of follow-up, crude incidence of dementia was 4.87 per 100 person-years (1.20 per 100 person-years for vascular dementia and 3.30 per 100 person-years for Alzheimer dementia). Compared with warfarin, DOAC showed a comparable risks of dementia, vascular dementia, and Alzheimer dementia. In subgroup analyses, DOAC was associated with a lower risk of dementia than warfarin, particularly in patients aged 65 to 74 years (hazard ratio, 0.815 [95% CI, 0.709–0.936]) and in patients with prior stroke (hazard ratio, 0.891 [95% CI, 0.820–0.968]). When comparing individual DOACs with warfarin, edoxaban was associated with a lower risk of dementia (hazard ratio, 0.830 [95% CI, 0.740–0.931]).

Conclusions

In this large Asian population with atrial fibrillation, DOAC showed a comparable risk of dementia with warfarin overall. DOACs appeared more beneficial than warfarin, in those aged 65 to 74 years or with a history of stroke. For specific DOACs, only edoxaban was associated with a lower risk of dementia than warfarin.

Cardiovascular Research Using the Korean National Health Information Database

The Korean National Health Information Database (NHID) contains nationwide claims data, including sociodemographic data, health care utilization, health screening data, and healthcare provider information. To compensate for the limitations of randomized clinical trials, real-world observational studies using claims data have emerged as a novel research tool. We summarized the structure of the Korean NHID and the recent researches conducted in the field of cardiovascular science. Epidemiological studies, prescription patterns, temporal trends, comparison of effectiveness and safety of treatments, variability index using laboratory data, and rare intractable disease constitute interesting topics of research in cardiovascular science using the NHID. The operational definition of covariates and clinical outcomes is important for researchers interested in using the NHID data as new tools to prove their hypothesis. A step-by-step approach adopted by a team of data scientists, epidemiologists, statisticians, and clinical researchers may be most effective while designing research studies. The ultimate direction of research using the NHID should aim to improve the welfare of the public by promoting public health, reducing medical costs, and guiding healthcare policies.