Underuse of Oral Anticoagulants for Nonvalvular Atrial Fibrillation: Past, Present, and Future

Trends in Oral Anticoagulant Use and Individual Expenditures Across the United States from 2014 to 2020

BACKGROUND

Landmark clinical trials have expended the indications for the direct oral anticoagulants (DOACs), but contemporary data on usage and expenditure patterns are lacking.

OBJECTIVE

This study aimed to assess annual trends in oral anticoagulant (OAC) utilization and expenditure across the United States (US) from 2014 to 2020.

METHODS

We utilized the Medical Expenditure Panel Survey (MEPS) to study the trends of use and expenditures of warfarin, dabigatran, rivaroxaban, apixaban, and edoxaban between 2014 and 2020 in the US. Survey respondents reported OAC use within the past year, which was verified against pharmacy records. Payment information was obtained from the respondent's pharmacy and was categorized as third-party or self/out-of-pocket. Potential indications and medical conditions of interest for OAC therapy were identified from respondent-reported medical conditions. We estimated the national number of OAC users and total expenditures across age, sex, race, ethnicity, insurance, and medical condition subgroups. Trends of OAC users' characteristics, expenditure, and number of prescriptions were evaluated using the Mann-Kendall test for trends.

RESULTS

Between 2014 and 2020, the number of warfarin users decreased from 3.8 million (70% of all OAC users) to 2.2 million (p = 0.007) [29% of all OAC users], while the number of DOAC users increased from 1.6 million (30% of all OAC users) to 5.4 million (p = 0.003) [70% of all OAC users]. The total expenditure of OACs in the US increased from $3.4 billion in 2014 to $17.8 billion in 2020 (p = 0.003), which was driven by the increase in DOAC expenditures (p = 0.003).

CONCLUSIONS

DOACs have replaced warfarin as the preferred OAC in the US. The increased costs associated with DOAC use may decline when generic formulations are approved.

Changing paradigms: from prevention of thromboembolic events to improved survival in patients with atrial fibrillation

Atrial fibrillation is associated with a five-fold increase in the risk of stroke. Current guidelines recommend the use of the CHA2DS2-VASc score to stratify the risk of stroke. In addition, guidelines recommend the identification of the conditions that increase the risk of haemorrhage to be modified and thus decrease the risk of bleeding. Nevertheless, many patients with a high thromboembolic risk are prescribed antiplatelet treatment or do not receive any antithrombotic therapy. In addition, therapeutic inertia is common in anticoagulated patients taking vitamin K antagonists, and underdosing is an emerging problem with direct oral anticoagulants, probably because many physicians consider the risk of stroke and the risk of major bleeding to be equal. It is necessary to develop a new approach to risk stratification, an approach that moves from morbidity to mortality, i.e., from stratification of the risk of stroke and major bleeding to stratification of the risk of mortality associated with stroke and the risk of mortality associated with bleeding. In this article, we propose a novel risk stratification approach based on the mortality associated with stroke and bleeding, illustrated by data derived from the literature.

Socioeconomic inequality in oral anticoagulation therapy initiation in patients with atrial fibrillation with high risk of stroke: a register-based observational study

OBJECTIVE

The study aimed to examine the association between socioeconomic factors (SEFs) and oral anticoagulation (OAC) therapy and whether it was influenced by changing guidelines. We hypothesised that inequities in initiation of OAC reduced over time as more detailed and explicit clinical guidelines were issued.

DESIGN

Register-based observational study.

SETTINGS

All Danish patients with an incident hospital diagnosis of atrial fibrillation (AF), aged ≥30 years old and with high risk of stroke from 1 May 1999 to 2 October 2015 were included. Absolute risk differences (RD) (95% CI) were used to measure the association.

PARTICIPANTS

154 448 patients (mean age 78.2 years, men 47.3%).

EXPOSURE

Education, family income and cohabiting status were the SEFs used as exposure.

OUTCOME

A prescription of OAC within -30 to +90 days of baseline (incident AF).

RESULTS

During 2002-2007, the crude RD of initiation of OAC for men with high education was 14.9% (12.8 to 16.9). Inequality reduced when new guidelines were published, and in 2013-2016 the crude RD was 5.6% (3.5 to 7.7). After adjusting for age, the RD substantially reduced. The same pattern was seen for cohabiting status, while inequality was smaller and more constant for income.

CONCLUSION

Patients with low income, low education and living alone were associated with lower chance of being initiated with OAC. For education and cohabiting status, the crude difference reduced around 2011, when more detailed clinical guidelines were implemented in Denmark. Our results indicate that new guidelines might reduce inequality in OAC initiation and that new, high-cost drugs increase inequality.

Modification of In-Hospital Recommendation and Prescription of Anticoagulants for Secondary Prevention of Stroke after Launch of Direct Oral Anticoagulants and Change of National Guidelines

INTRODUCTION

Approximately 1 out of 4 stroke patients suffers ischemic stroke secondary to atrial fibrillation (AF). Although indicated, withholding of anticoagulants for secondary prevention is a widespread phenomenon.

OBJECTIVE

We examined the longitudinal change of recommendation and prescription of secondary preventive anticoagulation in AF patients in an acute stroke center setting focusing on the impact of the introduction of direct oral anticoagulants (DOACs) and the change of national stroke prevention guidelines.

METHODS

Consecutive patients admitted with an acute cerebrovascular ischemic event underwent regular diagnostic work-up. Pseudonymized clinical data were entered into the institution's stroke registry. In those patients with AF, discharge letters were collected and evaluated for temporal trends and affecting factors of recommended and prescribed antithrombotic secondary medication at the time of discharge from hospital.

RESULTS

Of 7,175 patients admitted between January 2009 and December 2018, 1,812 (25.3%) suffered stroke caused by AF. Frequency of patients with recommended anticoagulation increased within the observation period from 66.7 to 95.8% (per year; adjusted odds ratio [OR], 1.309; confidence interval [CI], 1.153-1.486). Independently from this time trend, DOAC approval (adjusted OR, 4.026; CI 1.962-8.265) and guideline change (adjusted OR, 2.184; CI, 1.006-4.743) were associated with an increasing frequency of recommendation for anticoagulation. The rate of patients already receiving recommended anticoagulation for secondary prevention at discharge increased from 42.1 to 62.5%. Introduction of DOACs was not associated with this trend, and guideline change was even associated with decreasing frequency of anticoagulated patients at hospital discharge (adjusted OR, 0.641; CI, 0.414-0.991). Fear of early intracerebral bleeding was the most common reason for withholding anticoagulation (37%) at hospital discharge and stayed stable during the observation period.

CONCLUSIONS

Changing national guidelines with discard of contraindications for anticoagulation and the introduction of DOACs led to a broader recommendation of oral anticoagulation. However, both, new guidelines and DOACs, were not found to be associated with an increasing percentage of patients discharged from our hospital already on recommended anticoagulant prevention. This might be explained by the decreasing length of hospital stay during the study period and a missing evidence of early bleeding risk of DOACs in patients with acute brain infarction. Evidence-based data to close this therapeutic gap are needed.

Utilization of anticoagulants and predictors of treatment among hospitalized patients with atrial fibrillation in the USA

OBJECTIVE

To evaluate utilization of anticoagulants (ACs) and the predictors of treatment of patients with a diagnosis of atrial fibrillation (AF) during a hospital stay in the USA.

METHODS

Patients (≥18 years of age) who had a primary or secondary discharge diagnosis code of AF during a hospitalization (without a diagnosis of venous thromboembolism) were identified from the Premier Hospital database (1 January 2016-30 September 2017). AC treatments were examined during hospitalizations to assign AF patients into 3 study cohorts: those who received an oral AC (OAC), those who received parenteral AC only, and those who did not receive AC therapy. Multivariable logistic regression analyses were carried out to evaluate potential predictors of receiving parenteral AC only vs. OAC therapy, no AC therapy vs. OAC therapy, as well as the specific OAC drug choices.

RESULTS

Of the patients hospitalized with an AF diagnosis (n = 482,729; mean age: 74.7 years; 46.8% female; 82.9% White; 79.4% with Medicare), 42.6% received OAC therapy (most commonly, warfarin or apixaban), 35.3% parenteral AC only, and 22.2% no AC therapy. A key predictor of not receiving OAC therapy was having an AF diagnosis in the second position (applicable to 87.4% of study population). Greater comorbidity level and prior baseline bleeding were strong predictors of receiving parenteral AC only or not receiving any AC therapy vs. receiving OAC therapy. Predictors of receiving warfarin vs. apixaban included higher stroke risk and prior baseline bleeding.

LIMITATIONS

OAC utilization may have been underestimated since outpatient OAC utilization was not included in the analysis.

CONCLUSIONS

A substantial portion of hospitalized AF patients did not receive any AC therapy, particularly those patients with an AF diagnosis in the second position on hospital records. The predictors of inpatient AC treatment that were identified may be helpful in the clinical decision-making process for patients who are hospitalized with AF.

Clinical profile and management of rivaroxaban in patients with atrial fibrillation in routine practice in Spain: data from six nationwide studies

AIMS

To analyze the clinical profile and management of patients with nonvalvular atrial fibrillation taking rivaroxaban in routine practice in Spain.

METHODS

Clinical data from the observational studies HEROIC (cardiology and hematology; n=1,727), EMIR (cardiology; n=1,493), BRONCE-AP (primary care; n=133), SILVER-AP (primary care; n=457), ALADIN (internal medicine and neurology; n=249), and ESPARTA (internal medicine; n=110) of patients taking rivaroxaban were analyzed. The clinical profile was compared with those of the XANTUS and ROCKET-AF studies.

RESULTS

Overall, mean age was 74.9±9.4 years, CHA₂DS₂-VASc score was 3.7±1.5, and 43.2% had a HAS-BLED score ≥3. Patients included in the HEROIC and EMIR studies were older and more frequently had a creatinine clearance <50 mL/min and a higher thromboembolic risk than those in the XANTUS study, and patients included in the ALADIN study were older and had more prior cerebrovascular disease, but a lower thromboembolic risk than those in the ROCKET-AF trial. In those studies with available data, medication adherence and satisfaction with rivaroxaban were high.

CONCLUSION

Bearing in mind differences according to the clinical setting of each study, atrial fibrillation patients taking rivaroxaban in Spain were elderly and had a high thromboembolic risk. Medication adherence and satisfaction with rivaroxaban were high.

Comparison of Stroke Risk Stratification Scores for Atrial Fibrillation

Several stroke risk stratification scores have been developed to guide clinical decision-making in patients with nonvalvular atrial fibrillation (AF). The aim of this study was to compare the performance of the CHADS₂, CHA₂DS₂-VASc and R₂CHADS₂ risk scores to predict stroke. This retrospective cohort study was based on electronic medical records from Clalit Health Services (CHS), the largest payer provider healthcare organization in Israel. Data of CHS members with AF diagnosis between 2004 and 2015 were extracted. Demographic and co-morbidity data were used to calculate the 3 risk scores, and the performance of the scores to predict stroke were compared using area under the curve and net reclassification index. Of the 89,213 CHS members with AF, 52.3% were women and median age was 76 years. The proportions of patients at high risk were 66.2%, 86.7%, and 71.1% in the CHADS_2, CHA₂DS₂-VASc, and R₂CHADS₂, respectively, with stroke incidence rates of 2.91, 2.35, and 2.80 per 100 person-years, respectively. Area under the curves for stroke prediction were 0.61 for both CHADS₂ and CHA₂DS₂-VASc and 0.59 for R₂CHADS₂. Net reclassification index analysis demonstrated a net improvement of 0.089 in the index when CHA₂DS₂-VASc was compared with CHADS₂ and a net reduction of 0.083 when R₂CHADS₂ was compared with CHADS₂. In conclusion, current stroke stratification scores have comparable but limited ability to predict stroke in patients with AF. Stroke prevention strategies may vary depending on the applied stratification. There is a need for a better stroke risk stratification score for patients with AF.

Antithrombotic treatment patterns in patients with atrial fibrillation in Italy pre- and post-DOACs: the REPAIR study

AIM

To evaluate antithrombotic treatment patterns in patients in Italy with nonvalvular atrial fibrillation (NVAF) before and after direct oral anticoagulants (DOACs) were approved.

METHODS

This analysis included patients with a discharge diagnosis of NVAF in 2010 and 2014, which constituted the pre- and post-DOACs populations, respectively.

RESULTS

Approximately 90% of patients were eligible for oral anticoagulant (OAC) therapy. Overall use of OACs increased from 38% in 2010 to 45% in 2014; use of antiplatelet therapy decreased from 36 to 25%. Approximately 14% of eligible patients remained untreated.

CONCLUSION

Although an improvement in OAC prescription was observed post-DOACs launch, treatment patterns in Italy suggest that a proportion of patients with NVAF are still undertreated or do not receive appropriate therapy.

Atrial fibrillation in patients with first-ever stroke: Incidence trends and antithrombotic therapy before the event

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia among adults. Despite the proven advantages in primary and secondary stroke prevention in patients with AF, oral anticoagulation (OAC) therapy is still underused in many countries. In this study, we investigated the incidence of AF-related ischemic stroke over the past decade in South Korea and trends of preventive antithrombotic therapy use before stroke in a nationwide cohort.

Methods and findings

The data source for this study was a nationwide sample cohort comprising 1,025,340 individuals that was established by the nationwide health insurance system in 2002. A total of 10,215 patients with acute ischemic stroke (AIS) were selected from the cohort between 2004 and 2013. AF was identified in 1,662 patients, and 979 patients had preexisting AF before AIS. The annual proportion of patients with AIS with AF gradually increased from 13.4% to 22.6% over the study period (p for trends <0.001). Only 14.0% of patients with high risk AF were receiving OAC before the stroke, and this proportion remained relatively constant during the study period. However, the proportion of patients treated with antiplatelet agents had increased from 18.8% in 2004 to 45.3% in 2013, while that of patients receiving no antithrombotic agent decreased from 64.6% in 2004 to 43.9% in 2013. As a limitation, no information was available about non-vitamin K antagonist oral anticoagulants, because they were widely used since late 2014 in Korea.

Conclusions

The number of patients with AIS and AF has steadily increased over the last 10 years in Korea. However, a small portion of patients with AF were receiving OAC therapy before the stroke and about half of the patients did not receive any antithrombotic medication. Our study demonstrates that there is huge gap between clinical practice and treatment guidelines for patients with AF in Korea.