Switching to Another Oral Anticoagulant and Drug Discontinuation Among Elderly Patients With Nonvalvular Atrial Fibrillation Treated With Different Direct Oral Anticoagulants

Oral anticoagulant switching in patients with atrial fibrillation: a scoping review

INTRODUCTION

Oral anticoagulants (OACs) prevent stroke in patients with atrial fibrillation (AF). Several factors may cause OAC switching.

OBJECTIVES

To examine the phenomenon of OAC switching in patients with AF, including all available evidence; frequency and patterns of switch, clinical outcomes, adherence, patient-reported outcomes, reasons for switch, factors associated with switch and evidence gaps.

DESIGN

Scoping review.

DATA SOURCES

MEDLINE, Embase and Web of Science, up to January 2022.

RESULTS

Of the 116 included studies, 2/3 examined vitamin K antagonist (VKA) to direct-acting OAC (DOAC) switching. Overall, OAC switching was common and the definition of an OAC switch varied across. Switching from VKA to dabigatran was the most prevalent switch type, but VKA to apixaban has increased in recent years. Patients on DOAC switched more to warfarin than to other DOACs. OAC doses involved in the switches were hardly reported and patients were often censored after the first switch. Switching back to a previously taken OAC (frequently warfarin) occurred in 5%-21% of switchers.The risk of ischaemic stroke and gastrointestinal bleeding in VKA to DOAC switchers compared with non-switchers was conflicting, while there was no difference in the risk of other types of bleeding. The risk of ischaemic stroke in switchers from DOAC versus non-switchers was conflicting. Studies evaluating adherence found no significant changes in adherence after switching from VKA to DOAC, however, an increase in satisfaction with therapy were reported. Reasons for OAC switch, and factors associated with OAC switch were mostly risk factors for stroke and bleeding. Clinical outcomes, adherence and patient-reported outcomes were sparse for switches from DOACs.

CONCLUSIONS

OAC switching is common in patients with AF and patients often switch back to an OAC they have previously been on. There are aspects of OAC switching that have received little study, especially in switches from DOACs.

Incidence and Predictors of Switching and Dose Change of Direct Oral Anticoagulants among Elderly Patients with Nonvalvular Atrial Fibrillation: A 5-Year Analysis of a Large Administrative Database

In the last decade, novel oral anticoagulants (NOACs) have emerged as prominent therapeutic options in non-valvular atrial fibrillation (NVAF). We analysed the clinical burden and the switching rate between all available NOACs, and their dosage change over a period of 5 years in a representative population of patients with NVAF aged between 70 and 75 years. Methods and Results: This is a retrospective observational study on administrative databases, covering approximately 6.2 million health-assisted individuals by the Italian National Health System (around 11% of the entire Italian residents). Out of 4640 NVAF patients treated with NOACs and aged 70-75 years in 2017, 3772 (81.3%) patients were still in treatment with NOAC up to 2021 and among them, 3389 (73.0%) patients remained in treatment with the same NOAC during 2017-2021. In fact, 10.2% of patients switched NOAC type and 10.3% changed the dose of the same NOAC. Overall, after switching, the dabigatran and rivaroxaban groups lost, respectively, 13.5% and 2.8% of patients, while apixaban and edoxaban resulted in a relative percentage increase of 6.8% and 44.6% of patients, respectively. By a logistic regression analysis, the treatment with rivaroxaban, apixaban, and edoxaban (respect to dabigatran) was associated with a significant risk reduction of switch of 57%, 68%, and 44%, respectively. On the other hand, several features of high risk were associated with dose reduction. Conclusions. In our 5-year analysis of a large administrative database, a switching among NOACs or a change in NOAC dosages occurred in around 20% of elderly patients with NVAF. The type of NOAC was associated with a high switching rate, while several characteristics of high risk resulted as predictors of dose reduction of NOACs. Moreover, a worsening trend of clinical conditions occurred in patients maintaining the same NOAC treatment across 2017-2021.

Drug Utilization Pattern of Oral Anticoagulants in Patients with Atrial Fibrillation: A Nationwide Population-Based Study in Korea

INTRODUCTION

Treatment persistence for anticoagulant therapy is important in preventing thromboembolism in nonvalvular atrial fibrillation (NVAF) patients. Understanding drug utilization pattern and treatment changes in oral anticoagulant (OAC) users may facilite better NVAF management. Thus, our study aimed to examine OAC treatment patterns preceding events leading to switch or discontinuation and medication adherence in Korean NVAF patients.

METHODS

We conducted a drug utilization study on all Korean patients with atrial fibrillation (AF) newly prescribed OACs between July 2015 and November 2016 using the national claims data. We assessed treatment changes such as switching and discontinuation from index OAC and relevant events preceding the change and examined patient characteristics as predictors of changes that occurred among OAC users. Medication adherence was compared among OAC users by calculating the medication possession ratio (MPR).

RESULTS

A total of 48,389 NVAF patients were identified who initiated OACs within the study period. Most initiated nonvitamin K antagonist oral anticoagulants (NOACs) (22% apixaban, 24% dabigatran, 37% rivaroxaban), and 18% initiated warfarin. The frequency of switch to another OAC was 8.8% for apixaban, 16.1% for dabigatran, 6.6% for rivaroxaban, and 19.1% for warfarin. The frequency of discontinuation was lower for apixaban (22.9%), dabigatran (26.3%), and rivaroxaban (25.7%) than warfarin (31.6%). Compared to warfarin, NOAC users were less likely to switch treatment. Thromboembolic event was the most common clinical event preceding switch from warfarin to NOAC and from NOAC to warfarin. Discontinuation of OAC was often preceded by a bleeding event. Patients who initiated apixaban showed significantly higher mean MPR compared to those on dabigatran and warfarin.

CONCLUSION

In real-world practice in Korea, we have observed treatment change to be common in OAC users. Our results indicate better medication adherence with NOACs than with warfarin. (ClinicalTrials.gov registration number NCT03572972).

Switching of oral anticoagulants in patients with non-valvular atrial fibrillation: A narrative review

Approval of direct-acting oral anticoagulants (DOACs) for stroke prevention in atrial fibrillation (AF) was an important milestone, providing a wider range of treatment options and creating the possibility for drug switching after initiation. In addition to improved utilisation of oral anticoagulants (OACs) for stroke prevention, reports of switching among OACs are growing in the literature; switching may influence clinical outcomes, healthcare costs and patient satisfaction. This review aimed to summarise the current literature on the pattern of OAC switching in patients with AF, including reasons for switching and clinical consequences following switching. A literature search was conducted in PubMed, Scopus, and Embase on Jun 27, 2020. We included 39 articles published after 2013, following the introduction of apixaban. The review found that switching among OACs was common in clinical practice, significantly varying with the type of OAC. Studies reporting the reason for switching and clinical outcomes were comparatively limited. The decision to switch was often related to safety issues (usually bleeding), poor anticoagulation control and ease-of-use. Patient characteristics, clinical conditions and drug interactions were found to be associated with switching from OACs. Findings regarding bleeding outcomes following switching were inconsistent, possibly confounded by the rationale for switching and the switching protocol. Noting the limited number of studies included and their relatively short follow-up periods, switching did not have a significant impact on the risk of stroke and other thrombotic outcomes. Further prospective studies are needed to understand better potential rationales for switching and the clinical outcomes.

Switching across direct oral anticoagulants: a real-life-setting pilot prospective study

AIMS

Crossover between direct oral anticoagulants (DOACs) has been underinvestigated, but happens frequently in clinical practice. The purpose of this study was to evaluate causes, rates and outcomes of a DOAC-to-DOAC switch.

METHODS

Patients receiving their first DOAC prescription at the Anticoagulation Center, Cardiology Dept, Bologna-Bellaria Hospital in 2017-2018 were consecutively included and prospectively followed up. DOAC-to-DOAC switch was the main outcome; causes of switch (cardiovascular events and noncardiovascular drug-related adverse events) had direct biannual assessment before and after the switch.

RESULTS

Among 300 patients enrolled (mean age = 79.3 years, mean follow-up = 1.5 years), with no difference in cardiovascular risk factors depending on index DOAC, 13% underwent DOAC-to-DOAC switch, minor bleeding and noncardiovascular adverse events being the most frequent causes. Dabigatran carried a three-fold increase in risk of switch compared with other DOACs, but the mean age of patients who switched was 83. Factors leading to switch resolved in 87% of cases afterwards. Annual rates of cardiovascular/noncardiovascular V events did not differ before and after the switch.

CONCLUSION

DOAC-to-DOAC switch happens in 9% of patients using DOAC each year, and seems not to impact rates of cardiovascular events after switch. Dabigatran, in the elderly, might be associated with a higher risk of DOAC-to-DOAC switch. Further studies are needed to confirm the long-term safety and effectiveness of switching paradigm.

Switching between direct oral anticoagulants: a systematic review and meta-analysis

Crossover between direct oral anticoagulants (DOACs) has been underinvestigated, but happens frequently in clinical practice. It is still unknown whether DOACs have similar rates of switch, or whether some DOACs are more prone to be switched over time. We reviewed studies comparing DOAC-to-DOAC switch prevalence, and compared risk of switch depending on index DOAC through meta-analysis. Systematic review followed PRISMA guidelines and deposited protocol (PROSPERO#CRD42020152405). MEDLINE, EMBASE, and Cochrane-CENTRAL were searched up to 1/3/2020 for studies reporting on DOAC-to-DOAC switch. We determined by meta-analysis the pooled odds ratio (OR) for switch depending on index DOAC prescribed. Newcastle-Ottawa Scale was used for bias assessment. Among 221 results retrieved, 5 large studies (n = 259,308, mean age ranging 61.2-79.3) provided data on DOAC-to-DOAC switch. Studies were all large retrospective, observational and claims registry-based, with similar ascertainment of exposure and switch. Bias assessment revealed fair to high quality. Among DOACs, apixaban had consistently lower risk of DOAC-to-DOAC switch compared to dabigatran (OR 0.29, 95% CI 0.25-0.34) or rivaroxaban (OR 0.58, 95% CI 0.50-0.67), the former carrying a higher risk than the latter (OR 2.35, 95% CI 1.93-2.86). Results were robustly confirmed by sensitivity analysis. Apixaban might carry a lower risk of DOAC-to-DOAC switch compared to dabigatran and rivaroxaban. Further studies are needed to confirm long-term safety and effectiveness of switching paradigm.

Updating the Cost Effectiveness of Oral Anticoagulants for Patients with Atrial Fibrillation Based on Varying Stroke and Bleed Risk Profiles

BACKGROUND

Previous investigations into the cost effectiveness of direct oral anticoagulants only considered individual stroke risk but not bleed risk even though bleeding is an important and potentially fatal side effect for anticoagulated patients.

OBJECTIVE

This study aimed to evaluate the cost effectiveness of dabigatran, rivaroxaban, apixaban, and edoxaban vs warfarin in patients with atrial fibrillation with varying stroke/bleed risk profiles over a lifetime horizon.

METHODS

A Markov micro-simulation was adapted to examine the lifetime costs and quality-adjusted survival of five anticoagulants from a US private payer's perspective. The study hypothetical cohort consisted of 10,000 patients with atrial fibrillation with age, CHA₂DS₂-VASc, and HAS-BLED scores similar to a commercially insured patient with atrial fibrillation cohort. Model input parameters including the efficacy and safety of each strategy, utilities, and cost were estimated from public sources, published literature, and analysis conducted in the IBM MarketScan database. Lifetime cost, quality-adjusted life-years, and incremental cost-effectiveness ratios were assessed for each treatment strategy. Subgroup analyses stratified by age, stroke risk score alone, bleed risk score alone and both were performed. Uncertainty was assessed by a deterministic sensitivity analysis and a probabilistic sensitivity analysis.

RESULTS

The base-case analysis suggested dabigatran was the optimal treatment with an incremental cost-effectiveness ratio of $35,055 per quality-adjusted life-year relative to warfarin. Subgroup analyses stratified by age, stroke risk score, and bleed risk score alone were largely consistent with the base-case analysis. Subgroup analyses stratified by both stroke and bleed risk score showed edoxaban was the preferred treatment in patients with a low stroke and a low or medium bleed risk, and patients with a high stroke and low bleed risk. Apixaban was the preferred treatment in patients with a medium stroke and high bleed risk. Results of the deterministic sensitivity analysis indicate the model results were most sensitive to the drug cost and hazard ratio for stroke and bleeding event. Results of the probability sensitivity analysis showed dabigatran is cost effective vs. other treatments in 32.8% and 42.4% of iterations at a willingness to pay of $50,000/quality-adjusted life-year and a willingness to pay of $100,000/quality-adjusted life year, respectively.

CONCLUSIONS

From a US private payer's perspective, dabigatran appears cost effective compared with other anticoagulants. This study indicated risk stratification especially considering both stroke and bleed risk simultaneously is important not only in clinical practice but also in health technology assessment exercises among patients with atrial fibrillation.