Effectiveness and Safety of DOACs vs. Warfarin in Patients With Atrial Fibrillation and Frailty: A Systematic Review and Meta-Analysis

Role of a National Health Service Electronic Prescriptions Database in the Detection of Prescribing and Dispensing Issues and Adherence Evaluation of Direct Oral Anticoagulants

BACKGROUND

Anticoagulation therapy plays a crucial role in the management of atrial fibrillation (AF) by significantly reducing the risk of stroke. Direct oral anticoagulants (DOAC) became preferred over warfarin due to their superior safety and efficacy profile. Assessing adherence to anticoagulation therapy is necessary in clinical practice for optimising patient outcomes and treatment efficacy, thus emphasising its significance.

METHODS

A retrospective study utilised the Latvian National Health Service reimbursement prescriptions database, covering prescriptions for AF and flutter from January 2012 to December 2022. The proportion of days covered method was selected for adherence assessment, categorising it into three groups: (1) below 80%, (2) between 80% and 90%, and (3) above 90%.

RESULTS

A total of 1,646,648 prescriptions were analysed. Dabigatran prescriptions started declining after 2020, coinciding with a decrease in warfarin prescriptions since 2018. The total adherence levels to DOAC therapy were 69.4%. Only 44.2% of users achieved an adherence level exceeding 80%. The rate of paper prescriptions decreased from 98.5% in 2017 to 1.3% in 2022. Additionally, the utilisation of international non-proprietary names reached 79.7% in 2022. Specifically, 16.7% of patients selected a single pharmacy, whereas 27.7% visited one or two pharmacies. Meanwhile, other patients obtained medicines from multiple pharmacies.

CONCLUSIONS

The total adherence level to DOAC therapy is evaluated as low and there was no significant difference in age, gender, or "switcher" status among adherence groups. Physicians' prescribing habits have changed over a decade.

Effectiveness and safety in non-valvular atrial fibrillation patients switching from warfarin to direct oral anticoagulants in US healthcare claims

INTRODUCTION

There is a paucity of real-world studies examining the risks of stroke/systemic embolism (SE) and major bleeding (MB) among non-valvular atrial fibrillation (NVAF) patients switching from warfarin to a direct oral anticoagulant (DOAC). This retrospective study was conducted to compare the stroke/SE and MB risks between patients switched from warfarin to apixaban, dabigatran, or rivaroxaban in real-world clinical practice.

MATERIALS AND METHODS

This study used data from four United States commercial claims databases from January 1, 2012 to June 30, 2019. The study population included NVAF patients initially treated with warfarin and switched to apixaban, dabigatran, or rivaroxaban within 90 days of their warfarin prescription ending. Patients were matched 1:1 between the DOACs in each database using propensity scores and then pooled for the final analysis. Cox proportional hazards models were used to calculate the risk of stroke/SE and MB.

RESULTS AND CONCLUSIONS

The final population consisted of 2,611 apixaban-dabigatran, 12,165 apixaban-rivaroxaban, and 2,672 dabigatran-rivaroxaban pairs. Apixaban vs. dabigatran was associated with a lower risk of stroke/SE (hazard ratio [HR]: 0.61; 95% confidence interval [CI]: 0.39-0.96) and MB (HR: 0.67; 95% CI: 0.50-0.91). Apixaban vs. rivaroxaban was associated with a similar risk of stroke/SE (HR: 0.88; 95% CI: 0.73-1.07) and a lower risk of MB (HR: 0.60; 95% CI: 0.52-0.68). There was no significant difference in either risk between dabigatran and rivaroxaban. These results provide important insights into how the risks of stroke/SE and MB for NVAF patients vary when switching from warfarin to different DOACs.

The Effect of Levetiracetam Compared with Enzyme-Inducing Antiseizure Medications on Apixaban and Rivaroxaban Peak Plasma Concentrations

BACKGROUND AND OBJECTIVE

Post-stroke epilepsy represents an important clinical challenge as it often requires both treatment with direct oral anticoagulants (DOACs) and antiseizure medications (ASMs). Levetiracetam (LEV), an ASM not known to induce metabolizing enzymes, has been suggested as a safer alternative to enzyme-inducing (EI)-ASMs in patients treated with DOACs; however, current clinical guidelines suggest caution when LEV is used with DOACs because of possible P-glycoprotein induction and competition (based on preclinical studies). We investigated whether LEV affects apixaban and rivaroxaban concentrations compared with two control groups: (a) patients treated with EI-ASMs and (b) patients not treated with any ASM.

METHODS

In this retrospective observational study, we monitored apixaban and rivaroxaban peak plasma concentrations (Cmax) in 203 patients treated with LEV (n = 28) and with EI-ASM (n = 33), and in patients not treated with any ASM (n = 142). Enzyme-inducing ASMs included carbamazepine, phenytoin, phenobarbital, primidone, and oxcarbazepine. We collected clinical and laboratory data for analysis, and DOAC Cmax of patients taking LEV were compared with the other two groups.

RESULTS

In 203 patients, 55% were female and the mean age was 78 ± 0.8 years. One hundred and eighty-six patients received apixaban and 17 patients received rivaroxaban. The proportion of patients with DOAC Cmax below their therapeutic range was 7.1% in the LEV group, 10.6% in the non-ASM group, and 36.4% in the EI-ASM group (p < 0.001). The odds of having DOAC Cmax below the therapeutic range (compared with control groups) was not significantly different in patients taking LEV (adjusted odds ratio 0.70, 95% confidence interval 0.19-2.67, p = 0.61), but it was 12.7-fold higher in patients taking EI-ASM (p < 0.001). In an analysis in patients treated with apixaban, there was no difference in apixaban Cmax between patients treated with LEV and non-ASM controls, and LEV clinical use was not associated with variability in apixaban Cmax in a multivariate linear regression.

CONCLUSIONS

In this study, we show that unlike EI-ASMs, LEV clinical use was not significantly associated with lower apixaban Cmax and was similar to that in patients not treated with any ASM. Our findings suggest that the combination of LEV with apixaban and rivaroxaban may not be associated with decreased apixaban and rivaroxaban Cmax. Therefore, prospective controlled studies are required to examine the possible non-pharmacokinetic mechanism of the effect of the LEV-apixaban or LEV-rivaroxaban combination on patients' outcomes.

Unraveling the Paradox: Can Anticoagulation Improve Outcomes in Patients With Heart Failure and Increased Bleeding Risk?

Heart failure (HF) patients frequently present with comorbidities such as atrial fibrillation (AF) or other cardiovascular conditions, elevating their risk of thromboembolic events. Consequently, anticoagulation therapy is often considered for thromboprophylaxis, although its initiation in HF patients is complicated by concomitant bleeding risk factors. This review explores the paradoxical relationship between HF, increased bleeding risk, and the potential benefits of anticoagulation. Through an examination of existing evidence from clinical trials, observational studies, and meta-analyses, we aim to elucidate the role of anticoagulation in HF patients with increased bleeding risk. Despite guidelines recommending anticoagulation for certain HF patients with AF or other thromboembolic risk factors, uncertainty persists regarding the optimal management strategy for those at heightened risk of bleeding. The review discusses the pathophysiological mechanisms linking HF and thrombosis, challenges in bleeding risk assessment, and strategies to minimize bleeding risk while optimizing thromboprophylaxis. Shared decision-making between clinicians and patients is emphasized as essential for individualized treatment plans that balance the potential benefits of anticoagulation against the risk of bleeding complications. Furthermore, it examines emerging anticoagulant agents and their potential role in HF management, highlighting the need for further research to delineate optimal management strategies and inform evidence-based practice. In conclusion, while anticoagulation holds promise for improving outcomes in HF patients, careful consideration of patient-specific factors and ongoing research efforts are essential to optimize therapeutic strategies in this population.

Effectiveness and safety of direct oral anticoagulation vs. warfarin in frail patients with atrial fibrillation

AIMS

Although frail patients with atrial fibrillation (AF) carry a high risk of stroke and treatment-related bleeding complications, evidence for the safety and effectiveness of anticoagulation remains sparse. This study investigated the effectiveness and safety of direct oral anticoagulant (DOAC) vs. warfarin in frail AF patients.

METHODS AND RESULTS

Nationwide registry-based cohort study including 32 048 anticoagulation naïve frail patients (median age 80 years, 53% female) with incident AF during 2012-20. Frailty was assessed using the hospital frailty risk score. To address baseline confounding, we applied inverse probability of treatment weighting (IPTW) and marginal structural models with weighted pooled regression to compute weighted hazard ratios (wHRs) and risk differences for thromboembolism and major bleeding comparing specific DOAC doses with warfarin. After AF diagnosis, 6747 (21.1%) initiated warfarin, 17 076 (50.3%) initiated standard-dose DOAC, and 9179 (28.6%) initiated reduced-dose DOAC. Comparative effectiveness analyses in the IPTW pseudo-populations revealed similar thromboembolism risk between standard-dose DOAC and warfarin [wHR 0.95, 95% confidence interval (CI) 0.80-1.13] and between reduced-dose DOAC and warfarin (wHR 0.97, 95% CI 0.77-1.23). The 1-year thromboembolic event-free survival difference was -0.2% for DOAC, regardless of dosing, vs. warfarin. Major bleeding risk was significantly lower with standard-dose DOAC (wHR 0.69, 95% CI 0.59-0.87) and reduced-dose DOAC (wHR 0.67, 95% CI 0.55-0.81) vs. warfarin. The 1-year bleeding risk difference with DOAC ranged from -1.3% to -3.0%.

CONCLUSION

Our findings indicate comparable thromboembolism risk and significantly lower bleeding risk with both standard and reduced DOAC regimens compared with warfarin in frail AF patients in routine care.

Impact of frailty on the effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation: a nationwide cohort study

AIMS

Data on non-vitamin K antagonist oral anticoagulants (NOACs) use in patients with atrial fibrillation (AF) and frailty are scarce. Therefore, the impact of frailty on AF-related outcomes and benefit-risk profiles of NOACs in patients with frailty were investigated.

METHODS AND RESULTS

AF patients initiating anticoagulation between 2013 and 2019 were included using Belgian nationwide data. Frailty was assessed with the Claims-based Frailty Indicator. Among 254 478 anticoagulated AF patients, 71 638 (28.2%) had frailty. Frailty was associated with higher all-cause mortality risks [adjusted hazard ratio (aHR) 1.48, 95% confidence interval (CI) (1.43-1.54)], but not with thromboembolism or bleeding. Among subjects with frailty (78 080 person-years of follow-up), NOACs were associated with lower risks of stroke or systemic embolism (stroke/SE) [aHR 0.77, 95%CI (0.70-0.86)], all-cause mortality [aHR 0.88, 95%CI (0.84-0.92)], and intracranial bleeding [aHR 0.78, 95%CI (0.66-0.91)], a similar major bleeding risk [aHR 1.01, 95%CI (0.93-1.09)], and higher gastrointestinal bleeding risk [aHR 1.19, 95%CI (1.06-1.33)] compared with VKAs. Major bleeding risks were lower with apixaban [aHR 0.84, 95%CI (0.76-0.93)], similar with edoxaban [aHR 0.91, 95%CI (0.73-1.14)], and higher with dabigatran [aHR 1.16, 95%CI (1.03-1.30)] and rivaroxaban [aHR 1.11, 95%CI (1.02-1.21)] compared with VKAs. Apixaban was associated with lower major bleeding risks compared with dabigatran [aHR 0.72, 95%CI (0.65-0.80)], rivaroxaban [aHR 0.78, 95%CI (0.72-0.84)] and edoxaban [aHR 0.74, 95%CI (0.65-0.84)], but mortality risk was higher compared with dabigatran and edoxaban.

CONCLUSION

Frailty was an independent risk factor of death. Non-vitamin K antagonist oral anticoagulants had better benefit-risk profiles than VKAs in patients with frailty, especially apixaban, followed by edoxaban.

Diagnosis and Management of Atrial Fibrillation in Acute Ischemic Stroke in the Setting of Reperfusion Therapy: Insights and Strategies for Optimized Care

Reperfusion therapy in the form of intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT) has revolutionised the field of stroke medicine. Atrial fibrillation (AF) patients constitute a major portion of the overall stroke population; however, the prevalence of AF amongst acute ischemic stroke (AIS) patients receiving reperfusion therapy remains unclear. Limitations in our understanding of prevalence in this group of patients are exacerbated by difficulties in appropriately diagnosing AF. Additionally, the benefits of reperfusion therapy are not consistent across all subgroups of AIS patients. More specifically, AIS patients with AF often tend to have poor prognoses despite treatment relative to those without AF. This article aims to present an overview of the diagnostic and therapeutic management of AF and how it mediates outcomes following stroke, most specifically in AIS patients treated with reperfusion therapy. We provide unique insights into AF prevalence and outcomes that could allow healthcare professionals to optimise the treatment and prognosis for AIS patients with AF. Specific indications on acute neurovascular management and secondary stroke prevention in AIS patients with AF are also discussed.

The Effect of Direct Oral Anticoagulant Therapy (DOACs) on oral surgical procedures: a systematic review

BACKGROUND

Direct oral anticoagulants (DOACs) were developed to overcome the drawbacks of oral anticoagulants. However, not much has been discussed about the perioperative management of patients on DOACs during oral surgical procedures. Thus, we aim to determine the risk of perioperative and postoperative bleeding during oral surgical procedures in patients on DOACs.

METHODS

A detailed literature search was performed to find potentially relevant studies using the Cochrane Library, Clinical Key, ClinicalTrials.gov, Google Scholar, Ovid, ScienceDirect, and Scopus. Every article available for free in English literature for the past 10 years, between 2012 and 2022, was searched.

RESULTS

A total of 2792 abstracts were selected through a search strategy across various search engines. Based on inclusion and exclusion criteria, eleven clinical studies using DOACs as anticoagulants or studies comparing patients with and without DOACs under oral surgery procedures were found. The results were inconsistent and varied, with a few studies recommending DOAC administration with the bare minimum reported complications and others finding no statistically significant difference between discontinuation or continuation of drugs, especially across basic dental procedures.

CONCLUSION

Within the limitations of the study, it can be concluded that minor oral surgical procedures are safe for patients on DOAC therapy. However, the continuation or discontinuation of DOACs in patients undergoing oral surgical procedures remains controversial and requires further studies to extrapolate the results.

Discontinuation of oral anticoagulant use among nursing home residents with atrial fibrillation before hospice enrollment

BACKGROUND

Oral anticoagulants (OACs) are effective in reducing the risk of cardioembolic stroke due to atrial fibrillation. While most nursing home residents with atrial fibrillation qualify for anticoagulation based on clinical guidelines, the net clinical benefits of OACs may diminish as residents approach the end of life.

METHODS

We conducted a cross-sectional study of 30,503 US nursing home residents with atrial fibrillation (based on Minimum Data Set 3.0 and Medicare Part A records) who used OACs in the year before enrolling in hospice care during 2012-2016. Whether residents discontinued OACs before hospice enrollment was determined using Part D claims and date of hospice enrollment. Modified Poisson models estimated adjusted prevalence ratios (aPR).

RESULTS

Almost half (45.7%) of residents who had recent OAC use discontinued prior to hospice enrollment. Residents who were underweight (aPR: 1.02; 95% confidence interval [CI]: 1.01-1.03), those with high bleeding risk (aPR: 1.04, 95% CI: 1.03-1.05), and those with moderate or severe cognitive impairment (aPR: 1.02, 95% CI: 1.02-1.03) had a higher prevalence of OAC discontinuation before entering hospice. Residents with venous thromboembolism (aPR: 0.94, 95% CI: 0.93-0.96), statin users (aPR: 0.88, 95% CI: 0.87-0.89), and those on polypharmacy (≥10 medications, aPR: 0.72; 95% CI: 0.71-0.73) were less likely to discontinue OACs before enrollment in hospice.

CONCLUSION

Anticoagulants are often discontinued among older nursing home residents with atrial fibrillation before hospice enrollment; it is not clear that these decisions are driven solely by net clinical benefit considerations. Further research is needed on comparative outcomes to inform resident-centered decisions regarding OAC use in older adults entering hospice.

Direct oral anticoagulants versus vitamin K antagonists: Which one is more effective in atrial fibrillation

BACKGROUND

The optimal approach for anticoagulation in patients with bioprosthetic valves and atrial fibrillation (AF) remains a subject of debate. A meta-analysis using updated evidence to evaluate the efficacy and safety of direct oral anticoagulants (DOACs) compared to vitamin K antagonists (VKAs) in patients with AF and bioprosthetic valves to address this controversy.

METHODS

A comprehensive search was conducted in multiple databases, including PubMed, Scopus, Web of Science, ProQuest, and the Cochrane Central Register of Controlled Trials, up until March 2023. The search aimed to identify relevant randomized controlled trials (RCTs) that examined the efficacy and safety outcomes of both direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) in patients with bioprosthetic valves and atrial fibrillation. The primary outcomes of interest were major bleeding and all-cause mortality.

RESULTS

Our study demonstrated that despite the difference was not significant, the hazard of all-cause mortality was 2.5% higher in the DOAC group (HR = 1.03, 95% CI = [0.88, 1.19], p-value = .75). Similarly, the hazard of stroke (HR = 1.03, 95% CI = [0.87, 1.32], p-value = .71) and major bleeding (HR = 1.11, 95% CI = [0.89, 1.38], p-value = .36) were found to be respectively 3.2 and 10.7% higher in the DOAC group, although the difference was not significant. However, the hazard of intracranial hemorrhage was found to be 28.8 lower in the DOAC treatment group (HR = 0.71, 95% CI = [0.39, 1.31], p-value = .27), which again was not statistically significant.

CONCLUSIONS

Our meta-analysis demonstrates that in patients undergoing bioprosthetic valve surgery and presenting with AF afterward, DOAC and VKA are similar regarding life-threatening and all-cause mortality outcomes, including major bleeding, stroke, and intracranial hemorrhage.