Patterns of long-term use of non-vitamin K antagonist oral anticoagulants for non-valvular atrial fibrillation: Quebec observational study

Delay and Pay? Healthcare Costs Associated with Late Oral Anti-coagulant Prescribing in People with Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is associated with increased morbidity and mortality and exerts an increasingly significant burden on global healthcare resources, with its prevalence rising with an ageing population. Despite a substantial thromboembolic risk, particularly in the period immediately following diagnosis, oral anti-coagulation is frequently not initiated or is delayed. The aim of this study was to evaluate healthcare costs in people with AF, comparing those who were commenced on oral anti-coagulation in the immediate period following the index diagnosis date with those in whom initiation was late and those who never started anti-coagulation.

METHODS

This retrospective cost analysis used linked Scottish health data to identify adults newly diagnosed with AF between January 1st 2012 and April 30th 2019 with a baseline CHA2DS2-VASc score of ≥ 2. This AF population was sub-divided according to timing of the first prescription of oral anti-coagulant (OAC) during a 2-year follow-up period: never started (OAC never initiated), immediate OAC (OAC prescribed within 60 days of incident AF diagnosis), and delayed OAC (OAC prescribed more than 60 days after incident AF diagnosis). A two-part model was developed, adjusted for key covariates, including age, sex, and frailty, to estimate costs for inpatient admissions, outpatient care, prescriptions, and care home admissions, and overall costs.

RESULTS

Of an overall AF population of 54,385, 26,805 (49.3%) never commenced OAC, 7654 (14.1%) initiated an OAC late, and 19,926 (36.6%) were prescribed anti-coagulation immediately. The mean adjusted cost for the overall AF population was £7807 per person per year (unadjusted: £8491). Delayed OAC initiation was associated with the greatest adjusted estimated mean annual cost (unadjusted: £13,983; adjusted: £9763), compared to those that never started (unadjusted: £10,433; adjusted: £7981) and those that received an immediate OAC prescription (unadjusted: £3976; adjusted: £6621). Increasing frailty, mortality, and female sex were associated with greater healthcare costs.

CONCLUSION

AF is associated with significant healthcare resource utilisation and costs, particularly in the context of delayed or non-initiation of anti-coagulation. Indeed, there exists substantial opportunity to improve the utilisation and prompt initiation in people newly diagnosed with AF in Scotland. Interventions to mitigate against the growing economic burden of AF should focus on reducing admissions to hospitals and care homes, which are the principal drivers of costs; prescriptions and outpatient appointments account for a relatively small proportion of overall costs for AF.

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.

Efficacy and Safety of Anticoagulants in Patients with Atrial Fibrillation and History of Falls or Risk of Falls: A Systematic Review and Multilevel Meta-Analysis

INTRODUCTION

Atrial fibrillation (AF) is a major cause of stroke. Anticoagulants substantially reduce risk of stroke but are also associated with an increased risk of bleeding. Because of that, many patients do not receive anticoagulants, particularly patients at risk of falls. This systematic review and meta-analysis aims to compare anticoagulant treatment options for the management of atrial fibrillation patients at risk of falls or with a history of falls.

METHODS

We conducted a PRISMA systematic review (until March 2022), including studies evaluating safety and efficacy of different anticoagulants (vitamin K antagonist [VKA] versus non-vitamin K antagonist oral anticoagulant [NOAC]). Outcomes were ischemic stroke, major bleeding, intracranial hemorrhage, hemorrhagic stroke, myocardial infarction, gastrointestinal bleeding, cardiovascular and all-cause mortality. A multilevel meta-analysis was conducted adjusting for clustering effects within studies examining more than one effect size.

RESULTS

A total of 919 articles were identified, 848 after removing duplicates. The full text of 155 were screened and 10 articles were retained for final quantitative synthesis. Risk of bias was moderate to serious for the included studies. In meta-analysis, NOACs were associated with superior effectiveness compared with VKA for ischemic stroke/systemic embolism (hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.69-0.98; p < 0.05) and safety (HR 0.53, 95% CI 0.40-0.71; p < 0.05) for intracranial hemorrhage. There were no differences in other outcomes.

CONCLUSION

NOACs were associated with less intracranial hemorrhages and ischemic strokes/systemic embolisms than VKAs in AF patients at risk of falls. These findings suggesting preferred use of NOACs over VKAs have clinical implications for physicians, patients and policy makers.

Long-Term Medication Adherence Trajectories to Direct Oral Anticoagulants and Clinical Outcomes in Patients With Atrial Fibrillation

Background

Direct oral anticoagulants (DOACs) are widely used in patients with nonvalvular atrial fibrillation for stroke prevention. However, long‐term adherence to DOACs and clinical outcomes in real‐world clinical practice is not well understood. This study evaluated long‐term medication adherence patterns to DOAC therapy and clinical outcomes in a large US integrated health care system.

Methods and Results

We included adult patients with nonvalvular atrial fibrillation who newly initiated DOACs between 2012 and 2018 in Kaiser Permanente Southern California. Long‐term (3.5 years) adherence trajectories to DOAC were investigated using monthly proportion of days covered and group‐based trajectory models. Factors associated with long‐term adherence trajectories were investigated. Multivariable Poisson regression analyses were used to investigate thromboembolism and major bleeding events associated with long‐term adherence trajectories. Of 18 920 patients newly initiating DOACs, we identified 3 DOAC adherence trajectories: consistently adherent (85.2%), early discontinuation within 6 months (10.6%), and gradually declining adherence (4.2%). Predictors such as lower CHA₂DS₂‐VASc (0–1 versus ≥5) and previous injurious falls were associated with both early discontinuation and gradually declining adherence trajectories. Early discontinuation of DOAC therapy was associated with a higher risk of thromboembolism (rate ratio, 1.40; 95% CI, 1.05–1.86) especially after 12 months from DOAC initiation but a lower risk of major bleed compared with consistent adherence (rate ratio, 0.48; 95% CI, 0.30–0.75), specifically during the first 12 months following DOAC initiation. A gradual decline in adherence to DOACs was not statistically significantly associated with thromboembolism outcomes compared with consistent adherence.

Conclusions

Although a large proportion of patients with nonvalvular atrial fibrillation were adherent to DOAC therapy over 3.5 years, early discontinuation of DOAC was associated a higher risk of thromboembolic events. Future tailored interventions for early discontinuers may improve clinical outcomes.

Risk of fracture in patients with non-valvular atrial fibrillation initiating direct oral anticoagulants vs. vitamin K antagonists

AIMS

To determine the risk of fracture associated with direct oral anticoagulants (DOACs) compared with vitamin K antagonists (VKAs) in patients with non-valvular atrial fibrillation (NVAF), accounting for cumulative duration of use.

METHODS AND RESULTS

Using Quebec administrative healthcare databases, we formed a cohort of all patients aged 40 years or older newly diagnosed with NVAF, who filled a first prescription for DOACs or VKAs between 2011 and 2014. Exposure was modelled as a time-varying variable whereby patients were considered unexposed up to 180 days of cumulative duration of use (to account for a biologically meaningful exposure) and exposed thereafter. The final cohort included 10 306 new users of DOACs and 15 357 new users of VKAs. After propensity score-based fine stratification and weighting, use of DOACs for 180 days or greater was associated with a 35% decreased risk of fracture [crude incidence rates 7.5 vs. 15.3 per 1000 person-years; adjusted hazard ratio (HR) 0.65, 95% confidence interval (CI) 0.46-0.91] compared to VKA duration ≥180 days. Direct oral anticoagulants use was also associated with a lower risk of hip fracture (HR 0.51, 95% CI 0.31-0.86) compared with VKAs. There was no difference in the rate of fracture for shorter duration of use (HR 1.10; 95% CI 0.79-1.53). The risk was not modified by age, sex, chronic kidney disease, osteoporosis, history of fracture or falls.

CONCLUSION

Prolonged use of DOACs is associated with a lower risk of fracture compared with VKAs. These findings support the first-line recommendation for DOACs in patients with NVAF.

Utilization and long-term persistence of direct oral anticoagulants among patients with nonvalvular atrial fibrillation and liver disease

AIMS

We characterized the utilization and long-term treatment persistence of direct oral anticoagulants (DOACs) in patients with nonvalvular atrial fibrillation (NVAF) and liver disease.

METHOD

Using the UK Clinical Practice Research Datalink, we assembled a population-based cohort of NVAF patients with liver disease initiating oral anticoagulants between 2011 and 2020. Logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs) of the association between patient characteristics and initiation of DOACs vs vitamin K antagonists (VKAs). Cox proportional hazards models estimated hazard ratios (HRs) and 95% CIs of the association between patient characteristics and the switch from VKAs to DOACs vs remaining on VKAs. We also assessed the 5-year treatment persistence with DOACs vs VKAs, and whether ischemic stroke or bleeding preceded treatment discontinuation.

RESULTS

Our cohort included 3167 NVAF patients with liver disease initiating DOACs (n = 2247, 71%) or VKAs (n = 920, 29%). Initiators of DOACs were more likely to have prior ischemic stroke (OR 1.44, 95% CI 1.12-1.85) than VKA initiators but less likely to have used antiplatelet agents (OR 0.66, 95% CI 0.53-0.82). Patients switching to DOACs were more likely to have used selective serotonin reuptake inhibitors (HR 1.64, 95% CI 1.13-2.37) than those remaining on VKAs. At 5 years, 31% of DOAC initiators and 9% of VKA initiators remained persistent. Only few patients were diagnosed with ischemic stroke or bleeding prior to treatment discontinuation.

CONCLUSION

Most NVAF patients with liver disease initiated treatment with DOACs. Long-term persistence with DOACs was higher than with VKAs but remained relatively low.

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.

Supporting anticoagulant treatment decision making to optimise stroke prevention in complex patients with atrial fibrillation: a cluster randomised trial

Background

Anticoagulation for preventing stroke in atrial fibrillation is under-utilised despite evidence supporting its use, resulting in avoidable death and disability. We aimed to evaluate an intervention to improve the uptake of anticoagulation.

Methods

We carried out a national, cluster randomised controlled trial in the Australian primary health care setting. General practitioners received an educational session, delivered via telephone by a medical peer and provided information about their patients selected either because they were not receiving anticoagulation or for whom anticoagulation was considered challenging. General practitioners were randomised to receive feedback from a medical specialist about the cases (expert decisional support) either before or after completing a post-test audit. The primary outcome was the proportion of patients reported as receiving oral anticoagulation. A secondary outcome assessed antithrombotic treatment as appropriate against guideline recommendations.

Results

One hundred and seventy-nine general practitioners participated in the trial, contributing information about 590 cases. At post-test, 152 general practitioners (84.9%) completed data collection on 497 cases (84.2%). A 4.6% (Adjusted Relative Risk = 1.11, 95% CI = 0.86–1.43) difference in the post-test utilization of anticoagulation between groups was not statistically significant (p = 0.42). Sixty-one percent of patients in both groups received appropriate antithrombotic management according to evidence-based guidelines at post-test (Adjusted Relative Risk = 1.0; 95% CI = 0.85 to 1.19) (p = 0.97).

Conclusions

Specialist feed-back in addition to an educational session did not increase the uptake of anticoagulation in patients with AF.

Trial registration

ANZCTRN12611000076976 Retrospectively registered.

Real-World Adherence and Persistence to Direct Oral Anticoagulants in Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

BACKGROUND

Stroke reduction with direct oral anticoagulants (DOACs) in atrial fibrillation (AF) is dependent on adherence and persistence in the real-world setting. Individual study estimates of DOAC adherence/persistence rates have been discordant. Our aims were to characterize real-world observational evidence for DOAC adherence/persistence and evaluate associated clinical outcomes in patients with AF.

METHODS AND RESULTS

PubMed, EMBASE, and CINAHL were searched from inception to June 2018. Observational studies that reported real-world DOAC adherence/persistence in patients with AF were included. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analyses for pooled estimates were performed using DerSimonian and Laird random-effects models. Outcomes included DOAC mean proportion of days covered or medication possession ratio, proportion of good adherence (proportion of days covered/medication possession ratio ≥80%), persistence, DOAC versus vitamin K antagonists persistence, and clinical outcomes associated with nonadherence/nonpersistence. Forty-eight observational studies with 594 784 unique patients with AF (59% male; mean age 71 years) were included. The overall pooled mean proportion of days covered/medication possession ratio was 77% (95% CI, 75%-80%), proportion of patients with good adherence was 66% (95% CI, 63%-70%), and proportion persistent was 69% (95% CI, 65%-72%). The pooled proportion of patients with good adherence was 71% (95% CI, 64%-78%) for apixaban, 60% (95% CI, 52%-68%) for dabigatran, and 70% (95% CI, 64%-75%) for rivaroxaban. Similar patterns were found for pooled persistence by agent. The pooled persistence was higher with DOACs than vitamin K antagonists (odds ratio, 1.44 [95% CI, 1.12-.86]). DOAC nonadherence was associated with an increased risk of stroke (hazard ratio, 1.39 [95% CI, 1.06-1.81]).

CONCLUSIONS

Suboptimal adherence and persistence to DOACs was common in patients with AF, with 1 in 3 patients adhering to their DOAC <80% of the time, which was associated with poor clinical outcomes in nonadherent patients. Although it is convenient that DOACs do not require laboratory monitoring, greater effort in monitoring for and interventions to prevent nonadherence may be necessary to optimize stroke prevention. Increased clinician awareness of DOAC nonadherence may help identify at-risk patients.

Atrial fibrillation patients' experiences and perspectives of anticoagulation therapy changes

BACKGROUND

Atrial fibrillation (AF) patients' experiences with changes in their oral anticoagulant (OAC) therapy are understudied.

OBJECTIVE

The objective of this study was to qualitatively describe AF patients' experiences and perspectives of changes made to their OAC therapy (switches or discontinuations).

METHODS

A thematic analysis was performed on systematically-collected qualitative data from AF patients who experienced a therapy change (switching or discontinuing an OAC) as part of their participation in a large 2-year prospective observational study.

RESULTS

A total of 56 participants met the inclusion criteria. Six themes emerged from the data: 1. reasons for switch or discontinuation of therapy, 2. attitudes towards changes in therapy attributes, 3. challenges with taking medications after therapy change, 4. relief from perceived burden of medication after discontinuation, 5. patients' limited involvement in decision-making, and 6. inadequate education and follow up. Patients were found to request changes in therapy based on their subjective experience with it (rather than clinically justified reasons). They were found to have limited knowledge about their medications, differing reactions to changes in their therapy attributes after a switch, an overall negative attitude towards taking medications, adherence challenges after switching from once daily to twice daily medication, feelings of being excluded from the decision-making process about their therapy changes and feelings of being unsupported after these changes.

CONCLUSIONS

There are clear opportunities to improve patients' experiences with OAC therapy changes through improved shared decision-making and patient education/counselling.

Persistence of oral anticoagulant treatment for atrial fibrillation in the Netherlands: A surveillance study

BACKGROUND

In contrast to vitamin K antagonists (VKA), direct oral anticoagulants (DOAC's) are not strictly monitored and dose titrated by anticoagulation clinics in the Netherlands. This may affect drug persistence of atrial fibrillation (AF) patients, whom often require lifelong treatment.

OBJECTIVES

To assess persistence of DOACs and of VKAs in patients with AF.

METHODS

Dispensing data from the Dutch Foundation of Pharmaceutical Statistics were used to monitor persistence of AF patients to DOAC from 1 January 2012-1 April 2016. In addition, we estimated the persistence of AF patients to VKA between 1 January 2004 and 1 January 2012 in data from the Anticoagulation Clinic Leiden. Non-persistence was defined as the cumulative incidence of patients who completely stopped DOAC, switched to another oral anticoagulant or stopped their VKA.

RESULTS

DOAC users (n = 77 333) were younger than VKA users (n = 10 079; 70 vs 73 years). Non-Persistence to DOAC (ie stopping with any oral anticoagulant) was 34% at 1 and 64% at 4 years, compared to 22% at one and 36% at 4 years for VKA. Approximately a Twenty-five percent of those who had stopped their initial DOAC switched to another anticoagulant (VKA or another DOAC). Multivariable analyses revealed that young age, female sex, no concomitant drug use and non-adherence were predictors for non-persistence of DOAC.

CONCLUSIONS

Persistence to DOAC was low and in line with other observational studies, and higher for VKA. Our results show a clear correlation between age <60 years and worse persistence, as well as with female and non-adherence to DOAC.

Evidence-Practice Gaps in Postdischarge Initiation With Oral Anticoagulants in Patients With Atrial Fibrillation

Background

Oral anticoagulant (OAC) therapy reduces the risk of stroke in people with atrial fibrillation (AF), and is considered best practice; however, there is little Australian evidence around the uptake of OACs in this population.

Methods and Results

We used linked hospital admissions, pharmaceutical dispensing claims, medical services, and mortality data for people in Australia's 2 most populous states (July 2010 to June 2015). Among OAC‐naïve people hospitalized with AF, we estimated initiation of OAC therapy within 30 days of discharge, and persistence with therapy in the first year. We analyzed both outcomes using multivariable Cox regression. In 71 184 people with AF (median age 78 years, 49% female), 22.7% initiated OAC therapy. Initiation was lowest in July to December 2011 (17.0%) and highest in July to December 2014 (30.1%) after subsidy of the direct OACs. In adjusted analyses, initiation was most likely in people with a CHA₂DS₂‐VA score ≥7 (versus 0) (hazard ratio=6.25, 95% CI 5.08–7.69), and a history of venous thromboembolism (hazard ratio=2.65, 95% CI 2.49–2.83). Of the people who initiated OAC therapy, 39.9% discontinued within 1 year; a lower risk of discontinuation was associated with a CHA₂DS₂‐VA score ≥7 (versus 0) (hazard ratio=0.22, 95% CI 0.14–0.35), or initiation on a direct OAC (versus warfarin) (hazard ratio=0.55, 95% CI 0.50–0.60).

Conclusions

We found that OAC therapy was severely underutilized in people hospitalized with AF, even among high‐risk individuals. Reasons for this underuse, whether patient, prescriber, or hospital related, should be identified and addressed to reduce stroke‐related morbidity and mortality in people with AF.

Predictors of NOAC versus VKA use for stroke prevention in patients with newly diagnosed atrial fibrillation: Results from GARFIELD-AF

INTRODUCTION

A principal aim of the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) was to document changes in treatment practice for patients with newly diagnosed atrial fibrillation during an era when non-vitamin K antagonist oral anticoagulants (NOACs) were becoming more widely adopted. In these analyses, the key factors which determined the choice between NOACs and vitamin K antagonists (VKAs) are explored.

METHODS

Logistic least absolute shrinkage and selection operator regression determined predictors of NOAC and VKA use. Data were collected from 24,137 patients who were initiated on AC ± antiplatelet (AP) therapy (NOAC [51.4%] or VKA [48.6%]) between April 2013 and August 2016.

RESULTS

The most significant predictors of AC therapy were country, enrolment year, care setting at diagnosis, AF type, concomitant AP, and kidney disease. Patients enrolled in emergency care or in the outpatient setting were more likely to receive a NOAC than those enrolled in hospital (OR 1.16 [95% CI: 1.04-1.30], OR: 1.15 [95% CI: 1.05-1.25], respectively). NOAC prescribing seemed to be favored in lower-risk groups, namely, patients with paroxysmal AF, normotensive patients, and those with moderate alcohol consumption, but also the elderly and patients with acute coronary syndrome. By contrast, VKAs were preferentially used in patients with permanent AF, moderate to severe kidney disease, heart failure, vascular disease, and diabetes and with concomitant AP.

CONCLUSION

GARFIELD-AF data highlight marked heterogeneity in stroke prevention strategies globally. Physicians are adopting an individualized approach to stroke prevention where NOACs are favored in patients with a lower stroke risk but also in the elderly and patients with acute coronary syndrome.

Oral anticoagulation therapy use in patients with atrial fibrillation after the introduction of non-vitamin K antagonist oral anticoagulants: findings from the French healthcare databases, 2011-2016

OBJECTIVES

To describe (i) the trend in oral anticoagulant (OAC) use following the introduction of non-vitamin K antagonist oral anticoagulant (NOAC) therapy for stroke prevention in atrial fibrillation (AF) patients and (ii) the current patterns of use of NOAC therapy in new users with AF in France.

DESIGN

(i) Repeated cross-sectional study and (ii) population-based cohort study.

SETTING

French national healthcare databases (50 million beneficiaries).

PARTICIPANTS

(i) Patients with identified AF in 2011, 2013 and 2016 and (ii) patients with AF initiating OAC therapy in 2015-2016. PRIMARY AND SECONDARY OUTCOME MEASURES: (i) Trend in OAC therapy use in patients with AF and (ii) patterns of use of NOAC therapy in new users with AF.

RESULTS

Between 2011 and 2016, use of OAC therapy moderately increased (+16%), while use of antiplatelet therapy decreased (-22%) among all patients with identified AF. In 2016, among the 1.1 million AF patients, 66% used OAC therapy and were more likely to be treated by vitamin K antagonist (VKA) than NOAC therapy, including patients at higher risk of stroke (63.5%), while 33% used antiplatelet therapy. Among 192 851 new users of OAC therapy in 2015-2016 with identified AF, NOAC therapy (66.3%) was initiated more frequently than VKA therapy, including in patients at higher risk of stroke (57.8%). Reduced doses were prescribed in 40% of NOAC new users. Several situations of inappropriate use at NOAC initiation were identified, including concomitant use of drugs increasing the risk of bleeding (one in three new users) and potential NOAC underdosing.

CONCLUSIONS

OAC therapy use in patients with AF remains suboptimal 4 years after the introduction of NOACs for stroke prevention in France and improvement in appropriate prescribing regarding NOAC initiation is needed. However, NOAC therapy is now the preferred drug class for initiation of OAC therapy in patients with AF, including in patients at higher risk of stroke.

Drug interaction as a predictor of direct oral anticoagulant drug levels in atrial fibrillation patients

Data are limited on the effects of drug interactions on direct-acting oral anticoagulant (DOAC) levels. We evaluated the effects of the use of interacting drugs on DOAC levels in patients with atrial fibrillation (AF). We reviewed data of AF patients tested for DOAC levels in 2013-2017. The primary outcomes were drug levels exceeding the expected steady-state range, and in the highest quartile. A multivariate analysis was performed to evaluate the correlation of treatment by the use of interacting drugs, CYP3A4 and P-glycoprotein (P-gp) inhibitors, with the primary outcomes. Overall, 147 patients underwent DOAC level measurement [dabigatran (n = 31), rivaroxaban (n = 29), apixaban (n = 87)]. Thirty-three (22.4%) had drug levels exceeding the expected range. Seventy-nine (53.7%) patients were treated with at least one interacting drug. In multivariate analysis, the concomitant use of interacting drugs was an independent predictor for drug levels exceeding the expected range (OR 3.3, 95% CI 1.20-9.05). The defined daily dose of the interacting drug correlated positively with DOAC levels (r = 0.29, P = 0.001). Co-treatment with interacting drugs was associated with extremely high levels of dabigatran, (OR 16.6, 95% CI 1.29-215.18) but not of the other DOAC examined. Concomitant use of interacting drugs is associated with high DOAC levels in patients with AF. Further investigation is warranted to establish the differences between specific DOAC, evaluate the effect on patient outcomes, and characterize the role of DOAC monitoring in this setting.

Non-bleeding Adverse Events with the Use of Direct Oral Anticoagulants: A Sequence Symmetry Analysis

Introduction

Postmarketing pharmacovigilance reports have raised concerns about non-bleeding adverse events associated with direct oral anticoagulants (DOACs), but only limited results are available from large claims databases.

Objective

The aim of this study was to assess the potential association between DOAC initiation and the onset of four types of non-bleeding adverse events by sequence symmetry analysis (SSA).

Methods

SSA was performed using nationwide data from the French National Healthcare databases (Régime Général, 50 million beneficiaries) to assess a cohort of 386,081 DOAC new users for the first occurrence of four types of non-bleeding outcomes: renal, hepatic, skin outcomes identified by using hospitalization discharge diagnoses, and gastrointestinal outcomes by using medication reimbursement. Asymmetry in the distribution of each investigated outcome occurring before and after initiation of DOAC therapy was used to test the association between DOAC therapy and these outcomes. SSA inherently controls for time-constant confounders, and adjusted sequence ratios were computed after correcting for temporal trends. Negative (glaucoma) and positive (bleeding, depressive disorders) control outcomes were used and analyses were replicated on a cohort of 310,195 patients initiating a vitamin K antagonist (VKA).

Results

This study demonstrated the expected positive association between either DOAC or VKA therapy and hospitalised bleeding and initiation of antidepressant therapy, while no association was observed between either DOAC or VKA therapy and initiation of antiglaucoma medications. For DOAC therapy, signals were the associations with hepatic outcomes, including acute liver injury [for the 3-month time window, aSR₃ = 2.71, 95% confidence interval (CI) 1.79–4.52]; gastrointestinal outcomes, including initiation of drugs for constipation and antiemetic drugs (aSR₃ = 1.31, 95% CI 1.27–1.36; and 1.17, 95% CI 1.12–1.22, respectively); and kidney diseases (aSR₃ = 1.33, 95% CI 1.29–1.37).

Conclusion

Results of this nationwide study suggest that DOACs are associated with rare but severe liver injury and more frequent gastrointestinal disorders. A low risk of kidney injury with DOAC therapy can also not be excluded.

Electronic supplementary material

The online version of this article (10.1007/s40264-018-0668-9) contains supplementary material, which is available to authorized users.