Clinical trials with new oral anticoagulants. Additive value of indirect comparisons also named network meta-analyses

Mapping the characteristics, methodological quality and standards of reporting of network meta-analyses on antithrombotic therapies: An overview

BACKGROUND

Although a large number of network meta-analyses (NMAs) in the field of cardiology are available, little is known about their methodological quality. We aimed to map the characteristics and critically appraised the standards of conduct and evidence reporting of NMAs assessing antithrombotic therapies for the treatment or prophylaxis of heart diseases and cardiac surgical procedures.

METHODS

We systematically searched PubMed and Scopus to identify NMAs comparing the clinical effects of antithrombotic therapies. Overall characteristics of the NMAs were extracted and their reporting quality and methodological quality were evaluated using the PRISMA-NMA checklist and AMSTAR-2, respectively.

RESULTS

We found 86 NMAs published between 2007 and 2022. Comparisons among direct-acting oral anticoagulants were available in 61 (71%) NMAs. Although around 75% of NMAs stated that they followed international guidelines for conduct and reporting, only one third provided a protocol/register. Complete search strategies and publication bias assessment were lacking in around 53% and 59% of studies, respectively. Most NMAs (n = 77, 90%) provided supplemental material; however, only 5 (6%) made the complete raw data available. Network diagrams were depicted in most studies (n = 67, 78%), yet network geometry was described in only 11 (12.8%) of them. Mean adherence to the PRISMA-NMA checklist was 65.1 ± 16.5%. AMSTAR-2 assessment showed 88% of the NMAs had critically low methodological quality.

CONCLUSION

Although there is a wide diffusion of NMA-type studies on antithrombotics for heart diseases, their methodological and reporting quality remains suboptimal. This may reflect fragile clinical practices due to misleading conclusions from critically low-quality NMAs.

Klinische Studien zu neuen direkten oralen Antikoagulanzien

Um die Wirksamkeit und Verträglichkeit neuer direkter oraler Antikoagulanzien (DOAK) zu vergleichen, müssten idealerweise eine direkte Gegenüberstellung der Substanzen in klinischen Studien durchgeführt werden. Auf Grund des logistischen und finanziellen Aufwandes wird dies aber in absehbarer Zeit nicht geschehen. Indirekte Vergleiche, auch Netzwerkanalysen (NMA) genannt, lassen sich mit den vorliegenden Studien zwischen den DOAKs vornehmen. In der postoperativen Phase nach Knie- und Hüftgelenkersatz und bei Patienten mit Vorhofflimmern sind derzeit diese Vergleich möglich. Indirekte Vergleiche sind jedoch auch mit Einschränkungen behaftet.

Diese Arbeit gibt eine Übersicht der aktuell vorliegenden NMAs und versucht, deren Ergebnisse mit der Pharmakologie der DOAKs und den methodischen Problemen von NMAs zu beleuchten.

[Multidisciplinary meeting about the use of direct oral anticoagulants in nonvalvular atrial fibrillation]

Knowing the real impact of atrial fibrillation in the stroke, the Sociedad Mexicana of Electrofisiología y Estimulación Cardiaca (SOMEEC) had the initiative to develop a multidisciplinary meeting of experts the with the purpose to update the available scientific evidence from clinical practice guidelines, meta-analyses, controlled clinical trials, and complementing with the experience and views of a group of experts. To meet this goal, SOMEEC gathered a group of specialists in the area of cardiology, electrophysiology, neurology and hematology that given their experience in certain areas, they share the scientific evidence with the panel of experts to leave open a discussion about the information presented in this article. This document brings together the best scientific evidence available and aims to be a useful tool in the decision to use of new oral anticoagulants in nonvalvular atrial fibrillation and ischemic heart disease, or relating to the management of patients with stroke or renal failure, and even those that will be submitted to elective surgery and invasive procedures. In the same, they handled comparative schemes of follow-up and treatment which simplifies the decision making by the specialists participants.

Adherence to oral anticoagulants in patients with atrial fibrillation-a population-based retrospective cohort study linking health information systems in the Valencia region, Spain: a study protocol

INTRODUCTION

Adherence to oral anticoagulation (OAC) treatment, vitamin K antagonists or new oral anticoagulants, is an essential element for effectiveness. Information on adherence to OAC in atrial fibrillation (AF) and the impact of adherence on clinical outcomes using real-world data barely exists. We aim to describe the patterns of adherence to OAC over time in patients with AF, estimate the associated factors and their impact on clinical events, and assess the same issues with conventional measures of primary and secondary adherence-proportion of days covered (PDC) and persistence-in routine clinical practice.

METHODS AND ANALYSIS

This is a population-based retrospective cohort study including all patients with AF treated with OAC from 2010 to date in Valencia, Spain; data will be obtained from diverse electronic records of the Valencia Health Agency.

PRIMARY OUTCOME MEASURE

adherence trajectories.

SECONDARY OUTCOMES

(1) primary non-adherence; (2) secondary adherence: (a) PDC, (b) persistence. Clinical outcomes: hospitalisation for haemorrhagic or thromboembolic events and death during follow-up.

ANALYSIS

(1) description of baseline characteristics, adherence patterns (trajectory models or latent class growth analysis models) and conventional adherence measures; (2) logistic or Cox multivariate regression models, to assess the associations between adherence measures and the covariates, and logistic multinomial regression models, to identify characteristics associated with each trajectory; (3) Cox proportional hazard models, to assess the relationship between adherence and clinical outcomes, with propensity score adjustment applied to further control for potential confounders; (4) to estimate the importance of different healthcare levels in the variations of adherence, logistic or Cox multilevel regression models.

ETHICS AND DISSEMINATION

This study has been approved by the corresponding Clinical Research Ethics Committee. We plan to disseminate the project's findings through peer-reviewed publications and presentations at relevant health conferences. Policy reports will also be prepared in order to promote the translation of our findings into policy and clinical practice.

Critical appraisal of network meta-analyses evaluating the efficacy and safety of new oral anticoagulants in atrial fibrillation stroke prevention trials

OBJECTIVES

To critically appraise published network meta-analyses (NMAs) evaluating the efficacy or safety of the new oral anticogulants (NOACs) dabigatran, rivaroxaban, and apixaban for the prevention of stroke in patients with nonvalvular atrial fibrillation (AF).

METHODS

A systematic literature review was performed to identify the relevant NMAs using MEDLINE, EMBASE, Cochrane Library, Database of Abstracts of Reviews of Effects, and Health Technology Assessment. The synthesis studies were evaluated using the "Questionnaire to assess the relevance and credibility of the NMA."

RESULTS

Eleven NMAs evaluating NOACs among adults with nonvalvular AF were identified. Most NMAs included three large phase III randomized controlled trials, comparing NOACs to adjusted-dose warfarin (Randomized Evaluation of Long-Term Anticoagulation Therapy [RE-LY], Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation [ROCKET-AF], and Apixaban for Reduction of Stroke and Other Thromboembolic Events in Atrial Fibrillation [ARISTOTLE]). The main differences identified related to potential treatment effect modifiers regarding the mean time spent in therapeutic range (TTR) in the warfarin arm, the risk of stroke or systemic embolism across the trials (mean CHADS2 score: C = congestive heart failure, H = hypertension, A = older than age 75 years, D = diabetes mellitus, S2 = prior stroke or history of transient ischemic attack) or primary versus secondary prevention, and type of populations used in the analysis. Kansal et al. [Kansal AR, Sharma M, Bradley-Kennedy C, et al. Dabigatran versus rivaroxaban for the prevention of stroke and systemic embolism in atrial fibrillation in Canada: comparative efficacy and cost-effectiveness. Thromb Haemost 2012;108:672-82] appropriately adjusted the ROCKET-AF TTR to match the RE-LY population on the basis of individual patient data. Meta-regressions are not expected to minimize confounding bias given limited data, whereas subgroup analyses had some impact on the point estimates for the treatment comparisons.

CONCLUSIONS

Results of the synthesis studies were generally comparable and suggested that the NOACs had similar efficacy, although some differences were identified depending on the outcome. The extent to which differences in the distribution of TTR, CHADS2 score, or primary versus secondary prevention biased the results remains unclear.

Rivaroxaban: a review of its use in the prevention of stroke and systemic embolism in patients with atrial fibrillation

Rivaroxaban (Xarelto(®)), a direct factor Xa inhibitor, is approved for the prevention of stroke and systemic embolism in patients with atrial fibrillation (AF) in Canada or those with nonvalvular AF (NVAF) in the EU, US and Japan. It is administered at a fixed oral dose and generally does not require routine monitoring of coagulation parameters. In the ROCKET AF trial in patients with NVAF and a moderate to high risk of stroke, oral rivaroxaban 20 mg once daily (15 mg once daily in patients with moderate renal impairment) was noninferior to oral dose-adjusted warfarin once daily in preventing primary endpoint events (i.e. stroke and systemic embolism) in the per-protocol population (primary noninferiority analysis) and superior in the on-treatment safety population (primary superiority analysis). Several ROCKET AF subgroup analyses indicated that the treatment effect of rivaroxaban was consistent across patient subgroups stratified according to baseline factors, including the presence or absence of previous stroke or transient ischaemic attack. Patients with moderate renal impairment receiving the reduced rivaroxaban dosage (15 mg once daily) showed a treatment effect consistent with that seen with rivaroxaban 20 mg once daily in patients with normal renal function. The tolerability profile of rivaroxaban was generally acceptable in ROCKET AF, with no significant difference between rivaroxaban and warfarin in the incidence of major or nonmajor clinically-relevant bleeding events (primary safety endpoint). In the Japanese ROCKET AF trial, rivaroxaban 15 mg once daily (10 mg once daily in patients with moderate renal impairment) was noninferior to oral dose-adjusted warfarin once daily in the incidence of major or nonmajor clinically-relevant bleeding (primary study outcome). Thus, rivaroxaban is a reasonable alternative to warfarin for the prevention of stroke and systemic embolism in patients with NVAF.

Systematic review and network meta-analysis comparing antithrombotic agents for the prevention of stroke and major bleeding in patients with atrial fibrillation

OBJECTIVE

To examine the comparative efficacy and safety of antithrombotic treatments (apixaban, dabigatran, edoxaban, rivaroxaban and vitamin K antagonists (VKA) at a standard adjusted dose (target international normalised ratio 2.0-3.0), acetylsalicylic acid (ASA), ASA and clopidogrel) for non-valvular atrial fibrillation and among subpopulations.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

A systematic literature search strategy was designed and carried out using MEDLINE, EMBASE, the Cochrane Register of Controlled Trials and the grey literature including the websites of regulatory agencies and health technology assessment organisations for trials published in English from 1988 to January 2014.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials were selected for inclusion if they were published in English, included at least one antithrombotic treatment and involved patients with non-valvular atrial fibrillation eligible to receive anticoagulant therapy.

RESULTS

For stroke or systemic embolism, dabigatran 150 mg and apixaban twice daily were associated with reductions relative to standard adjusted dose VKA, whereas low-dose ASA and the combination of clopidogrel plus low-dose ASA were associated with increases. Absolute risk reductions ranged from 6 fewer events per 1000 patients treated for dabigatran 150 mg twice daily to 15 more events for clopidogrel plus ASA. For major bleeding, edoxaban 30 mg daily, apixaban, edoxaban 60 mg daily and dabigatran 110 mg twice daily were associated with reductions compared to standard adjusted dose VKA. Absolute risk reductions with these agents ranged from 18 fewer per 1000 patients treated each year for edoxaban 30 mg daily to 24 more for medium dose ASA.

CONCLUSIONS

Compared with standard adjusted dose VKA, new oral anticoagulants were associated with modest reductions in the absolute risk of stroke and major bleeding. People on antiplatelet drugs experienced more strokes compared with anticoagulant drugs without any reduction in bleeding risk. To fully elucidate the comparative benefits and harms of antithrombotic agents across the various subpopulations, rigorously conducted comparative studies or network meta-regression analyses of patient-level data are required.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO registry-CRD42012002721.