Direct Oral Anticoagulants Versus Vitamin K Antagonists in Real-life Patients With Atrial Fibrillation. A Systematic Review and Meta-analysis

INTRODUCTION AND OBJECTIVES

To assess the effectiveness of direct oral anticoagulants vs vitamin K antagonists in real-life patients with atrial fibrillation.

METHODS

A systematic review was performed according to Cochrane methodological standards. The results were reported according to the PRISMA statement. The ROBINS-I tool was used to assess risk of bias.

RESULTS

A total of 27 different studies publishing data in 30 publications were included. In the studies with a follow-up up to 1 year, apixaban (HR, 0.93; 95%CI, 0.71-1.20) and dabigatran (HR, 0.95; 95%CI, 0.80-1.13) did not significantly reduce the risk of ischemic stroke vs warfarin, whereas rivaroxaban significantly reduced this risk (HR, 0.83; 95%CI, 0.73-0.94). Apixaban (HR, 0.66; 95%CI, 0.55-0.80) and dabigatran (HR, 0.83; 95%CI, 0.70-0.97) significantly reduced the major bleeding risk vs warfarin, but not rivaroxaban (HR, 1.02; 95%CI, 0.95-1.10), although with a high statistical heterogeneity among studies. Apixaban (HR, 0.56; 95%CI, 0.42-0.73), dabigatran (HR, 0.45; 95%CI, 0.39-0.51), and rivaroxaban (HR, 0.66; 95%CI, 0.49-0.88) significantly reduced the risk of intracranial bleeding vs warfarin. Reduced doses of direct oral anticoagulants were associated with a slightly better safety profile, but with a marked reduction in stroke prevention effectiveness.

CONCLUSIONS

Data from this meta-analysis suggest that, vs warfarin, the stroke prevention effectiveness and bleeding risk of direct oral anticoagulants may differ in real-life patients with atrial fibrillation.

Direct oral anticoagulants: An update

Vitamin K antagonists were the only choice for chronic oral anticoagulation for more than half a century. Over the past few years, direct oral anticoagulants have emerged, including one direct thrombin inhibitor (dabigatran etexilate) and three factor Xa inhibitors (apixaban, edoxaban and rivaroxaban). In randomised controlled trials comparing direct oral anticoagulants with traditional vitamin K antagonists, the direct oral anticoagulants all showed a favourable benefit-risk balance in their safety and efficacy profile, in prevention of thromboembolic events in patients with atrial fibrillation and in the prevention and treatment of venous thromboembolism and acute coronary syndrome. In 2008, dabigatran was the first direct oral anticoagulant approved by the European Medicine Agency. Subsequently, rivaroxaban, apixaban and edoxaban were also authorised. This article reviews the evidence related to the use of these drugs.

[Oral anticoagulation in atrial fibrillation: What is the guideline for using new drugs?]

OBJECTIVE

To assess whether there are differences between atrial fibrillation (AF) patients initiating new direct-acting oral anticoagulants (DOAC) therapy and vitamin K antagonist (VKA) therapy in an emergency service.

METHODS

Descriptive, observational, prospective study. We enrolled patients with AF who were visited in a hospital emergency service over one year.

RESULTS

This study included 492 patients with AF, and 189 subjects received anticoagulant therapy, 104 with VKA (55%), and 85 with DOAC (45%). The VKA group: mean age 76.1 years, male 50.9% and female 49.1%, CHA₂DS₂-VASc mean 3.2±1.3 points, and a HAS-BLED mean of 1.9±0.8 points. The DOAC group: mean age 73.4 years, male 37.6% and female 63.3%, CHA₂DS₂-VASc mean 3.1±1.6 points, and a HAS-BLED mean of 1.7±0.8 points. On analysing the medical history, 17.3% of patients in the VKA group had a previous stroke, and 13.5% significant valve disease, as well as 7.1 and 1.2% of patients, respectively, in the DOAC group. In the analysis of the DOAC types, 24.2% of patients in the dabigatran group had a previous stroke, 22.7% in the rivaroxaban group had ischaemic heart disease.

CONCLUSIONS

Patients with AF who start on treatment in emergency services with VKA or with DOAC show a similar profile of age, gender, CHA₂DS₂-VASc score, and HAS-BLED score. The patients with a history of valvular or ischaemic heart disease received more VKA than DOAC. When the patient has a history of stroke, the DOAC more used is dabigatran, and in patients with ischaemic heart disease it is preferred to give rivaroxaban.

[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.

[Cost-effectiveness analysis of apixaban versus acetylsalicylic acid in the prevention of stroke in patients with non-valvular atrial fibrillation in Spain]

Objetivo

Evaluar el coste-utilidad de apixabán frente al ácido acetilsalicílico (AAS) en la prevención del ictus en pacientes con fibrilación auricular no valvular (FANV) con contraindicación de antagonistas de la vitamina K en España.

Métodos

Se adaptó un modelo de Markov, simulando toda la vida del paciente. Los datos de eficacia y seguridad provienen del ensayo clínico AVERROES. Perspectivas del análisis: Sistema Nacional de Salud (SNS) y sociedad. El coste de los medicamentos se calculó según las dosis recomendadas. Los costes de las complicaciones y el manejo de la FANV proceden de fuentes españolas.

Resultados

Si una cohorte de 1.000 pacientes con FANV fuese tratada durante toda su vida con apixabán en lugar de AAS, se evitarían 48 ictus isquémicos, 10 embolismos sistémicos y 53 muertes relacionadas. Cada paciente tratado con apixabán obtendría más años de vida ganados (0,303 AVG) y más años de vida ajustados por calidad (0,277 AVAC ganados). Los costes para el SNS serían superiores con apixabán (1.742 € más por paciente), pero la inclusión de los costes informales generaría 2.887 € de ahorro por paciente. El resultado sería un coste por AVG y AVAC ganado de 5.749 € y 6.289 € respectivamente para el SNS, siendo apixabán dominante (más eficaz con menos costes que AAS) desde la perspectiva de la sociedad. Los análisis de sensibilidad confirmaron la estabilidad del caso base.

Conclusiones

Según el presente modelo, apixabán sería un tratamiento coste-efectivo en comparación con AAS en la prevención del ictus en pacientes con FANV en España.

Cost-effectiveness Analysis Comparing Apixaban and Acenocoumarol in the Prevention of Stroke in Patients With Nonvalvular Atrial Fibrillation in Spain

INTRODUCTION AND OBJECTIVES

Cost-effectiveness analysis of apixaban (5 mg twice daily) vs acenocoumarol (5mg/day) in the prevention of stroke in patients with nonvalvular atrial fibrillation in Spain.

METHODS

Markov model covering the patient's entire lifespan with 10 health states. Data on the efficacy and safety of the drugs were provided by the ARISTOTLE trial. Warfarin and acenocoumarol were assumed to have therapeutic equivalence.

PERSPECTIVES

The Spanish National Health System and society. Information on the cost of the drugs, complications, and the management of the disease was obtained from Spanish sources.

RESULTS

In a cohort of 1000 patients with nonvalvular atrial fibrillation, administration of apixaban rather than acenocoumarol would avoid 18 strokes, 71 hemorrhages (28 intracranial or major), 2 myocardial infarctions, 1 systemic embolism, and 23 related deaths. Apixaban would prolong life (by 0.187 years) and result in more quality-adjusted life years (by 0.194 years) per patient. With apixaban, the incremental costs for the Spanish National Health System and for society would be € 2,488 and € 1,826 per patient, respectively. Consequently, the costs per life year gained would be € 13,305 and € 9,765 and the costs per quality-adjusted life year gained would be € 12,825 and € 9,412 for the Spanish National Health System and for society, respectively. The stability of the baseline case was confirmed by sensitivity analyses.

CONCLUSIONS

According to this analysis, apixaban may be cost-effective in the prevention of stroke in patients with nonvalvular atrial fibrillation compared with acenocoumarol.

[Improvements in oral anticoagulant therapy for atrial fibrillation]

For the last decades vitamin K antagonists have been the most effective anticoagulant treatment of atrial fibrillation. New molecules are being designed, mainly due to the great amount of disadvantages in the management of conventional anticoagulation. Dabigatran, rivaroxaban and apixaban will soon be available as an alternative to warfarin/acenocumarol. All of them have demonstrated to be non-inferior to warfarin in preventing stroke and systemic embolism, with even dabigatran 150 mg bid and apixaban being superior. They have also a lower risk of bleeding, especially regarding severe/fatal and intracranial hemorrhages. This is a real revolution. The advance of these new anticoagulants will be limited only by the higher cost, and will progressively become the protagonists of oral anticoagulation in patients with nonvalvular atrial fibrillation.