title: Modification of outcomes with aspirin or apixaban in relation to CHADS(2) and CHA(2)DS(2)-VASc scores in patients with atrial fibrillation: a secondary analysis of the AVERROES study.
abstract: BACKGROUND
  The impact of apixaban versus aspirin on ischemic stroke and major bleeding in relation to the CHADS(2) and CHA(2)DS(2)-VASc stroke risk scores in atrial fibrillation has not been investigated.
  
  
  RESULTS
  In this secondary analysis of the AVERROES trial, our principal objective was to assess the effect of treatment with aspirin or apixaban on ischemic stroke and major bleeding, in relation to the CHADS(2)/CHA(2)DS(2)-VASc scores. We found no significant heterogeneity for treatment efficacy on ischemic stroke for apixaban when subdivided by stroke risk strata, based on CHADS(2)/CHA(2)DS(2)-VASc. Effects were consistent irrespective of baseline risk, and thus, absolute benefits were greatest in the high-risk groups. There was also no significant heterogeneity for apixaban versus aspirin with regard to major bleeding, when subdivided by CHADS(2)/CHA(2)DS(2)-VASc scores. In multivariable analysis, significant predictors of stroke on aspirin were age ≥75 years, prior stroke or transient ischemic attack, estimated glomerular filtration rate <60 mL/min, and nonparoxysmal atrial fibrillation. Proportions of the study cohort classified as low/moderate/high risk using the CHADS(2) and CHA(2)DS(2)-VASc scores were 0.3%/71.7%/28.1% and <0.1%/10.5%/89.5%, respectively.
  
  
  CONCLUSIONS
  In an atrial fibrillation population, apixaban was superior to aspirin for stroke prevention, with similar rates of major bleeding, in the presence of one or more stroke risk factors, with consistency of the treatment effect by CHADS(2)/CHA(2)DS(2)-VASc scores.
authors: University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, UK. g.y.h.lip@bham.ac.uk
authors: Gregory Y H
authors: GY
authors: Lip
authors: Stuart
authors: S
authors: Connolly
authors: Salim
authors: S
authors: Yusuf
authors: Olga
authors: O
authors: Shestakovska
authors: Greg
authors: G
authors: Flaker
authors: Robert
authors: R
authors: Hart
authors: Fernando
authors: F
authors: Lanas
authors: Denis
authors: D
authors: Xavier
authors: John
authors: J
authors: Eikelboom
mesh_terms: D000368:Aged; D001241:Aspirin / Q000009:adverse effects / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D002545:Brain Ischemia / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D005343:Fibrinolytic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D006305:Health Status Indicators; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011720:Pyrazoles / Q000009:adverse effects / Q000627:therapeutic use*; D011728:Pyridones / Q000009:adverse effects / Q000627:therapeutic use*; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents; D011720:Pyrazoles; D011728:Pyridones; C522181:apixaban; D001241:Aspirin