title: Use and associated risks of concomitant aspirin therapy with oral anticoagulation in patients with atrial fibrillation: insights from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) Registry.
abstract: BACKGROUND
  The role of concomitant aspirin (ASA) therapy in patients with atrial fibrillation (AF) receiving oral anticoagulation (OAC) is unclear. We assessed concomitant ASA use and its association with clinical outcomes among AF patients treated with OAC.
  
  
  RESULTS
  The Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry enrolled 10 126 AF patients from 176 US practices from June 2010 through August 2011. The study population was limited to those on OAC (n=7347). Hierarchical multivariable logistic regression models were used to assess factors associated with concomitant ASA therapy. Primary outcomes were 6-month bleeding, hospitalization, ischemic events, and mortality. Overall, 35% of AF patients (n=2543) on OAC also received ASA (OAC+ASA). Patients receiving OAC+ASA were more likely to be male (66% versus 53%; P<0.0001) and had more comorbid illness than those on OAC alone. More than one third of patients (39%) receiving OAC+ASA did not have a history of atherosclerotic disease, yet 17% had elevated Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) bleeding risk scores (≥5). Major bleeding (adjusted hazard ratio, 1.53; 95% confidence interval, 1.20-1.96) and bleeding hospitalizations (adjusted hazard ratio, 1.52; 95% confidence interval, 1.17-1.97) were significantly higher in those on OAC+ASA compared with those on OAC alone. Rates of ischemic events were low.
  
  
  CONCLUSIONS
  Patients with AF receiving OAC are often treated with concomitant ASA, even when they do not have cardiovascular disease. Use of OAC+ASA was associated with significantly increased risk for bleeding, emphasizing the need to carefully determine if and when the benefits of concomitant ASA outweigh the risks in AF patients already on OAC.
  
  
  BACKGROUND
  URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT01165710.
authors.affiliation: MPH, Duke University Medical Center and Duke Clinical Research Institute, 2400 Pratt St, Ste 7009, Durham, NC 27705, USA.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Steinberg
authors.forename: Sunghee
authors.initials: S
authors.lastname: Kim
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Piccini
authors.forename: Gregg C
authors.initials: GC
authors.lastname: Fonarow
authors.forename: Renato D
authors.initials: RD
authors.lastname: Lopes
authors.forename: Laine
authors.initials: L
authors.lastname: Thomas
authors.forename: Michael D
authors.initials: MD
authors.lastname: Ezekowitz
authors.forename: Jack
authors.initials: J
authors.lastname: Ansell
authors.forename: Peter
authors.initials: P
authors.lastname: Kowey
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Singer
authors.forename: Bernard
authors.initials: B
authors.lastname: Gersh
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Mahaffey
authors.forename: Elaine
authors.initials: E
authors.lastname: Hylek
authors.forename: Alan S
authors.initials: AS
authors.lastname: Go
authors.forename: Paul
authors.initials: P
authors.lastname: Chang
authors.forename: Eric D
authors.initials: ED
authors.lastname: Peterson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001241:Aspirin / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000401:mortality; D001562:Benzimidazoles / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D002561:Cerebrovascular Disorders / Q000453:epidemiology; D000077144:Clopidogrel; D015897:Comorbidity; D000069604:Dabigatran; D004357:Drug Synergism; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000139:chemically induced; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000453:epidemiology; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011446:Prospective Studies; D012042:Registries / Q000706:statistics & numerical data; D012306:Risk; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use; D016896:Treatment Outcome; D015091:beta-Alanine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D001562:Benzimidazoles; D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors; D015091:beta-Alanine; D000077144:Clopidogrel; D000069604:Dabigatran; D013988:Ticlopidine; D001241:Aspirin
keywords: anticoagulants; aspirin; atrial fibrillation; hemorrhage; outcome assessment (health care)