title: Underuse of oral anticoagulants in atrial fibrillation: a systematic review.
abstract: BACKGROUND
  Atrial fibrillation is associated with substantial mortality and morbidity from stroke and thromboembolism. Despite an efficacious oral anticoagulation therapy (warfarin), atrial fibrillation patients at high risk for stroke are often under-treated. This systematic review compares current treatment practices for stroke prevention in atrial fibrillation with published guidelines.
  
  
  METHODS
  Literature searches (1997-2008) identified 98 studies concerning current treatment practices for stroke prevention in atrial fibrillation. The percentage of patients eligible for oral anticoagulation due to elevated stroke risk was compared with the percentage treated. Under-treatment was defined as treatment of <70% of high-risk patients.
  
  
  RESULTS
  Of 54 studies that reported stroke risk levels and the percentage of patients treated, most showed underuse of oral anticoagulants for high-risk patients. From 29 studies of patients with prior stroke/transient ischemic attack who should all receive oral anticoagulation according to published guidelines, 25 studies reported under-treatment, with 21 of 29 studies reporting oral anticoagulation treatment levels below 60% (range 19%-81.3%). Subjects with a CHADS(2) (congestive heart failure, hypertension, age >75 years, diabetes mellitus, and prior stroke or transient ischemic attack) score >or=2 also were suboptimally treated, with 7 of 9 studies reporting treatment levels below 70% (range 39%-92.3%). Studies (21 of 54) using other stroke risk stratification schemes differ in the criteria they use to designate patients as "high risk," such that direct comparison is not possible.
  
  
  CONCLUSIONS
  This systematic review demonstrates the underuse of oral anticoagulation therapy for real-world atrial fibrillation patients with an elevated risk of stroke, highlighting the need for improved therapies for stroke prevention in atrial fibrillation.
authors.affiliation: BioMedCom Consultants Inc., Montréal, QC, Canada. isla_ogilvie@biomedcom.org
authors.forename: Isla M
authors.initials: IM
authors.lastname: Ogilvie
authors.forename: Nick
authors.initials: N
authors.lastname: Newton
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Welner
authors.forename: Warren
authors.initials: W
authors.lastname: Cowell
authors.forename: Gregory Y H
authors.initials: GY
authors.lastname: Lip
mesh_terms: D000284:Administration, Oral; D000925:Anticoagulants / Q000008:administration & dosage* / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications* / Q000188:drug therapy*; D006801:Humans; D020521:Stroke / Q000517:prevention & control*; D013923:Thromboembolism / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants