title: Bleeding and stroke risk in a real-world prospective primary prevention cohort of patients with atrial fibrillation.
abstract: BACKGROUND
  All stroke risk stratification schemes categorize a history of stroke as a "truly high" risk factor. Therefore, stratifying stroke risk in atrial fibrillation (AF) should perhaps concentrate on primary prevention. However, the risk factors for stroke also lead to an increase in the risk of bleeding. Our objective was to evaluate the agreement among the currently used stroke risk stratification schemes in "real-world" patients with AF in the primary prevention setting, their correlation with adverse events recorded during warfarin treatment, and the relationship between stroke and bleeding risk.
  
  
  METHODS
  We prospectively followed up 3,302 patients with AF taking warfarin for primary prevention. Stroke risk was assessed using the CHADS(2) (congestive heart failure, hypertension, age ≥ 75 years, diabetes, previous stroke or transient ischemic attack), Atrial Fibrillation Investigators, American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy, American College of Cardiology/American Heart Association/European Society of Cardiology, and National Institute for Health and Clinical Excellence schemas, and for bleeding risk, the outpatient bleeding risk index was calculated. Bleeding and thrombotic events occurring during follow-up were recorded.
  
  
  RESULTS
  Patients classified into various stroke risk categories differed widely for different schemes, especially for the moderate- and high-risk categories. The rates of bleeding and thrombotic events during follow-up were 1.24 and 0.76 per 100 patient-years, respectively. All stroke stratification schemes correlated closely to bleeding risk. Stroke rate increased progressively from low- to moderate- to high-risk patients.
  
  
  CONCLUSIONS
  Stroke risk stratification models differed widely when categorizing subjects into the moderate- and high-stroke-risk categories. Bleeding and stroke risk were closely correlated and both were low among low-risk patients and were similarly high among moderate/high-risk groups.
authors.affiliation: Department of Heart and Vessels, Thrombosis Centre, Azienda Ospedaliera Universitaria Careggi, Firenze, Italy. Electronic address: polida@aou-careggi.toscana.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Poli
authors.affiliation: Haemostasis and Thrombosis Centre, A O Istituti Ospitalieri di Cremona, Cremona, Italy.
authors.forename: Sophie
authors.initials: S
authors.lastname: Testa
authors.affiliation: Department of Medical and Surgical Critical Care, Thrombosis Centre, University of Florence, Firenze, Italy.
authors.forename: Emilia
authors.initials: E
authors.lastname: Antonucci
authors.affiliation: Department of Medical and Surgical Critical Care, Thrombosis Centre, University of Florence, Firenze, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Grifoni
authors.affiliation: Haemostasis and Thrombosis Centre, A O Istituti Ospitalieri di Cremona, Cremona, Italy.
authors.forename: Oriana
authors.initials: O
authors.lastname: Paoletti
authors.affiliation: Centre for Cardiovascular Sciences, University of Birmingham, City Hospital, Birmingham, England.
authors.forename: Gregory Y H
authors.initials: GYH
authors.lastname: Lip
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000139:chemically induced / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D011322:Primary Prevention; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000517:prevention & control*; D014812:Vitamin K / Q000037:antagonists & inhibitors; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D014812:Vitamin K; D014859:Warfarin