Oral anticoagulation in nonvalvular atrial fibrillation in clinical practice: impact of CHADS(2) score on outcome.

OBJECTIVES: CHADS(2) score predicts embolic risk in patients with nonvalvular atrial fibrillation (NVAF), but also bleeding risk in patients receiving oral anticoagulation (OAC). Our objective is to analyze the effectiveness and safety of OAC in patients with NVAF in daily clinical practice, according to embolic risk evaluated by means of CHADS(2) score.

METHODS: All consecutive outpatients with permanent NVAF seen at 2 cardiology clinics were prospectively followed for embolic events (transient ischemic attack, ischemic stroke, peripheral embolism) and severe bleedings. OAC was prescribed according to the recommendations of scientific associations. CHADS(2) score was obtained for each patient.

RESULTS: From February 1, 2000 to July 31, 2003, 796 outpatients fulfilled the inclusion criteria. OAC was prescribed to 564 (71%) patients. After 2.4 +/- 1.9 years of follow-up, the embolic event rates (per 100 patient-years) for each stratum of the CHADS(2 )score for patients with/without OAC were: 1/4.1, p = 0.23 (CHADS(2) = 0); 0.6/7.1, p = 0.0018 (CHADS(2) = 1); 0.5/5.1, p = 0.0014 (CHADS(2) = 2); 2.4/12.5, p = 0.0017 (CHADS(2) = 3) and 2.9/20, p = 0.013 (CHADS(2) >or=4). The severe bleeding rates for the same CHADS(2) score strata were 3/0.8, 0.8/0.7, 1.3/0.7, 0.4/0, and 2.9/5 in patients with/without OAC (n.s.).

CONCLUSION: OAC is effective and safe in daily clinical practice in patients with NVAF and CHADS(2) score >or=1.