RISK OF BLEEDING IN VERY OLD ATRIAL FIBRILLATION PATIENTS ON WARFARIN: RELATIONSHIP WITH AGEING AND CHADS2 SCORE
Abstract number: O-M-036
Poli1 D., Antonucci1 E., Mannini1 L., Abdullahi Said1 A., Rogolino1 A., Lucarini1 L., Falciani1 M., Abbate1 R., Gensini2 G., Prisco1 D.
11Dept of Medical and Surgical Critical Care, Thrombosis Centre, Azienda Ospedaliero-Universitaria, Azienda Ospedaliero-Universitaria Careggi, Florence 22Dept of Medical and Surgical Critical Care, Thrombosis Centre, Azienda Ospedaliero-Universitaria, Don Carlo Gnocchi Foundation, ONLUS IRCCS, Florence, Italy
How-to-cite Poli D, Antonucci E, Mannini L, Abdullahi Said A, Rogolino A, Lucarini L, Falciani M, Abbate R, Gensini G, Prisco D. RISK OF BLEEDING IN VERY OLD ATRIAL FIBRILLATION PATIENTS ON WARFARIN: RELATIONSHIP WITH AGEING AND CHADS2 SCORE. J Thromb Haemost 2007; 5 Supplement 2: O-M-036
Abstract
Introduction: In atrial fibrillation (AF) patients, age>=75 years is one of the major risk factors for stroke. However, it is not clear if an upper limit for the indication to OAT exists
Methods: For this reason, we performed a prospective study on 290 AF patients on OAT aged >=75 years (median age 82 years, total follow-up period 814 pt-yrs) followed by our Anticoagulation Clinic.
Results: Seventeen major bleeding events were recorded (rate 2.1 x100 pt/yrs), 11 of which cerebral (1.35 x100 pt/yrs). The occurrence of major bleedings was associated with history of previous TIA or stroke [OR 3.4 (1.1-12.5), p=0.01] and with diabetes [4.4 (1.3-14.7) p=0.01]. We found a trend to a progressive increase in the rate of bleeding risk with the increase of the CHADS2 score: patients with score 4-6 showed a rate of 3.4 x100 pt/yrs with respect to 1.5 x100 pt/yrs of patients with lower score. Number Needed to Harm (NNH) was calculated for the classes of CHADS2 score and age and compared with Number Needed to Treat (NNT) obtained from a metanalysis of clinical trials. For CHADS2 score 1 and 2-3, NNH was 51 and 68 respectively without significant changes across the different classes of age (75-79, 80-84, >85 years). The corresponding NNT was 58 and 32 respectively. For CHADS2 score 4-6, NNH was 29 (vs NNT of 16), but its values varied among the 3 groups of ages reaching a value of 10 in patients >=85 years.
Conclusions: Our data suggest: 1) in patients with CHADS2=1 the indication of OAT is questionable, 2) in patients >85 years with CHADS2 4-6 both NNH and NNT are quite low and the use of OAT should be highly individualised. In all the other patients the balance is in favour of OAT.
