[Hemorrhagic complications of oral anticoagulant therapy: results of a prospective multicenter study ISCOAT (Italian Study on Complications of Oral Anticoagulant Therapy)].
BACKGROUND
To assess the incidence of bleeding complications during oral anticoagulant therapy (OAT) in a population of patients representative of daily practice in Italian anticoagulation clinics.


METHODS



METHODS
prospective, inception-cohort, multicentre.


METHODS
Thirty-four anticoagulation clinics federated in the Italian Federation of Anticoagulation Clinics.


METHODS
2745 consecutive patients, included from beginning of their first OAT course. Most patients were aged between 60 and 79 y (57.8%), with 8% being > or = 80 y. Venous thromboembolism was the most frequent indication for OAT (one third of all the patients), followed by non ischemic heart disease which mainly included atrial fibrillation (16.8% of patients). Warfarin (in 63.8% of patients) and acenocoumarol were the only anticoagulant drugs used. The targeted anticoagulation intensity was low (INR < or = 2.8) in 71% of patients and high (INR > 2.8) in the remainder.


RESULTS
Fatal, major and minor bleeding events. Thrombotic events were also recorded, though not analyzed in the present report.


RESULTS
During the 2011 patient-years (pt-y) of follow-up, 153 bleeding complications (7.6% pt-y) were recorded--5 fatal (all cerebral haemorrhages, 0.25% pt-y), 23 major (1.1% pt-y) and 125 minor (6.2% pt-y). The rate of events did not vary according to sex, coumarin type, size of enrolling centre or targeted therapeutic range; it was higher in older patients (10.5% pt-y in those aged > or = 70 y, relative risk--RR--1.75, p < 0.001), in cases where indication for anti-coagulant treatment was peripheral and/or cerebrovascular disease (12.5% pt-y; RR 1.80, p < 0.01) and during the first 90 days of treatment (11% pt-y, RR 1.75, p < 0.001). One fifth of bleeding events occurred at a very low anticoagulation intensity (INR < 2; the category rate being 7.7% pt-y); the rate was 4.8% pt-y in the 2.0-2.9 INR category, reaching 9.5% pt-y, 40.5% pt-y and 200% pt-y in the 3-4.4, 4.5-6.9 and > or = 7 INR categories respectively (RR for INR levels > 4.5 = 7.91, p < 0.0001).


CONCLUSIONS
The overall rate of bleeding events recorded in the present study was much lower than that recorded in other (including recent) observational and experimental studies. The risk of bleeding increased in the following cases: age > 70 y; arterial vascular disease as indication for OAT; first 3 months of treatment; INR values > or = 4.5. OAT has become safer in recent years, particularly if monitored in special anticoagulation clinics. Caution should be exercised when prescribing OAT in elderly patients and the intensity anticoagulation levels should be closely monitored to minimize incidental periods of overanticoagulation.
Palareti
G
G
Divisione di Angiologia e Malattie della Coagulazione, Policlinico S. Orsola-Malpighi, Bologna.
Leali
N
N
Coccheri
S
S
Poggi
M
M
Manotti
C
C
D'Angelo
A
A
Pengo
V
V
Erba
N
N
Moia
M
M
Ciavarella
N
N
Devoto
G
G
Berretini
M
M
Musolesi
S
S
D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects*; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D014859:Warfarin / Q000009:adverse effects
D000925:Anticoagulants; D014859:Warfarin
Complicanze emorragiche della terapia anticoagulante orale: risultati dello studio prospettico multicentrico ISCOAT (Italian Study on Complications of Oral Anticoagulant Therapy).