[Oral anticoagulants and atrial fibrillation]

Oral anticoagulants (OA) are effective in the prevention of cerebrovascular events among patients with atrial fibrillation (AF). However, several studies showed OA to be widely underused in these patients. The purpose of this study was to assess the use of OA and associated factors with non-use of this treatment.

We conducted a retrospective study of 233patients affected by non valvular AF hospitalized in our institution between 2005 and 2007. Patients were stratified in three groups for stroke's risk (high, moderate and low) according to the international antithrombotic therapy recommendations.

The average age of our patients was 64+/-14 years, with 35% of subjects being older than 75years. Hypertension was the more frequently reported risk factor for stroke (61%), followed by diabetes mellitus (19%) and congestive heart failure (12%). Five percent of the patients reported a stroke or a systemic embolic event history. Of the 233patients studied, 48% were stratified to the high risk group, among them 75% were being treated with OA, 20% with Aspirin and 5% were taking no medications. To explore possible reasons for not prescribing anticoagulation, we analysed 27patients at high risk who did not receive OA. We found a low benefit/risk ratio (37%), neuropsychological impairment in 5%, a past bleeding episode in 6% but almost 50% of those patients reported no risk factors for haemorrhage.

In our retrospective study, among 25% high-risk patients with non valvular AF were not treated with OA and one half of the patients report none of the factors associated with perceived or actual risk factors for bleeding. These data confirmed OA underuse, despite guidelines that delineate higher-risk patient populations for whom anticoagulation is recommended.