Safety assessment of new oral anticoagulants

To compare the occurrence of haemorrhages among the different oral anticoagulants (OAC) and to analyse factors that influence it.

Single-centre, observational, retrospective study. After studying the total population treated with OAC, patients who were treated with an OAC from July 2015 to December 2015 in the II Sector of the Zaragoza Hospital, who consulted the Emergency Department of the Miguel Servet University Hospital and presented a haemorrhagic event, were analysed. Patients' demographic data, clinical variables and data on the haemorrhagic event characteristics were gathered.

There were 9,452 patients treated with an OAC, 371 (3.9%) of which presented a haemorrhagic event. The frequency per OAC was; 4.1% (311) in patients treated with vitamin K antagonists, 3.8% (33) with rivaroxaban, 3.3% (19) with dabigatran and 2.1% (8) with apixaban. In the multivariate analysis, only the choice of anticoagulant and sex had a statistically significant influence of a lower risk of haemorrhage, in particular the dose of apixaban at 2.5mg and being female. (OR=0.1, CI=0.014-0.71 and OR=0.688, CI=0.55-0.85, respectively).

According to the results obtained, females and patients undergoing treatment with apixaban presented lower haemorrhagic risk, although there are doubts about whether this better safety profile is related to underdosing, which could influence its effectiveness. Therefore, these results should be analysed with caution and further studies are needed to confirm this data.