Traumatic Intracranial Hemorrhage in Users of Oral Antithrombotic Drugs

Oral antithrombotic medications (OAM) are used for the prevention and treatment of thrombotic disorders. Among hemorrhagic complications of OAMs, intracranial hemorrhage (ICH) may have particularly devastating consequences with high morbidity, disability and mortality rates. The efficacy and safety profiles of OAMs are generally assessed in randomized controlled trials (RCT), but included patients are often highly selected and may not be representative of users in everyday clinical practice in terms of follow-up routines, age, gender, drug compliance, and polypharmacy. Moreover, it is often unclear whether or not traumatic ICHs are registered and reported in RCTs. Drifts in indications and treatment criteria may also be seen in everyday practice and drug discontinuation due to precautionary concerns including compliance, fall risk and comorbidity may be forgotten. Collectively, these factors may lead to other and potentially higher traumatic ICH rates in general clinical use than reported in RCTs. The incidence rates of traumatic ICH in patients on OAMs in the general population remain unknown. In this nationwide registry based pharmacoepidemiological study we will investigate the incidence and case fatality of traumatic ICH in users of OAMs in Norway from 2008 through 2014.