Abstract P443: Identification of Traumatic and Non-Traumatic Intracranial Bleeding Subtypes in Patients With Non-Valvular Atrial Fibrillation Receiving Oral Anticoagulant Therapy Using Primary Care Data From the United Kingdom

Abstract

Introduction: Classification of intracranial bleeding (ICB) by trauma status is important in research relating to anticoagulant therapy. We evaluated trauma status of ICB subtypes - intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH) and subdural hematoma (SDH) - in a large population of patients with non-valvular atrial fibrillation (NVAF) receiving oral anticoagulant (OAC) therapy. Methods: Using the IQVIA Medical Research Data UK primary care database, we followed 45,164 patients with NVAF newly prescribed OAC therapy to identify incident ICB cases, and categorized them as ICH, SAH or SDH based on the coded description. We identified cases with a code suggesting the event was traumatic (e.g. head injury) or non-traumatic within 90 days either side of the ICB event, and manually reviewed the patient records for cases without such a code to identify other entries indicating trauma in the time period. ICH and SAH cases without a trauma/non-trauma code were classed as non-traumatic and SDH cases without a trauma/non-trauma code were classed as traumatic. Results: A total of 286 ICB cases were identified: 45.5% ICH, 41.9% SDH, 12.6% SAH. Classification of cases is shown in the Table. Most traumatic cases were SDH (77.3%, 85/110); most non-traumatic cases were ICH (66.5%, 117/176). Classification by the presence of a trauma/non-trauma code was 82.5% for SDH, 33.3% for SAH and 10.8% for ICH. Classification of all but one non-traumatic ICH case and all non-traumatic SAH cases were by the absence of a trauma/non-trauma code. For SDH, 75.3% of traumatic SDH cases were based on a trauma code, and 100% of non-traumatic SDH cases were based on a non-trauma code. Conclusion: Among patients with NVAF receiving OAC therapy, the majority of incident ICB cases were non-traumatic. Classification of SDH was predominantly made from trauma/non-trauma codes; cases of ICH and SAH were mostly based on the absence of trauma/non-trauma codes using non-trauma as the default category.