Risk factors for intracranial hemorrhage during vitamin K antagonist therapy in patients with nonvalvular atrial fibrillation: A case‐control study

Summary Background Intracranial hemorrhage ( ICH ) is the most fearful side effect of oral anticoagulant therapy. It is still unclear which risk factor is involved in ICH during vitamin K antagonists ( VKA s) treatment and if commonly used bleeding risk scores are able to predict ICH . Purpose Search for individual risk factors and bleeding risk scores ( HAS ‐ BLED , ATRIA and ORBIT ) associated with ICH s in patients with atrial fibrillation treated with VKA s. Methods This is a retrospective case‐control study in a single Thrombosis Center. During a 7‐year period, patients with nonvalvular atrial fibrillation ( NVAF ) who developed ICH during VKA s were identified as cases. Four control patients matched for gender, age and length of VKA s were assigned to each case. The association between considered risk factors and ICH s was evaluated using a linear logistic regression method and expressed as odds ratio. Receiver operator characteristic ( ROC ) curves to assess the predictive ability of bleeding risk scores HAS ‐ BLED , ATRIA and ORBIT were also evaluated. Results Fifty‐one cases of ICH , most of whom were 80 years of age or older (72.5%), were retrieved from the Thrombosis Center's database. Compared to 204 controls, no individual risk factors were associated with ICH . Poor ability to predict ICH was also found using ROC curves (C‐statistic for HAS ‐ BLED , ATRIA , and ORBIT were 0.55, 0.53 and 0.54, respectively). Conclusions ICH s during VKA therapy preferentially occur in very elderly patients. The risk of ICH is not predicted by the commonly used risk scores.