Abstract 4145883: Elevated International Normalized Ratio Is Associated with Severity of Intracerebral Hemorrhage for Patients Taking Direct Oral Anticoagulants

Introduction/Background: While the international normalized ratio (INR), a marker of functioning of the extrinsic and final common pathways of the coagulation cascade is associated with increased intracerebral hemorrhage (ICH) mortality for patients taking warfarin, it is not understood how it might be associated with outcomes in patients taking direct oral anticoagulants (DOACs), given the inconsistent and variable effect of DOACs on INR. Research Questions/Hypothesis: To determine whether INR is associated with increased ICH severity in patients with recent exposure to a DOAC. Methods/Approach: We included patients taking Apixaban or Rivaroxaban prior to acute presentation with ICH to hospitals participating in the Get With the Guidelines - Stroke registry, a nationwide quality improvement registry. The primary exposure was INR, which we modeled as a continuous variable with restricted cubic splines. The primary endpoint was stroke severity on presentation, measured by the National Institutes of Health Stroke Scale (NIHSS). Secondary endpoints included Glasgow Coma Scale (GCS) <=8 on admission, in-hospital mortality, composite of in-hospital mortality and discharge to hospice, and modified Rankin Scale (mRS) at discharge. We adjusted for key confounding factors, specifically age, sex, race/ethnicity, insurance status, and medical history, while taking into account within-hospital clustering. Results/Data: In total, 13,251 patients were included of whom 7,545 were exposed to apixaban and 5,706 were exposed to rivaroxaban. As shown in Table 1, for patients taking Apixaban, elevated INR was associated with increased likelihood of NIHSS >=21 (aOR 1.02 [95% CI 1.00-1.04, p=0.03] per 0.1 above 1.1) and in-hospital mortality (aOR 1.11 [95% CI 1.05-1.16, p<.001) per 0.1 above 1.1). For patients taking Rivaroxaban, similar trends were seen (aOR 1.21 [95% CI 1.08-1.35, p<.001] per 0.1 up to 1.2 for NIHSS >=21, aOR 1.13, [95% CI 1.09-1.16, p<.001] per 0.1 up to 1.6, for in-hospital mortality). Conclusion(s): Elevated INR at admission is associated with worsened ICH severity for patients taking Apixaban or Rivaroxaban.