Stratifying the risks of oral anticoagulation in patients with liver disease.
BACKGROUND
Chronic liver disease presents a relative contraindication to warfarin therapy, but some patients with liver disease nevertheless require long-term anticoagulation. The goal is to identify which patients with liver disease might safely receive warfarin.


METHODS AND RESULTS
Among 102 134 patients who received warfarin from the Veterans Affairs from 2007 to 2008, International Classification of Diseases-Ninth Revision codes identified 1763 patients with chronic liver disease. Specific diagnoses and laboratory values (albumin, aspartate aminotransferase, alanine aminotransferase, creatinine, and cholesterol) were examined to identify risk of adverse outcomes, while controlling for available bleeding risk factors. Outcomes included percent time in therapeutic range, a measure of anticoagulation control, and major hemorrhagic events, by International Classification of Diseases-Ninth Revision codes. Patients with liver disease had lower mean time in therapeutic range (53.5%) when compared with patients without (61.7%; P<0.001) and more hemorrhages (hazard ratio, 2.02; P<0.001). Among patients with liver disease, serum albumin and creatinine levels were the strongest predictors of both outcomes. We created a 4-point score system: patients received 1 point each for albumin (2.5-3.49 g/dL) or creatinine (1.01-1.99 mg/dL), and 2 points each for albumin (<2.5 g/dL) or creatinine (≥2 mg/dL). This score predicted both anticoagulation control and hemorrhage. When compared with patients without liver disease, those with a score of zero had modestly lower time in therapeutic range (56.7%) and no increase in hemorrhages (hazard ratio, 1.16; P=0.59), whereas those with the worst score (4) had poor control (29.4%) and high hazard of hemorrhage (hazard ratio, 8.53; P<0.001).


CONCLUSIONS
Patients with liver disease receiving warfarin have poorer anticoagulation control and more hemorrhages. A simple 4-point scoring system using albumin and creatinine identifies those at risk for poor outcomes.