Retrospective Review on the Safety and Efficacy of Direct Oral Anticoagulants Compared With Warfarin in Patients With Cirrhosis

A diagnosis of cirrhosis was confirmed using a combination of the codes from the ninth and tenth editions of the International Classification of Diseases (ICD) for cirrhosis, documentation of diagnostic confirmation by clinicians from the gastroenterology or hepatology services, and positive liver biopsy result. Liver function tests, liver ultrasound results, and FibroSure biomarker assays were used to aid in confirming the diagnosis of cirrhosis but were not considered definitive. Patients were excluded from the trial if they had indications for anticoagulation other than NVAF and VTE and/or were prescribed triple antithrombotic therapy (dual antiplatelet therapy plus an anticoagulant). Patients who switched anticoagulant therapy during the trial period (ie, switched from warfarin to a DOAC) were also excluded from the analysis.

Patient demographic characteristics that were collected included weight; body mass index (BMI); etiology of cirrhosis; Child-Turcotte-Pugh, Model for End-Stage Liver Disease (MELD), and CHA₂DS₂-VASc score; concomitant antiplatelet, nonsteroidal anti-inflammatory drug (NSAID), proton pump inhibitor (PPI), and histamine-2 receptor antagonist (H2RA) medications; presence of gastric and/or esophageal varices; active malignancies; albumin, total bilirubin, serum creatinine, INR, and platelet laboratory values; and indication and duration of anticoagulation therapy.

Two patient lists were used to identify patients for inclusion in the warfarin arm. The first patient list was generated using the US Department of Veterans Affairs (VA) Cirrhosis Tracker, which identified patients with an ICD-9/10 code for cirrhosis and an INR laboratory value. Patients generated from the VA Cirrhosis Tracker with an INR > 1.5 were screened for a warfarin prescription and then evaluated for full study inclusion. The second patient list was generated using the VA Advanced Liver Disease Dashboard which identified patients with ICD-9/10 codes for advanced liver disease and an active warfarin prescription. Patients with an active warfarin prescription were then evaluated for full study inclusion. A single patient list was generated to identify patients for inclusion in the DOAC arm. This patient list was generated using the VA DOAC dashboard, which identified patients with an active DOAC prescription and an ICD-9/10 code for cirrhosis. Patients with an ICD-9/10 code for cirrhosis and prescribed a DOAC were screened for full study inclusion. Patient data were collected from the MEDVAMC Computerized Patient Record System (CPRS) electronic health record (EHR). The research study was approved by the Baylor College of Medicine Institutional Review Board and the VA Office of Research and Development.

Outcomes

The primary endpoint for the study was all-cause bleeding. The secondary endpoints for the study were major bleeding and failed efficacy. Major bleeding was defined using the International Society on Thrombosis and Haemostasis (ISTH) 2005 definition: fatal bleeding, symptomatic bleeding in a critical organ area (ie, intracranial, intraspinal, intraocular, retroperitoneal, intraarticular, pericardial, or intramuscular with compartment syndrome), or bleeding causing a fall in hemoglobin level of > 2 g/dL or leading to the transfusion of ≥ 2 units of red cells.⁶ Failed efficacy was a combination endpoint that included development of VTE, stroke, myocardial infarction (MI), and/or death. A prespecified subgroup analysis was conducted at the end of the study period to analyze trends in the DOAC and warfarin groups with respect to all-cause bleeding. All-cause bleeding risk was stratified by weight, BMI, Child-Turcotte-Pugh score, MELD score, presence of gastric and/or esophageal varices, active malignancies, percentage of time within therapeutic INR range in the warfarin group, indications for anticoagulation, and antiplatelet, NSAID, PPI, and H2RA therapy.