Identifying Clinical Predictors of Switching From Direct Oral Anticoagulants to Warfarin

Purpose: Direct oral anticoagulants (DOACs) have been shown to be as effective or superior to warfarin, but warfarin use remains constant. Knowledge regarding the patient population who have switched from a DOAC to warfarin is limited. The objective of this study was to identify clinical predictors which may influence a patient’s likelihood of switching from a DOAC to warfarin for atrial fibrillation (AF) or venous thromboembolism (VTE). Methods: In this single-center, case-control study, patients who switched from a DOAC to warfarin were compared with patients who remained on a DOAC. Baseline demographics were compared between the switch and control groups. Independent factors that increased the likelihood of switching from a DOAC to warfarin were analyzed using logistic regression. Results: A total of 150 patients were included in the control (n = 100) and switch (n = 50) groups. Patients switched from a DOAC to warfarin had more medications at baseline (9 [7, 13] vs 11 [8, 18], P = 0.009). The presence of heart failure (HF) increased the likelihood of switching (odds ratio [OR] = 3.95, confidence interval [CI] = 1.70-9.21, P = 0.002), and for every 10 mL/min increase in creatinine clearance (CrCl), the likelihood of switching decreased ( R = 0.89 [0.80-0.99], P = 0.026). Patients with pulmonary embolism (PE) were less likely to switch from a DOAC to warfarin (OR = 0.20, CI = 0.05-0.86, P = 0.031). Explicitly listed reasons for switching included left ventricular assist device (LVAD) implantation (20%) and valve replacement procedures (20%). Conclusion: Congestive HF was a clinical predictor associated with an increased likelihood of switching from a DOAC to warfarin. Anticoagulation therapy for PE and higher CrCl was associated with a decreased likelihood in switching from DOAC to warfarin.