Identifying Clinical Predictors of Switching From Direct Oral Anticoagulants to Warfarin

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). 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. 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%). 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.