Despite available evidence documenting the superiority of NOACs versus warfarin for stroke prevention in NVAF, a substantial proportion of these patients continue to receive warfarin with time in therapeutic range (iTTR) achieved only 60-65% of the time. Although transitioning these patients to a NOAC for stroke prevention seems reasonable, little real world evidence exists that defines these patients’ characteristics to better understand their risk profile.

Patients with a NVAF diagnosis and who were prescribed warfarin between 01/01/2017 through 12/31/2018 were included in this study. Patients’ mean iTTR was calculated as the number of days INR was within target range (2<INR<3) divided by total number of days observed. Patients were grouped into uncontrolled (iTTR≤65%) or controlled (iTTR>65%) INR. Those with uncontrolled INR were further defined as: poor control (iTTR<45%), or moderately poor control (iTTR 45%-65%), and also according to sub-therapeutic (INR<2) or supra-therapeutic (INR>3) groups.

A total of 3,109 patients with a mean iTTR of 50.2% were included. Overall, 60% presented with uncontrolled INR. Among these patients, mean iTTR was 24.0% with 71.0% considered sub-therapeutic, and 29% supra-therapeutic. In addition, 24.9% displayed moderately poor INR control, with the remaining 75.1% having exhibited poor INR control. Most often, the moderately poor and poor control groups were found to have a sub-therapeutic iTTR (68.8% and 71.8%, respectively).

Results demonstrated that the majority of NVAF patients prescribed warfarin for stroke prevention displayed poor control of INR, potentially increasing their stroke risk. Further investigation is needed to determine if transitioning these patients to a NOAC may help offset this risk.