TTR and atrial fibrillation: This difference may be explained, at least in part, by the decreased amount of time in therapeutic range (TTR) in warfarin users in our study (47.3 ± 28.3%), which was approximately 8% lower than the mean TTR seen in ROCKET-AF (approximately 55%).26Of note, prior data suggest that OSA patients are more difficult to maintain in therapeutic range, while on a VKA.27