Use of non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients: insights from a specialist atrial fibrillation clinic.

Abstract

Non-vitamin K antagonist oral anticoagulants (NOACs) are broadly preferable to vitamin K antagonists (VKAs) for stroke prevention in non-valvular atrial fibrillation (AF) given their overall net clinical benefit. We report an audit of the profile of OAC usage and adverse events in patients attending a specialist AF clinic. Patients attending our specialist AF clinic who were commenced on NOACs for SPAF between January 2013 and August 2014 were included and electronic medical records were retrospectively reviewed between August 2014 and November 2014, to collect demographic, clinical and outcome data. Outcomes included cerebrovascular and bleeding events, death, switching between NOACs or to VKA, dose changes, cessation of NOACs and the reasons for these. To provide perspective, descriptive comparisons were made with a historical cohort of warfarin users attending the specialist AF clinic prior to the introduction of NOACs. We report data on 813 patients as follows: (i) 233 consecutive patients (mean (standard deviation) age 74 (10) years, 45.1% female) initiated on NOACs, with median (interquartile range) CHA2 DS2 -VASc score 3 (2-5) and HAS-BLED score 1 (1-2); and (ii) a historical cohort of 580 patients on warfarin (mean (SD) age 75 (10) years, 42.1% female) with broadly similar demographics. Overall, 54.5% (127/233) were started on rivaroxaban, 22.7% (53/233) on dabigatran and 22.7% on apixaban. Two patients experienced a transient ischaemic attack; 31 patients (13%) contributed to 37 documented bleeding events of which five bleeds (in four patients, 1.7%) were classified as major. There were seven deaths; cause of death was not available for three and the others were not related to NOACs. Eighteen (7.7%) patients switched NOACs, 2 (0.9%) patients switched to warfarin and 8 (3.4%) had their NOACs stopped. There were no ischaemic strokes in the NOAC cohort, compared with nine in the warfarin cohort, with a similar rate of major bleeding (1.7% for NOACs and 1.6% for warfarin). There were more gastrointestinal haemorrhages in the NOAC cohort (3.4% vs. 0.7% with warfarin). In this specialist AF clinic, patients prescribed NOACs had a favourable adverse event profile with good efficacy for stroke prevention, with a low rate of cessation or switch to warfarin.