P1897Prescription of guideline recommended oral anticoagulation and reasons reported for non-use of OAC in patients with atrial fibrillation: Data from the German AFNET-2 Registry
Authors: Naebauer M , Gerth A , Steinbeck G , Wegscheider K , Kirchhof P , Breithardt G 
Published: October 2019

Abstract

Background
Oral anticoagulation (OAC) reduces thromboembolic events and mortality in patients with atrial fibrillation (AF). Anticoagulation rates have substantially increased over recent years. Still, a number of patients are not receiving guideline recommended OAC.

Purpose
To investigate clinical factors and reasoning associated with non-prescription of OAC in a current German registry.

Methods
The German AFNET 2 registry is a prospective multi-center registry on atrial fibrillation comprising a total of 3491 patients from all levels of medical care (general practitioners, cardiologists, hospitals; enrolment 5/2014 to 3/2016). The registry was conducted in collaboration with the EORP program of the ESC. Here, only patients with non-valvular AF and at least two clinical risk factors for stroke (using CHA2DS2-VASc score) were considered.

Results
The study population consisted of 2856 patients, 58.4% male, mean age 75.5±7.8 years, mean CHA2DS2-VASc score 4.1±1.5, mean HAS-BLED score 1.8±1.0. Overall, the rate of OAC was 94.3%. 54% of these received Vitamin K antagonists (VKA) and 46% NOAC. 2.3% received antiplatelets only. Patients newly initiated on OAC mostly received a NOAC (82.5% of patients). Anticoagulation rate was lower in elderly patients (age <80 years: 95.0%, age ≥80 years 92.8%, p<0.05). No difference in OAC was seen between men and women (94.1% and 94.6%, respectively). Patients with high bleeding risk (HAS-BLED ≥3) received significantly less OAC than patients at low bleeding risk (95.3 vs 90.6%, p<0.001). Patients on antiplatelet therapy received OAC in only 78.0% compared to patients without antiplatelet therapy in 96.6% (p<0.001). In patients without OAC (n=162 patients), reasons stated for non-prescription of OAC were patient's unwillingness to take OAC (13.6%), physician preference (12.3%), prior bleeding event (10.5%), renal dysfunction (8.6%), frequent falls (5.6%), current anaemia (5.6%), current operation/intervention (4.9%), current bridging with LMW heparin (4.9%), and other reasons (9.3%). Using logistic regression analysis, non-prescription of OAC was strongly associated with antiplatelet therapy (HR=0.082), anaemia (HR=0.41), dementia (HR=0.37), and previous extra- (HR=0.2) or intracranial haemorrhage (HR=0.35). Predictors of OAC use were prior stroke/embolism (HR=2.35), hypertension (HR=2.23), heart failure (HR=1.51), and previous stent implantation (HR=2.12). When considered as a score, a HAS-BLED score ≥3 was strongly associated with non-prescription of OAC (HR=0.51).

Conclusions
Within registries, the guideline recommended use of OAC is very high in Germany indicating high guideline adherence by prescribing physicians. However, use of antiplatelet therapy was associated with non-prescription of OAC. In addition, a high HAS-BLED score appears to be a relevant argument for withholding proven OAC for stroke prevention in patients with AF.

Acknowledgement/Funding
BMS Germany; DZHK