title: Treatment Changes among Users of Non-Vitamin K Antagonist Oral Anticoagulants in Atrial Fibrillation.
abstract: Patients with atrial fibrillation discontinuing anticoagulant therapy are left unprotected against ischaemic stroke. Further, switching between oral anticoagulants may be associated with a transiently increased risk of bleeding or thromboembolism. However, there is a paucity of real-life data on pattern of switching and discontinuation of oral anticoagulants. To address this, we conducted a nationwide drug utilization study including all registered Danish atrial fibrillation patients initiating a non-VKA oral anticoagulant (NOAC) between August 2011 and February 2016. We assessed changes in anticoagulant treatment, including switching between oral anticoagulants and discontinuation of NOACs, and explored patient characteristics predicting these changes. We identified 50,632 patients with atrial fibrillation initiating NOAC therapy within the study period. The majority initiated dabigatran (49.9%) and one-third had previously used VKA. Within 1 year, 10.1% switched to VKA, 4.8% switched to another NOAC and 14.4% discontinued treatment. The frequencies of switching to VKA and discontinuation were highest among NOAC users of young age (<55 years) and with low CHA2DS2-VASc score (=0). However, the majority of patients (87.3%) stopping NOAC treatment had a CHA2DS2-VASc score ≥1. We conclude that switching from VKA to NOAC, and to a lesser extent from NOAC to VKA, is common, as is early treatment discontinuation. The majority of treatment changes are observed in patients at increased risk of stroke. More research is warranted on the risks of bleeding and thromboembolism associated with switching and discontinuation of NOACs as well as the underlying reasons why these treatment changes occur.
authors: Clinical Pharmacology and Pharmacy, Department of Public Health, University of Southern Denmark, Odense, Denmark.
authors: Maja
authors: M
authors: Hellfritzsch
authors: Department of Internal Medicine, Hospital Unit West, Herning, Denmark.
authors: Steen Elkjaer
authors: SE
authors: Husted
authors: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.|Faculty of Health, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors: Erik Lerkevang
authors: EL
authors: Grove
authors: Clinical Pharmacology and Pharmacy, Department of Public Health, University of Southern Denmark, Odense, Denmark.
authors: Lotte
authors: L
authors: Rasmussen
authors: Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark.
authors: Birgitte Klindt
authors: BK
authors: Poulsen
authors: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Søren Paaske
authors: SP
authors: Johnsen
authors: Clinical Pharmacology and Pharmacy, Department of Public Health, University of Southern Denmark, Odense, Denmark.
authors: Jesper
authors: J
authors: Hallas
authors: Clinical Pharmacology and Pharmacy, Department of Public Health, University of Southern Denmark, Odense, Denmark.
authors: Anton
authors: A
authors: Pottegård
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D001777:Blood Coagulation / Q000187:drug effects*; D003718:Denmark; D057915:Drug Substitution; D017723:Drug Utilization Review; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D020521:Stroke / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors; D016896:Treatment Outcome; D014812:Vitamin K / Q000037:antagonists & inhibitors
chemical_list: D000925:Anticoagulants; D014812:Vitamin K