title: Inadequate stroke prevention in Korean atrial fibrillation patients in the post-warfarin era.
abstract: BACKGROUND
  Anticoagulation therapy with warfarin or direct oral anticoagulants (DOACs) is recommended for atrial fibrillation (AF) patients who are at a high risk for stroke. This study aimed to investigate the utilization of anticoagulants since the introduction of DOACs in South Korea.
  
  
  METHODS
  This was a cross-sectional study using claim-based national data from 2011 to 2014 derived from the Aged Patient Sample (APS) compiled by the Health Insurance Review & Assessment Service (HIRA). Patients with a high risk for thromboembolism were identified as those having a CHA2DS2-VASc (congestive heart failure, hypertension, age≥75, diabetes mellitus, stroke (or transient ischemic attack), vascular disease, sex) score of ≥2. Patients at a high risk for bleeding with an ATRIA (anticoagulation and risk factors in atrial fibrillation) bleeding score of >4 were excluded. Anticoagulant underutilization was estimated in these high-risk patients. Demographic and clinical factors associated with warfarin and DOAC underutilization were explored using a logistic regression model.
  
  
  RESULTS
  Anticoagulant underutilization among high-risk patients for stroke decreased from 68% to 62.5% between 2011 and 2014; however, there was further scope for improvement. The risk factors for underutilization were identified as follows: female sex, old age, having medical aid insurance, presence of vascular disease, and limited anticoagulant options.
  
  
  CONCLUSIONS
  Our study demonstrates that a large population of AF patients in South Korea failed to obtain adequate stroke prevention treatment, even in the era of DOAC usage. A more aggressive approach to provide optimal antithrombotic therapy is warranted.
authors.affiliation: College of Pharmacy, Chosun University, Gwangju, Korea.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Choi
authors.affiliation: College of Pharmacy, Yeungnam University, Gyeongsan, Korea.
authors.forename: Iyn-Hyang
authors.initials: IH
authors.lastname: Lee
authors.affiliation: College of Pharmacy, Pusan National University, Busan, Korea. Electronic address: jenk@pusan.ac.kr.
authors.forename: Nam Kyung
authors.initials: NK
authors.lastname: Je
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D056910:Republic of Korea / Q000453:epidemiology; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: Atrial fibrillation; DOACs; Stroke; Underutilization; Warfarin