Utilization of oral anticoagulants in Korean nonvalvular atrial fibrillation patients

Background Although the majority of clinical guidelines indicate the use of NOAC (nonvitamin K antagonist oral anticoagulant) over vitamin K antagonist in nonvalvular atrial fibrillation patients, there is no information on real-world prescription factors that lead to a specific type of oral anticoagulant selection. Objective To evaluate the prescription factors for choosing a specific oral anticoagulant for nonvalvular atrial fibrillation patients in Korea. Setting Nationwide sampled database in South Korea. Methods In this study, we defined nonvalvular atrial fibrillation patients as having one or more hospitalizations or two or more out-patient visits with a stroke risk score (CHA2DS2-VASc scores) ≥ 2 eligible for oral anticoagulant therapy from Jan 1st, 2016 to Dec 31st, 2016. Baseline characteristics were analyzed, including sex, age, comorbidities, CHA2DS2-VASc, bleeding risk score (mHAS-BLED), prescribing specialty, insurance type, medical institution type and location. Univariate and multivariate logistic regression analyses were conducted for being prescribed NOAC compared with vitamin K antagonist. Main outcome measure Adjusted odds ratio of the NOAC group and vitamin K antagonist group. Results Of 9,226 patients eligible for oral anticoagulant therapy, 4999 patients (54.2%) received oral anticoagulant therapy, and 4517 patients took NOAC or vitamin K antagonist only during the study period. Prior stroke, transient ischemic attack, thromboembolism, thyroid disease, dyslipidemia, cancer, mHAS-BLED ≥ 5, in-patient care, and specialty in internal medicine and neurology were positive predictors of NOAC use over vitamin K antagonist, whereas young age (≤64), renal dysfunction, and secondary care institution were negative predictors of NOAC use over vitamin K antagonist. Conclusions The presence of comorbidities was linked to NOAC use over vitamin K antagonist, which is different from prescription factor studies in other countries and requires further study.