Background and objective: Adherence to oral anticoagulants is crucial for the prevention of ischemic stroke in atrial fibrillation patients; however, evidence of oral-anticoagulant adherence from developing countries is still lacking. This study aimed to evaluate the current situation and predictors of oral-anticoagulant adherence in non-valvular atrial fibrillation (NVAF) patients in China.
Methods: Records of NVAF patients were obtained from a regional claims database. Both initiation and adherence to oral anticoagulants were calculated from linked records. Factors of oral-anticoagulant initiation were identified using Cox regression.
Results: Among 33,463 NVAF patients, only 13.9% initialized warfarin treatment after the indexed hospital visit. Stratified by CHA2DS2-VASc scores, 20.9% of patients in the low-risk group were on warfarin, followed by 15.3% and 10.7% from the middle and high-risk groups, respectively. Among patients who initialized warfarin, only 40.4% filled the first repeat prescription within 3 months. Concurrent statin use, hypertension and heart failure were associated with higher warfarin initiation rate. Factors such as age above 75, female sex, manufacture workers, discharge from the primary-care center, antiplatelet use, and diabetes, ischemic and hemorrhagic stroke were associated with lower rate of warfarin initiation. Additionally, initiating warfarin treatment reduced risk of ischemic stroke in middle and high-risk patients.
Conclusion: Oral anticoagulation was significantly under-used in NVAF patients in China. Age, sex, concurrent drug usage, and disease history were associated factors. Improving warfarin adherence was promising to reduce ischemic stroke risk of NVAF patients.
Keywords: Atrial fibrillation; adherence; ischemic stroke; oral anticoagulant; risk factors.