Should we initiate oral anticoagulants for patients with atrial fibrillation staying well without oral anticoagulants for years?

Abstract

Abstract Background Although non-vitamin K antagonist oral anticoagulants (NOACs) were more and more commonly prescribed for stroke prevention for patients with atrial fibrillation (AF), underuse of OACs is still not uncommon. Data about the initiations of OACs in AF patients who did not experience ischemic stroke without any OACs for years since incident AF was diagnosed were limited. We aimed to investigate the associations between the initiations of warfarin or NOACs and clinical outcomes among this population. Methods From January 1st, 2007 to December 31st, 2010, a total of 167,176 newly-diagnosed AF patients aged ≥20 years were identified from the Taiwan National Health Insurance Research Database as the study population. Among the study population, 32,917 patients with a CHA2DS2-VASc score >1 for males or >2 for females who did not receive warfarin or NOACs and survived for at least 90 days after June 1st, 2015 were defined as the “original non-OAC cohort”. These patients were then categorized into 3 groups according to the stroke prevention strategies they received after June 1st, 2015; that is, without OACs (n=31,195), warfarin (n=230) and NOACs (n=1,492). Results Compared to patients staying on non-OACs, the risk of ischemic stroke was lower for patients who initiated NOACs (aHR 0.867; p=0.043). The risk of all-cause mortality was lower for patients who started to receive warfarin (aHR 0.876; p=0.036) or NOACs (aHR 0.798; p=0.047). The composite risk of ischemic stroke or major bleeding was also lower for patients who initiated warfarin (0.849; p<0.001) or NOACs (0.789; p<0.001) (Figure 1). Compared to warfarin, NOACs use was associated with a lower risk of ischemic stroke (aHR 0.819; p<0.001), ischemic stroke or intracranial hemorrhage (aHR 0.927; p=0.042) or ischemic stroke or major bleeding (aHR 0.912; p<0.001). Conclusions Initiations of OACs, especially NOACs, should still be considered for AF patients who stayed well without OACs for years since incident AF was diagnosed. Funding Acknowledgement Type of funding sources: None.