Clinical outcomes of nonvitamin K oral anticoagulants and acenocoumarol for stroke prevention in contemporary practice: A population-based propensity-weighted cohort study

Abstract

AIMS: Acenocoumarol is a vitamin-K antagonist (VKA) primarily used in certain countries (e.g. India, Netherlands, Spain). The half-life of acenocoumarol is similar to that of non-VKA oral anticoagulants (NOAC), unlike warfarin, and this could affect comparative effectiveness and safety (CES). However, data on CES for NOAC come almost exclusively from studies using warfarin as the comparator. We aimed to assess outcomes of NOAC and acenocoumarol in people with non-valvular atrial fibrillation (NVAF) in real-world clinical practice. METHODS: This is a population-based retrospective cohort study. All new users of oral anticoagulants from November 2011 to December 2015 with NVAF were included (n = 41,560). Data were obtained by linking several health electronic records of the Valencia region, Spain. Incidence rates were estimated. We used the inverse probability of treatment weighted Cox analysis to control for indication bias when assessing the risk of effectiveness and safety outcomes for each NOAC compared with acenocoumarol. Several sensitivity analyses were performed. RESULTS: We did not find differences in the risk of mortality, ischaemic stroke or any gastrointestinal bleeding. However, we did find a decreased risk of intracranial haemorrhage for dabigatran (HR: 0.34, 95% CI 0.20-0.56) and rivaroxaban (HR: 0.55, 95% CI 0.35-0.85) as compared to acenocoumarol. In subanalyses, apixaban showed a higher risk of ischaemic stroke in high-risk persons (≥75 years and CHA2DS2-VASC score ≥ 2). CONCLUSIONS: No differences in clinical outcomes were found between NOAC and acenocoumarol overall, although dabigatran and rivaroxaban showed a lower risk of intracranial haemorrhage. Findings on the potential inferiority of specific NOAC in high-risk subgroups should be studied further.