Key result
Rising OAC use is linked to a ~33% decline in AF-associated ischemic strokes.
Why the study?
Atrial fibrillation is a major cause of ischemic stroke, and risk is substantially reduced by oral anticoagulants, but temporal trends in AF-associated ischemic stroke needed investigation.
Did the incidence of atrial fibrillation-associated ischemic stroke decline between 2012 and 2021 alongside increased oral anticoagulant use in Auckland, New Zealand?
Did the incidence of atrial fibrillation-associated ischemic stroke decline between 2012 and 2021 alongside increased oral anticoagulant use in Auckland, New Zealand?
Increased community use of oral anticoagulants over a decade was associated with a significant decline in atrial fibrillation-associated ischemic strokes, though ethnic and sex disparities persist.
Declining AF-stroke incidence coincided with rising OAC use; observational data leave causality open and require prospective confirmation.
Background Atrial fibrillation (AF) is a major cause of ischemic stroke (IS), and this risk can be substantially reduced with oral anticoagulants (OACs). Using the population‐based ARCOS (Auckland Regional Community Stroke) study, we investigated the temporal trends in AF‐associated IS. Methods We analyzed ARCOS IV (March 2011–February 2012) and ARCOS V (September 2020–August 2021). AF‐associated IS incidence was compared using Poisson exact methods. Regional OAC dispensing trends were also evaluated. Propensity score–weighted logistic regression estimated the marginal association between cohort and AF‐associated IS after standardizing for vascular risk factors. Interaction tests were performed for ethnicity, and sex‐specific differences were assessed using heterogeneity testing. OAC‐associated intracerebral hemorrhage rates were also examined. Results Among 1694 (ARCOS IV) and 1982 (ARCOS V) IS cases, the proportion of AF‐associated IS declined from 32.4% to 21.5% (−10.8% [95% CI −13.7 to −8.0], P <0.0001). Crude AF‐associated IS incidence fell from 49.0 to 32.7 per 100 000 population. A larger decline occurred in women (relative risk, 0.56) than men (relative risk, 0.76; p =0.02 for heterogeneity). Temporal reductions differed by ethnicity, with greater decline in the “Other” ethnicity categories, but not in Māori or Pacific peoples. During the same period, patients dispensed OACs increased from 1094 to 1928 per 100 000 ( P <0.001). OAC‐associated intracerebral hemorrhage increased from 2.1 to 3.6 per 100 000, equating to 11 IS cases prevented per excess intracerebral hemorrhage. Conclusion AF‐associated IS incidence declined in Auckland between 2012 and 2021, during a period of substantially increased community OAC use. Persistent ethnic inequities and sex‐specific variation highlight the need for improved AF detection, risk stratification, and prevention strategies.
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Mahawish et al. (2026) studied this question. AF-associated ischemic stroke incidence in Auckland declined from 49.0 to 32.7 per 100,000 between 2012 and 2021, coinciding with OAC use increase from 1094 to 1928 per 100,000.
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