Cardiovascular

Anticoagulation in Atrial Fibrillation With Previous Intracranial Bleeding: Competing Adverse Events in a Nationwide Cohort.

Tiili P, Lehto M, et al. • Neurology • 2026

Cohort PubMed 42906071 DOI 10.1212/WNL.0000000000218719
TL;DR

In patients with atrial fibrillation and previous intracranial bleeding, oral anticoagulation was associated with lower risks of ischemic stroke and death; DOAC use was not associated with increased intracranial bleeding risk, whereas warfarin use was.

Key Findings

Results

Among 1,502 Finnish patients with first-ever AF and prior intracranial bleeding, most did not receive oral anticoagulation, and DOACs were the least used strategy.

  • Nationwide registry cohort of patients with first-ever AF diagnosed 2010-2018 and intracranial bleeding at least 120 days earlier; follow-up began 90 days after AF diagnosis.
  • Median age was 78 years (IQR 71-85), 44% were female, and 41% had only traumatic intracranial bleeding.
  • 15% received DOACs, 29% warfarin, and 56% no OAC, based on drug purchases.
Results

Adjusted 1-year absolute risks of ischemic stroke were lowest with DOACs and highest with no OAC.

  • Adjusted 1-year IS risks were 0.7% (DOAC), 2.1% (warfarin), and 4.1% (no OAC).
  • Risks were estimated with adjusted cumulative incidence functions using inverse probability of treatment weighting in a competing-risks framework.
Results

Adjusted 1-year absolute risks of recurrent intracranial bleeding were highest with warfarin.

  • Adjusted 1-year intracranial bleeding risks were 1.2% (DOAC), 2.7% (warfarin), and 1.9% (no OAC).
Results

Adjusted 1-year absolute risk of death from other causes was lowest with DOACs and highest with no OAC.

  • Adjusted 1-year risks of death from other causes were 4.7% (DOAC), 8.6% (warfarin), and 14.7% (no OAC).
Results

Compared with no OAC, DOAC use was associated with lower risks of ischemic stroke and death without increased intracranial bleeding risk.

  • IS: HR 0.17, 95% CI 0.04-0.71.
  • Death: HR 0.20, 95% CI 0.09-0.46.
  • Intracranial bleeding: HR 0.70, 95% CI 0.19-2.50, a wide interval including no difference.
  • Analyses used cause-specific Cox regression with inverse probability of treatment weighting.
Results

Compared with no OAC, warfarin use was associated with lower risks of ischemic stroke and death but increased risk of intracranial bleeding.

  • IS: HR 0.49, 95% CI 0.26-0.93.
  • Death: HR 0.60, 95% CI 0.44-0.80.
  • Intracranial bleeding: HR 1.85, 95% CI 1.01-3.41.
Results

Among warfarin users, good time in therapeutic range (TTR ≥70%) was associated with substantially lower risks of ischemic stroke and death, with attenuated associations for poorer or missing TTR.

  • TTR ≥70%: IS HR 0.24, 95% CI 0.08-0.79.
  • TTR ≥70%: death HR 0.19, 95% CI 0.10-0.36.
  • Associations were attenuated with poorer or missing TTR.
  • Warfarin users were stratified by TTR.
Conclusions

The authors caution that limited information on the prior intracranial bleeding and potential residual confounding warrant careful interpretation, and they conclude the findings support individualized anticoagulation decisions.

  • The study was observational and registry-based, with treatment defined by drug purchases.
  • Inverse probability of treatment weighting was used to balance baseline characteristics, but residual confounding may remain.

What This Means

This study looked at about 1,500 people in Finland who developed atrial fibrillation (an irregular heartbeat that raises stroke risk) after having previously had bleeding inside the skull. Doctors often worry about giving blood thinners to such patients because of the risk of more bleeding, but not treating leaves them exposed to stroke. Using national health registries, the researchers compared people taking newer blood thinners (DOACs), warfarin, or no blood thinner. More than half received none. After statistically balancing differences between the groups, people taking DOACs had lower rates of ischemic stroke and of death from other causes than those taking no blood thinner, and no clear increase in recurrent brain bleeding, although the estimate was imprecise. Warfarin was also linked to fewer strokes and deaths, but with a higher risk of recurrent brain bleeding. Among warfarin users, those whose blood thinning was well controlled (time in therapeutic range of 70% or more) had the best outcomes. This research suggests that blood thinners, especially DOACs, may be associated with better outcomes in this high-risk group. However, this was an observational study, so it cannot prove that the drugs caused the differences, and details about the earlier bleeding were limited. The authors say the results support individualized treatment decisions rather than a one-size-fits-all approach.

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Citation

Tiili P, Lehto M, Halminen O, Lehtonen O, Haukka J, Linna M, et al.. (2026). Anticoagulation in Atrial Fibrillation With Previous Intracranial Bleeding: Competing Adverse Events in a Nationwide Cohort.. Neurology. https://doi.org/10.1212/WNL.0000000000218719