Competing risks of ischaemic stroke and intracranial haemorrhage in untreated new-onset atrial fibrillation: a nationwide study
A Luojus, O Halminen, M Vilpponen, K Teppo, O Lehtonen, A L Aro, J Haukka, M Linna, J Kuoppala, P Mustonen, M Niemi, J Putaala, J Hartikainen, J E K Airaksinen, M LehtoAbstract
Background and aims
After introduction of direct oral anticoagulants (DOACs) the coverage of oral anticoagulation (OAC) therapy in patients with atrial fibrillation (AF) has improved, leaving a smaller proportion of patients with new-onset AF without anticoagulation. The risk of ischaemic stroke (IS) and intracranial haemorrhage (ICH) of non-anticoagulated patients in large DOAC era cohorts are seldom reported.
We analysed the one-year nationwide incidence of IS and ICH in non-anticoagulated patients with new-onset AF.
Methods
The Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) - study is nationwide retrospective register-based linkage study which covers all patients with AF in Finland between years 2004 and 2018 at all levels of care. Patients with new-onset AF in years 2011-2017 without OAC therapy initiation within a year of AF diagnosis were analysed for one-year incidences of IS and ICH. Patients with prior OAC use or date of death within 90-days of cohort entry were excluded from the analysis. Non-anticoagulated patients were assigned to groups according to their CHA2DS2-VA -scores, and cumulative incidences with death as a competing risk were plotted for IS and ICH.
Results
Out of 141 399 patients with new-onset AF, 41 076 patients (mean age 68.1 years, mean CHA2DS2VA-score of 2.4) were non-anticoagulated and eligible for outcome analysis. In one-year follow-up a total of 883 IS events were recorded with IS incidence of 2.26/100 patient years (py) (Table 1). The respective rates of IS in CHA2DS2VA -groups were 0.21/100 py for CHA2DS2VA 0p, 0.52/100 py for CHA2DS2VA 1p, 1.35/100 py for CHA2DS2VA 2p, 3.41/100 py for CHA2DS2VA 3p, 4.39/100 py for CHA2DS2VA 4p, and 5.61/100 py for CHA2DS2VA >4p. Similarly, 344 ICH events were recorded overall with ICH rate of 0.88/100 py in the cohort. The respective rates of ICH in CHA2DS2VA -categories were 0.26/100 py for CHA2DS2VA 0p, 0.34/100 py for CHA2DS2VA 1p, 0.86/100 py for CHA2DS2VA 2p, 1.27/100 py CHA2DS2VA 3p, 1.35/100 py for CHA2DS2VA 4p, and 1.66/100 py for CHA2DS2VA >4p. Cumulative incidences with confidence intervals for IS and ICH are depicted in Figure 1a & 1b.
Conclusion
Overall, the one-year nationwide incidence rate of IS was 2.5-fold higher than the rate of ICH in non-anticoagulated new-onset patients with AF. The cumulative incidences of IS and ICH were highest in groups with high CHA2DS2VA -scores.