Adverse events in clinically complex elderly patients with atrial fibrillation according to oral anticoagulation status

Background: Few data are available about the impact of oral anticoagulants (OAC) in patients with Atrial Fibrillation (AF) and clinical complexity (CC). Methods: We conducted a retrospective study utilising data from the TriNetX network. Based on ICD-10-CM codes entered between 2020 and 2022, AF patients aged ≥75 years on long-term OAC with CC were categorised into two groups based on OAC use in the year before entering the study (maintained vs discontinued). CC was defined as BMI ≤23 kg/m2, and/or history of bleeding, and/or chronic kidney disease. The primary outcomes were the one-year risk of all-cause death, major cardiovascular events (MACE), and major bleeding. Cox regression analyses were used to calculate hazard ratios (HRs) and 95% CIs before and after 1:1 propensity score matching (PSM). Findings: We identified 6554 AF CC patients who discontinued OAC (mean age 81.5 ± 6.0 years, 46.7% females) and 23,212 AF patients with CC who maintained OAC (81.3 ± 6.0 years, 49.4% females). Before PSM, AF CC patients who discontinued OAC had a higher prevalence of intracranial, gastrointestinal haemorrhages, and antiplatelet use, with no significant differences after PSM. OAC discontinuation was associated with a higher risk of all-cause death (HR 1.22, 95% CI 1.11–1.35) and MACE (HR 1.38, 95% CI 1.25–1.53). The one-year risk of major bleeding was similar in those who discontinued or maintained OAC (HR 1.05, 95% CI 0.94–1.18), although it was significantly higher during the early follow-up (HR 1.51, 95% CI 1.24–1.83). The risk of primary outcomes decreased over time, with the risk of bleeding becoming not significant. Interpretation: AF CC patients who discontinued OAC have a high risk of adverse events. New antithrombotic and integrated care approaches to reduce thrombotic risk without increasing bleeding risk are needed in these patients. Funding: This study received no funding.