Risk of death, thromboembolic events, and bleeding in elderly patients with Atrial Fibrillation and Clinical Complexity who are not taking oral anticoagulation

Abstract Background Patients with Atrial Fibrillation (AF) often exhibit Clinical Complexity (CC), defined as ≥2 features, i.e. patients aged ≥75 years plus a body mass index (BMI) < 23/kg/m2 and/or bleeding history and/or chronic kidney disease. No data are available about the clinical course of patients with Atrial Fibrillation (AF) and CC who are not taking oral anticoagulation (OAC). Purpose To assess the risk of thrombotic and hemorrhagic events in patients with Atrial Fibrillation (AF) and CC who are not taking OAC. Methods Retrospective study with a health care research network (TriNetX). Based on the ICD-10-CM codes entered between 2011-2022 from 85 health care organizations mainly located in the United States, AF patients ≥75 years with CC were categorized into two groups based on the use of OAC during the last year before the study period. The primary outcomes were the one-year risk of death, major cardiovascular events ([MACE]: heart failure, stroke, and myocardial infarction), and major bleeding (central nervous system, gastrointestinal, internal bleeding, and hypovolemic shock). Secondary outcomes were each component of the primary outcome and catheter ablation. Cox regression analyses were used to calculate hazard ratios (HRs) and 95% CIs following propensity score matching 1:1. Results Overall, we identified 271,402 AF CC patients not on OAC (80.1±6.8 years, 46.5% females) and 87,101 AF CC patients on OAC (79.8±6.5 years, 47.6% females). Before PSM, AF CC patients not on OAC showed no significant differences in cardiovascular and bleeding risk factors but were less treated with pharmacological treatment than AF CC patients on OAC. After PSM, no significant differences were found between the two groups, but AF CC not on OAC were at higher risk of all-cause death (HR 1.54, 95%CI 1.50-1.57), MACE (HR 1.13, 95%CI 1.11-1.16), and major bleeding (HR 1.34, 95%CI 1.31-1.38), when compared to AF CC on OAC. AF CC patients not on OAC were associated with a higher risk of each component of the primary outcome and with a lower use of catheter ablation procedures (HR 0.48, 95%CI 0.43-0.54) (Table 1). The risk of the composite outcomes was the highest in those with all the three CC components. A progressive increase in OAC prescription was observed during the follow-up period, with increasing of NOACs and lower use of warfarin being observed. There was a clear temporal relationship between increasing OAC prescription and incidence of bleeding in CC patients (Figure 1) Conclusions AF CC patients not on OAC have a high risk of all-cause death, thrombotic and hemorrhagic events. Over time, increasing NOAC use was associated with more bleeding in CC patients. New antithrombotic approaches aimed at reducing thrombotic risk without increasing bleeding risk are needed in these patients.Figure 1 OAC new prescriptions