Demographic and Clinical Characteristics of Patients Treated With Lecanemab Stratified by Amyloid-Related Imaging...

Background Amyloid-related imaging abnormalities (ARIAs) are among the most important safety considerations during lecanemab treatment for Alzheimer's disease (AD). Although APOE ε4 carrier status is a recognized ARIA risk factor, the relationship between ARIAs and routine demographic and clinical characteristics in real-world practice remains incompletely characterized. This study evaluated demographic, vascular comorbidity, and APOE genotype characteristics among patients treated with lecanemab, stratified by ARIA status. Methodology We conducted a retrospective cohort study of patients with AD treated with lecanemab at a single academic institution from December 4, 2023, to October 28, 2025. Of 324 identified patients, 318 were included in the primary analysis. Demographic and clinical variables were extracted from the electronic health record. ARIA status and subtype were determined from clinical MRI interpretations by board-certified neuroradiologists. Patients were stratified by presence and type of ARIA development during treatment. Results Among 318 included patients, 98 (30.8%) developed ARIA and 220 (69.2%) did not. Among ARIA-positive patients, nine (9.2%) had ARIA-E only, 50 (51.0%) had ARIA-H only, and 39 (39.8%) had mixed ARIA-E/H. Age was similar between ARIA-positive and ARIA-negative patients (74.4 vs. 73.6 years; p = 0.437). ARIAs occurred in 33.9% of female patients and 26.8% of male patients (p = 0.218), and in 52.9% of non-White patients and 29.6% of White non-Hispanic patients (p = 0.078). Hypertension, hyperlipidemia, and diabetes were not associated with ARIA. APOE ε4 carriers had a higher incidence of ARIA than non-carriers (35.3% vs. 22.8%; p = 0.029), although differences across individual APOE genotypes did not reach statistical significance (p = 0.135). Conclusions In this real-world cohort of patients treated with lecanemab, ARIAs occurred in nearly one-third of patients. APOE ε4 carrier status was the only evaluated demographic, clinical, or genetic variable significantly associated with ARIAs. Sex- and race/ethnicity-related differences were exploratory and require validation in larger, more diverse prospective cohorts. These findings support genotype-informed ARIA surveillance while emphasizing the need for broader representation in studies of anti-amyloid therapy safety.