Epilepsy as a marker of cognitive decline in cerebral amyloid angiopathy: Evidence from a large multi-institutional cohort.

INTRODUCTION Cerebral amyloid angiopathy (CAA) is an amyloid mediated cortical and leptomeningeal small-vessel disease that commonly presents with lobar intracerebral hemorrhage, cognitive impairment, and transient neurological symptoms. Epilepsy occurs in 20-33 % of patients with CAA, but their association with cognitive function and survival remains incompletely defined.

Methods

We conducted a retrospective cohort study using the Mayo Clinic Platform, which contains multi-institutional de-identified longitudinal electronic health records. Adult patients (≥18 years) with CAA were identified using ICD-10 code I68.0 and natural language processing of clinical notes including Boston criteria 2.0. Epilepsy was defined per ILAE criteria with ICD-10 codes and documentation in clinical notes, and cognitive dysfunction diagnosis was confirmed using patient history. Propensity score matching (1:1) was performed at the date of CAA diagnosis. Time-to-event outcomes were estimated using Kaplan-Meier methods and Cox proportional hazards regression for 60 months follow-up. RESULT Among the 2717 patients with CAA (mean age 74.5 years), 733 patients (27.0 %) had epilepsy. 673 propensity score-matched pairs were included in the final analysis. Epilepsy was associated with a higher risk of cognitive dysfunction (HR 1.34, 95 % CI 1.13-1.60). No statistically significant difference was noted in all-cause mortality between cohorts (HR 1.07, 95 % CI 0.86-1.33).

Conclusion

Epilepsy in patients with CAA was associated with higher risk of cognitive decline. There was no difference in all-cause mortality, but the confidence interval does not exclude a clinically meaningful effect in either direction. These findings highlight patients with epilepsy as a subgroup of CAA cases with increased risk for cognitive decline. Prospective studies with validated cognitive assessments are needed to confirm this association.