A Retrospective Database Study for the Development and Validation of Algorithms for Intracerebral Hemorrhage and Seizures in Alzheimer's Disease

The primary objective of this study is to develop and validate claims-based algorithms to identify intracerebral hemorrhage \>1 cm in diameter, ensuring differentiation from amyloid-related imaging abnormality-microhemorrhage and hemosiderin deposit (ARIA-H; microhemorrhage, superficial siderosis) in participants with Alzheimer's disease (AD) using claims data in the United States (US) with linkage to electronic health records (EHRs), and to estimate the positive predictive values (PPVs) of the algorithms. The secondary objective of the study is to validate claims-based algorithms to identify new-onset seizures in participants with AD using US claims data with linkage to EHRs and to estimate the PPVs of the algorithms.

Inclusion Criteria: * Before or on the outcome event date, have at least 1 ICD-10-CM diagnosis code for AD in medical claims in an inpatient setting; or have at least 2 ICD-10-CM diagnosis codes in medical claims in an outpatient setting, at least 7 days and less than 365 days apart * Have at least 365 days of continuous coverage with medical and pharmacy benefits before the outcome event date * Have EHR data available for (1) the outcome event date or (2) during the period of up to 30 days before and up to 90 days after the outcome event date * Have unstructured EHR information (ie, clinical notes) available for any encounter (1) on the outcome event date or (2) during the period of 30 days before to up to 45 days after the outcome event date Exclusion Criteria: * New-onset seizure outcome only: Have any ICD-10-CM diagnosis code for seizure or epilepsy before the outcome event date