Table 1.

Algorithms to identify Alzheimer's disease (AD) cases in electronic health records from primary care, using codes from the international statistical classification of diseases and related health problems, version 10 (ICD-10) and from the Anatomical Therapeutic Chemical (ATC)

Algorithm	Definition of AD case
A1	Diagnosed patients: have an ICD10 code for AD (F00 or G30).
A2	Diagnosed or treated patients: have a code for AD (ICD10: F00 or G30) or for prescription or billing of anti-dementia drugs (ATC: N06DA, N06DX01).
A3	Diagnosed or treated patients without previous conditions: have a code for AD (ICD10: F00 or G30) or for prescription or billing of anti-dementia drugs (ATC: N06DA, N06DX01). Treated patients were included if they had no code of dementia diagnosis or had a code of unspecified dementia (F03), and were excluded if they had a code for: a specific subtype of dementia such as Lewy bodies dementia, vascular or frontotemporal dementia (ICD10: F01, F02); Parkinson (ICD10: G20-G22); anti-Parkinson drugs (ATC: N04); or cerebrovascular disease (ICD10:I60- I69, G45, G46) within two years prior to AD diagnosis.