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Phenotype submission - Alzheimer’s disease

Cohort Definition Name : Earliest event of Alzheimer’s disease derived from Imfeld, 2

Contributor name : Azza Shoaibi’

Contributor OrcId : 0000-0002-6976-2594’

Logic Description : 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

Recommended study application : traget, outcome

Assertion statement : This cohort definition was executed on at least one real person-level observational health data source and resulted in a cohort with at least 1 person.

Target Clinical Description : Alzheimer Disease (AD) is an age associated progressive neurodegenerative disorder associated with neuritic plaque that presents with predominance of memory and visuospatial deficit. It is the most common cause of dementia (acquired loss of cognitive ability). Long term treatment is supportive and symptomatic therapy, while patients in the early stages of AD may benefit from cholinesterase inhibitors (e.g., Donepezil). Memantine is a newer receptor antagonist that has been found to slow down functional decline in moderate-to-severe AD. The differential diagnosis of AD includes frontotemporal dementia, dementia with Lewy Bodies, vascular dementia, normal pressure hydrocephalus, Huntington disease, Creutzfeldt-Jakob disease, and Parkinson disease

Evaluation conclusion : This deffinition is an implementaion of a previolsy validated phenotype algorythem by Imfeld. Et all. The publication can be found here: https://www.tandfonline.com/doi/full/10.2147/CLEP.S206770 . The researchers colncluded that Using the dataset linkage, PPV was 74.8 (95% CI: 73.1–76.4) for algorithm A1 (AD diagnoses), and 72.3 (95% CI: 70.7–73.9) for algorithm A3 (diagnosed or treated patients without previous conditions); sensitivity was 71.4 (95% CI: 69.6–73.0) and 83.3 (95% CI: 81.8–84.6) for algorithms A1 (AD diagnoses) and A3, respectively. Stratified results did not differ by age, but PPV and sensitivity estimates decreased amongst men and severe patients, respectively. Our assessmnet indicats that adding treated patients without previous conditions add around 5-20% to patient counts- potantially improving sesntivity and the the clinical profile of those with and without the alzhimer specific codes were faily similar with handful of covariets having a mean difference of more than 0.1 on day zero and at baseline (-999 to zero). A lot of these variables are different by design (part of the different criteria) such as Alzheimer codes and dementia codes.

Imported to the OHDSI Phenotype Library. It may be expected to be found with id = 862 in the next release. Thank you