(C-013) Characterization of the Alzheimer's Disease (AD) Population within England using electronic health records: a clinical practice research datalink study (CPRD) using AD algorithms

Background: Clinical trials of new Alzheimer’s Disease (AD) drugs strive to be representative of real-world AD populations. Real world data can be utilized to broadly characterize AD patients and benchmark representativeness of clinical trials.

Objectives: To this end, this study uses the Clinical Practice Research Datalink (CPRD) linked to Hospital Episodes Statistics (HES) to characterize demographics, comorbidities, co-medications, and healthcare resource (HCRU) use in patients newly diagnosed with AD in England.

Methods: During an index period from Jan-2019 to Dec-2019, this study identified three CPRD Aurum cohorts with newly diagnosed and/or treated Alzheimer’s disease. The three cohorts included two cohorts compiled using disease-based algorithms (Cohort A: 1-year Imfeld et al. 2013 and Cohort B: 1-year Douros et al. 2021) and one cohort compiled using a medication-based algorithm (Cohort C: new users of cholinesterase inhibitors). Patients were limited to those with HES linkage, and additional sub-cohorts for patients who were 60+ years of age. Demographics, comorbidities, co-medications and HCRU present any time prior (up to 1-1-2000) pre-cohort qualification are described (CPRD protocol number 23_003485).

Results: This study identified 9,934 and 10,375 patients as newly diagnosed AD using the Imfeld and Douros algorithms (Cohorts A and B) and 7,472 patients as new users of cholinesterase inhibitors (Cohort C). The cohorts were not mutually exclusive. Overall, the three sub-cohorts (age 60+) of patients were similar in terms of demographics with mean (SD) age of 81.48(7.20)-82.99(7.32) and gender 59.47-62.57% female and 37.43-40.53% male. Common comorbidities across these three sub-cohorts include cardiovascular (CV) diseases such as myocardial infarction (21.25-25.81%) and heart failure (21.90-26.97%), hypertension (67.08-71.10%), chronic kidney disease (29.04-33.10%), diabetes (25.90-28.17%), arthritis (50.82-53.16%), COPD (59.99-63.22%) and anxiety/depression (31.61-33.30%). Co-medications received such as anti-hypertensives, lipid modifying drugs, anti-diabetics, systemic corticosteroids, anti-depressants, COPD treatment and cardiac medications reflect these conditions. Up to 34% of AD patients had one specialist visit recorded in AURUM. Nearly half of the patients had one emergency or hospital inpatient visit recorded in HES for 2019.

Conclusions: This study provides an important basis for understanding representativeness of AD clinical trial populations and a novel insight into AD population in England. This study found that the AD population has a history of CV risk, diabetes, COPD and stroke as well as immunosuppression due to treatments with systemic corticosteroids.