Using routinely acquired electronic patients records (EPRs) and brain imaging to study novel risk factors for vascular dementia in older hospital patients

Introduction

Delirium and infection are risk factors for dementia, with infection more strongly linked to vascular than Alzheimer's-type dementia. It is unclear whether regional atrophy and white matter changes (WMC) of vascular origin modify these relationships. To inform future studies, we determined rates of cognitive frailty and frequency of brain scans in consecutive older hospital in-patients using routinely acquired electronic patient records (EPRs) data.

Methods

The Oxford Cognitive Comorbidity and Ageing Research Database (ORCHARD) includes real-world EPR data from consecutive older patients admitted to four general hospitals in Oxfordshire, UK (n=660,000 population). ORCHARD includes detailed data on cognitive frailty (dementia history, delirium diagnosis using the Confusion Assessment Method-CAM and 10-point Abbreviated-Mental-Test Score, AMTS), comorbidities, nutrition, falls risk, frailty, clinical observations, laboratory tests, and routine brain imaging. Long-term dementia outcomes are obtained from electronic records linkage including to regional mental health databases. Atrophy is rated using the Global Cortical Atrophy scale (GCA) and WMC using the Age-Related WMC (ARWMC) scale.

Results

Between 2017 and 2019, there were 51,202 consecutive unplanned admissions (adults >70 years with >1 unplanned admission lasting >1 day). The mean/SD age of patients was 82/7 years. Cognitive frailty was present in 17,466 (34.5%, 95%CI 34.0-34.9%) overall: delirium=7,411 (14.6%), delirium+dementia=4,757 (9.4%), dementia=3,784 (7.5%), AMTS<8=1,514 (3%). In a subset of 1100 consecutive patients, 668 patients had available brain imaging (CT: 96%, MRI: 22%, both: 18%). On the rated CT scans (n=290 for atrophy, n=117 for WMC), global atrophy was mild in 12%, moderate in 71%, and severe in 17%; temporal lobe atrophy was absent in 1%, mild in 49%, moderate in 46%, and severe in 4%; WMC was mild in 58%, moderate in 38%, and severe in 3%.

Discussion

Cognitive frailty, particularly delirium without dementia, was prevalent in older patients with unplanned hospital admission. Over half of older patients had brain imaging available with high rates of moderate/severe atrophy and WMC. These findings suggest that routinely acquired EPR can be combined with available brain imaging to explore (vascular) dementia risk factors such as delirium and infection in hospital “Big Data” studies.