Abstract TP22: Delirium, Infection, and Risk of Dementia in Patients With and Without Cerebral Small Vessel Disease

Abstract

Background: The increased risk of dementia after delirium and infection might be influenced by cerebral small vessel disease-SVD. We determined associations between hospitalisations with delirium, and with infection on follow-up after TIA/minor stroke and 5-year dementia risk, stratified by moderate/severe SVD on baseline brain imaging. Methods: In a population-based study (n=94 567) of TIA/minor stroke (NIHSS<3) ascertained 2002-2012 (Oxford Vascular Study-OXVASC), hospitalisations on follow-up were identified from the Oxford Cognitive Comorbidity, Frailty and Ageing Research Database-ORCHARD. Delirium and infection were defined by ICD-10 coding supplemented by hand-searching of hospital records. Dementia was diagnosed using clinical/cognitive assessment, medical records and death certificates. Dementia risk was determined using time-varying Cox analysis with multivariable adjustment. Findings: Among 1,369 patients (n=655 TIA, n=714 minor stroke, mean/SD age=72/13 years, 674 female, 364 moderate/severe SVD), 209 (15%) developed dementia. Hospitalisation during follow-up occurred in 891 (65%) patients of whom 103 (12%) had ≥1 delirium episode and 236 (26%) had ≥1 infection episode. Hospitalisation without delirium/infection did not predict subsequent dementia (HR=1.01,95%CI:0.86-1.20). In contrast, hospitalisation with delirium predicted subsequent dementia independently of infection in patients with and without SVD (HR=2.64,1.47-4.74 vs. 3.41,1.91-6.09, both p<0.001) especially in those with normal baseline cognition (HR=4.01,2.23-7.19 vs 3.94,1.95-7.93,both p<0.001). However, hospitalisation with infection only predicted dementia in those with moderate/severe SVD (HR=1.75,1.04-2.94 vs 0.68,0.39-1.20,p diff =0.023). Interpretation: The increased risk of dementia after delirium is unrelated to the presence of SVD, whereas infection increases risk only in patients with SVD, suggesting differences in underlying mechanisms and in potential preventive strategies.