Abstract
BACKGROUND: Dementia is an increasing public health concern, particularly in aging societies. While most prevalence estimates in Thailand are derived from community-based studies, less is known about the burden and risk factors of dementia in tertiary care outpatients, who often present with multimorbidity. METHODS: We conducted a retrospective cross-sectional study using secondary data from patients aged ≥60 years attending internal medicine, neurology, and geriatric outpatient clinics of Phramongkutklao Hospital, a tertiary hospital in Bangkok, Thailand, between January 1 and December 31, 2024. Dementia was identified using a hierarchical algorithm incorporating International Classification of Diseases, Tenth Revision (ICD-10) diagnostic codes, prescriptions for anti-dementia medications, and cognitive test results, with sensitivity analyses using stricter definitions. Independent variables included demographic characteristics, vascular and non-vascular comorbidities, medication use, and laboratory results. Prevalence was calculated with 95% confidence intervals (CI). Poisson regression with robust variance estimation was used to calculate crude and adjusted prevalence ratios (aPR) for associated factors. RESULTS: Of 4,100 older adults, 512 had dementia (12.5%). Alzheimer's disease was the most frequent subtype, accounting for 278 cases (54.3% of dementia; 6.8% of the total sample). In univariable analysis, dementia was associated with age ≥80 years, female sex, low education, hypertension, diabetes mellitus, stroke/transient ischemic attack (TIA) history, depression, and an Anticholinergic Cognitive Burden (ACB) score ≥3. After adjustment, age ≥80 years remained the strongest determinant (aPR 2.41, 95% CI 1.92-3.01). Female sex (aPR 1.28, 95% CI 1.07-1.53), education ≤6 years (aPR 1.64, 95% CI 1.33-2.01), hypertension (aPR 1.21, 95% CI 1.02-1.43), diabetes mellitus (aPR 1.27, 95% CI 1.07-1.52), stroke/TIA (aPR 1.89, 95% CI 1.52-2.35), depression (aPR 1.48, 95% CI 1.16-1.90), and ACB score ≥3 (aPR 1.36, 95% CI 1.09-1.70) were all independently associated with dementia. CONCLUSION: Dementia was common among tertiary care outpatients, with prevalence higher than community-based estimates. Advanced age, female sex, low education, vascular comorbidities, depression, and anticholinergic medication burden were significant correlates. These findings highlight the need for routine screening, aggressive vascular risk factor management, and medication review in tertiary care settings to mitigate the burden of dementia.