Polypharmacy following Dementia Diagnoses in Vietnam: Results from Real-World Data in Outpatient Settings

Introduction: Polypharmacy might be clinically appropriate if it improves health outcomes of people with dementia. However, polypharmacy was associated with higher risks of impairment in cognitive, physical, and emotional abilities. Several studies on polypharmacy among people with dementia were performed globally but not in Vietnam. This study aimed to investigate the epidemiology of polypharmacy among people with dementia in Vietnam.

This retrospective cohort study included outpatient individuals who were diagnosed with dementia between January 1, 2023, and April 15, 2024, in the Vietnam National Geriatric Hospital. Data were extracted from medical records, including dementia diagnosis, drug utilization, medical history before dementia diagnosis, comorbidities, and sociodemographic. The monthly quantity of drugs used was categorized as "no polypharmacy" 0-4 drugs, "polypharmacy" ≥5 drugs, and "hyperpolypharmacy" ≥10 drugs. The primary outcome was the incidence of polypharmacy following dementia diagnosis. The prescription of potentially inappropriate medications in people with dementia, identified using the American Geriatrics Society Beers criteria, was also evaluated. Multivariable logistic regression was employed to find associated risk factors of polypharmacy.

During the follow-up from dementia diagnosis to June 30, 2024, there were 64 people having polypharmacy (median age at dementia diagnosis 73.5, 68.8% females) and 342 people without polypharmacy (median age at dementia diagnosis 74.0, 64.0% females). Age at dementia diagnosis, sex, regions of residence, and education were not associated with having polypharmacy in people with dementia. Compared to people with Alzheimer's disease, significantly higher probabilities of having polypharmacy were seen in people with vascular dementia (odds ratio [OR] 4.63, 95% confidence interval [CI] 2.16-9.92) and other dementias (OR 4.61, 95% CI 2.31-9.18). People with dementia at severe stage were at lower chance of having polypharmacy (OR 0.19, 95% CI 0.05-0.63). Potentially inappropriate medications were more frequent in the polypharmacy group (n = 27, 42.2%), compared to the non-polypharmacy group (n = 59, 17.3%). Prescribing antipsychotics in the polypharmacy group doubled that in the non-polypharmacy group (34.4% versus 16.1%).

Lower incidence of polypharmacy among people with dementia compared to previous studies might either imply the improvement in managing the prescription of potentially inappropriate medications or be underestimated by not including inpatient individuals. Future studies are necessary to clarify the impact of polypharmacy on health outcomes of people with dementia.