OBJECTIVES: Adverse drug reactions (ADRs) are a leading cause of hospitalizations in older individuals with dementia. However, there is little prospective evidence on ADR-related hospitalizations in this demographic. This study aimed to investigate the proportion, clinical features, causality, severity, preventability, outcome, and predictors of ADR-related hospitalizations in older patients with dementia or cognitive impairment at the Royal Hobart Hospital, Tasmania, Australia.

METHODS: We conducted a prospective cross-sectional study, screening a convenience sample of patients aged ≥65 years with dementia or cognitive impairment undergoing unplanned overnight medical or geriatric admissions. ADR-related admissions were determined through expert consensus based on medical records and patient interviews. The causality, preventability, severity, and outcome were evaluated for each ADR-related admission. Variables significantly associated with ADR-related hospital admissions were included in a logistic regression model.

RESULTS: Of the 162 admissions screened over a 7-month period, 21% were ADR-related. Overall, 74% of these ADR-related admissions were deemed preventable. Gastrointestinal ADRs were the most common (22.2%), followed by cardiovascular (15.6%) and neuropsychiatric (20.0%) reactions. Cardiovascular drugs (40.7%), including renin-angiotensin system agents (15.3%), diuretics (10.2%), and beta-blockers (8.5%), were mainly implicated. ADRs were classified as definite (2.9%) or probable (97.1%) according to the Naranjo algorithm. ADR severity was moderate in 91.9% and severe in 8.8% of hospitalizations. ADRs resolved in 67.6% and the patient recovered, with 8.8% resulting in fatalities and 23.5% remaining unknown due to transfer to other healthcare facilities. Benzodiazepines (OR, 3.1; CI, 1.1–8.5) and hospital admission in the preceding month (OR, 3.1; CI, 1.2–7.8) were identified as independent predictors for ADRs.

CONCLUSIONS: ADRs contributed to one in five unplanned overnight hospital admissions among older patients with dementia or cognitive impairment. Most ADRs were preventable, highlighting the need for targeted and tailored interventions for this vulnerable population.