Predictors of Adverse Drug Reaction-Related Hospitalisations Among People with Dementia: A Retrospective Case-Control Study.

Introduction: Adverse drug reactions (ADRs) are common among people with dementia; however, little is known about the magnitude and predictors associated with ADR-related hospitalisation among these individuals. This study aimed to determine the magnitude, types, drugs implicated and predictors of ADRs associated with hospitalisation among people with dementia.

Methods: This retrospective case-control study analysed medical records of individuals aged ≥ 65 years with dementia admitted to major public hospitals in Tasmania, Australia, from July 2010 to July 2021. Adverse drug reactions and implicated drugs were identified using administrative data and cross-checked with hospital medical records, with consensus reached among the research team.

Results: Of the 7928 people admitted to hospital at least once within the study period, 1876 (23.7%) experienced at least one ADR-related hospitalisation. Of these, 300 case patients with 311 ADRs and 300 control patients were randomly selected. The most common types of ADRs were renal (acute kidney injury; AKI) (36.0%), followed by neuropsychiatric (17.6%), cardiovascular (16.0%) and haematological (13.1%). Diuretics, renin-angiotensin system (RAS) inhibitors and anti-thrombotics constituted the main implicated drug classes. The ADR-related hospitalisation was associated with: chronic kidney disease (CKD) (OR 8.00, 95% CI 2.63-24.28, p < 0.001), Australian-born (OR 1.62, 95% CI 1.08-2.43, p = 0.019), hypertension (OR 1.48, 95% CI 1.01-2.17, p = 0.044) and the number of medicines (OR 1.06, 95% CI 1.00-1.12, p = 0.022). Potentially inappropriate medication use and anticholinergic burden did not predict ADR-related hospitalisation.

Conclusions: These predictors could help identify the individuals at the highest risk and enable targeted interventions to be designed.