A matched case-control study on polypharmacy and co-medications one year before drug treatment for Alzheimer's disease

Background: Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by amyloid-beta plaques and neurofibrillary tangles. With an aging population, both AD and comorbidities are increasingly common. Managing comorbidities often requires multiple medications, leading to polypharmacy, defined as the concurrent use of five or more medications. Objective: This study aimed to estimate and compare the prevalence of polypharmacy one-year prior AD diagnosis compared to non-AD individuals. Methods: A matched cross-sectional design used data from the IADB.nl prescription database (1994-2021), including individuals aged 65 and older with at least one AD medication prescription within a year. Controls were matched by age and sex at a 9:1 ratio. Analyses were stratified by time period (<= 2010 and >2010) and further by sex and age. Results: 4150 AD individuals were included and matched with 37,350 controls. AD individuals had a higher prevalence of polypharmacy compared to controls, <= 2010 (OR: 1.15, 95% CI: 1.03-1.29), > 2010 (OR: 1.25, 95% CI: 1.16-1.36). Females with AD had slightly higher odds of polypharmacy than males. The prevalence was consistent across different time periods and age groups, with the highest odds in individuals aged 65-74. Conclusions: AD individuals in the Netherlands exhibit a significantly higher prevalence of polypharmacy in a year pre-AD diagnosis. The findings highlight the complexity of managing multiple comorbid conditions in AD individuals, emphasizing the need for regular review and optimization of medication regimens and the inclusion of non-pharmacological interventions to minimize adverse outcomes and improve quality of life.