Risk Factors for Initiation of Potentially Inappropriate Medications in Community-Dwelling Older Adults with and without Alzheimer's Disease.

Background: Various criteria have been created to define potentially inappropriate medications (PIMs) to help improve the quality and safety of medicine use in older patients. Individuals with Alzheimer's disease (AD) may be at higher risk of adverse drug events associated with PIMs (such as falls).

Objective: Our objective was to determine the risk factors for PIM initiation in a nationwide cohort of community dwellers aged ≥65 years with and without AD.

Methods: The Finnish nationwide MEDALZ cohort includes all patients diagnosed with AD in 2005-2011 (n = 70,718) and two comparison individuals without AD (non-AD) matched for age, sex and region of residence for each person with AD. After a 1-year washout period for PIM use and exclusion of those aged <65 years, we included 50,494 patients with AD and 106,306 comparison subjects. PIM use was defined according to Finnish criteria.

Results: Subjects without AD initiated PIMs more frequently than those with AD (16.4 vs. 12.2%, respectively; p < 0.001). The most common PIMs were muscle relaxants and urinary antispasmodics. Older individuals (aged ≥75 years) were less likely to initiate PIMs. In the AD group, women were less likely to initiate PIMs than men. More comorbidities were associated with PIM initiation, especially in the non-AD group. The use of opioids or psychotropic medicines was associated with PIM initiation in both cohorts. Regional differences between university hospital districts were observed.

Conclusion: PIM initiation was dependent on patient characteristics and possibly also some healthcare system-related factors such as differing regional treatment practices. It is important that medicines prescribed to the older vulnerable population are assessed regularly to avoid adverse effects and ensure safe pharmacotherapy, especially in those with multiple comorbidities.