Drug Burden Index and Cognitive and Physical Function in Aged Care Residents: A Longitudinal Study

Objectives: Anticholinergic/antimuscarinic and sedative medications (eg, benzodiazepines) have been found to be associated with poorer cognitive and physical function and mobility impairment in older age. However, previous studies were mostly conducted among community-dwelling older individuals and had often a cross-sectional design. Accordingly, our aim was to examine longitudinal associations between cumulative exposure to anticholinergic and sedative medications and cognitive and physical function among residents from aged care homes. Design: Longitudinal study. Setting and Participants: A total of 4624 residents of Dutch aged care homes of whom data were collected between June 2005 and April 2014. Methods: Outcome measures were collected with the Long-Term Care Facilities assessment from the international Residential Assessment Instrument (interRAI-LTCF) and included the Cognitive Performance Scale, the Activities of Daily Living (ADL) Hierarchy scale, a timed 4-meter walk test, distance walked, hours of physical activity, and days being outside. Cumulative exposure to anticholinergic and sedative medications was calculated with the Drug Burden Index (DBI), a linear additive pharmacological dose-response model. Associations were examined with linear mixed models to take the potential dependence of observations into account (ie, data were collected at repeated assessment occasions of residents who were clustered in aged care homes). Analyses were adjusted for sex, age, dementia, comorbidity (neurological, psychiatric, cardiovascular, oncological, and pulmonary), fractures, depressive symptoms, and medications excluded from the DBI. Results: We observed significant longitudinal associations between a higher DBI and poorer ADLs, fewer hours of physical activity, and fewer days being outside. We found no significant longitudinal association between a higher DBI and poorer cognitive function. Conclusions and Implications: Over time, cumulative exposure to anticholinergic and sedative medications is associated with poorer physical but not cognitive function in aged care residents. Careful monitoring of aged care residents with high cumulative anticholinergic and sedative medication exposure is needed.