The effects of polypharmacy and Drug Burden Index on transitions in cognitive function and death: the CHAMP study

Background: Cognitive impairment is a disabling condition and is associated with mortality. Multiple medication use and the use of sedative and anticholinergic medications are associated with poor clinical outcomes including excess morbidity and cognitive impairment.

Objective: To investigate the effects of multiple medication use and Drug Burden Index (DBI) on transitions in cognitive function and death in community-dwelling older men.

Methods: Data from the Concord Health in Ageing Men Project (CHAMP) were utilised. Community-dwelling men aged 70 years and over living in Sydney, Australia attended clinic visits and filled out questionnaires at baseline, two and five years. Cognitive impairment was defined using the Mini-Mental State Exam over the three waves. The total number of medications and DBI (a measure of exposure to anticholinergic and sedative medications) were collected at each wave. Data on mortality over 9 years were obtained. Multi-state modelling for panel data was used to quantify the effects of the total number of medications and DBI on transitions in cognitive function (not cognitively impaired or cognitively impaired) and simultaneously, progression to death.

Results: After adjustment for confounders, each additional medication used was associated with a 10% greater risk of transitioning from the state of no cognitive impairment to death (95% CI: 1.05, 1.15). Every unit increase in DBI (e.g. exposure to the minimum dose of two anticholinergic or sedative medications) was associated with a 41% greater risk of transitioning from the state of no cognitive impairment to death (95% CI: 1.21, 1.65).

Conclusions: These findings suggest that older community-dwelling men who are not experiencing cognitive impairment may benefit from a medication review before being prescribed additional medications. Future research is warranted to elucidate further the effect of medication use on transitions in cognitive status and progression to death in the cognitively impaired.