Cognitive effects of reducing anticholinergic drug burden in a frail elderly population: a randomized controlled trial

Abstract

Background: Observational studies report a relationship between anticholinergic drug scale (ADS) score and cognitive function. This study investigated whether a reduced ADS score improved cognitive function in a frail elderly population.

Methods: This randomized, controlled, single-blinded trial, recruited long-term residents with an ADS score of greater than or equal to 3 from 22 nursing homes in Norway. The participants were randomly allocated (1:1) to intervention or control. The intervention was a pharmacist-initiated reduction of ADS score after multidisciplinary drug reviews. Primary end point was Consortium to Establish a Registry for Alzheimer's Disease 10-wordlist test for immediate recall. Secondary end points were Mini-Mental Sate Examination, delayed recall and recognition of words, saliva flow, and serum anticholinergic activity (SAA).The participants were retested after 4 and 8 weeks, and the study groups were compared after adjusting for baseline differences.

Results: Eighty-seven patients were included. The median ADS score was reduced by 2 units (p < .0001) in the intervention group and remained unchanged in the control group. After 8 weeks, the adjusted mean difference in immediate recall was 0.54 words between the intervention and control group (95% confidence interval [CI]: -0.91, 2.05; p = .48). The study groups did not differ significantly in any of the other cognitive end points, salvia flow, or SAA at either follow-up (p > .18).

Conclusion: Pharmacist-initiated drug changes significantly reduced ADS score but did not improve cognitive function in nursing home residents. Moreover, the drug changes did not reduce SAA or mouth dryness significantly, which might indicate limited applicability of the ADS score to prevent prescription risks in this population.