Small longitudinal study of serum anticholinergic activity and cognitive change in community-dwelling older adults

The discriminative ability of serum anticholinergic activity (SAA) to differentiate between older individuals with stable versus deteriorating cognition remains undetermined. We examined the relationship between SAA changes, the presence or absence of a mild neurocognitive disorder, age and anticholinergic medication over a one-year time period.

SAA at baseline and one-year follow-up was measured for 121 older adults without dementia. Participants were classified at both timepoints as being cognitively intact or meeting the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for a mild neurocognitive disorder. Medications were assessed according to the Anticholinergic Cognitive Burden (ACB) scale.

SAA changes did not discriminate between individuals whose cognition remained stable versus those with improvement or decline (H[3]=0.725, p=0.867). SAA change did not vary between age groups, and could not reliably differentiate between individuals on ACB medication or not.

While SAA does not appear to be a valid biomarker for cognitive decline, longitudinal studies with a larger sample size and longer duration are required to confirm this finding.