Association between anticholinergic (atropinic) drug exposure and cognitive function in longitudinal studies among...

With increasing age, adults are often exposed to anticholinergic drugs and are prone to potential adverse drug reaction, among which cognitive impairment. If the short-term cognitive effects of anticholinergic drugs are well established, their long-term cognitive effects have less been studied.

To provide a systematic review of longitudinal studies which assessed the effect of anticholinergic exposure on cognition in individuals over 50 years.

We searched the MEDLINE database for studies with a minimal 6-month follow-up, assessing anticholinergic exposure through a biological measure or a clinical list and reporting at least one cognitive outcome. We used the modified Newcastle-Ottawa scale and additional criteria regarding the anticholinergic exposure to assess studies' methodological quality. Given the heterogeneity of the studies, we performed a systematic review.

Among the 1574 references retrieved, 25 studies were included. Anticholinergic medications were mostly defined through the Anticholinergic Cognitive Burden Scale (n = 14/25). Six studies evaluated baseline drug collection, 14 used longitudinal aggregated measure, and 5 multiple drug exposure measures over time. Seventeen studies assessed anticholinergic burden. Cognitive function was assessed by mild cognitive impairment/dementia incidence (n = 15) or neuropsychological tests (n = 14). Most studies were of poor quality and retrieved discordant results. However, studies with good quality (n = 4) suggested a relationship between anticholinergic drug exposure and/or burden and cognitive function.

Our review suggests a deleterious effect of anticholinergic exposure on mid/long-term cognitive function but should be confirmed in studies with improved methodology. Meanwhile, prescription of anticholinergic drugs should remain cautious.