Medication use is associated with cognitive deficits in people with multiple sclerosis

People with multiple sclerosis (pwMS) receive medications with anticholinergic and sedative effects that may contribute to cognitive decline. We studied the short-term effect of these medications and polypharmacy on cognitive deficit among pwMS.

This retrospective cross-sectional study of an MS referral centre included pwMS who attended clinic between 1/10/2022 and 31/11/2023 (n = 486). The Drug Burden Index (DBI) and Anticholinergic Effect on Cognition (AEC) scales assessed the cognitive burden of their medications. Polypharmacy was defined as taking ≥5 medications. Objective cognitive performance, specifically processing speed, was assessed using the Symbol Substitution Task (SST), while subjective cognitive deficits were evaluated with the Perceived Deficit Questionnaire-5 (PDQ-5). The associations between medication burden (DBI and AEC) and polypharmacy with cognitive deficits (SST and PDQ-5) were assessed through multivariable regression analysis. Adjustments were made for age, sex, EDSS, years since diagnosis and psychological distress and wellbeing (Mental Health Inventory).

486 pwMS were included in analysis. Medication burden (DBI and AEC) was associated with objective cognitive deficit (SST) (unstandardised B= -1.6, 95 %CI (-2.6, -0.5) with p = 0.003 and B= -0.8, (-1.4, -0.3) with p = 0.003 respectively). Medication burden (DBI and AEC) was furthermore associated with subjective cognitive decline (PDQ-5) (B = 0.8 (0.4, 1.2 with p < 0.001) and B = 0.3 (0.1, 0.5 with p = 0.009)). These associations were also seen for polypharmacy (SST B = -2.3 (-4.4, -0.1 with p = 0.04)) and PDQ-5 (B = 1.1 (0.2, 1.9 with p = 0.016)).

Anticholinergic medications, sedative medications and polypharmacy are negatively associated with cognition in pwMS. Caution should be applied in their prescribing. Research is warranted to investigate how to appropriately approach deprescribing in pwMS.