Objectives To estimate the association between the duration and level of exposure to different classes of anticholinergic drugs and subsequent incident dementia. Design Case-control study. Setting General practices in the UK contributing to the Clinical Practice Research Datalink. Participants 40 770 patients aged 65-99 with a diagnosis of dementia between April 2006 and July 2015, and 283 933 controls without dementia. Interventions Daily defined doses of anticholinergic drugs coded using the Anticholinergic Cognitive Burden (ACB) scale, in total and grouped by subclass, prescribed 4-20 years before a diagnosis of dementia. Main outcome measures Odds ratios for incident dementia, adjusted for a range of demographic and health related covariates. Results 14 453 (35%) cases and 86 403 (30%) controls were prescribed at least one anticholinergic drug with an ACB score of 3 (definite anticholinergic activity) during the exposure period. The adjusted odds ratio for any anticholinergic drug with an ACB score of 3 was 1.11 (95% confidence interval 1.08 to 1.14). Dementia was associated with an increasing average ACB score. When considered by drug class, gastrointestinal drugs with an ACB score of 3 were not distinctively linked to dementia. The risk of dementia increased with greater exposure for antidepressant, urological, and antiparkinson drugs with an ACB score of 3. This result was also observed for exposure 15-20 years before a diagnosis. Conclusions A robust association between some classes of anticholinergic drugs and future dementia incidence was observed. This could be caused by a class specific effect, or by drugs being used for very early symptoms of dementia. Future research should examine anticholinergic drug classes as opposed to anticholinergic effects intrinsically or summing scales for anticholinergic exposure. Trial registration Registered to the European Union electronic Register of Post-Authorisation Studies EUPAS8705.

Objectives: to determine the effect of drugs with anti-cholinergic properties on relevant health outcomes. Design: electronic published and unpublished literature/trial registries were systematically reviewed. Studies evaluating medications with anti-cholinergic activity on cognitive function, delirium, physical function or mortality were eligible. Results: forty-six studies including 60,944 participants were included. Seventy-seven percent of included studies evaluating cognitive function (n = 33) reported a significant decline in cognitive ability with increasing anti-cholinergic load (P < 0.05). Four of five included studies reported no association with delirium and increasing anti-cholinergic drug load (P > 0.05). Five of the eight included studies reported a decline in physical function in users of anti-cholinergics (P < 0.05). Three of nine studies evaluating mortality reported that the use of drugs with anti-cholinergic properties was associated with a trend towards increased mortality, but this was not statistically significant. The methodological quality of the evidence-base ranged from poor to very good. Conclusion: medicines with anti-cholinergic properties have a significant adverse effect on cognitive and physical function, but limited evidence exists for delirium or mortality outcomes.

Peer reviewed article authored by (Noll Campbell, Malaz Boustani, Tony Limbil, Carol Ott, et al.). Read article or submit your manuscript for publishing.