Effect of Anticholinergic Medications on the Risk of Dementia: A Systematic Review and Meta-analysis Protocol.

Introduction: The most frequent dementia is senile dementia or Alzheimer disease. Meanwhile, anticholinergic drugs can potentially modify the risk factors. As different studies have achieved dissimilar results and the clinical findings of these interventions have not been conclusive, the objective of this research will be to evaluate the effect of anticholinergic drugs on the risk of dementia.

Methods: This systematic review and meta-analysis with no language limitation will search WoS, EMBASE, and MEDLINE via PubMed, Scopus, ProQuest electronic databases, and Grey Literature between December 15, 1988, and December 15, 2021. Our search strategy with suitability criteria covers cohort, case-control, nested case-control, randomized, and non-randomized clinical trial studies evaluating the effect of anticholinergic drugs on the risk of dementia. Two authors will independently implement the selection phase, data extraction, and quality assessment. The reviewers will evaluate the risk of bias using the Newcastle-Ottawa, Cochrane risk of bias tool and ROBINS-I (risk of bias in non-randomized studies - of interventions) quality assessment scale. We will conduct a meta-analysis with a random or fixed effect model according to the severity of methodological heterogeneity. The results will be presented via the forest plot for the final studies' data composition, demonstrating the separated and combined frequency and their corresponding 95% CIs, summary tables, and narrative summaries.

Conclusion: The results of different studies in this field are various. This study's findings and other studies will help physicians and other health professionals before prescribing these drugs. Older people, especially those with polypharmacy, should be carefully assessed for the risk of dementia, Alzheimer or a variety of cognitive disorders.