Relationship between general anesthesia and Alzheimer disease: A protocol for a systematic review and meta-analysis

BACKGROUND: Alzheimer disease (AD) entails a long-term progressive decline in the cognitive ability to think and remember, and it has become a major concern for patients receiving surgery and anesthesia. However, studies investigating the relationship between general anesthesia and AD have yielded inconsistent results. Therefore, we plan to perform a systematic review and meta-analysis to determine the relationship between general anesthesia and AD, and to verify whether general anesthesia is an independent risk factor for AD. METHODS: A systematic and comprehensive search will be performed using MEDLINE, EMBASE, and Google scholar from their inception to August 2017. Peer-reviewed cohort and case-control studies including nested case-control studies reporting the relationship between general anesthesia and AD will be eligible for inclusion. The quality of included studies will be assessed using the Newcastle–Ottawa scale. Heterogeneity of estimates across studies as well as publication bias will be assessed. This systematic review and meta-analysis will be performed according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines and reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. All statistical analyses will be conducted using the Stata SE version 15.0. RESULTS: The results of this systematic review and meta-analysis will be published in a peer-reviewed journal. CONCLUSION: Our study will provide the evidence for the relationship between general anesthesia and dementia. The review will benefit patients and anesthesiologists, surgeons, and policymakers. ETHICS AND DISSEMINATION: Ethical approval and informed consent are not required, as the study will be a literature review and will not involve direct contact with patients or alterations to patient care. TRIAL REGISTRATION: The protocol for this review has been registered in the PROSPERO network (registration number: CRD42017073790).