Prevalence, classification, risk factors and outcome impact of delirium in patients with COVID-19: a meta-analysis protocol for systematic review

Introduction Previous studies have shown mixed results that delirium may result in a high risk of adverse clinical outcomes in patients with COVID-19. The aim of this meta-analysis is to summarise the evidence of prevalence, classification, risk factors and outcomes impact of delirium in adult patients with COVID-19. Methods A systematic search will be performed in PubMed, EMBase, ISI Knowledge via Web of Science and preprint databases (MedRxiv and BioRxiv) (from inception until June 2021) to identify all cohort studies concerning delirium in adult patients with COVID-19. The primary outcome will be the prevalence of delirium with different classifications (hyperactive, hypoactive or mixed type). The secondary outcomes will include the association of risk factors and the association with all-cause mortality during hospitalisation. Univariable or multivariable meta-regression and subgroup analyses will be conducted for the study design and patient characteristics. Sensitivity analyses were used to assess the robustness of our results by removing each included study at one time to obtain and evaluate the remaining overall estimates of primary and secondary outcomes. Ethics and dissemination Ethical approval is not an essential element for the systematic review protocol in accordance with the Institutional Review Board /Independent Ethics Committee of Beijing Hospital. This meta-analysis will be disseminated through a peer-reviewed journal for publication. PROSPERO registration number CRD42020224871.