Risk factors for delirium among hospitalized adults with COVID-19: A systematic review and meta-analysis of cohort studies

This study aims to systematically assess the risk factors, the overall strength of association, and evidence quality related to delirium among adults hospitalized with COVID-19. A comprehensive search was conducted in thirteen databases from inception to February 10, 2023. The included databases were thoroughly searched, including PubMed, Web of Science, Proquest, Ovid MEDLINE, CINAHL, Scopus, the Cochrane Library, FMRS, Wanfang Database, Chinese Biomedical Database (CBM), China Knowledge Resource Integrated Database (CNKI), Weipu Database (VIP), and Embase. The search was limited to articles published in English and Chinese. The selected studies were screened, data were extracted, and the quality was evaluated using the Newcastle-Ottawa Scale. Meta-analysis was performed using RevMan 5.4 software. The certainty of the evidence was assessed using the GRADE criteria. A total of 22 cohort studies with a sample size of 11,957 individuals were included in the analysis. Among these studies, 20 were of high quality, while the remaining 2 were of moderate quality. The risk factors that showed the strongest association with delirium were prior cognitive impairment (including dementia), mechanical ventilation, and ICU admission. Age, frailty (Clinical Frailty Scale score > 5), antipsychotic use, benzodiazepine use, neutrophil-to-lymphocyte ratio, and vasopressor use were identified as moderate risk factors for delirium. According to the GRADE evaluation, ICU admission, benzodiazepine use, neutrophil-to-lymphocyte ratio, and vasopressor use had a high-quality body of evidence, while antipsychotic usage had an intermediate-quality body of evidence. All other risk factors had a low-quality body of evidence. This systematic review and meta-analysis identified several medium- to high-intensity risk factors for delirium in hospitalized adults with COVID-19. ICU admission, benzodiazepine usage, neutrophil-to-lymphocyte ratio, antipsychotic use, and vasopressor use were associated with delirium and were supported by medium- to high-quality evidence. These findings provide healthcare professionals with an evidence-based basis for managing and treating delirium in hospitalized adults with COVID-19.