The Impact of Dementia on the Clinical Outcome of COVID-19: A Systematic Review and Meta-Analysis.

Liu, Nanyang; Sun, Jiahui; Wang, Xiyuan; Zhao, Ming; Huang, Qianqian; Li, Hao

BACKGROUND The emergence of the coronavirus disease 2019 (COVID-19) has brought large challenges to dementia patients. We reviewed the existing literature on COVID-19 to assess the incidence and mortality of dementia comorbidities in COVID-19 patients. OBJECTIVE To investigate the impact of pre-existing dementia comorbidities on COVID-19. METHODS We searched the PubMed, Embase, and Web of Science databases for patients with preexisting dementia who were diagnosed with COVID-19. The statistical data on the prevalence and mortality of dementia comorbidities were examined. A fixed-or random-effect model was used to calculate the overall pooled risk estimates. Forest plots were generated to show the summarized results. RESULTS A total of 265 articles were retrieved from the three databases. After removing duplicates and performing two screenings, 10 articles were selected for meta-analysis, including 119,218 participants. Overall, the meta-analysis of the 10 studies showed that the incidence of dementia in COVID-19 patients was (R: 9%, [95% CI: 6% to 13%]). Moreover, the meta-analysis of 9 studies showed that the mortality rate of individuals with dementia after being infected with COVID-19 was higher than that of individuals with no dementia (OR: 5.17 [95% CI: 2.31 to 11.59]). Substantial heterogeneity was observed in this meta-analysis. Significant publication bias was also found. CONCLUSION Emerging literature shows that dementia comorbidities are a high risk factor for the prevalence and mortality of COVID-19. Our results should have an impact on preventive interventions and encourage more targeted approaches to prioritize older people with specific risk factors, such as dementia.