Prevalence of dementia and its impact on mortality in patients with coronavirus disease 2019: A systematic review and meta-analysis

Aim In this systematic review and meta-analysis, we aimed to evaluate the prevalence of dementia in patients with COVID-19 and its association with mortality. We also aimed to discover whether age, sex and other comorbidities might affect the association between dementia and mortality. Methods We carried out a systematic literature search using PubMed, SCOPUS, EuropePMC and the Cochrane Central Database. The outcome of interest was mortality, defined as clinically validated mortality/death/non-survivor in the studies. The pooled effect estimates were presented as odds ratio and adjusted odds ratio. Results A total of 56 577 patients from 10 studies were included. The prevalence of dementia in this pooled analysis was 10% (7-13%). Dementia was associated with increased mortality in both pooled unadjusted (odds ratio 2.80, 95% CI 1.85-4.24, P < 0.001; I-2 = 93.7%) and adjusted effect estimates (adjusted odds ratio 1.80, 95% CI 1.45-2.24, P < 0.001; I-2 = 72.9%). The association between dementia and mortality was influenced by age (coefficient -0.047, P < 0.001) and hypertension (coefficient -0.009, P = 0.020). Conclusions This study showed that dementia was associated with increased mortality in COVID-19 patients. The association was affected by age and comorbidities. Geriatr Gerontol Int 2020; center dot center dot: center dot center dot-center dot center dot.