Risk of COVID‐19 infection, hospitalization, and mortality in older adults with versus without dementia during the first wave of COVID‐19 pandemic: A Swedish nationwide study

Abstract

AbstractBackgroundThe difference in the risk of COVID‐19 infection, hospitalization, and mortality between older adults with and without dementia is understudied. This study aimed to compare the risk of COVID‐19 infection, hospitalization, and mortality between dementia patients aged 65 years and above with non‐dementia counterparts, during the first wave of COVID‐19 in Sweden.MethodThis observational study included data from 2,031,069 older adults in Sweden (2015‐2020), based on the linkage of various Swedish nationwide registries. Outcomes included COVID‐19 infection, hospitalization, and mortality during the first wave of COVID‐19 in Sweden (from 01 March to 31 August 2020). We performed flexible parametric survival models to investigate the association between outcomes and having dementia, adjusted by age at the start of the first COVID‐19 wave in Sweden, sex, Charlson Comorbidity Index, hospital frailty risk score, and other sociodemographic covariates. Subgroup analyses were conducted on age groups, sex and living arrangement (nursing homes versus community dwelling).ResultCompared to the non‐dementia group (n = 1,965,194), the dementia patients (n = 65,875) were older (median 82.0 years, IQR 77.0‐87.0 versus 74.0 years, IQR 69.0‐79.0), had higher proportions of women (59.1% versus 53.2%), living alone (60.0% vs 47.5%), living in nursing homes (39.0% vs. 2.2%) and having lower socioeconomic positions. Comorbidities were more common among the dementia group, as shown by their higher Charlson Comorbidity Index or hospital frailty risk score. Our main analyses showed the dementia group was at higher risks of COVID‐19 infection (hazard ratio (HR) 3.13, 95% confidence interval (95% CI) 3.00‐3.27), COVID‐19 hospitalization (HR 1.32, 95% CI 1.23‐1.42) and COVID‐19 death (HR 4.01, 95% CI 3.75‐4.29), compared to the non‐dementia group. The dementia group living in nursing homes had higher risks of COVID‐19 infection and death, but a lower likelihood of COVID‐19 hospitalization (HR 0.79, 95% CI 0.68‐0.92), compared to the non‐dementia group.ConclusionWe confirmed that the older adults with dementia had higher risks of COVID‐19 infection, hospitalization, and mortality, than those without dementia during the first wave of COVID‐19 in Sweden. However, dementia patients living in nursing homes were at a lower risk of COVID‐19 hospitalization, compared to older adults without dementia.