Impact of dementia on outcomes in older patients with COVID-19: A nationwide inpatient sample analysis

Objective

Although existing evidence suggests a potential link between dementia and adverse outcomes in patients with COVID-19, a definitive relationship is uncertain. This study aimed to evaluate the impact of dementia on in-hospital outcomes of patients in the presence of COVID-19.

Methods

The US Nationwide Inpatient Sample (NIS) was searched for patients 65 years or older hospitalised for COVID-19 in 2020. Patients were categorised into those with and without dementia before COVID-19 infection. Outcomes included in-hospital mortality, discharge to long-term care, length of stay (LOS), total hospital costs and complications. Propensity score matching (PSM) was used to balance the baseline characteristics between the groups. Regression analyses were performed to assess the associations between dementia and outcomes.

Results

After PSM, 42,214 patients were included, with equal distribution of most study variables between groups. Dementia was associated with increased in-hospital mortality (adjusted odds ratio [aOR] = 1.17, 95% confidence interval [CI]: 1.11–1.23), discharge to long-term care facilities (aOR = 4.0, 95% CI: 3.8–4.2), occurrence of any complications (aOR = 1.33, 95% CI: 1.27, 1.38), 1.12 days longer LOS (95% CI: .93–1.31) and 2.68 thousand USD higher total hospital costs (95% CI: .72–4.64). For specific complications, dementia was associated with significantly increased risks of acute respiratory distress syndrome (aOR = 1.19, 95% CI: 1.14–1.24) encephalitis, myelitis and encephalomyelitis (aOR = 4.60, 95% CI: 1.33–15.93), as well as delirium, respiratory failure and acute kidney injury.

Conclusion

Dementia is associated with worse outcomes of older patients with COVID-19.