Dementia linked to greater risk for COVID-19 breakthrough infections, hospitalizations

Those diagnosed with dementia faced a greater risk for COVID-19 breakthrough infections and hospitalizations than those without, according to a study published in Alzheimer’s & Dementia.

“An estimated 5.8 million Americans 65 years of age or older and 50 million people worldwide are living with Alzheimer’s and other dementias,” Lindsey Wang, of the Center for Artificial Intelligence in Drug Discovery at the Case Western Reserve University School of Medicine in Cleveland, and colleagues wrote. “Strong risk factors for cognitive decline and dementia include ... psychiatric disorders, many of which are also demonstrated risk factors for COVID-19 infection and adverse outcomes.”

Wang and colleagues sought to acquire data on COVID-19 breakthrough infections in vaccinated patients previously diagnosed with dementia in the United States.

The retrospective cohort study included 262,847 older adults (mean age, 73.8 years) who were vaccinated between December 2020 and August 2021, with no COVID-19 infection prior to vaccination.

Among the participants, 4,385 had been diagnosed with mild cognitive impairment, 2,764 had a prior Alzheimer’s disease diagnosis, 1,244 had a diagnosis of vascular dementia, 259 were diagnosed with Lewy body dementia, and 229 had a diagnosis of frontotemporal dementia.

Rates of new cases of COVID-19 infection, measured by cases perperson-day, in the vaccinated population were examined and stratified by age, gender and race. Separate analyses were done for dementia subtypes and non-dementia.

Kaplan-Meier analysis was performed to estimate the probability of hospitalizations. Comparison of outcomes between patients with versus without breakthroughs were made using Cox proportional hazards model.

Results showed that, among fully vaccinated patients with dementia, the overall risk of COVID-19 breakthrough infections ranged from 8.6% to 12.4%. Patients with dementia were at increased risk for breakthrough infections compared with patients without dementia, with the highest odds for patients with Lewy body dementia (adjusted OR, 3.06; 95% CI, 1.45-6.66), followed by vascular dementia (aOR, 1.99; 95% CI, 1.42- 2.80), AD (aOR, 1.53; 95% CI 1.22-1.92), and mild cognitive impairment (aOR, 1.78; 95% CI 1.51-2.11).

Data additionally revealed the incidence rate of breakthrough infections among fully vaccinated patients with dementia increased since December 2020 and accelerated after May 2021. The overall risk for hospitalization after breakthrough infections in patients with dementia was 39.5% for AD, 46.2% for vascular dementia, and 30.4% for mild cognitive impairment.

“Future studies are warranted, including continuing to evaluate breakthrough infections in vaccinated patients with dementia, especially with the emergence of different virus variants,” Wang and colleagues wrote.