To evaluate the impact of SARS-CoV-2 infection on the rate of progression to dementia in patients diagnosed with MCI prior to the COVID-19 pandemic.

Older age and vascular risk factors are associated with increased risk for developing more severe forms of COVID-19 and with increased rates of progression to dementia from MCI.  We sought to determine if SARS-CoV-2 infection affects the rate of progression to dementia in a cohort of MCI patients diagnosed prior to the COVID-19 pandemic.

Consecutive MCI patients between June 30, 2019 and February 28, 2020 were identified by chart review in a large academic memory loss clinic. Patients were followed at regular intervals using telehealth and in-person visits. Progression to dementia was confirmed through neuropsychological testing and repeat imaging studies were completed. The impact of COVID-19, demographics and vascular risk factors on the rate progression to dementia was determined using logistic regression and Receiver Operator Characteristic (ROC) analyses. Significance was set at p < 0.05.

There were 118 patients diagnosed with MCI (mean age 75 years, average of 2.8 vascular risk factors). Thirty-three (28%) progressed to dementia over an average follow-up of 18 months. SARS-CoV-2 infection was confirmed by PCR in 18 patients (15.3%), with mild or moderate symptoms in most cases. Progression to dementia was noted in 10/18 (55.6%) patients with versus 23/100 (23%) patients without COVID-19 (p = 0.011). Age and SARS-CoV-2 infection were significantly associated with cognitive decline (AUC 0.724, 95% CI 0.623-0.825, p = 0.0002). On multiple logistic regression, COVID-19 was associated with a 4.39 (95% CI 1.48-13.04) increased odds of progression to dementia after adjusting for age (p = 0.008).

These results indicate that Sars-CoV-2 infection in MCI patients with multiple vascular risk factors increases the risk for progression to dementia at 18 months.