Impact of SARS-CoV-2 infection on the progression of Alzheimer's disease: A prospective cohort study

Background SARS-CoV-2 infection is associated with neurological sequelae and may accelerate Alzheimer's disease (AD) progression through neuroinflammation and protein aggregation. However, longitudinal evidence regarding the cognitive impact of COVID-19 in patients with AD remains scarce, and this interaction requires further clarification. Objective To explore whether COVID-19 accelerates cognitive decline in patients with AD. Methods A total of 120 participants were enrolled, including 63 in the COVID-19 group and 57 in the non-COVID-19 group. The primary outcomes were disease decline and disease deterioration over three months, assessed using CDR-SB. Disease deterioration indicated clinically meaningful worsening, whereas disease decline captured subtler progression. Multivariable logistic regression adjusted for demographic, clinical, lifestyle, genetic, and disease severity factors. Overlap-Weighted Propensity Score Matching was additionally performed to reduce confounding during the 3-month follow-up. Results COVID-19 significantly increased the risk of disease decline (OR = 10.39, 95% CI:3.87 to 27.87, p < 0.001) and disease deterioration (OR = 10.37, 95% CI: 2.71 to 39.65, p = 0.001). APOE ε4 carrier status was associated with a higher risk of deterioration (OR = 1.72), while those with unknown APOE status exhibited an even greater risk (OR = 5.20, 95% CI:1.32 to 20.53, p = 0.019). Secondary analyses confirmed that COVID-19 patients experienced significantly greater increases in CDR-SB scores compared to non-COVID-19 patients. Conclusions SARS-CoV-2 infection was associated with greater short-term cognitive worsening over a three-month period in patients with AD, underscoring its potential public health relevance and the need for early surveillance to guide timely clinical management.