Characterizing long-COVID brain fog: a retrospective cohort study

Area of Science:

• Neurology
• Immunology
• Infectious Diseases

Background:

• Post-COVID condition (PCC) frequently involves neurocognitive impairment, affecting individuals of all ages.
• Risk factors, biomarkers, and clinical progression of PCC-related neurocognitive symptoms remain poorly understood.

Purpose of the Study:

• To compare clinical risk factors, biochemical markers, and longitudinal trajectories in patients with and without neurocognitive impairment (NC+ vs. NC-) within a PCC cohort.
• To identify independent risk factors associated with neurocognitive impairment in PCC patients.

Main Methods:

• Retrospective longitudinal cohort study using a provincial database of confirmed PCC patients.
• Cross-sectional analysis of demographic, clinical, and biochemical data at initial consultation.
• Multivariate regression to identify risk factors for neurocognitive impairment.
• Longitudinal assessment of health-related quality of life (HR-QoL) using Eq-5D-5L-vas scores.

Main Results:

• Independent risk factors for neurocognitive impairment included being female, experiencing milder acute infection, and having pre-existing mental health diagnoses.
• Patients with neurocognitive impairment (NC+) showed lower IgG, IgG1, and IgG3 levels compared to NC- patients.
• The NC+ cohort reported poorer HR-QoL at 8 months post-infection, with gradual improvement over 20 months.

Conclusions:

• Neurocognitive impairment is a severe PCC phenotype with distinct risk factors, immune system aberrations, and a protracted recovery.
• Early identification of individuals at risk for neurocognitive impairment is crucial for timely and intensive medical intervention.