Long COVID psychiatric sequelae, biochemical markers & tau protein: A 3-year follow-up study

Background: A significant percentage of COVID-19 survivors experience long-term neuropsychiatric and physical issues. Baseline biochemical parameters may be linked to these psychiatric sequelae.

Aim: This study aimed to explore the association between baseline biochemical parameters and psychiatric outcomes in COVID-19 survivors three years post-infection.

Methods: We enrolled 100 COVID-19 survivors (mild and severe) and conducted comprehensive biochemical, endocrine, and psychiatric evaluations using peripheral blood samples and psychological assessments (GAD-7, PHQ-9, MoCA, ISI) at 3 years of follow-up assessment. Tau protein levels were measured at follow-up. Baseline biochemical data were retrieved from medical records, and linear regression analysis was used to identify predictors of psychiatric symptoms.

Results: HbA1c levels were significantly higher in severe cases at baseline (7.08±2.11 vs. 6.22±1.62) and follow-up (6.54±2.01 vs. 5.78±1.07). Severe cases also had elevated p-tau protein levels (99.34±120 vs. 59.7 ± 45.9). Low sodium and potassium at baseline were negatively correlated with anxiety and depression scores, predicting anxiety (8 %) and depressive symptoms (6 %) in mild cases. Low calcium predicted depressive (10 %) and anxiety symptoms (7.5 %) across all cases.

Conclusion: COVID-19 survivors with a history of severe infection displayed higher p-tau and HbA1c levels, indicating potential new-onset diabetes and neuronal damage. Electrolyte imbalances, particularly sodium, potassium, and calcium, during acute infection predicted long-term psychiatric symptoms, including depression, anxiety, and somatization.