Evaluation of cognitive functions and dementia two years after COVID-19 infection

Background: The Coronavirus disease 2019 (COVID-19) causes high morbidity and mortality in the acute period. Some patients with COVID-19 continue to have symptoms for a long time. However, data on the long-term effects of COVID-19, particularly on cognitive disorders is scarce. We aimed to evaluate cognitive functions and dementia in patients who survived two years after discharge from hospital due to acute covid-19 infection. Methods: Two hundred and five patients who had neurological symptoms during index hospitalization for COVID-19 infection were evaluated two years after discharge, and 64 patients were included in the study. According to cognitive assessments, patients were grouped as having normal cognitive levels (48 patients) or impaired cognitive levels (16 patients). Results: The impaired cognitive level was found in 16 (25.0%) of patients who underwent cognitive tests. Age, the pre-existence of neurological comorbidity, mean intensive care unit day, and Beck's Anxiety Inventory and Beck's Depression Inventory scores in the impaired cognitive level group were significantly higher than the normal cognitive level group (p:0.001, p:0.013, p:0.015, p:0.004 and p:0.008). The frequency of cognitive impairment in patients who developed altered mental state during hospitalization was 36.0%, while it was 17.9% in patients with normal mental state. Age, the pre-existence of neurological comorbidity, and anxiety were determined as independent risk factors for impaired cognitive level. In addition, we detected new-onset dementia in 8 patients (12.5%). Conclusion: We found a high frequency of cognitive impairment and new-onset dementia among COVID-19 survivors who developed neurological manifestations during the acute infection phase.