Cognitive Impairment and Fatigue in Intensive Care Patients Three Months after the Acute Phase of COVID-19 Infection: Follow-Up with Focus on Differences between the First and Later Waves of the Pandemic

Background. Cognitive symptoms and fatigue may persist after intensive care unit (ICU) care. It remains unclear whether post-COVID-19 symptoms are related to ICU care itself or the infection. Objective. The primary aim was to investigate the prevalence of residual cognitive impairment and fatigue after ICU care for COVID-19 and to evaluate the importance of demographic factors. A secondary aim was to investigate whether differences in ICU treatment between the first wave (March 2020 to July 2020) and later waves (August 2020 to January 2021) of COVID-19 were associated with differences in cognitive outcomes. Design. Prospective follow-up study. Subjects/Patients. Swedish cohort of COVID-19 patients referred from ICU. Methods. Montreal Cognitive Assessment (MoCA), Multidimensional Fatigue Inventory-20 (MFI-20), Hospital Anxiety and Depression Scale, Insomnia Severity Scale, and RAND-36 were administered approximately three months after admission to ICU. Mann-Whitney tests were used to investigate group differences, and multiple linear regression was used to investigate the relationship between fatigue and covarying factors. Results. 71 patients completed follow-up, and 60 patients underwent a cognitive screening of which 30% had MoCA scores indicative of cognitive impairment (<26 points). Higher age was related to poorer cognitive performance. Patients scored above the normal range on all subscales on the MFI-20. There was a significant difference in length of ICU stay between wave one and following waves, but no statistically significant differences emerged on cognitive screening. Intubated patients' fatigue ratings were lower compared to those not intubated-despite longer ICU stay. No difference in MoCA scores emerged between patients who were, or were not, intubated. Conclusion. Cognitive impairment and fatigue were evident in patients three months after a severe COVID-19 infection, but global cognitive functioning was not related to ICU length of stay. Less fatigue among patients who had been intubated merits further investigation.