Risk factors of long-term brain health outcomes after hospitalization for critical illness

Background
Brain health may be impaired years after hospitalization for critical illness, and similar impairments occur after hospitalization for COVID-19. However, it remains unclear which patients are most likely to experience long-term brain health consequences and whether these adverse events differ between non-COVID critical illness and COVID-19.

Methods
In a prospective observational study, we enrolled patients hospitalized for (1) non-COVID critical illness (pneumonia, myocardial infarction, or ICU-requiring conditions) or for (2) COVID-19, from March 2020 to June 2021. Brain health was assessed at 18-month follow-up with cognitive, psychiatric, and neurological tests. We used both logistic regression and prediction models to test for associations between different variables and brain health.

Results
We included 245 patients: 125 hospitalized for non-COVID critical illness and 120 for COVID-19 [mean age 61.2 (± 13.6) years, 42% women]. Brain health was impaired in 76% of patients (72% critical illness, 81% COVID-19; p = 0.14) at 18-month follow-up. The strongest predictive factors associated with impaired brain health were education < 13 years, age ≥ 70 years, and neuroticism traits in the best performing model (AUC = 0.63). When analyzing non-COVID critical illness and COVID-19 patients separately, low education was one of the few factors associated with impaired brain health in both groups (AUCs for best models: 0.66 and 0.69).

Conclusion
Brain health is comparably impaired after hospitalization for critical illness and COVID-19. Factors like higher age, lower education and neuroticism may help identifying vulnerable individuals, who could benefit from close monitoring to improve brain health after critical illness, regardless of the underlying disease etiology.