The impact of sepsis, delirium, and psychological distress on self-rated cognitive function in ICU survivors—a prospective cohort study

Background Many intensive care unit (ICU) survivors develop psychological problems and cognitive impairment. The relation between sepsis, delirium, and later cognitive problems is not fully elucidated, and the impact of psychological symptoms on cognitive function is poorly studied in ICU survivors. The primary aim of this study was to examine the relationship between sepsis, ICU delirium, and later self-rated cognitive function. A second aim was to investigate the association between psychological problems and self-rated cognitive function 3 months after the ICU stay. Methods Patients staying more than 24 h at the general ICU at the Karolinska University Hospital Solna, Stockholm, Sweden, were screened for delirium with the Confusion Assessment Method-ICU (CAM-ICU) during their ICU stay. Sepsis incidence and severity were recorded. Three months later, 216 patients received the Cognitive Failures Questionnaire (CFQ), Hospital Anxiety and Depression Scale (HADS), and Post-Traumatic Stress Symptoms-10 (PTSS-10) questionnaires via postal mail. Results One hundred twenty-five patients (60%) responded to all questionnaires. Among respondents, the incidence of severe sepsis or septic shock was 42%. The overall incidence of delirium was 34%. Patients with severe sepsis/septic shock had a higher incidence of delirium, with an odds ratio (OR) of 3.7 (95% confidence interval (CI), 1.7-8.1). Self-rated cognitive problems 3 months post-ICU were found in 58% of the patients. We did not find any association between sepsis or delirium and late self-rated cognitive function. However, there was a correlation between psychological symptoms and self-rated cognitive function, with the strongest correlation between PTSS-10 scores and CFQ scores (r = 0.53; p < 0.001). Conclusions ICU delirium is more common in severely septic/septic shock patients. In our cohort, neither severe sepsis nor ICU delirium was associated with self-rated cognitive function 3 months after the ICU stay. Ongoing psychological symptoms, particularly post-traumatic stress was associated with worse self-rated cognitive function. Psychological symptoms need to be taken into account when assessing cognitive function in ICU survivors.