Plasma HMGB1 levels and physical performance in ICU survivors.

PURPOSE: Physical impairment after critical illness is recognized as a part of the post-intensive care syndrome (PICS). About one third of intensive care unit (ICU) survivors suffer from long-term physical disability, yet the underlying pathophysiological mechanisms remain poorly understood. The pro-inflammatory alarmin, high mobility group box 1 (HMGB1), promotes muscle dysfunction in experimental models, and HMGB1 stays elevated in some patients after ICU discharge. Accordingly, we investigated the relationship between HMGB1 plasma levels and physical performance in ICU survivors. METHODS: Prospective cohort study of 100 ICU survivors from the general ICU at the Karolinska University Hospital, Sweden. Patients returned for follow up at 3 (58 patients) and 6 months (51 patients) after ICU discharge. Blood samples were collected, and a 6-minute walk test (6-MWT), a handgrip-strength test (HST), and a timed-stands test (TST) were performed. RESULTS: Compared to reference values of the different physical tests, 16% of patients underperformed at all tests at 3 months and 12% at 6 months. All test results, except hand-grip strength left, improved significantly over the follow-up period (P < .05). There was no significant association between plasma HMGB1 levels at 3 and 6 months and scores on the three tests (6-MWT, TST, and HST) (P = .50-0.69). CONCLUSION: In this follow-up study of ICU survivors, we found no significant association between plasma HMGB1 levels and physical performance. Additional follow-up studies of HMGB1 plasma levels and muscle function in ICU survivors are still warranted. EDITORIAL COMMENT: HMGB-1, a marker of cell damage and activation, is known to increase in ICU patients. In study participants at 3- to 6-month post-ICU stay, HMGB-1 levels were still elevated, although no association to the primary outcome, physical performance, was found. Mechanisms for failure to recover physical performance post-ICU remain unclear, and investigations into cause of post-intensive care syndrome need to continue. TRIAL REGISTRATIONS: ClinicalTrials.gov identifier NCT02914756.

Lack of clinically relevant correlation between subjective and objective cognitive function in ICU survivors: a prospective 12-month follow-up study.

BACKGROUND: Cognitive impairment and psychological distress are common in intensive care unit (ICU) survivors. Early identification of affected individuals is important, so intervention and treatment can be utilized at an early stage. Cognitive Failures Questionnaire (CFQ) is commonly used to screen for subjective cognitive function, but it is unclear whether CFQ scores correlate to objective cognitive function in this population. METHODS: Between 2014 and 2018, 100 ICU survivors aged 18-70 years from the general ICU at the Karolinska University Hospital, Solna, were included in the study. Out of these, 58 patients completed follow-up at 3 months after ICU discharge, 51 at 6 months, and 45 at 12 months. Follow-up included objective cognitive function testing using the Cambridge Neuropsychological Test Automated Battery (CANTAB) and subjective cognitive function testing with the self-rating Cognitive Failures Questionnaire (CFQ), as well as psychological self-rating with the Post-Traumatic Stress Symptoms Scale-10 (PTSS-10) and Hospital Anxiety and Depression Scale (HADS). RESULTS: The prevalence of cognitive impairment as measured by four selected CANTAB tests was 34% at 3 months after discharge, 18% at 6 months, and 16% at 12 months. There was a lack of significant correlation between CANTAB scores and CFQ scores at 3 months (r = - 0.134-0.207, p > 0.05), at 6 months (r = - 0.106-0.257, p > 0.05), and at 12 months after discharge (r = - 0.070-0.109, p > 0.05). Correlations between CFQ and PTSS-10 scores and HADS scores, respectively, were significant over the follow-up period (r = 0.372-0.710, p ≤ 0.001-0.023). In contrast, CANTAB test scores showed a weak correlation with PTSS-10 and HADS scores, respectively, at 3 months only (r = - 0.319-0.348, p = 0.008-0.015). CONCLUSION: We found no clinically relevant correlation between subjective and objective cognitive function in this cohort of ICU survivors, while subjective cognitive function correlated significantly with psychological symptoms throughout the follow-up period. Treatment and evaluation of ICU survivors' recovery need to consider both subjective and objective aspects of cognitive impairment, and subjective reports must be interpreted with caution as an indicator of objective cognitive function.