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 remains 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 three (58 patients) and six months (51 patients) after ICU discharge. Blood samples were collected, and a 6-min walk test (6-MWT), a handgrip-strength test (HST), and a timed-stands test (TST) performed.

RESULTS: Compared to reference values of the different physical tests, 16% of patients underperformed at all tests at three months and 12% at six months. All test results, except hand-grip strength left, improved significantly over the follow-up period (p < 0.05). There was no significant association between plasma HMGB1 levels at three and six months and scores on the three tests (6-MWT, TST, HST) (p = 0.50 - 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.