The Diagnosis and Treatment of Low T3 Syndrome in Neurocritical Patients

Background: Low serum T3 level is considered as a strong predictor of mortalities and poor prognosis in critical care patients. Few reports, however, focus on neurocritical patients. The application of hormone replacement therapy (HRT) in neurocritical patients with low T3 syndrome also remains controversial. We studied the role of low T3 state as a predictor in neurocritical patients and presented our experience of HRT from a single-center perspective.Methods From January 2012 to October 2018, a total of 32 neurocritical patients with low T3 syndrome were admitted to the neuro-intensive care unit (NICU) of Peking Union Medical College Hospital. Among them, 18 (56.25%) patients received HRT (HRT group) since the diagnosis of low T3 syndrome, while the other 14 (43.75%) patients did not (non-HRT group). We collected the clinical baseline and laboratory data of all the patients and conducted follow-up from 3 to 72 months. Overall survival was assessed by the Kaplan-Meier curve and compared by the log-rank test. Univariate and multivariate regression analysis was applied to estimate the prognostic power of HRT for mortality. We also performed the Mann-Whitney U test or t-test to assess the influence of HRT on the final neurological function.Results The cohort consists of 32 patients, with an average Glasgow Coma Scale (GCS) of 6.41 (HRT=6.44±3.14, non-HRT=6.36±2.06). The neurocritical events include postoperative complications (n=18), traumatic brain injury (n=8), and spontaneous intracerebral hemorrhage (n=6). A total of 15 (46.87%) deaths were recorded (HRT=7, non-HRT=8). In the HRT group, the low T3 situation in 5 patients (33.3%) was corrected and 10 (66.7%) were not. It turns out that the overall survival rate of the non-HRT group was significantly lower than that of the HRT group (P=0.034, 16.445 vs. 47.470 months). The non-HRT group has 3.322 times the mortality risk of the HRT group, according to univariate regression analysis, while the multivariate regression analysis showed no significant difference in mortality risk between the two groups (P=0.087, HR=0.340 95%CI 0.099-1.172). There was no significant difference in the short and long-term effects of HRT on neurological function (short-term GCS P=0.587, long-term GCS P=0.419, long-term GOS P=0.419).Conclusion Low T3 syndrome can significantly influence the prognosis of neurocritical patients. Therefore much attention should be paid to the changes in serum T3 level during treatment. Although it is unclear to what extent can HRT improve the short or long-term outcome of neurological function, it can significantly benefit the survival of neurocritical patients.