Predictive value of thyroxine for prognosis in pediatric septic shock: a prospective observational study

Background Thyroid hormone plays an important role in the adaptation of metabolic function to critically ill. The relationship between thyroid hormone levels and the outcomes of septic shock is still unclear. The aim of this study was to assess the predictive value of thyroid hormone for prognosis in pediatric septic shock. Methods We performed a prospective observational study in a pediatric intensive care unit (PICU). Patients with septic shock were enrolled from August 2017 to July 2019. Clinical and laboratory indexes were collected, and thyroid hormone levels were measured on PICU admission. Results Ninety-three patients who fulfilled the inclusion criteria were enrolled in this study. The incidence of nonthyroidal illness syndrome (NTIS) was 87.09% (81/93) in patients with septic shock. Multivariate logistic regression analysis showed that T4 level was independently associated with in-hospital mortality in patients with septic shock (OR: 0.965, 95% CI: 0.937-0.993, p = 0.017). The area under receiver operating characteristic (ROC) curve (AUC) for T4 was 0.762 (95% CI: 0.655-0.869). The cutoff threshold value of 58.71 nmol/L for T4 offered a sensitivity of 61.54% and a specificity of 85.07%, and patients with T4 < 58.71 nmol/L showed high mortality (60.0%). Moreover, T4 levels were negatively associated with the pediatric risk of mortality III scores (PRISM III), lactate (Lac) level in septic shock children. Conclusions Nonthyroidal illness syndrome is common in pediatric septic shock. T4 is an independent predictor for in-hospital mortality, and patients with T4 < 58.71 nmol/L on PICU admission could be with a risk of hospital mortality.