Predictive value of thyroid hormone assessment in septic patients in comparison with C-reactive protein

Introduction

Thyroid dysfunction is associated with mortality in critically ill patients. We investigated the predictive value of the thyroid hormone compared to CRP in septic patients.

Methods

80 patients were included in a prospective, randomized study done in the critical care department.

Results

FT3, FT4, and TSH levels on the fifth day were below the normal range in 61.3%, 31.2%, and 23.8% patients respectively. There was a significant decrease in the FT3 level on admission compared to the fifth day (p < 0.001). By comparison of thyroid hormone levels in patients with sepsis, severe sepsis and septic shock; we found the mean level of FT3 was lower in patients with septic shock (1.3 ± 0.4 pg/ml) and severe sepsis (1.7 ± 0.2 pg/ml) as compared to patients with sepsis (2.4 ± 1.2 pg/ml). The mean FT3 level increased in survivors (2.9 ± 1.03 pg/ml) compared to non survivors (1.9 ± 0.89 pg/ml) (p < 0.001). Correlation of FT3 on the 5th day to CRP (r = −0.332, p = 0.039), FT3 on 5th day to IL-6 (r = −0.339, p = 0.035) in non survivors. Correlation of FT3 on the 5th day to APACHE II (r = −0.359, p = 0.025) and SOFA score (r = −0.427, p = 0.007). ROC curves indicated that FT3 on the 5th day had the greatest power for predicting ICU mortality (sensitivity 87.2% and specificity 73.2%). CRP (sensitivity 100% and specificity 92.7%) is a better tool than IL-6 (sensitivity 92.3% and specificity 80.5%) in predicting mortality in sepsis.

Conclusion

FT3 levels were negatively correlated to CRP and IL-6 levels as well as APACHE II, SOFA scores. FT3 may be used as a marker of disease severity and a predictor of mortality.