Nutritional and prognostic significance of serum hypothyroxinemia in hospitalized patients with liver cirrhosis

Background/Aims: A variety of severe illnesses can induce changes in thyroid hormone metabolism, leading to findings referred to as “sick euthyroid syndrome”. In several groups of patients the reduction of serum thyroxine concentration (T4), characteristic of the low-T4 variant of sick euthyroid syndrome, has been found to be a good predictor of survival. Although the pathophysiology of hormonal alterations has not yet been defined, nutritional deficits have been suggested to play a role. The study aimed to define the prognostic and nutritional significance of serum thyroxine in liver cirrhosis. Methods: Thyroid hormones and nutritional status were evaluated in a group of 75 consecutive hospitalized patients with cirrhosis, followed-up clinically for 12 months. Results: A low-T4 variant of sick euthyroid syndrome was found in 23 of the 75 enrolled patients with cirrhosis (30.6%). Serum T4, but not serum T3, correlated with mid-arm muscle circumference (p<0.01), an indicator of muscle protein compartment. While both serum T3 and T4 correlated directly with serum proteins and inversely with Child-Pugh score, only T4 was predictive of outcome. Patients with the low-T4 variant of sick euthyroid syndrome showed significantly lower short- and long-term survival rates compared to those with normal serum T4 concentrations (p<0.008 at 3 months, p<0.001 at 6 months and 1 year). A multivariate analysis using the proportional hazards Coxʹs regression procedure showed that serum T4, but not serum T3 or nutritional parameters, improves the prognostic capacity of Child-Pugh score (p<0.01). Conclusions: These data indicate that the low T4-variant of sick euthyroid syndrome distinguishes a subgroup of patients with cirrhosis at risk for decreased survival. The inclusion of T4 in the Child-Pugh score, by improving its prognostic power, may otpimize the selection of patients with advanced cirrhosis to receive specific therapy such as transplantation.