Differential T4 Degradation Pathways in Young Patients with Preterminal and Terminal Renal Failure

Abstract

The aim of this study is to analyze thyroid hormone parameters in large homogenous patient cohorts with preterminal (stage 4) and terminal (stage 5) renal failure in an area of low iodine intake. Thyroid parameters were measured in healthy controls (n=48), patients with preterminal renal failure (n=48) and patients with terminal renal failure undergoing hemodialysis (n=288). All patients were assessed by measurement of TSH, T4, T3, fT4, rT3, Tg and TPO-antibodies. There was a significant decrease of T4 and fT4 from healthy controls to patients with preterminal renal failure and to patients with terminal renal failure. T3 showed a decrease from healthy controls to patients with preterminal renal failure and to patients with terminal renal failure (1.54+/-0.06 microg/l VS. 1.05+/-0.05 microg/l VS. 1.09+/-0.23 microg/l, p<0.001 VS. controls). rT3 was significantly decreased in patients with terminal renal failure (0.24+/-0.01 microg/l VS. 0.25+/-0.02 microg/l VS. 0.16+/-0.01 microg/l, p<0.001). The rT3/T3 ratio was significantly elevated in patients with preterminal renal failure (p<0.01). TSH concentrations were in the normal range in all groups. Our data suggest different T4 degradation pathways in patients with preterminal and terminal renal failure.