Numerous abnormalities of thyroid hormones in end-stage renal disease (ESRD) 
have been described. Our aim was to analyze the impact of these abnormalities on 
survival. In 167 hemodialyzed ESRD patients, TSH and thyroid hormone levels (T4, 
fT4, T3, fT3, rT3) were determined. The patients were then prospectively 
followed up for up to 5 years and the possible impact of any observed 
abnormalities on their mortality was studied. Only 16.8 % patients had all six 
tests within the reference range. The pattern of nonthyroidal illness syndrome 
was found in 56.3 %. Low T3 was particularly common (44.3 %), and clearly 
associated with increased 6- and 12-month mortality and decreased overall 
survival (log rank test, P=0.007). Independent of T3 levels (Spearman 
correlation, NS), increased rT3 was more frequently observed (9.9 %) than 
expected from the literature, and was also related to increased mortality and 
decreased survival (log rank test, P=0.021). Increased rT3 may be more common in 
ESRD patients than previously described, and together with decreased T3 it may 
serve as an indicator of poor prognosis in subsequent months.