BACKGROUND: Serum free triiodothyronine (fT3) level is suggested to be a risk 
factor for mortality in unselected dialysis patients. We investigated the 
prognostic value of serum fT3 levels and also low-T3 syndrome on overall 
survival in a large cohort of hemodialysis (HD) patients with normal 
thyroid-stimulating hormone levels.
METHODS: A total of 669 prevalent HD patients were enrolled in the study. Serum 
fT3 level was measured by enzyme immune assay in frozen sera samples at the time 
of enrollment. Overall mortality was assessed during 48 months of follow-up.
RESULTS: Baseline fT3 was 1.47 ± 0.43 (0.01-2.98) pg/ml, and low-T3 syndrome was 
present in 71.7% of the cases. During a mean follow-up of 34 ± 16 months, 165 
(24.7%) patients died. fT3 level was a strong predictor for mortality in crude 
and adjusted Cox models including albumin or high-sensitivity C-reactive protein 
(hs-CRP). Further adjustment for both albumin and hs-CRP made the impact of fT3 
on mortality disappear. The presence of low-T3 syndrome was associated with 
mortality in only the unadjusted model.
CONCLUSIONS: Low-T3 syndrome is a frequent finding among HD patients, but it 
does not predict outcome. However, serum fT3 level is a strong and inverse 
mortality predictor, in part explained by its underlying association with 
nutritional state and inflammation.