Are low concentrations of serum triiodothyronine a good marker for long-term mortality in hemodialysis patients?

Abstract

Low serum free triiodothyronine (FT3) concentrations have been reported in a high percentage of chronic renal failure patients and have been considered as an independent predictor of mortality in dialysis patients. Our aim has been to evaluate the prognostic value of FT3 levels for long-term mortality in stable hemodialysis patients surviving at least 12 months. We retrospectively analyzed 89 stable hemodialysis patients (50 males; mean age 67.9 +/- 11.8 years). All patients had a baseline clinical and analytical evaluation. We analyzed the relationship between baseline FT3 and mortality by means of survival analysis (Kaplan-Meier) and Cox regression analysis. Mean values of thyroid function test were: thyrotropin (TSH) 2.02 +/- 1.5 microU/ml, free thyroxine (FT4) 1.26 +/- 0.23 ng/dl, and FT3 2.7 +/- 0.4 pg/ml. During a median follow-up time of 33.6 +/- 14.9 (12 - 62) months, 41 patients died. FT3 was similar in patients who died or survived (2.6 +/- 0.5 vs. 2.7 +/- 0.4 pg/ml ns). Kaplan-Meier analysis did not show significant differences in mean survival according to tertiles of FT3. In multivariate Cox regression analysis, FT3 was not a predictor of mortality (RR 0,001; 95% CI; 0.000 to 1.73). These data suggest that low FT3 levels are not predictive for mortality in a subgroup of stable HD patients who could survive more than 12 months.