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

Abstract

Introduction: 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.

Objective: 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.

Patients and measurements: 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.

Results: 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).

Conclusions: 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.