Increased reverse triiodothyronine is associated with shorter survival in independently-living elderly: the Alsanut study

Abstract

Objective: Increased reverse tritiodothyronine (T 3 ) used to be described as a part of euthyroid sick syndrome (ESS). It was demonstrated to be associated with increased mortality in acutely ill patients. It can also be found with low or normal T 3 in non-severely ill subjects but its significance remains unclear. Patients and design: The Alsanut study included a representative sample of 440 independently-living subjects aged 65 or over constituted between January 1988 and September 1989. Past and current medical history and nutritional data were collected at inclusion. Baseline thyroid hormone (TSH, FT 4 , FT 3 and rT 3 ) serum levels were measured. Life status was determined on 1 December 2005. Results: Of the 374 elderly subjects included in the final analysis, 52 had abnormal TSH (43 with hyperthyroidism, nine with hypothyroidism) and 80.7% had died by 1 December 2005. There was no statistical difference in survival between subjects according to thyroid function (PZ0.54). Of the 322 elderly subjects with normal TSH, mortality rate was 81.1%. ESS was found in 3.4%, whereas 8.1% of the participants displayed elevated rT 3 with normal FT 3 . Time to death was strongly related to rT 3 (P!0.0001) and FT 3 (P!0.0001) in a univariate analysis. After adjusting for other confounding variables, rT 3 was the only thyroid hormone associated with shorter survival (PZ0.014). Conclusions: RT 3 was the only thyroid hormone associated with shorter survival in a representative population of independently-living elderly. In these subjects, isolated elevated rT 3 might be an equivalent of ESS, reflecting declining health.

Biomarkers of Aging: From Function to Molecular Biology

“…Other hormonal changes including thyroid-stimulating hormone (TSH), free thyroxine (FT4) and triiodothyronine (FT3) have also been evaluated on their link to health outcomes in elderly, but only low FT3 levels were associated with an increased risk for morbidity and mortality [ 22 ]. These findings are consistent with other studies investigating aged populations, showing an association of low serum FT3 with reduced parameters of physical performance and muscle strength [ 51 ], as well as an increased disease-burden and mortality [ 51 , 52 ].…”

The influence of hypothyroidism and substitution treatment on thyroid hormone conversion ratios and rT3 concentration in patients with end-stage renal failure

“…does not intensify the activity of the pathway for the production of rT3. The decrease in rT3 concentration is also explained by its redistribution from vessels to extravascular space and the increase of rT3 cellular uptake [23]. In the present study, lower rT3 values were observed in dialysis patients than in patients without RF.…”

“…IV). Positive correlation between concentrations of rT3 and total protein was found in patients without ESRD, but this might be associated with the nutrition status of the patients [6,23]. Treatment with thyroid hormones in this group of patients did not change the conversion rates (Tab.…”

The nonthyroidal illness syndrome in the non-critically ill patient

“…Except for the well-described prognostic significance of NTIS in the severity of illness and mortality of hospitalized patients, the Alsanut study of Forestier et al [14] evaluated a non-severely ill elderly population and revealed a negative correlation between rT3 levels and time to death, suggesting that elevated rT3 levels might reflect declining health.…”