Thyroid Hormones May Predict Death Risk

Anti-aging specialists pay attention to the complete suite of thyroid hormones and their changes over time, and now similar attention may be warranted in the hospital setting. Among older patients hospitalized for an acute illness, serum levels of free  triiodothyronine (FT3) may predict the risk of death, whether as inpatients or within 7 years after discharge.   Pedro Iglesias, from Hospital Ramon y Cajal (Spain), and colleagues completed a prospective observational cohort of 404 men and women, average age 85.9 years, who were admitted to hospital for a range of acute conditions and followed for seven years.  On admission, the patients were given thyroid function tests, looking at levels of Tthyroid stimulating hormone (TSH), free thyroxine (FT4), and free  triiodothyronine (FT3).  As inp[atients, 61 died and an additional 262 died later.  Of the 81 survivors, the researchers found that most had normal levels of all three hormones, although the proportion of those with normal FT3 was only 54.3%, the percentage of those with normal TSH and FT4 were both above 88%.  Of the 61 who died in hospital, most had normal TSH and FT4 but only nine patients had normal FT3, and the remaining 52 (85.2%) had low levels of the hormone. The pattern was similar for those who died after discharge, but the disparity in FT3 levels was not as sizeable -- 170 (or 64.9%) had low levels and 91 (or 34.7%).  The team also observed that of the 144 patients who had normal FT3 levels at the start of the study, only nine (6.2%) died while hospitalized. The study authors conclude that: “Alterations in [thyroid function test] results during hospitalization are associated with long-term mortality in elderly patients. In particular, low levels of [free triiodothyronine, FT3] are significantly related to all-cause and [cardiovascular] mortality.”