Relationship between serum erythropoietin levels and rT3, T4 concentrations in elderly patients with non-thyroidal illnesses

Thyroid function, plasma erythropoietin and tumor necrosis factor (TNF-alpha) concentrations were measured in 28 elderly patients with chronic non-thyroidal illnesses (NTI) and in 8 healthy subjects as a control group. In the NTI group, the existence of an impairment of thyroid function has been demonstrated in about 85% of the subjects, with a lower T(3) concentration; a low T(3) syndrome with low T(3) levels and high reverse-T(3) (rT(3)) plasma concentrations could be found in 25% of the subjects. A direct correlation between erythropoietin and rT(3) and an inverse correlation between erythropoietin and T(4) were found on NTI patients with endocrine abnormalities.