Incidence of sideropenia and effects of iron repletion treatment in women with subclinical hypothyroidism

Summary

Sideropenia affects ca. 20% of the world population, and iron dependent anemia is the most frequent type of anemia worldwide. The aim of the study was to investigate the incidence of sideropenia and dependent anemia in patients with subtle changes of the thyroid function, such as subclinical hypothyroidism (SH). 57 women with SH and 61 euthyroid controls (CG) were studied. Serum concentrations of T4, T3, TSH, anti-TPO, anti-Tg, ferrum (Fe), ferritin (Frt) total iron binding capacity (TIBC) and blood count were determined. In SH 17 patients (29.8%) presented low Fe levels (<50 µg/dl). 9 (15.7%) also had decreased Frt, confirming iron deficiency, whereas 8 patients presented additionally diminished hematocrit and hemoglobin levels, suggesting manifested sideropenic anemia. In CG, 10 persons (16%) had sideropenia, 6 (9.8%) had low Fe and Frt and only 3 (4.9%) had blood count alterations suggesting manifested sideropenic anemia. In SH, anti-TPO were positive in 39 patients (68%), whereas, in CG only 2 (3.2%) were positive. 8 patients with SH and manifested sideropenic anemia were treated with ironproteinsuccinylate (I-PSL), (80 mg Fe + + +/day, for three months), a new iron compound. The repletion treatment safely led to the clinical and laboratory correction of sideropenia and showed a good tolerability. Furthermore, iron treatment provoked a minor increase of T₄ and a mild decline of TSH, but the levels were not significant. These results suggest that sideropenia is a common finding in patients with slightly decreased thyroid activity, and that determination of Frt should be routinely advised. Finally, in the assessment of sideropenia and dependent anemia, evaluation of the thyroid function must be taken into account.

Key words

Sideropenia - ferritin - TSH - anti-TPO - iron repletion - subclinical hypothyroidism