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

Sideropenia affects ca. 20% of the world population, and iron dependent ane mia is the most frequent type of anemia worldwide. The aim of the study was to investigate the incidence of sideropenia and dependent anemia in patien ts with subtle changes of the thyroid function, such as subclinical hypothy roidism (SH). 57 women with SH and 61 euthyroid controls (CG) were studied. Serum concentrations of T4, T3, TSH, anti-TPO, anti-Tg, ferrum (Fe), ferri tin (Frt) total iron binding capacity (TIBC) and blood count were determine d. In SH 17 patients (29.8%) presented low Fe levels (<50 mu g/dl). 9 (15.7 %) also had decreased Frt, confirming iron deficiency, whereas 8 patients p resented additionally diminished hematocrit and hemoglobin levels, suggesti ng 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 s uggesting manifested sideropenic anemia. In SH, anti-TPO were positive in 3 9 patients (68%), whereas, iri CG only 2 (3.2%) were positive. 8 patients w ith SH and manifested sideropenic anemia were treated with ironproteinsucci nylate (I-PSL), (80 mg Fe + + +/day, for three months), a new iron compound . The repletion treatment safely led to the clinical and laboratory correct ion of sideropenia and showed a good tolerability. Furthermore, iron treatm ent provoked a minor increase of T-4 and a mild decline of TSH, but the lev els were not significant. These results suggest that sideropenia is a commo n finding in patients with slightly decreased thyroid activity, and that de termination of Frt should be routinely advised. Finally, in the assessment of sideropenia and dependent anemia, evaluation of the thyroid function mus t be taken into account.