Endocrine Abstracts

Background: Overt newly diagnosed hyperthyroidism is frequently associated with mild anemia. However, there are limited data on long term evolution under methimazole treatment. Our aim was to study the baseline characteristics and evolution of anemia in the hyperthyroidism setting.

Methods: We retrospectively assessed 58 consecutive patients [46 (79.3%) women] presenting with newly diagnosed overt thyrotoxicosis (43 Graves disease, 9 toxic nodular goiters, 4 toxic adenomas and 2 drug induced hyperthyroidism) in our practice. Of these, 30 were reassessed after 4-6 months of methimazole treatment. No patient had treatment for anemia. We measured thyroid-stimulating hormone, free thyroxine, hemoglobin (Hb), hematocrit, red blood cells, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration at both baseline and 4-6 months assessments. Anemia was defined by a Hb value <12 g/dl in women and <14 g/dl in men.

Results: At baseline, 19 patients (32.76%) had normochromic normocytic anemia, of whom 14 (73.63%) were women. Mean Hb was 11.5±0.25 g/dl and 12.4±0.97 g/dl in women and men respectively. FreeT4 (39.53±20.2 pmol/l) inversely correlated with Hb in women (r=0.45, P=0.05), but not in men. All patients (25 women, 5 men) that were assessed after 4-6 months of methimazole treatment had normal Hb levels (including 7 women and 1 man with anemia at baseline).

Conclusion: Our study demonstrated that hyperthyroidism is frequently associated with mild

normochromic normocytic anemia. 4-6 months of methimazole treatment leads to resolution of anemia.