RESUMO
BACKGROUND: Graves' disease (GD) is associated with hyperthyroidism. Thyrotoxicosis adversely affects multiple organ systems including haematopoiesis. Anaemia occurring specifically in GD has not been systematically studied previously. OBJECTIVE: To define the prevalence and characteristics of the anaemia associated with GD. DESIGN: Eighty-seven newly diagnosed patients with GD were recruited. Haematological indices, thyroid function and inflammatory parameters were examined at presentation and following successful treatment of hyperthyroidism. SETTING: Tertiary care academic referral centre. RESULTS: Thirty-three per cent of subjects presented with anaemia. The prevalence of anaemia not attributable to other causes (GD anaemia) was 22%. GD anaemia affected 41.6% (10/24) of men compared to 17.5% of women (11/63). Mean erythropoietin (EPO) levels (15.5 +/- 5.3 mIU/ml) were within normal reference limits but significantly higher (P = 0.004) than those of the non-anaemic controls. Hgb correlated inversely with EPO (P = 0.05) and CRP (P = 0.04) levels, a relationship that persisted after multivariate adjustment for TT3 or TT4. With antithyroid therapy for 16 +/- 6.3 weeks, Hgb levels normalized in 8 out of 9 subjects with GD anaemia (10.7 +/- 0.8 to 13.5 +/- 1.3 g/dl, P = 0.0001). After normalization of Hgb, mean MCV and TIBC were significantly increased, and median ferritin and mean EPO were significantly decreased. CONCLUSIONS: GD anaemia is common, resembles the anaemia of chronic disease, and is associated with markers of inflammation. It corrects promptly with return to the euthyroid state following treatment.
