Could Red Cell Distribution Width be a Marker in Hashimoto's Thyroiditis?

Aims: Hashimoto's Thyroiditis (HT) is the most common autoimmune thyroiditis worldwide and characterized with lymphomonocytic inflammation of the thyroid gland. Red cell distribution width (RDW) reflects erythrocyte anisocytosis and besides it increases in iron deficiency anemia, recent studies reported that RDW was also associated with conditions characterized with overt or subclinical infl ammation. We aimed to answer whether RDW increased in Hashimoto's thyroiditis. Methods: Patients with HT admitted to outpatient clinic of our hospital were included to the study. Patients with anemia (especially iron deficiency), diabetes mellitus, chronic inflammatory disease and on medication that may affect hemogram results (e.g., aspirin) excluded from the study. Patient characteristics, thyroid stimulating hormone (TSH), Free T3 (FT3), Free T4 (FT4), Anti-thyroid peroxidase (Anti-TPO), Anti-Thyroglobulin (Anti-TG), leukocyte count (WBC), Hemoglobin (Hb), Hematocrit (Htc), mean corpuscular volume (MCV), RDW and platelet count (PLT) values of the study cohort were obtained from computerized database of our institution. Results: There was no significant difference between study and control groups in terms of WBC, Hb, Htc, MCV, PLT, PDW and FT3 levels. However, FT4 level was significantly lower and TSH was significantly higher in study group compared to controls. RDW was significantly increased in study group compared to control group. Conclusion: We suggest that elevated RDW values in patients without iron deficiency anemia may require further evaluation for HT, especially in female population.