Association between thyroid hormone levels and hematological indices among women with thyroid disorders.

Background: Dysfunctions in thyroid hormones induce various effects on hematopoiesis such as anemia, changes in red blood cells (RBC) and platelet counts, as well as changes in hematological indices. The aim of the present study was to assess the association between thyroid hormone levels and hematological indices among women with thyroid dysfunction who were attending an outpatient clinic in Mosul, Iraq.

Methods: This case-control study was conducted at Al-Wafa Specialist Centre for Diabetes and Endocrine Diseases from April to July 2024. A total of 300 women participated in this study (100 with hypothyroidism, 100 with hyperthyroidism, and 100 with normal thyroid function serving as controls). The hematological indices of the three groups were analyzed and compared. Blood indices were analyzed using the Mythic-18 hematology analyzer. Ethical approval was obtained before data collection, and written consent was obtained from all participants.

Results: All RBC indices [hemoglobin (Hb), RBC count, hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC)] were significantly lower in patients with hypothyroidism compared to those in the control group (p ≤ 0.05), except for red blood cell distribution width (RDW), which was significantly higher in patients with hypothyroidism (p = 0.000).White blood cell count was significantly lower in patient with hypothyroidism compared to those in the control group (p = 0.000). In contrast, no statistically significant differences were observed in any blood indices in patients with hyperthyroidism compared to the control group. A statistically significant negative correlation was identified between thyroid-stimulating hormone and Hb, RBC count, HCT, MCV, MCH, alongside a statistically significant positive correlation with RDW.

Conclusion: The dysfunction of thyroid hormones has an impact on blood indices. Anemia is frequently observed in patients with thyroid dysfunction, especially in cases of hypothyroidism. Variations in blood indices may indicate underlying thyroid disorders. Therefore, it is imperative not to disregard the assessment of thyroid hormones in cases of unexplained anemia or unaccounted changes in blood indices.