Association of Thyroid Dysfunction with Anemia in Hospitalized Patients

Abstract

Background: Thyroid dysfunction may contribute to anemia through impaired erythropoietin production, altered iron metabolism, nutritional deficiencies, and reduced bone marrow activity. Objective: To evaluate the association between thyroid dysfunction and anemia among hospitalized patients. Methods: This retrospective observational study was conducted at Department of Medicine PNS Hafeez Islamabad from June 2024 to June 2025 and included 120 hospitalized patients who underwent thyroid function testing and complete blood count evaluation. Baseline demographic variables included age, gender, body mass index, duration of hospitalization, smoking status, diabetes mellitus, hypertension, chronic kidney disease, cardiovascular disease, and previous history of thyroid disorders. Results: The mean age of patients was 51.8 ± 15.2 years, and 66 (55.0%) were female. Among the participants, 62 (51.7%) were euthyroid, 42 (35.0%) had hypothyroidism, and 16 (13.3%) had hyperthyroidism. Mean hemoglobin was significantly lower in hypothyroid patients than in hyperthyroid and euthyroid patients (10.9 ± 1.6 vs. 11.6 ± 1.5 vs. 12.8 ± 1.4 g/dL; p<0.001). Anemia was present in 28 (66.7%) hypothyroid, 8 (50.0%) hyperthyroid, and 19 (30.6%) euthyroid patients (p<0.001). Hypothyroid patients also had lower ferritin and vitamin B12 levels and a greater frequency of moderate, severe, microcytic, and macrocytic anemia. Conclusion: Thyroid dysfunction was significantly associated with anemia among hospitalized patients, with hypothyroidism showing the strongest relationship. Routine assessment of thyroid function, iron stores, and vitamin B12 levels may improve the diagnosis and management of unexplained anemia in hospitalized patients...