Biomarker Test Characteristics and Their Relationship to Healthcare Practices in Iraqi Patients Receiving Hyperthyroidism Treatment

Background: Hyperthyroidism results from the excessive release of thyroid hormones, and the biomarkers must be appropriately monitored to guide treatment selection and confirm its response. Objectives: The present study aims to determine the effect of carbimazole on thyroid hormones in Iraqi patients, as it is a commonly used antithyroid drug. Methods: A prospective, controlled, observational study was conducted at Al-Sader Teaching Hospital in Misan city, Iraq, where 50 adult hyperthyroid patients newly diagnosed were recruited and divided into three groups: One group being treated with carbimazole (treatment, n = 25), another group not receiving any treatment but monitored (without treatment, n = 25), and healthy controls (n = 10) as individuals with normal thyroid and reproductive hormone profiles and no history of infertility or chronic illness. Ten age-matched healthy individuals served as controls. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3) were measured using enzyme-linked immunosorbent assay (ELISA) at baseline and after three months. Results: This study revealed significant differences in TSH (P < 0.0001), fT4 (P < 0.0001), and fT3 (P = 0.039) levels among the three groups. The post-hoc analysis revealed that the treatment group had increased TSH along with decreased values of fT4 and fT3 compared to the without-treatment group, implying successful hormonal suppression by carbimazole. Strong positive correlation coefficients between TSH and fT4 were further achieved in healthy control (R = 0.637, P = 0.047) and treatment (R = 0.664, P = 0.036) groups. Conclusions: Carbimazole shows effectiveness in modulating the levels of thyroid hormones in Iraqi patients suffering from hyperthyroidism, emphasizing the significance of biomarker monitoring as critical tools for optimizing treatment outcomes. This study, thus, demonstrated the clinical significance and practical application of regular TSH testing as a treatment practice for the specific context of Iraq.