Correlation of Fibroblast Growth Factor-23 with Thyroid Disorder in Patients with Chronic Kidney Disease

Abstract Background: Various thyroid functional test abnormalities are commonly observed in chronic kidney disease (CKD) due to alterations in thyroid hormone synthesis, metabolism, and regulation. Objectives: The objectives of this study were to detect the levels of thyroid hormones at various stage of CKD and find a correlation of thyroid hormones with fibroblast growth factor-23 (FGF23). Materials and Methods: A cross-sectional study was conducted at an outpatient clinic (patient with chronic renal failure). Eighty patients reported chronic renal failure in an outpatient clinic from June 2020 to February 2021. Experimental work was carried out at private laboratories in Kirkuk, Iraq. Results: According to the findings of this study, the age group with the highest risk of renal failure was 61–70 years, with a rate of 25%. The highest age group of patients with renal failure was 51–60 years with 23.8%, whereas the lowest age group of patients with renal failure was 31–40 years with 6.3%. FGF23 levels in the end stage increased significantly ( P ≤ 0.05) as compared with other CKD stages. About thyroid hormones, T3 and T4 levels in the end stage were significantly lower ( P < 0.05) than in other CKD stages. However, thyroid-stimulating hormone (TSH) levels in the end stage increased significantly ( P < 0.05) compared with other CKD stages. The findings of this study revealed an inverse association between FGF23 and T3, with increased levels of FGF23 resulting in lower levels of T3, and the levels of correlation were R 2 = 0.5931, also increased levels of FGF23 resulting in lower levels of T4, and the levels of correlation were R 2 = 0.6356. Finally, the increase in levels of FGF23 lead to an increase in levels of TSH and the levels of correlation were R 2 = 0.7106. Conclusions: Based on the results of this study, the study showed that there is a strong association between thyroid hormones and chronic renal failure. There is a decrease in thyroid hormone levels with an increase in fibroblast growth factor 23 levels.