Thyroid Function Disorders 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 study aims at investigating the prevalence of thyroid function disorders in patients with CKD and its association with the degree of renal failure. Methods: A cross-sectional study was performed on patients with CKD, at the Nephrology unit, Hawler Teaching Hospital, Erbil, Iraq from 1 July 2020 to 31 December 2020. Demographic features such as age, sex, and body mass index (BMI) were recorded; blood tests were done, including serum-free triiodothyronine (FT3), free thyroxin (FT4), thyrotropin (TSH), and creatinine. The CKD-EPI (epidemiological) equation was used to estimate glomerular filtration rate (eGFR).The participants were classified according to their thyroid function, age, BMI, and eGFR. The association of thyroid dysfunction with gender, age, BMI, and eGFR was studied. Results: A total of 104 patients with CKD enrolled in the current study: Half of them were on conservative treatment, and the other half were on a chronic hemodialysis (HD) program. Fifty four (51.9%) of them were male, mean age was 53.99 ± 14.59 years, mean BMI was 25.19 ± 3.14 kg/m2, and most of them (63.5%) were overweight. According to eGFR classification, most of the participants (70.2%) were at stage 5 CKD, 20.2% at stage 4, and 9.6% at stage 3. From the study population, it was observed that 34 out of 104 (32.7%) participants presented with thyroid function disorders. Among them, 22 (21.2%) patients presented with subclinical hypothyroidism, seven (6.7%) had overt hypothyroidism, three (2.9%) hyperthyroidism, and two (1.9%) subclinical hyperthyroidism. Hypothyroidism (clinical and subclinical) was positively associated with increasing age and advanced CKD. Conclusion: Thyroid function disorders are common among patients with CKD. Hypothyroidism, the most prevalent one, was positively associated with increasing age, low eGFR, and in patients on HD therapy.