Relationships of Chronic Kidney Disease and Thyroid Dysfunction in Patients with Stage 4 and 5 Chronic Kidney Disease: A Cross-Sectional Study

Introduction: Chronic kidney disease (CKD) affects the pituitary-thyroid axis and peripheral metabolism of thyroid hormones, thereby causing dysfunction of thyroid hormones. This study aimed to highlight the correlation between thyroid dysfunction and the staging of chronic kidney disease. Methods: Fifty patients with CKD were studied between 2014–2017 in a tertiary care centre in Western India. These patients were split into a subgroup for Stage 4 and 5 CKD, based upon estimated glomerular filtration rate as per the Kidney Disease Improving Global Outcomes (KDIGO) guidelines. Thyroid function tests and lipid levels were compared in the different CKD subgroups by analysis of variance. Pearson’s correlation coefficient was used to evaluate the thyroid dysfunction with respect to degree of renal dysfunction in the study population. Results: Thyroid abnormalities were seen in 68% of the author’s patients. Euthyroid sick syndrome (ESS) was the most prevalent thyroid hormonal abnormality seen in 32% (n=16), followed by hypothyroidism category seen in the remaining 36% (n=18) of the study population. Of these, 18% (n=9) of the patients had subclinical hypothyroidism, while the remaining 18% (n=9) manifested overt hypothyroidism. Results showed that ESS had a positive correlation with estimated glomerular filtration rate (r=0.822; p<0.001). No significant differences were found between groups in thyroxine or thyroid-stimulating hormone (p>0.05). Linear regression in unadjusted analysis revealed that deranged low-density lipoprotein levels was found to be significantly associated negatively with hypothyroidism (p<0.001) in patients with CKD. Conclusion: Patients with Stage 4 and 5 CKD have many hormonal disturbances, of which ESS is a common occurrence, and has a significant association with dyslipidaemia, increasing morbidity in these patients. Hypothyroidism is more prevalent in patients with severe renal dysfunction, as a result of higher uremic milieu in these patients.