The "vicious circle" of thyroid metabolism in patients with chronic kidney disease

Background. Decreased thyroid function is common in patients with chronic kidney disease. Under conditions of hypothyroidism, there is significant changes in lipid metabolism, nitrogen excretion function of the kidneys. THE AIM. To study the parameters of the functional state of the thyroid gland in patients with various stages of chronic kidney disease. Patients and methods . A one-stage cross-sectional study of patients with glomerulopathies without clinically significant diseases of the cardiovascular system with preserved EF (> 55 % according to Simpson) from April 2019 to March 2020 was carried out. The study included 270 patients. To identify subclinical hypothyroidism (SH), the TSH level was determined. Patients were divided into groups according to TSH level: low TSH, normal TSH, and subclinical hypothyroidism. In patients, the indicators of biochemical blood analysis, data from a complex laboratory functional examination of the kidneys were assessed. Results. The detection rate of SH in patients with different stages of CKD was 17.56 %. Patients with SH were significantly older than the group of patients with normal TSH levels (p=0.002). In the group of patients with subclinical hypothyroidism, anti-TPO antibodies were detected only in 9.6 % of patients. A correlation was found between GFR and free T3 in patients with 3B and 4 stages of CKD (r=0.3, p<0.05). In the group of patients with subclinical hypothyroidism, there was a decrease in total protein and albumin, an increase in daily proteinuria, a decrease in total calcium, increased inorganic phosphorus, chlorine, decreased renal transport of uric acid. Conclusion. Increased TSH levels are associated with advanced stages of CKD. The increase in TSH levels in patients with CKD is not associated with female sex and older age. In most patients with glomerulopathies, an increase in TSH levels is not an outcome of autoimmune thyroiditis. SH in CKD patients is associated with severe impairment of renal nitrogen excretion function, protein, and electrolyte metabolism.