Evaluation of Thyroid Function Status in Patients with Chronic Kidney Disease

Abstract

Chronic Kidney Disease is a worldwide health problem with an increasing incidence and prevalence. Abnormalities in the structure and function of the thyroid gland and in the metabolism and plasma concentration of thyroid hormones are common in patients with Chronic Kidney Disease. In view of variability of thyroid function tests in patients with CKD in previous studies, a prospective study of various thyroid functions is undertaken to establish a correlation if any between thyroid dysfunction and severity of renal diseases. Method: A prospective study was conducted on 50 patients with Chronic Kidney Disease on conservative management. Quantitative determination of T3, T4, TSH was done by Enzyme Linked Immunosorbent Assay and data were analyzed. Results: 24 patients had low T3 syndrome (0.2-1.9ng/ml, mean 0.665) which accounts for 48% of the patients, 11 patients had low T4 syndrome (0.5-9.5µg/ml, mean 5.631) which accounts for 22% of the patients and 5 patients had primary hypothyroidism TSH >20µIU/ml. Excluding Primary Hypothyroidism, analysis of serum T3,T4 and TSH in the study subjects shows very high significance χ2 = 20.82, p < 0.001. Distribution of Thyroid Dysfunction in this study among various creatinine clearance levels showed that as glomerular filtration rate declines, number of patients with low T3 syndrome increased χ2 = 8.47, p < 0.05, significant difference. In patients with low T3 syndrome, the mean values of TSH in various stages of renal disease are within normal range mean 4.85, values of TSH did not show any linear correlation with GFR. Number of patients with low T4 syndrome did not correlate with severity of renal disease. Thyroid Dysfunction occurred in 58% of the patients with chronic kidney disease in our study. Conclusion: Thyroid dysfunction does not indicate a state of hypothyroidism, but a reflection of the state of chronic illness/malnutrition. The low T3 state of CKD can be viewed as being protective, promoting conservation of protein. The number of patients with low T3 syndrome progressively increases with the severity of renal failure.