Correlation between severity of chronic kidney disease and thyroid dysfunction

Kidneys play a significant role in thyroid hormone metabolism by conversion of thyroxine (T4) to triiodothyronine (T3) and abnormal thyroid function tests are frequently observed in patients of chronic kidney disease. The aim of present study was to analyse the thyroid function in patients of chronic kidney disease and its correlation with severity of kidney disease. Fifty patients of chronic kidney disease were included. All patients were on conservative management and were divided into 3 groups. Those with creatinine clearance < 7.5 ml/minute were placed in group A (n = 21), with creatinine clearance 7.5 - 15 ml/minute in group B (n = 21) and with creatinine clearance > 15 ml/minute in group C (n = 8). Thyroid profile was studied in all patients. The results were compared to age and sex matched healthy controls. Thirty-five patients (70%) of chronic kidney disease were found to be having abnormal thyroid functions. The mean values of serum total T3, free T3, total T4, free T4 were significantly reduced and that of thyroid stimulating hormone (TSH) were significantly higher in cases as compared to controls and these abnormities in thyroid function test increased as the creatinine clearance decreased (from group C to group A). It is concluded that thyroid dysfunction occurs in patients with chronic kidney disease. Mean values of TT3, FT3, TT4, FT4 reduced and that of TSH increased as severity of renal failure increased.