SICK EUTHYROID SYNDROME IN CHRONIC KIDNEY DISEASE

Abstract

BACKGROUND: Sick euthyroid syndrome is an undermined entity seen in many chronic illness. CKD is one of the forerunners in terms of magnitude in the list of chronic illnesses. Also there is evidence of abnormal thyroid metabolism at several levels in uremia. Hence the need to evaluate thyroid function in CKD patients exists, as revealed by recent studies. AIMS: To study thyroid function test in patients of chronic renal failure. Also, to study the correlation between thyroid function test and severity of renal failure, defined by creatinine clearance. MATERIALS & METHODS: In a cross sectional observational case control study, 50 patients of chronic renal failure either on conservative management or on maintenance haemodialysis and 50 normal healthy subjects as control were enrolled. Creatinine clearance was calculated by Cockcroft - Gault Equation. Thyroid function tests were done by C.L.I.A (Chemiluminescence Immunoassay). RESULTS: Of the 50 patients (M:F - 58:42%), with a mean age 40.58 +/- 12.65 years, 28 (56%) were on conservative management, 22 (44%) were on hemodialysis for a minimum period of three months. All patients were clinically euthyroid. Thyroid function tests were normal (all parameters within normal range) in 13 (26%) patients. However 37 (74%) out of 50 patients of CKD had deranged thyroid function test (sick euthyroid syndrome). Mean Total T3 in patients of CKD and controls were 71.52 +/- 27.88ng/dl and 95.34 +/- 16.31ng/dl respectively (p < 0.005). Mean Free T3 in patients of CKD and controls were 2.19 +/- 0.70pg/ml and 3.23 +/- 0.79pg/ml respectively ( p < 0.005). Mean Total T4 in patients of CKD and controls were 6.03 +/- 1.60 mu g/dl and 6.88 +/- 1.06 mu g/dl respectively ( p < 0.005). Mean Free T4 in patients of CKD and controls were 1.18 +/- 0.55ng/ml and 1.29 +/- 0.24ng/dl respectively ( no statistically significant difference). Mean TSH in patients of CKD and controls were 2.90 +/- 1.39 vs. 2.81 +/- 0.99 mu IU/ml respectively ( no statistically significant difference). On applying correlation statistics, no statistically significant correlation was found between creatinine clearance and thyroid function test (r NS). Similarly, no statistically significant correlation was found between blood urea, serum creatinine, and various thyroid function test. CONCLUSION: Our study indicated low Total T3, Free T3 and Total T4 levels in 74% CKD patients as compared to controls. However, Free T4 and TSH level were found to be comparable to controls. Deranged thyroid function in patients of CKD could be due to sick euthyroid syndrome. No statistically significant correlation was found between thyroid function test and severity of renal failure.