Incidence Of Low T3 Syndrome In Chronic Kidney Disease And Its Clinical Significance

[Background]Epidemiological survey indicated that chronic kidney disease (CKD) has been a global public health problem. In china, the prevalence rate of CKD above 40 is 8%-9%, investigated by Chinese Society of Medical Sciences of Nephrology. Chronic kidney failure (CKF) can cause multiple metabolic disorders such as water and salt metabolism, blood system, cardiovascular system, endocrine system. Further studies have found that nearly 1/4 of the end-stage renal disease (ESRD) patients with thyroid dysfunction. As a major hormone in human body, Thyroid hormone plays an important role in regulating the nutritional and metabolic energy of sugar, protein, water, electrolytes, vitamins, fats and other substances. For those CKD patients, thyroid dysfunction may lead the body a series of physiological and pathophysiological changes.[Objective]Observe the incidence of thyroid dysfunction in patients with CKD. Compare those patients with abnormal and normal thyroid function in renal function, nutritional status, calcium and phosphorus metabolism, blood glucose, blood lipids, etc. Investigate the clinical significance of hypothyroidism in CKD patients.[Methods]Fristly, collecting all CKD patients treated from June 2012 to May 2013, whose thyroid function tests were performed. CKD with hypothyroidism patients were selected as the study group, choose the patients with normal thyroid function as a control group, whose ages and gender were match for the study group. Univariate analysis were performed between two groups of renal function, nutritional status, calcium and phosphorus metabolism, glucose, lipids and inflammatory cytokines. Establish a data base using excel, adopt the data by parallel and double entry. Using SPSS 17.0 software for statistical analysis, normal distribution of measurement data used standard deviation of mean to express and compared with t-test. Non-normally distributed measurement data used M(R) to represent and compared with rank sum test. Count date used percentage to show and compared with chi-square test.[Results]1. The incidence of thyroid dysfunction in patients with CKD Excluded from the original thyroid disease, taking drugs that may affect thyroid function, sepsis, surgery, myocardial infarction,279 patients were enrolled from 300 CKD paitients. The incidence of hypothyroidism, low T3 syndrome, and low T4 syndrome were 4.7%,5.4%, and 47.0%. According to the glomerular filtration rate (eGFR) staging, constituent ratio of hypothyroidism in CKD 1,2,3,4, and ESRF:22.2%,22.5%,59.6%,71.0, and 76.1%. The incidence of thyroid dysfunction decreased significantly from CKD3.2.The clinical significance of low T3 syndrome in patients with CKD The subjects of the study are patients more than CKD3, low fT3 as low T3 syndrome group (76 cases), normal fT3 patients as the control group (38 cases), the age and gender of both groups have no statistically significant (P>0.05).2.1 The relationship between nutritional status and low T3 syndrome Alb, PA, TP, and Hb of low T3 syndrome group were significantly lower than the control group (P<0.05). Pearson correlation analysis shows there were positive correlations between TP (R=0.488,0.431), PA (R=0.363,0.280), Alb (R=0.533,0.493), Hb (R=0.417,0.456) and TT3,fT3 (P=0.000)2.2 The relationship between blood system and low T3 syndrome Hb, Hct, RBC of low T3 syndrome group were significantly lower than the control group (P<0.05). Pearson correlation analysis shows there were positive correlations between Hb (R=0.417, 0.456),Hct (R=0.395,0.435), RBC (R=0.497,0.553) and TT3, fT3 (P=0.000)2.3 The relationship between calcium and phosphorus metabolism and low T3 syndrome Blood Ca, P, PTH of low T3 syndrome group and control group have no statistically significant (P>0.05), and Pearson correlation analysis also shows there were no significant correlations between Blood Ca, P, PTH and TT3, fT3 (P>0.05)2.4 The relationship between blood glucose, lipids and low T3 syndrome Blood glucose, blood lipids of low T3 syndrome group and control group have no statistically significant (P>0.05), and Pearson correlation analysis also shows there were no significant correlations between blood glucose, blood lipids and TT3, fT3 (P>0.05)2.5 the relationship between inflammatory factors and low T3 syndrome CRP, IL-6 of low T3 syndrome group were significantly lower than the control group (P<0.05). Pearson correlation analysis shows there were positive correlations between CRP (R=-0.457,-0.289), IL-6 (R=-0.445,-0.268) and TT3, fT3 (P=0.000)[Conclusion]CKD patients have a higher incidence of thyroid dysfunction, of which low T3 syndrome occurs most frequently, especially for the CKD 3 patients or even. Alb, PA, TP and Hb, Hct, RBC were significantly lower than the control group; but the two groups of blood Ca, P, PTH and FBG, HAblc have no statistically significant. It infers that the severity of CKD is proportional to the thyroid function, and the reason may be closely related to the nutritional status of patients with CKD, not the change of internal environment such as blood glucose and lipid. Meanwhile, TT3, fTt3 level were negatively correlated to CRP, IL-6.