The Correlation Between Thyroid Hormones And Renal Interstitial Fibrosis In Patients With Chronic Kidney Disease

Objective:We tested the contents of thyroid hormones in peripheral blood of chronic kidney disease(CKD),aiming to investigate the relationship between thyroid hormones and renal interstitial fibrosis.Method:Clinical and pathological data of 369 patients with CKD diagnosed in the first Hospital of Jilin University from January 2019 to October 2022 were collected retrospectively.Patients were divided into 3 groups according to the severity of renal interstitial fibrosis: 247 cases in T0 group(no or mild lesion),91 cases in T1 group(moderate lesion)and 31 cases in T2 group(severe lesion),which was based on 2016 Ig A nephropathy Oxford classification and Katafuchi criteria.Collecting the age,gender,weight,high,systolic pressure,diastolic pressure and previous medical history,free triiodothyronine(FT3),free thyroxine(FT4),thyroid stimulating hormone(TSH),serum creatinine(Scr),urea nitrogen(BUN),uric acid(UA),albumin(Alb),24 h urine protein quantitation(24h-UTP),estimate glomerular filtration rate(e GFR),hemoglobin(Hb)and other clinical indicators in order to compare with the changes in measures of thyroid function among 3 groups patients and explore the correlation between them.And risk factors for renal interstitial fibrosis were analyzed using logistic regression analysis.Results:1.A total of 369 patients were enrolled,including 167 euthyroid,56 hypothyroid,34 subclinical hypothyroid,96 euthyroid sick syndrome,12 hyperthyroid and 4 subclinical hyperthyroid.2.Serum FT3 gradually decreased in CKD patients while the degree of interstitial fibrosis increased.The levels of serum FT3 in T0 group,T1 group and T2 group were3.81±0.98pmol/l,3.50±0.96poml/l,3.19±0.63pmol/l,and this difference was statistically significant(P<0.01).Whereas there was no relation in FT4 and TSH(P>0.05).3.Correlation analysis between serum FT3 levels and clinical indicators in CKD patients: FT3 levels were negatively correlated with Scr,BUN,24h-UTP(r=-0.291,-0.321,-0.348,P<0.05),and positively correlated with e GFR levels(r=0.316,P<0.05).4.Correlation analysis between serum FT3 levels and renal interstitial fibrosis in CKD patients: serum FT3 concentration had a negative correlation with the degree of interstitial damage(r=-0.228,P<0.01),namely that the lower FT3 levels,the more severe fibrosis in kidney.There was no correlation between FT3,TSH and the severity of renal interstitial fibrosis(P>0.05).5.Correlation analysis between pathological feature and renal interstitial fibrosis in CKD patients: segmental glomerulosclerosis(S)was positively correlated with renal interstitial fibrosis(r=0.424,P<0.05).Glomerular mesangial hypercellularity(M)was positively correlated with renal interstitial fibrosis(r=0.278,P<0.05).6.Univariate regression showed that hypertension,Scr,BUN,segmental glomerulosclerosis,glomerular mesangial hypercellularity,lower e GFR,lower Hb and lower FT3 were all risk factors for moderate and severe interstitial fibrosis.The above factors were included in multivariate logistic regression: segmental glomerulosclerosis [OR: 5.07,95%CI(2.589-9.930),P<0.001;OR: 42.17,95%CI(1.579-1126.429),P<0.05] and lower e GFR [OR:0.969,95%CI(0.957,0.982),P<0.001;OR: 0.859,95%CI(0.788-0.937),P<0.01] were risk factors for moderate and severe interstitial fibrosis.Besides this,glomerular mesangial hypercellularity was also a risk factor for severe interstitial fibrosis [OR: 7.694,95% CI(1.268-46.701),P<0.05].Conclusions:1.Serum FT3 levels of CKD patients were gradually decreased with the aggravation of renal interstitial fibrosis,indicating that maybe FT3 can be used to predict the degree of renal interstitial fibrosis.2.Serum FT3 levels of CKD patients were negatively related to the degree of renal interstitial fibrosis,suggesting that FT3 may has a protective effect on kidney.3.Segmental glomerulosclerosis,glomerular mesangial hypercellularity and lower e GFR were risk factors of renal interstitial fibrosis.