Correlation Between TyG Index And CKD In Middle-aged And Elderly People

Objective To investigate the correlation between the new insulin resistance surrogate index triglyceride-glucose（TyG）index and the prevalence and incidence risk of chronic kidney disease（CKD）in the middle-aged and elderly population aged 40～75 years in Lanzhou City.Methods An epidemiological survey was conducted in Lanzhou,Gansu by means of cluster random sampling in 2011,including questionnaire survey,physical examination,and laboratory examination.Baseline populations were selected according to the inclusion criteria and exclusion criteria,followed up after 3 to 5 years,4579 subjects with complete data from the two surveys were analyzed.Subjects were divided into CKD group and non-CKD group according to whether they had CKD or not,the clinical data characteristics between the two groups were compared.According to the quartiles of the baseline TyG index,they were divided into groups:Q1 group（TyG≤8.48）,Q2 group（TyG 8.49～8.85）,Q3 group（TyG 8.86～9.23）,and Q4 group（TyG>9.23）,the characteristics of baseline data were compared between the groups.and the prevalence of CKD with different TyG index levels was analyzed.The association of the TyG index with baseline clinical and demographic indicators was analyzed using partial correlation.After 3～5 years of non-interventional follow-up,the incidence of CKD in different TyG index groups was calculated,the baseline data of the population with CKD and those without CKD were compared.The Cox proportional hazards model was constructed to analyze the risk factors of CKD and the correlation between different levels of TyG index and the risk of CKD.The receiver operating characteristic（ROC）curve of the TyG index to predict the risk of CKD was drawn,and the area under the curve（AUC）and the best cut-off value for predicting the incidence of CKD were calculated.Results1.In the overall study population,the prevalence of CKD was 26.1%,of which the prevalence of males was 19.8%and the prevalence of females was 28.6%.Compared with the non-CKD group,the TyG index of the CKD group was significantly increased（P<0.05）.According to the quartile analysis of the TyG index,it was found that with the increase of the TyG index,the e GFR of the study population gradually decreased,and the level of UACR gradually increased（all P<0.05）.The prevalence of CKD increased with the TyG index from Q1 to Q4,and the prevalence of CKD in the Q4 group was significantly higher than that in the Q1～Q3 groups（all P<0.05）.In males,the prevalence of CKD in the Q4 group was higher than that of Q3 group,and in females,the prevalence of CKD in the Q4 group was higher than that in Q1 and Q2 groups（all P<0.05）.2.Partial correlation analysis showed that in baseline population,TyG index was positively correlated with WC,HC,WHR,BMI,SBP,DBP,TG,TC,LDL-C,FPG,Hb A1c,TG/HDL-C,negatively correlated with HDL-C and e GFR（all P<0.05）,and it had no significant correlation with age,2h PG and UACR（all P>0.05）.3.After 3～5 years of non-interventional follow-up（average follow-up of 3.1years）,there were 236 new cases of CKD,including 77 males and 159 females,with a cumulative incidence rate of 7.0%（7.5%in males and 6.7%in females）.With the increase of TyG index quartiles,the cumulative incidence of CKD increased sequentially（P<0.05）,the cumulative incidence of CKD in the Q4 group was more than twice that of the Q1 group.Baseline TyG index was significantly different between the new-onset CKD population and the non-CKD population（P<0.05）.4.Using univariate Logistic regression to analyze the risk factors of CKD,it was found that the risk factors for the incidence of CKD included the elderly,the history of dyslipidemia,hypertension,and diabetes,and higher levels of BMI,WC,HC,WHR,SBP,DBP,FPG,Hb A1c,TG,TG/HDL-C,TyG index,etc.,while higher education level and higher level of HDL-C were protective factors for CKD（all P<0.05）.5.Multivariate Cox regression analysis showed that elderly,history of hypertension and high level of Hb A1c were risk factors for CKD,and higher education level was a protective factor for CKD risk（all P<0.05）.Increased TyG index was an independent risk factor for abnormal e GFR and CKD（all P<0.05）.After adjusting for multiple confounding factors,it was found that compared with the first quartile,the 2nd and 3rd quartiles had significantly increased risk of CKD,the hazard ratios（HR）were1.594（95%CI:0.999-2.544,P=0.050）and 1.911（95%CI:1.101-3.316,P=0.021）,respectively（all P>0.05）.6.Draw the ROC curve to analyze the predictive value of FPG,TG,and TyG index levels on the risk of CKD.The results showed that in the overall population,the ability to predict CKD was:AUC_{TyG index}>AUC_FPG>AUC_TG,and the best cut-off values were 8.63,6.10mmol/L,and 1.40mmol/L,respectively;after further gender stratification,it was found that when the TyG index was higher than 9.27 in men or higher than 8.73 in women,the risk of CKD increased（P<0.05）.Conclusion1.The incidence of CKD of the middle-aged and elderly population is relatively high in this study,and there is no significant gender difference.For this part of the population,especially the middle-aged and elderly population with glucose and lipid metabolism disorders,hypertension,regular monitoring of renal function should be performed to identify kidney damage early and intervene as soon as possible.2.There is an association between the level of TyG index and CKD in the middle-aged and elderly population.Elevated TyG index is an independent risk factor for CKD,and it is a great predictor of CKD.Whether in the general population or after gender stratification,the TyG index has a stronger predictive ability than FPG and TG for CKD.3.As a great predictor of CKD,the best cut-off value of the TyG index in the total population is 8.63,the sensitivity is 0.797,and the specificity is 0.365.It is found that the sensitivity of the TyG index to predict CKD is higher in women,it is more valuable for the prediction of CKD in females than males.