| Objective:Renal size measured by ultrasound is often used to evaluate the degree of chronicity and prognosis and is often corrected according to body shape.These clinical experiences need to be verified.This study explored the correlation between various corrected kidney sizes and the rapid progression and chronicity of renal failure and compared the clinical value of various indexes in predicting the end point of renal failure.Methods:A total of 579 patients with chronic kidney disease(CKD)stage 3-4 who underwent renal biopsy in 14 years were analyzed retrospectively.The clinical data were collected and length and width of the kidney were corrected by height,weight or body mass index.The clinical value of these kidney size indexes was studied in four parts.Firstly,linear correlation was used to explore the relationship between renal size and baseline estimated glomerular filtration rate(eGFR).And then we study the correlation between kidney size and the rapid progression of renal failure.The rapid progression of renal failure is based on the decline of eGFR>5ml/min/1.73m2 every year and 30%in the first year respectively.The variables with P<0.1 in univariate logistic regression analysis were included in multivariate logistic regression to analyze the correlation.In the next part,we explored the clinical value of kidney size in predicting the decline of eGFR by 50%or progression to CKD stage 5.Lasso regression was used to screen non kidney size variables to construct Cox regression model and calculate C index.Then different kidney size indexes were added to the model to construct new regression models.If the C index of new model was improved,the renal size was regarded as significant index.The above parts were analyzed as a whole,and then stratified according to eGFR,whether there was acute renal injury during hospitalization,whether there was renal cyst,and whether it was diabetes nephropathy.At last,we studied the relationship between renal size and pathological chronicity in 270 patients with IgA nephropathy.T,T1 or T2 of Oxford pathological grade were used as chronicity index,and logistic regression was used to evaluate the relationship between renal size and chronicity index.After analyzing the overall trend,the cases with acute renal injury and renal cyst were removed for subgroup analysis.Results:There was little linear correlation between some renal size and eGFR.Most renal size indexes have nothing to do with the rapid progress of renal failure.Body shape did not increase the correlation between renal size and eGFR.Except that stratified analysis showing that kidney size index was related to the rapid progress of renal failure,most indexes had no correlation.After stratified analysis,right kidney length adjusted by the weight or BMI and left kidney width adjusted by weight in patients with non-diabetes nephropathy correlated with the annual decrease of eGFR>5ml/min/1.73m2.And their OR values(95%confidence interval)were 0.51(0.27-0.92),0.74(0.57-0.96),0.25(0.07-0.83),0.57(0.34-0.91)and 0.27(0.07-0.92)respectively.The length of left kidney and the length of left and right kidney after height adjustment in patients with CKD stage 3b were correlated with the decrease of eGFR by 30%,and their values(95%confidence interval)were 1.73(1.12-2.67),2.76(1.40-5.50)and 2.37(1.13-4.96),respectively.In the Lasso Cox regression model,different kidney size indexes were added to construct a new model.The model predicted that the decline of eGFR by 50%and the C index range of CKD stage 5 were 0.63-0.81 and 0.62-0.74,respectively.In the overall analysis,the renal size index had no value in predicting the end point of renal failure.The renal size index of 579 patients had no value in predicting the end point of renal failure.In the stratified study of CKD stage 3 a,the height adjusted left kidney length and right kidney length can predict the decline of eGFR by 50%,with C indexes of 0.71 and 0.70,respectively.The left kidney length,left kidney length adjusted by height in patients with CKD stage 3b and right kidney length adjusted by weight in patients with CKD stage 4 could predict the progression to CKD stage 5.The C index was 0.73,0.71 and 0.67 respectively.For IgA nephropathy,various kidney size indexes were not related to the degree of pathological chronicity T classification.Conclusion:There is little correlation between renal size and baseline renal function and the rapid progress of renal function,but renal size has nothing to do with the degree of renal chronicity in patients with IgA nephropathy.Only some renal size indexes in stratification have medium predictive value for renal failure.However,the clinical value of renal size is limited considering the complexity of stratification analysis. |
