Evaluation of cystatin C-derived glomerular filtration rate equations in Chinese population

Optimal Glomerular Filtration Rate Equations for Various Age Groups, Disease Conditions and Ethnicities in Asia: A Systematic Review

(1) Background: The performance of estimated glomerular filtration rate (eGFR) equations in the Asian population has been widely questioned. The primary objective of this study was to gather evidence regarding optimal GFR equations in Asia for various age groups, disease conditions, and ethnicities. The secondary objective was to see whether the equations based on the combination of creatinine and cystatin C biomarkers if employed are satisfactory across different age groups and disease conditions in various ethnicities in Asia compared to those based on either of the single biomarkers. (2) Methods: Validation studies that had both creatinine and cystatin C-based equations either alone or in combination, validated in specific disease conditions, and those which compared the performance of these equations with exogenous markers were eligible only. The bias, precision, and 30% accuracy (P30) of each equation were recorded accordingly. (3) Results: Twenty-one studies consisting of 11,371 participants were included and 54 equations were extracted. The bias, precision, and P30 accuracies of the equations ranged from -14.54 to 9.96 mL/min/1.73 m², 1.61 to 59.85 mL/min/1.73 m², and 4.7% to 96.10%. The highest values of P30 accuracies were found for the JSN-CKDI equation (96.10%) in Chinese adult renal transplant recipients, for the BIS-2 equation (94.5%) in Chinese elderly CKD patients, and Filler equation (93.70%) also in Chinese adult renal transplant recipients. (4) Conclusions: Optimal equations were identified accordingly and it was proven that combination biomarker equations are more precise and accurate in most of the age groups and disease conditions. These can be considered equations of choice for the specific age groups, disease conditions, and ethnicities within Asia.

Relationship between Arterial Stiffness and Renal Function Determined by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) Equations in a Chinese Cohort Undergoing Health Examination

Background

The association between arterial stiffness and cardiovascular risk in CKD and ESRD patients is well established. However, the relationship between renal function estimation and properties of large arteries is unclear due to the four different methods used to quantify glomerular filtration. This study investigated the relationship between carotid-femoral pulse wave velocity (c-fPWV), as a measure of arterial stiffness, and accepted metrics of renal function.

Methods

This cross-sectional study was conducted in 431 health examination individuals in China, enrolled from January 2017 to June 2019. c-fPWV and blood pressure were measured, and blood samples were obtained for all participants. Four different methods were used to determine the estimated glomerular filtration rate (eGFR) as described by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) equations: (i) CKD-EPI_SCr formula based on SCr, (ii) CKD-EPI_CysC formula based on CysC, (iii) CKD-EPI_SCr/CysC formula based on Cr and CysC, and (iv) MDRD.

Results

Of all of the study participants (average age 53.1 ± 13.0 years, 68.1% male), 23.7% had diabetes mellitus and 66.6% had hypertension. The average eGFR values determined by the CKD-EPI_SCr, CKD-EPI_CysC, CKD-EPI_SCr/CysC, and MDRD equations were 91.9 ± 15.6, 86.8 ± 21.4, 89.6 ± 18.3, and 90.7 ± 16.6 ml/min/1.73m^2, respectively. c-fPWV was significantly and negatively correlated with eGFR determined by CKD-EPI_SCr (r = −0.336, P < 0.001), CKD-EPI_CysC (r = −0.385, P < 0.001), CKD-EPI_SCr/CysC (r = −0.378, P < 0.001), and MDRD (r = −0.219, P < .001) equations. After adjusting for confounding factors, c-fPWV remained significantly and negatively correlated with eGFR determined by the CKD-EPI_CysC equation (β = −0.105, P = 0.042) and significantly and positively correlated with age (β = 0.349, P ≤ 0.01), systolic pressure (β = 0.276, P ≤ 0.01), and hypoglycemic drugs (β = 0.101, P = 0.019).

Conclusion

In a health examination population in China, c-fPWV is negatively correlated with eGFR determined by four different equations; however, only the metric of eGFR determined by the equation for CKD-EPI_CysC showed an independent relation with c-fPWV.

The Ratio of NT-proBNP to CysC1.53 Predicts Heart Failure in Patients With Chronic Kidney Disease

Background: The N-terminal pro B type natriuretic peptide (NT-proBNP) is important for prognosis of heart failure in patients with chronic kidney disease (CKD). However, the NT-proBNP level is easily affected by renal insufficiency, which limits its clinical use. Methods: This study included 396 patients with CKD. Plasma levels of NT-proBNP and cystatin C (CysC) were measured during hospitalization. The echocardiographic parameters were also detected. Patients were divided into the heart failure group and control group according to the European Society of Cardiology Guideline on Chronic Heart Failure 2021. Multiple modeling analysis of the values of NT-proBNP and CysC, including NT-proBNP/Cyscn and NT-proBNP/nCysC was performed. The receiver operating characteristic (ROC) curve, combined with the cardiac function, was used to determine the formula with the best diagnostic efficiency. Then, the sensitivity and specificity of new predictors for cardiac insufficiency in CKD patients were calculated. Pearson correlation analysis was used to analyze the relationship between new predictors and the NT-proBNP level. The clinical data of CKD patients from another local hospital were used to validate the new predictors and the cut-off values. Results: An elevated NT-proBNP/CysC1.53 ratio was an independent risk factor for cardiac dysfunction in CKD and the best predictor derived from multiple modeling analysis. There was no correlation between the NT-proBNP/CysC1.53 ratio and the NT-proBNP level (r = 0.376, p = 6.909). The area under the ROC curve for the NT-proBNP/CysC1.53 ratio was 0.815 (95% confidence interval: 0.772-0.858), and for a cut-off point of 847.964, this ratio had a sensitivity of 78.24%, and a specificity of 69.44%. When applied to the data of CKD patients from another local hospital, the NT-proBNP to CysC1.53 ratio had a sensitivity of 70.27% and a specificity of 67.74%. Conclusion: The NT-proBNP to CysC1.53 ratio was superior to NT-proBNP alone for predicting cardiac dysfunction in patients with CKD.

Physiologically based pharmacokinetic model of renally cleared antibacterial drugs in Chinese renal impairment patients

To preliminarily develop physiologically based population models for Chinese renal impairment patients and to evaluate the prediction performance of new population models by renally cleared antibacterial drugs. First, demographic data and physiological parameters of Chinese renal impairment patients were collected, and then the coefficients of the relative demographic and physiological equation were recalibrated to construct the new population models. Second, drug‐independent parameters of ceftazidime, cefodizime, vancomycin, and cefuroxime were collected and verified by Chinese healthy volunteers, Caucasian healthy volunteers, and Caucasian renal impairment population models built in Simcyp. Finally, the newly developed population models were applied to predict the plasma concentration of four antibacterial drugs in Chinese renal impairment patients. The new physiologically based pharmacokinetic (PBPK) population models can predict the main pharmacokinetic parameters, including area under the plasma concentration–time curve extrapolated to infinity (AUC_inf), renal clearance (CL_r), and peak concentration (C_max), of ceftazidime, cefodizime, vancomycin, and cefuroxime following intravenous administrations with less than twofold error in mild, moderate, and severe Chinese renal impairment patients. The accuracy and precision of the predictions were improved compared with the Chinese healthy volunteers and Caucasian renal impairment population models. The PBPK population models were preliminarily developed and the first‐step validation results of four antibacterial drugs following intravenous administration showed acceptable accuracy and precision. The population models still need more systematic validation by using more drugs and scenarios in future studies to support their applications on dosage recommendation for Chinese renal impairment patients.

Comparison of commonly used creatinine-based GFR estimating formulas in elderly female non-diabetic patients with chronic kidney disease

Introduction: Measuring glomerular filtration rate (GFR) with the isotopic method is a gold standard. However, it is an elaborate and expensive procedure, so in everyday practice GFR is estimated with creatinine-based formulas. Despite the number of studies, it remains unclear which GFR estimating equation is the most accurate, especially in increasing elderly population. Aim: The aim of this study was to compare the commonly used formulas to assess which one of them should be used in elderly female non-diabetic patients suffering from chronic kidney disease (CKD) Material and methods: 336 non-diabetic females aged 70 and more were qualified to the study. On the basis of serum creatinine concentration, estimated GFR (eGFR) was estimated using various formulas. Results and discussion: The eGFR and CKD stages differ significantly depending on the used formula. The modification of diet in renal disease equation (MDRD) formula showed slightly, but still significantly, better correlation with creatinine concentration in serum than the CKD epidemiology collaboration equation. The Cockcroft-Gault equation formula was significantly inferior to above mentioned equations. The receiver operating characteristic curves showed that MDRD is the most sensitive equation and the differences between formulas compared in pairs were significant. Conclusions: Due to its highest correlation with creatinine and its highest sensitivity and specificity, the MDRD formula seems to be the most accurate equation to estimate GFR in elderly non-diabetic females.