A Validation Study on eGFR Equations in Chinese Patients With Diabetic or Non-diabetic CKD

Relationship Between 1,5-Anhydroglucitol and Renal Function Assessed by Dynamic Renal Scintigraphy in Type 2 Diabetes

CONTEXT

The reliability of serum 1,5-anhydroglucitol (1,5-AG) in patients with type 2 diabetes and renal insufficiency remains controversial.

OBJECTIVE

To evaluate the relationship between renal function and serum 1,5-AG and to assess the extent to which renal function influences 1,5-AG.

METHODS

A total of 5337 participants with type 2 diabetes were enrolled. The measured glomerular filtration rate (mGFR) was assayed using 99mTc-DTPA dynamic renal scintigraphy. All subjects were stratified into 5 groups based on mGFR (≥120 [n = 507], 90-120 [n = 2015], 60-90 [n = 2178], 30-60 [n = 604], and <30 mL/min/1.73 m2 [n = 33]).

RESULTS

Overall, the serum 1,5-AG and mGFR levels were 3.3 (1.7-7.0) μg/mL and 88.6 ± 24.1 mL/min/1.73 m2, respectively. mGFR was found to be negatively correlated with 1,5-AG levels (r = -0.189, P < .001). Multiple linear regression revealed that mGFR was independently and negatively related to serum 1,5-AG after adjusting for covariates including hemoglobin A1c (HbA1c; P < .001). In subgroups with mGFR ≥ 30 mL/min/1.73 m2, the correlation coefficients between 1,5-AG and HbA1c, fasting plasma glucose, postprandial plasma glucose, and the differences between postprandial and fasting plasma glucose remained significant (range, -0.126 to -0.743, all P < .01). However, the link between 1,5-AG and traditional glycemic markers was attenuated in individuals with mGFR < 30 mL/min/1.73 m2. Sensitivity analysis after excluding anemic patients showed similar results regarding the relationship between serum 1,5-AG and HbA1c across the mGFR subgroups.

CONCLUSION

Although we observed a weak inverse correlation (r = -0.189) between mGFR and serum 1,5-AG in type 2 diabetes, 1,5-AG remains a valid marker for assessing glucose control in subjects with mild or moderate renal dysfunction.

The varied Q creatinine in multi ethnics population and impact of adopting three different estimated glomerular filtration rates based on creatinine in adult populations: a call for performance validation

Background

The determination of kidney function is commonly done by estimating the glomerular filtration rate (eGFR) using serum creatinine levels. Various eGFR formulas, including the recently developed European Kidney Function Consortium (EKFC) and the Chronic Kidney Disease Epidemiology Collaboration(CKD-EPI), have been adopted and are commonly utilized in clinical settings. Nevertheless, the extent of acceptance among these formulations in the multi ethnics populace is still undetermined. Thus, this study aimed to evaluate the performance of these formulations across different glomerular filtration rate categories in the adult population.

Methods

The research involved a total of 9,557 individuals (median age of 40 years and 85% being male) who underwent routine medical examinations. Enzymatic or modified Jaffe techniques were employed to measure serum creatinine levels. The CKD-EPI2009 eGFR was employed as corresponding GFR in the comparisons. The Bland-Altman method was used to determine the average discrepancies and 95% confidence intervals of eGFR between each formula. Ultimately, in order to compare the equations, Lin's correlation coefficients were calculated for various eGFR categories.

Results

The median creatinine level in the different island population showed variability. The CKD-EPI 2009 as well as different equations showed categorical agreement within the range of 91.42 to 92.77%. The correlations between CKD-EPI2009 and CKD-EPI 2021 and EKFC were 0.998 and 0.79, respectively (p < 0.001).

Conclusion

A substantial variation in creatinine and eGFR assessment were observed among different eGFR analysis for the adult population. Prospective study in various clinical contexts using measured GFR is essential to validate eGFR.

GFRs in Chinese CKD: A systematic review

PURPOSE

This was an evidence-based study to assess which creatinine-based equation was most useful for estimated glomerular filtration rate (eGFR) in Chinese adults with chronic kidney disease (CKD).

METHODS

Multiple databases were searched to collect relevant studies on creatinine-based eGFR equations for Chinese adults with CKD in Chinese and English from January 2009 to January 2023, using "glomerular filtration rate", "GFR equations", "Chinese CKD", "chronic kidney disease", "equation development" and "equation validation". The quality of each study was assessed using the diagnostic test accuracy review by RevMan 5.4 software. The equation name, study publication year, first author, reference method for eGFR, CKD numbers, age (age ranges) of individuals, mGFR value, bias, precision, and 30% accuracy (P30) of each included equation were recorded accordingly by 2 independent investigators.

RESULTS

Of the 838 studies identified, 23 studies based on 6 creatinine-based GFR equations were included in the present review, ie, the CKD-EPI, Asian modified CKD-EPI, FAS, EKFC, Xiangya, and BSI1 equations. A total of 2979 CKD patients were included for FAS equation external assessment, and the total P30 was 72.6 %; 970 CKD patients for the EKFC equation, and the total P30 was 73.1 %. 1778 CKD patients (≥60 years of age) with a mean eGFR from 39.7 to 47.6 mL/min/1.73 m2 were pooled to assess the prediction accuracy of the BSI1 equation and demonstrated that the bias was small (-3.8-3.5 mL/min/1.73 m2), the precision was excellent (10.2-16.8 mL/min/1.73 m2), and the total P30 was 69.6 %.

CONCLUSIONS

Currently, the FAS and EKFC equations have higher P30 for eGFR among Chinese adult CKD patients. The bias and precision of BSI1 formulas was acceptable for eGFR in elderly ≥ 60 years of age, while the P30 was relatively low. Therefore, there is a clinical need to develop more accurate equations for eGFR in older CKD adults. While promising, these findings require further validation in large well controlled clinical studies.

Comparative Determination of Glomerular Filtration Rate Estimation Formulae in Type 2 Diabetic Patients: An Observational Study

Assessing glomerular filtration rate (GFR) involves collecting timed urine samples for 24 hours, requiring significant time and resources in the clinical setting. Using predictive GFR formulae to assess renal function may be a better alternative. Our goal was to determine which predictive GFR formula had the highest level of concordance with the GFR that has been measured in a resource-poor setting. This is an observational study. We selected fifty (50) individuals diagnosed with type 2 diabetes (T2DM) in Kumasi, Ghana. The sociodemographic and clinical characteristics were obtained using a structured questionnaire. Urine was obtained from each subject over 24 hours. The levels of glucose (FBG) and creatinine in patients' blood, as well as the levels of creatinine in their urine, were measured after the patients had fasted overnight. Participants had a mean age of 57.4 ± 10.7 (years), BMI of 27.8 ± 4.1 (kg/m2), FBG of 9.0 ± 3.1 (mmol/L), and creatinine concentrations of 95.6 ± 29.1 (μmol/L). A Krouwer plot was used to compare the measured GFR with three formulae: Chronic Kidney Disease Epidemiology (CKD-EPI), Modification of Diet in Renal Disease (MDRD), and Cockroft-Gault (CG) for GFR prediction. Among the 3 estimates, CG showed nonsignificance (p > 0.05) with the measured GFR. The primary finding was that the GFR calculated using the CG formula was not different from the GFR measured, suggesting that CG is the most appropriate alternative GFR estimate among a cross-section of T2DM patients in Ghana.

Estimating Glomerular Filtration Rate in China: Is the European Kidney Function Consortium (EKFC) Equation the Solution?

The new European Kidney Function Consortium (EKFC) creatinine-based equation has been developed to be applicable over the entire age range (from 2 to 100 years) without any loss of performance in young adults and without loss of continuity in estimating glomerular filtration rate (GFR) between adolescents and adults. This goal is obtained by better taking into account the relationship between serum creatinine (SCr) and age in the estimating GFR model. This is accomplished by rescaling SCr, namely, dividing SCr by so-called Q value which is the median normal value of SCr concentration in a given healthy population. The better performance of the EKFC equation, compared to the current equations, has been shown in large European and African cohorts. Such good results are also suggested in cohorts from China, including in the current issue of Nephron. The good performance of the EKFC equation is observed, especially when the authors used a specific Q value for their populations notwithstanding GFR was measured by a controversial method. Using a population-specific Q value could make the EFKC equation universally applicable.

Comparison of estimated glomerular filtration rate equations based on serum creatinine-, cystatin C- and creatinine-cystatin C in elderly Chinese patients

BACKGROUND

This study aimed to further evaluate the accuracy of eleven GFR equations in different subgroups of an elderly Chinese hospitalized population.

METHODS

All participants of the study were divided into seven separate groups including age-subgroup, sex-subgroup, GFR Staging-subgroup and whether combined with diabetic, hypertensive, coronary heart disease (CHD) and cerebrovascular disease. Referring to Tc-99m-DTPA dual plasma sample clearance method, six serum creatinine (Cr)-based [Cockcroft-Gault (CG), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI_Cr), Lund-Malmö Revised (LMR), Berlin Initiative Study (BIS1), Full Age Spectrum (FAS_Cr) and European Kidney Function Consortium (EKFC)], two serum cystatin C(Cys)-based (CKD-EPI_Cys and FAS_Cys), and three Cr-Cys combination based (CKD-EPI_Cr-Cys, BIS2 and FAS_Cr-Cys) equations were employed. Bias, interquartile range of the median difference (IQR), P30, and GFR misclassification rate were calculated to compare the performance of the selected equations.

RESULTS

A total of 359 elderly Chinese patients were enrolled. Overall, median mGFR was 36.91(25.26,56.32)ml/min/1.73 m². Smaller biases (ml/min/1.73 m²) were shown in CKD-EPI_Cr and BIS1 equations (0.75 and 0.61). IQR (ml/min/1.73m²) was least with BIS2 equation and FAS_Cr-Cys equation (10.34 and 10.65). For accuracy (P30), performance of FAS_Cr-Cys, BIS2, and BIS1 equation was superior (78.3%, 78.0%, and 74.7%, respectively). In terms of RMSE (ml/min/1.73 m²), BIS1 and FAS_Cr-Cys equation performed better (12.44 and 12.51).

CONCLUSIONS

Overall, this study showed that the eGFR equations were less accurate in the diabetic and non-hypertension group than in the non-diabetic and hypertension group, respectively. Among all enrolled equations, the BIS2 and FAS_Cr-Cys equations might be the best choice to evaluate glomerular filtration rate in Chinese elderly patients.

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.

Construct a classification decision tree model to select the optimal equation for estimating glomerular filtration rate and estimate it more accurately

Chronic kidney disease (CKD) has become a worldwide public health problem and accurate assessment of renal function in CKD patients is important for the treatment. Although the glomerular filtration rate (GFR) can accurately evaluate the renal function, the procedure of measurement is complicated. Therefore, endogenous markers are often chosen to estimate GFR indirectly. However, the accuracy of the equations for estimating GFR is not optimistic. To estimate GFR more precisely, we constructed a classification decision tree model to select the most befitting GFR estimation equation for CKD patients. By searching the HIS system of the First Affiliated Hospital of Zhejiang Chinese Medicine University for all CKD patients who visited the hospital from December 1, 2018 to December 1, 2021 and underwent Gate's method of ^99mTc-DTPA renal dynamic imaging to detect GFR, we eventually collected 518 eligible subjects, who were randomly divided into a training set (70%, 362) and a test set (30%, 156). Then, we used the training set data to build a classification decision tree model that would choose the most accurate equation from the four equations of BIS-2, CKD-EPI(CysC), CKD-EPI(Cr-CysC) and Ruijin, and the equation was selected by the model to estimate GFR. Next, we utilized the test set data to verify our tree model, and compared the GFR estimated by the tree model with other 13 equations. Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Bland-Altman plot were used to evaluate the accuracy of the estimates by different methods. A classification decision tree model, including BSA, BMI, 24-hour Urine protein quantity, diabetic nephropathy, age and RASi, was eventually retrieved. In the test set, the RMSE and MAE of GFR estimated by the classification decision tree model were 12.2 and 8.5 respectively, which were lower than other GFR estimation equations. According to Bland-Altman plot of patients in the test set, the eGFR was calculated based on this model and had the smallest degree of variation. We applied the classification decision tree model to select an appropriate GFR estimation equation for CKD patients, and the final GFR estimation was based on the model selection results, which provided us with greater accuracy in GFR estimation.

The Chronic Kidney Disease Epidemiology Collaboration equations perform less well in an older population with type 2 diabetes than their non-diabetic counterparts

Objectives

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are based on creatinine alone (CKD-EPIcr), cystatin C alone (CKD-EPIcys) and combined creatinine and cystatin C (CKD-EPIcr-cys). It remains unclear whether these equations perform differently in older adults with type 2 diabetes than they do in non-diabetic older individuals.

Methods

This single-center cross-sectional study was performed in adults aged ≥ 65 years between January 2019 and December 2021. Glomerular filtration rate (GFR) was measured by technetium-99m-diethylene triamine pentaacetic acid (^99mTc-DTPA) renal dynamic imaging. The bias (difference between measured and estimated GFR), precision [interquartile range (IQR) of the median difference between measured GFR and estimated GFR] and accuracy P30 (percentage of estimated GFR within 30% of measured GFR) were considered the criteria of equation performance.

Results

Finally, 476 participants were enrolled, including 243 adults with type 2 diabetes and 233 non-diabetic adults. The mean age of the included participants was 71.69 ± 6.4 years and 262 (55%) were male. The mean measured GFR was 49.02 ± 22.45 ml/min/1.73 m². The CKD-EPIcr-cys equation showed significantly greater bias and lower accuracy (P30) in individuals with diabetes than in the non-diabetic group (median bias, 4.08 vs. 0.41 ml/min/1.73 m², respectively, p < 0.05; P30, 63.78% vs. 78.54%, respectively, p < 0.05). The precision IQR indicated that CKD-EPIcr-cys had also lower precision in individuals with diabetes than in the non-diabetic controls (17.27 vs. 15.49 ml/min/1.73 m², respectively). Similar results were observed for CKD-EPIcr and CKD-EPIcys equations. The P30 of all three equations failed to reach 80% in diabetic and non-diabetic groups.

Conclusions

The performance of the CKD-EPI equations was lower in a group of patients aged ≥ 65 years with type 2 diabetes than in non-diabetic counterparts. However, each equation still had limitations regarding accuracy in older adults with or without diabetes.

Systematic Review and Meta-Analysis Program Based on Effectiveness of a Multidisciplinary Model of Care for Patients with Chronic Kidney Disease

The effectiveness of the multidisciplinary nursing model in the nursing of chronic kidney disease (CKD) by using meta-analysis is explored. Relevant literatures that are in line with the multidisciplinary nursing model for CKD intervention are searched and screened from domestic and foreign literature databases such as Wanfang Medical Center, CNKNET, VIP, and PubMed, and Meta-analysis is conducted with RevMan 5.2 software. A total of 6 literatures are included, and the publication bias of the included literatures is low. Meta-analysis shows that the multidisciplinary group had a better Hb compliance rate, Hb level, Scr, eGFR, SBP, and DBP than the traditional group. The experimental results show that multidisciplinary nursing intervention can improve the nursing effect of patients with CKD and help to improve Hb, Scr, blood pressure, and glomerular filtration function of patients.

Shrunken Pore Syndrome Is Associated with Renal Function Decline in Female Patients with Kidney Diseases

Background

Shrunken pore syndrome (SPS) represents selective impairment of kidney filtration of low-molecular-weight molecules between 1 and 30 kDa and has been related to outcomes including morbidity, mortality, and cardiovascular events. However, the prevalence and kidney outcomes of SPS have not been investigated in patients with IgA nephropathy (IgAN) and membranous nephropathy (MN).

Methods

We retrospectively collected information of 536 patients including 414 with IgAN and 122 with MN. SPS was mainly defined by cystatin C-based eGFR < 70% of creatinine-based eGFR using the CAPA-LM equation pairs, while CKD-EPI equations were also employed in sensitivity analyses. Prevalence rate of SPS and its association with end-stage renal disease (ESRD) or severe eGFR decline (≥50% eGFR reduction or doubling of baseline creatinine) were investigated.

Results

44% (8%) patients were identified as possessing SPS using the CAPA-LM definition. ESRD happened in 24 patients during the average follow-up period of 27.7 months. Despite dramatic increase of incidence rate of ESRD for SPS, significant hazard ratio (HR) only existed in IgAN patients after multivariable adjustment (HR: 8.35, 95% CI: 2.10~33.26), but lost significance in sensitivity analyses. 36 patients were determined as having experienced severe eGFR decline after excluding transient creatinine fluctuation. SPS was associated with severe eGFR decline by Kaplan-Meier survival analyses in the overall population as well as the IgAN, MN, male, and female subpopulations, which remained significant in multivariable adjustments in all groups except IgAN. However, only in female patients the association between SPS and eGFR decline remained significant in all the sensitivity analyses.

Conclusions

SPS was independently associated with eGFR decline in female patients with IgAN and MN.

The Prevalence, Progress and Risk Factor Control of Chronic Kidney Disease in Chinese Adults With Type 2 Diabetes Mellitus in Primary Care

Objective

This study aimed to evaluate the prevalence of chronic kidney disease (CKD) in Chinese adults with T2DM in primary care, and the association of HbA1c, blood pressure (BP) and triglycerides (TG), i.e. ABC control at follow up (FU) with the progress and regression of CKD.

Methods

A total of 5123 patients with ≥3 measurements of estimated glomerular filtration rate (eGFR), urinary albumin-to-creatinine ratio (UACR), HbA1c, BP, LDL-C and TG, and FU ≥ 12 months were included into final analysis. The presence of CKD was defined as the presence of albuminuria (UACR ≥ 30 mg/g), impaired eGFR (eGFR < 60 ml/min/1.73 m2) or both, and was categorised as low, moderate and high/very high risk. The change of CKD risk for outcome was categorised as stable (no change), progress (risk increase) and regress (risk decrease) from baseline to the last visits (LV).

Results

The prevalence of CKD, impaired eGFR and albuminuria was 29.6%, 5.8% and 27.1% at baseline, with 70.4%, 20.3%, 7.0% and 2.3% of patients distributed in low, moderate, high and very high risk group. There were 3457 (67.5%), 1120 (21.8%) and 546 (10.7%) patients had CKD outcome risk stable, progressed and regressed respectively. The proportion of patients reaching targets of BP ≤ 130/80 mmHg, HbA1c<7.5%, LDL-C<2.60 mmol/L increased from baseline to FU and LV, together with increased usage of insulin, RAS inhibitors and lipid lowering medications. After multivariable adjustment, the HbA1c<7.5% (OR: 0.66, 95%CI 0.56-0.78), TG< 1.7 mmol/L (OR: 0.81, 95%CI 0.68-0.96) at FU and BP ≤ 130/80 mmHg at LV (OR: 0.82, 95%CI 0.70-0.95) was negatively associated with CKD outcome risk progress.

Conclusion

The prevalence of CKD was high with 21.8% of patients progressing to higher CKD outcome risk at FU, attention should be paid on long term and better ABC control.

The UK Chinese population with kidney failure: Clinical characteristics, management and access to kidney transplantation using 20 years of UK Renal Registry and NHS Blood and Transplant data

Background

Little is known about the clinical demographics of and access to transplantation for Chinese diaspora populations with kidney disease.

Methods

The UK Renal Registry provided data on adults with ethnicity recorded as ‘Chinese’ or ‘White’ starting Kidney Replacement Therapy (KRT) 1/1/97-31/12/17. Baseline characteristics were compared between Chinese and White patients. Multivariable logistic regression models were used to investigate the relationships between Chinese ethnicity and i) being listed for deceased-donor transplantation at start of KRT, ii) being listed 2 years after start of KRT, iii) pre-emptive kidney transplantation, iv) kidney transplantation 3 years after start of KRT, and v) living-donor kidney transplantation (LDKT).

Results

UK Chinese patients were younger at start of KRT (61.6 vs 65.6 years, p <0.001) and had more diabetic kidney disease (29% vs 20%, p<0.001) and glomerulonephritis (21% vs 13%, p<0.001) than White patients. We found evidence of interaction between ethnicity and sex. Compared to UK White men, UK Chinese men had lower odds of pre-emptive transplant (aOR 0.28, 95% CI [0.10–0.76]) and transplant within 3 years of KRT start (aOR 0.65, [95% CI 0.49–0.87], P = 0.004). UK White women and Chinese women had the same likelihood of pre-emptive transplant (aOR 0.78, 95% CI [0.38–1.61]), or transplant within 3 years of KRT start (aOR 0.94, 95% CI [0.60–1.46]). Both UK Chinese men and women had markedly lower odds of LDKT compared to Whites aOR 0.34 [95% CI 0.21–0.53].

Conclusions

UK Chinese are less likely to receive a LDKT. UK Chinese men have lower odds of accessing pre-emptive wait-listing and transplantation. Understanding whether these disparities reflect modifiable barriers will help ensure equitable access to transplantation.

The Association Between the Decline of eGFR and a Reduction of Hemoglobin A1c in Type 2 Diabetic Patients

Objective

This study aimed to explore the relationship between short-term (≤12 months) changes in the estimated glomerular filtration rate (eGFR) and hemoglobin A1c (HbA1c) in patients with type 2 diabetes (T2D).

Method

A total of 2,599 patients with T2D were enrolled if they were registered in the Diabetes Sharecare Information System, were aged 18-75 years, and had 2-3 HbA1c and eGFR measurements within the preceding 12 months. The studied patients were categorized into five groups based on eGFR, i.e., the relatively stable (RS), fast decline (FD), modest decline (MD), modest increase (MI), and fast increase (FI) groups.

Results

The median eGFR changes from baseline were -22.14, -6.44, 0.00, 6.32, and 20.00 ml/min per 1.73 m2 for patients in the FD, MD, RS, MI, and FI groups, respectively. Up to 1,153 (44.4%) subjects experienced an eGFR decline of ≥3.5 ml/min per 1.73 m2, including 821 (31.6%) FD subjects and 332 (12.8%) MD subjects. A decreased trend was found between the eGFR change and HbA1c decrease category, even after multivariable adjustment. In general, an eGFR FD was frequently found in patients who had an HbA1c reduction of ≥3.00% and a baseline HbA1c ≥8.0%; alternatively, such a result was also observed for a urinary albumin-to-creatinine ratio (UACR) of 30.0-300.0 mg/g, regardless of a diabetes duration of <10.0 or ≥10.0 years, or in patients who had an HbA1c reduction of ≥1.00% accompanied by hyperfiltration.

Conclusions

Some patients with T2D experienced an eGFR FD or MD during the ≤12-month follow-up period. A significant downward trend in eGFR change was demonstrated alongside an HbA1c reduction, independent of UACR stage, diabetes duration, and hyperfiltration. Sustained monitoring and cautious interpretation of the HbA1c and eGFR changes will be needed in clinical practice.

Performance of 4 Creatinine-based Equations in Assessing Glomerular Filtration Rate in Adults with Diabetes

AIMS

To evaluate diagnostic performance of glomerular filtration rate (GFR) estimated by modification of diet in renal disease (MDRD), chronic kidney disease epidemiology collaboration (CKD-EPI), full age spectrum (FAS), and revised Lund-Malmö (r-LM) equations in adults with diabetes.

METHODS

Individuals were included in this cross-sectional study if they had at least 1 measurement of technetium-99m diethylenetriamine-pentaacetic acid (99mTc-DTPA) GFR (mGFR) and serum creatinine (1487 patients with 2703 measures). GFR calculated by estimation equations was compared with mGFR. Diagnostic performance was assessed using concordance correlation coefficient (CCC), bias, precision, accuracy, reduced major axis regression (RMAR), and Bland-Altman plot. Analysis was repeated in subgroups based on sex, diabetes type, Hemoglobin A1C, and GFR level.

RESULTS

Of all patients, 1189 (86%) had type 2 diabetes. Mean mGFR, MDRD, CKD-EPI, FAS, and revised Lund-Malmö eGFR were 66, 72, 74, 71, and 67 mL/min/1.73m2, respectively. Overall, the r-LM had the highest CCC (0.83), lowest bias (-1.4 mL/min/1.73 m2), highest precision (16.2 mL/min/1.73 m2), and highest accuracy (P10 = 39%). The RMAR (slope, intercept) in r-LM, FAS, MDRD, and CKD-EPI was 1.18, -13.35; 0.97, -2.9; 1, -6.4, and 1.04, -11.3, respectively. The Bland-Altman plot showed that r-LM had the lowest mean difference and the narrowest 95% limit of agreement (-1.0, 54.1 mL/min/1.73 m2), while mean difference was more than 5-fold higher in FAS, MDRD, and CKD-EPI (-5.2, -6.3, and -8.2, respectively).

CONCLUSIONS

In adults with diabetes the revised Lund-Malmö performs better than MDRD, CKD-EPI, and FAS in calculating point estimates of GFR.

Renal function is associated with plasma trimethylamine-N-oxide, choline, L-carnitine and betaine: a pilot study

INTRODUCTION

Chronic kidney disease (CKD) is characterized by decreased glomerular filtration rate (GFR) due to a variety of causes. Most patients remain undiagnosed at early stage of CKD and proceed to end stage CKD due to unawareness and lacking of efficient biomarkers. Trimethylamine-N-oxide (TMAO) and its predecessor products: choline, L-carnitine and betaine are associated with reduced renal function. However, whether the combined variation of the four metabolites could contribute in prediction and stratification of impaired glomerular function in Chinese CKD patients is unknown. Our aim is to investigate the associations of plasma TMAO, choline, L-carnitine and betaine with glomerular filtration in CKD patients.

MATERIALS AND METHODS

A total of 65 CKD patients and 64 healthy controls were enrolled in this study. Fasting plasma metabolites were detected using liquid chromatography-based method.

RESULTS

Plasma TMAO, choline, betaine and L-carnitine levels were differentially correlated with eGFR. The four metabolites were independently associated with CKD after adjustment for multiple traditional risk factors. The combination of the four metabolites had good performance at discriminating CKD from healthy controls (AUC = 0.96) as well as discriminating low eGFR from high eGFR in CKD (AUC = 0.96).

CONCLUSION

Combinations of TMAO and its precursors were associated with glomerular function and might be utilized in evaluation of CKD.