Relationship between insulin resistance and increased carotid artery intima-media thickness in non-diabetic kidney disease patients

Objective To evaluate the relationship of insulin resistance (IR) and carotid artery intima-media thickness (CA-IMT), plaque status in non-diabetic non-dialysis chronic kidney disease (CKD) patients with different stages. Methods One hundred and seventeen non-diabetes non-dialysis CKD patients were enrolled into this cross-sectional observational study. Insulin resistance index (HOME-IR) was assessed by the homeostasis model assessment. Patients with HOME-IR≥1.73 were defined as insulin resistance. And patients with CA-IMT≥0.9 mm were defined as thickening. The blood pressure measurement, heart Doppler ultrasound, bilateral carotid artery ultrasound examination, blood biochemistry and urine protein test were performed, eGFR was calculated by EPI formula. Results The prevalence of IR was 47.01% in 117 non-diabetic non-dialysis CKD patients, and it was 35.71%, 50.00% and 54.55% in eGFR≥60ml•min-1•(1.73 m2)-1 group, 30≤eGFR＜60ml•min-1•(1.73 m2)-1 group, and eGFR＜30ml•min-1•(1.73 m2)-1 group separately. In eGFR＜30ml•min-1•(1.73 m2)-1 group, cystain C, homocysteine, parathyroid hormone, Scr, BUN, uric acid, interventricular septal thickness, left ventricular dimension, left ventricular posterior wall thickness were significantly higher than that in the other two groups (P＜0.01), while the level of hemoglobin was significantly lower (P＜0.01); then the levels of serum albumin and systolic pressure were higher than that in the eGFR≥60ml•min-1•(1.73 m2)-1 group, however, the levels of total cholesterol and low-density lipoprotein-cholesterol were lower than that in the eGFR≥60ml•min-1•(1.73 m2)-1 group. Correlation analysis showed that insulin resistance index was significantly correlated with CA-IMT (r=0.444, P=0.006）in the eGFR＜30ml•min-1•(1.73 m2)-1 group, however, there wasn’t correlation in other two groups. And although insulin resistance wasn’t correlated with soft plaque, it was significantly correlated with hard plaque (χ2=6.476, P=0.011) in the eGFR＜30ml•min-1•(1.73 m2)-1 group. The Logistic regression analysis results displayed aging increase was the independent risk factor of the CA-IMT thickening for non-diabetes non-dialysis CKD patients but not insulin resistance. Conclusions HOMA-IR is correlated with CA-IMT and hard plaque when eGFR＜30ml•min-1•(1.73 m2)-1 in non-diabetes non-dialysis CKD patients. However, the insulin resistance isn’t the independent risk factor of the CA-IMT thickening for non-diabetes non-dialysis CKD patients.     

Cystatin C-based calculation of glomerular filtration rate in kidney transplant recipients

Cystatin C (Cys C) has been shown to be an alternative marker of renal function. However, estimation of the glomerular filtration rate (GFR) based on Cys C has received little attention. Recently, several Cys C-based equations were developed in different patient cohorts. To date, the benefit of a Cys C-based GFR calculation in patients after renal transplantation (RTx) remains to be elucidated. We compared the diagnostic accuracy of three Cys C-based formulae (Larsson, Hoek, Filler which used an immunonephelometric method) with the results of the Modification of Diet in Renal Disease (MDRD) formula. GFR was measured by means of technetium-diethylenetriamine pentaacetic acid ((99m)Tc-DTPA) clearance in 108 consecutive patients after RTx. Correlation coefficients of all calculated GFR estimates with the true GFR were high but did not differ significantly from one another (0.83-0.87). The MDRD and Filler equations overestimated GFR significantly, whereas the Larsson equation significantly underestimated GFR. Bias of the Hoek formula was negligible. Precision of the Hoek (8.9 ml/min/1.73 m(2)) and Larsson equations (9.6 ml/min/1.73 m(2)) were significantly better than MDRD equations (11.4 ml/min/1.73 m(2); P< or =0.035 each). Accuracy within 30% of real GFR was 67.0 and 65.1% for the MDRD and Filler formulae, and 77.1% for the Larsson and Hoek formulae, respectively. Accuracy within 50% of true GFR for the Hoek formula (97.2%) was better than for the MDRD equations (85.3%). Cys C-based formulae may provide a better diagnostic performance than creatinine-based equations in GFR calculation after RTx.     

Effect of ACEI/ARBs on peritoneal protein loss in peritoneal dialysis patients

Objective To observe the effect of ACEI/ARBs on peritoneal protein loss in peritoneal dialysis patients. Methods Total of 81 peritoneal dialysis patients were included in the study. Thirty-seven cases were treated with ACEI/ARBs(ACEI/ARBs group), forty-four cases did not receive any ACEI/ARBs (Control group). After 6 mouths, the effect of ACEI/ARBs on peritoneal protein loss was evaluated, and the effects of residual renal function and dialysis age on the peritoneal protein loss were statistically analyzed. Results (1) The peritoneal protein loss was reduced in ACEI/ARBs group, the difference was 1.2(0, 1.6) g/24 h, while in the control group, the protein loss had no statistically significant change, the difference between the two group was statistically significant (P＜0.05). (2) When the patients’ eGFR＞2 ml•min-1•(1.73 m2)-1, the difference of the protein loss in ACEI/ARBs group was 1.4(1.2, 2.3) g/24 h , the difference between the two group was statistically significant(P＜0.01); when patients’ eGFR＜2 ml•min-1•(1.73 m2)-1, the differences of the protein loss between the two groups had no significant difference (P＞0.05). (3) When the dialysis ages＜12 months , the difference of the protein loss was 1.0(0.8, 1.4) g/24 h in ACEI/ARBs group，the differences between the two groups was statistically significant (P＜0.05); when the dialysis ages was from 12 months to 24 months or more than 24 months, The differences of the protein loss between the two groups and control group were both not statistically significant (P＞0.05). Conclusion ACEI/ARBs can reduce peritoneal protein loss in PD patient，the effect was better when patients’ residual renal function was better or dialysis age was shorter.     

Application of MDRD and CKD-EPI equations in patients with peripheral arterial diseases

Objective To compare the performance of newly developed Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and Modification of Diet in Renal Disease (MDRD) equation in patients with peripheral arterial diseases (PAD). Methods A total of 841 patients with PAD were enrolled in this retrospective cohort study. Estimated glomerular filtration rate (eGFR), calculated by MDRD and CKD-EPI equation respectively, was analyzed by Spearman correlation analysis, Bland-Altman method and Kappa test for the evaluation of correlation and consistency. Net re-classification improvement (NRI) was adopted to compare the death risk assessment between these two equations. Results Although the eGFR was 4.33 ml•min-1•(1.73 m2)-1 higher with MDRD equation than with CKD-EPI equation, there were still significant correlation and fine consistency between eGFRMDRD and eGFRCKD-EPI (Kappa：0.749, r=0.991, P＜0.05). The CKD-EPI equation re-classified 9 (1.1%) patients upward to higher eGFR category and 143 (17.0%) patients downward to lower eGFR category. Besides, the performance of risk assessment for all-cause death was better with CKD-EPI equation than with MDRD equation (NRI=0.059, P＜0.05), which was not the case for cardiovascular death (NRI=0.022, P＞0.05). Conclusions There is no solid evidence suggesting that CKD-EPI equation performs better than MDRD equation.     

Calculation of glomerular filtration rate based on cystatin C in cirrhotic patients.

BACKGROUND: Plasma creatinine and creatinine clearance are of limited value for the estimation of renal function in cirrhotics. In these patients, cystatin C (Cys C) has been proposed as an alternative marker of glomerular filtration rate (GFR) and Cys C-based equations for calculation of GFR have been developed in non-cirrhotic patient cohorts. METHODS: We retrospectively analyzed correlation, bias, precision and accuracy of two Cys C-based formulae (Larsson and Hoek) for GFR estimation in comparison with two creatinine-based equations (Cockroft & Gault and MDRD). The Cys C was determined by an immunonephelometric method. The GFR was measured by means of inulin clearance in 44 consecutive patients with liver cirrhosis. RESULTS: On average, inulin clearance was 28.3 (95% CI: 29.2-41.3 ml/min/1.73 m2). Creatinine as well as Cys C-based equations overestimated the true GFR by 105-154%. However, Cys C-based equations showed significantly lower bias and higher precision than the creatinine-based formulae. Correlation and accuracy tended to be better with the Hoek and Larsson equation than with the Cockroft & Gault or MDRD formulae. Hoek and Larsson equations showed a similar diagnostic performance in all statistical procedures. CONCLUSION: Our data suggest a significant improvement of GFR estimation in liver cirrhotics by means of the Cys C-based Hoek and Larsson formulae. However, all estimates remain a crude approximation of true GFR and thus cannot replace gold standard methods.     

Effect of serum uric acid level on renal function in elderly hypertensive patients: a retrospective cohort study

Objective To explore the relationship of serum uric acid level with estimated glomerular filtration rate (eGFR) of elderly patients with hypertention based on a retrospective cohort study. Method The subjects included 465 cases who had a readmission after 3 years of follow-up in an original cohort of 1648 patients with diagnosis of essential hypertension in Fujian Provincial Hospital from August 2007 to September 2009. Multiple regression analysis was performed to examine the effect of serum uric acid level on renal function. Results Four hundred and sixty-five subjects were followed up for an average of 3.9 years. Mean patient age was 68.3±9.7 years. There was no significant difference in uric acid between the baseline and 3 years later (P＞0.05). Multiple regression analysis showed that after adjustment for age, gender, diabetes, body mass index, blood pressure etc, each 100 μmol/L-higher uric acid at baseline was associated with 4.40 ml•min-1•(1.73m2)-1 decrease in eGFR[95% confidence interval (CI): -6.25--2.55, P＜0.01]. According to the alteration of the serum uric acid, all patients were divided into the group with decreased uric acid and the group with increase uric acid. The eGFR was lower in patients with increased uric acid than that in patients with decreased uric acid 3 years later [(70.63±21.54) ml•min-1•(1.73m2)-1 vs (79.62±21.16) ml•min-1•(1.73 m2)-1, P＜0.01] and there was no significant difference at baseline between the two groups (P＞0.05). Multiple logistic regression analysis showed that after adjusting for aging, gender, diabetes, alteration of blood pressure etc, baseline uric acid was associated with a higher risk for eGFR decreasing more than 10 ml•min-1•(1.73m2)-1 3 years later [hazard ratio (HR)=2.11, 95%CI: 1.24-3.59, P＜0.01]; increased uric acid 3 years later resulted in a higher risk for renal function deterioration (HR=2.60, 95%CI: 1.67-4.07, P＜0.01). Conclusions Elderly hypertensive patients with baseline hyperuricemia have a lower eGFR, resulting an increased risk of chronic kidney disease. While the patients with declined uric acid had a lesser imparied renal function. It suggests that the improvement of uric acid may help to slow down the deterioration of renal function in elderly hypertensive patients.     

Alternative definition of acute kidney injury following liver transplantation: based on serum creatinine and cystatin C levels

OBJECTIVE: The aim of this study was to verify the estimation and the predictive abilities of serum creatinine (Cr), serum cystatin C (Cys C), and related formulas for acute kidney injury (AKI). PATIENTS AND METHODS: Thirty patients who underwent cadaveric donor liver transplantation were enrolled in this prospective study. Glomerular filtration rate (GFR) was assessed by the 99mTc DTPA clearance method and estimated by Cr-predicted clearances (Cockcroft-Gault method [CG] and abbreviated Modification of Diet in Renal Disease equation [MDRD]) as well as by 3 other Cys C-based formulas (Hoek, Filler, and Larsson). AKI was confirmed as GFR<80 mL/min/1.73 m2 in the first posttransplantation week. RESULTS: GFR was significantly correlated with reciprocal Cr, reciprocal Cys C, and the 5 formulas (P<.001 for all). The receiver operating characteristic (ROC) area of Cys C was larger than that of Cr (.937 vs .794, P<.05). ROC area of Hoek, or Filler or Larsson was also larger than that of CG or MDRD (.937, .935, .937 vs .802, .849, P<.05 for all). ROC analysis showed the cutoff values were 1.0 mg/dL for Cr and 1.57 mg/L for Cys C. Hoek, Filler, and Larsson equations all underestimated AKI; their optimal cutoff values should be adjusted to 47, 56, and 44 mL/min/1.73 m2, respectively. CONCLUSION: Cys C is a better predictor of AKI than Cr. A value of more than 1.57 mg/L might be considered a new definition of AKI.     

MDRD方程在我国慢性肾脏病患者中的改良和评估

目的开发适合我国慢性肾脏病(CKD)患者的肾小球滤过率(GFR)评估方程。方法收集国内不同地域、肾功能不同分期的CKD患者684例的有关资料。随机选取454例为开发组,230例为验证组。以双血浆法~(99m)Tc-DTPA血浆清除率为GFR参考值。(1)在简化MDRD方程中添加种族系数；(2)多元逐步回归线法开发新的GFR评估方程；(3)将上述两种改良的方程与改良前简化MDRD方程进行偏离度、精确度、准确性比较。结果684例患者中,男352例,女332例,平均年龄(49．9±15．8)岁。上述两种改良的简化MDRD方程在肾功能不同分期内偏离度分别为543．0、677．2和2175．0任意单位；精确度分别为57．5、56．5和60．7 ml·min~(-1)·(1．73 m~2)~(-1)；准确性均优于改良前简化MDRD方程,差异有统计学意义(30%的准确性由66．1%提高至77．8%和79．6%,P＜0．05)。结论基于我国CKD人群特点,改良的简化MDRD方程与改良前方程相比,表现了显著的优势,可以替代改良前简化MDRD方程,应用于我国CKD患者的GFR评估。     

Cystatin C-based equations in renal transplantation: moving toward a better glomerular filtration rate prediction?

Creatinine-based glomerular filtration rate (GFR) estimators perform poorly in renal transplant recipients. Cystatin C might be a better alternative to serum creatinine in assessing renal graft function. We compared several cystatin C-based equations with the modification diet renal disease (MDRD) equation in 120 adult renal transplant recipients for whom the GFR was measured by the gold standard inulin clearance. Mean inulin-measured GFR was 52.6 mL/min/1.73 m (range, 13-119). The Hoek, Rule, Le Bricon, and Filler cystatin C-based formulas showed significantly better performances (accuracy 30% of 82%, 81%, 78%, and 71%), than the MDRD equation (58%, Mac Nemar test, P<0.01). Sensitivity to detect a GFR below 60 mL/min/1.73 m was significantly higher for the Hoek and the Rule equations (0.95, 95% CI 0.91-1) than for the MDRD equation (0.76, 95% CI 0.67-0.85). These data confirm that cystatin C as a GFR marker offers significant advantages over creatinine in renal transplantation.     

A Comparison of GFR estimating formulae based upon s-cystatin C and s-creatinine and a combination of the two.

BACKGROUND: Current recommendations (KDIGO and NKF-K/DOQI) are that patients with chronic kidney diseases (CKD) should be classified in stages 1-5 based on GFR. A serum creatinine-based prediction equation (abbreviated MDRD formula) can be used to estimate GFR (eGFR). Cystatin C has been proposed as an alternative filtration marker to creatinine. We present validation of currently used formulae for eGFR based upon s-creatinine and s-cystatin C and we compare two different methods for the determination of cystatin C. METHODS: S-cystatin C and s-creatinine were measured in 644 patients referred for determination of GFR by plasma clearance of iohexol during the period 1 June 2004 to 31 December 2005. S-cystatin C was determined by turbidimetry using two different reagents (DAKO A/S and Gentian A/S). The 644 patients were divided into two groups. Group 1 was used to calculate own eGFR-formulae based on s-cystatin C (Orebro-cyst). Group 2 was used to validate the formulae. Three creatinine-based equations (Cockcroft-Gault, MDRD and Jelliffe) and seven cystatin C-based (Larsson, Hoek, Filler, leBricon, Grubb and Orebro-cyst DAKO, Gentian) were evaluated. Evaluation was done according to the recommendations by K/DOQI. RESULTS: In the test sample (group 2) mean GFR (iohexol clearance) was 50.4 ml/min/1.73 m(2) (range 12-150)-mean s-cystatin C (DAKO AS) was 1.63 mg/l and mean s-cystatin C (Gentian AS) 1.92 mg/l. The s-cystatin C concentrations obtained by the Gentian method were approximately 10% lower than the DAKO method within the normal GFR range but were approximately 40% higher within the low GFR range. Bias for the creatinine-based equations was in the range -0.9 to 5.9 ml/min/1.73 m(2) and for the cystatin C-based equations in range -2.4 to 7.9 ml/min/ 1.73 m(2). Accuracy within 30% ranged from 68.6 to 80.4% and 54.0 to 82.9%, respectively. By combining both, an accuracy within 30% for 87.0% could be reached (MDRD/cystatin C by Gentian). Overall the patients were correctly classified for the different stages of CKD in 62.1-64.0% for the creatinine-based equations, 61.5-72.0% for the cystatin C-based equations and 70.2-73.9% for the combination. CONCLUSION: Estimating GFR using formulae based on s-creatinine or s-cystatin C alone was equally accurate according to the NKF K/DOQI guidelines. A formula that combines both provided a greater accuracy. If Cystatin C, which is clearly more expensive, is used, the choice of the cystatin C determination method and an adjusted prediction equation is essential. Use of the IDMS-traceable MDRD seems to yield the best cost-benefit ratio for routine practice.     

Prognostic comparison of patients starting peritoneal dialysis within two weeks and more than two weeks after catheter implantation

Objective To compare the outcomes of patients starting peritoneal dialysis (PD) within two weeks and more than two weeks after catheter implantation. Methods All the patients undergoing Tenckhoff catheter implantation and initiating PD in Renji Hospital from January 2001 to December 2010 were enrolled in the study. Patients started PD within 2 weeks after catheter insertion were defined as urgent group, and those started PD 2 weeks later were defined as planned group. Kaplan?Meier curves and Log-rank tests were used to compare outcomes between two groups. Results Among 657 patients in this study, median break-in period was 6 days of 469 (71.4%) patients in urgent group and 26 days of 188 (28.6%) patients in planned group. Compared to planned group, patients of urgent group were younger [(52.6±17.3) vs (56.1±15.3) year, P＝0.017], had less eGFR [(5.36±2.03) vs (6.50±2.50) ml•min-1•(1.73 m2）-1, P＜0.01], lower serum albumin [(34.0±5.7) vs (36.2±5.9) g/L, P＜0.01] and hemoglobin [(76.9±18.8) vs (80.8±17.9) g/L, P＝0.018], and higher phosphate [(2.19±0.67) vs (1.98±0.52) mmol/L, P＜0.01]. Urgent group presented more catheter dysfunctions needed to transfer to hemodialysis (2.1% vs 0%, P＝0.044). The 1-, 2-, 3- and 5-year technique survival rates of urgent and planned group were 94% vs 98%, 92% vs 94%, 90% vs 92% and 86% vs 85% respectively. There was no significant difference in technique survival (Log-rank＝1.536, P＝0.22) and peritonitis?free survival (Log-rank＝0.035, P＝0.85) between two groups. The 1-, 2-, 3- and 5-year patient survival rates of urgent and planned group were 90% vs 95%, 81% vs 90%, 74% vs 79% and 67% vs 74% respectively, and no significant difference was found (Log-rank＝2.364, P＝0.12). Conclusions Although patients needing urgent initial PD have poorer residual renal function and nutritional condition compared to those of planned initial PD, their outcomes are similar. Peritoneal dialysis may be a feasible and safe dialysis modality for patients who need urgent start.     

Comparison between creatinine and cystatin C-based GFR equations in renal transplantation.

BACKGROUND: Estimation of glomerular filtration rate (GFR) from serum creatinine (Scr) or cystatin C (Cys C) exhibit variable performances. METHODS: We compared the performances of 14 Scr and 9 Cys C estimated GFR equations using inulin clearance (Clin) as the reference test in 103 stable renal transplant populations. Bias, precision, receiving operation characteristics (ROC), accuracy within 30% ranges from the reference method and agreements of each test were compared. RESULTS: Mean Clin was 46.4+/-20.9 ml/min/1.73 m2. Scr and Cys C levels correlated well with each other (r=0.83, P<0.0001) and with Clin (r=-0.57 and -0.53, P<0.001, respectively). ROC analysis demonstrated no superiority of Cys C over Scr. Gats equation achieved the highest accuracy of 70% in patients with GFR>or=60 ml/min/1.73 m2. In patients with GFR>or=60 ml/min/1.73 m2, the Nankivell equation demonstrated the highest accuracy of 73.91%. Cys C-based equations were not depicted to be thoroughly accurate. Bias, precision and agreement were otherwise similar in all GFR tests. CONCLUSION: Scr-based equations did not appear to be inferior to Cys C-based equations as a means to estimate GFR in renal transplant patients.     

Epidemiology investigation of chronic kidney disease in the Zhuang nationality village from the Guangxi Zhuang Autonomous Region

Objective To investigate the prevalence and risk factors of chronic kidney disease (CKD) in the rural adult population of Zhuang nationality from the Guangxi Zhuang Autonomous Region. Methods A cross-sectional survey in a village of Zhuang agglomerated settlement was performed by cluster sampling. Demography data of participants were collected using questionnaire. Kidney damage indexes were examined and risk factors were explored. Morning spot urine albumin to creatinine ratio ≥30 mg/g was defined as albuminuria. Estimated glomerular filtration rate (eGFR) by abbreviated MDRD equation ＜60 ml•min-1•(1.73 m2)-1 was defined as reduced renal function. Morning spot urine dipstick (1＋or greater) and then ＞3 red blood cells/HP by microscopy was defined as hematuria. The crude and adjusted prevalence of indicators of kidney damage were calculated and risk factors associated with the presence of CKD was analyzed by Logistic regression. Results A total of 2104 subjects older than 18 years were enrolled in the study, of whom 2036 persons agreed and completed. After adjustment for age and gender, the prevalence of albuminuria, haematuria and reduced eGFR was 1.1%, 3.4% and 2.2%, respectively. The prevalence of chronic kidney disease was 5.7％ and the awareness rate was 5.3％. Independent risk factors associated with CKD were age, gender and hypertension. Conclusions In the Zhuang nationality village of Guangxi Zhuang Autonomous Region, 5.7％ people have either proteinuria, haematuria and/or reduced eGFR, indicating the presence of kidney damage, with awareness rate of only 5.3%. Independent risk factors associated with chronic kidney disease are age, gender and hypertension, which are similar to developed countries and domestic big cities.     

Comparison of different equations for estimated glomerular filtration rate in patients with chronic kidney disease

Objective To compare different equations for estimated glomerular filtration rate (eGFR) in patients with chronic kidney disease (CKD). Methods Hospitalized patients with CKD from the nephrology department of the First Affiliated Hospital of Nanjing Medical University (Jiangsu Province Hospital) were recruited between December 2014 and May 2015. The calculations of eGFR and 24 h creatinine clearance rate (Ccr) were accomplished in three days after admission. The eGFRs were calculated separately using the 24 h creatinine clearance rate adjusted by the standard body surface area (Ccr_BSA), Cockcroft-Gault equation adjusted by the standard body surface area (eCcr_BSA), CKD-EPI creatinine equation (EPI_Cr), CKD-EPI cystatin C equation (EPI_CysC), CKD-EPI creatinine-cystatin C equation (EPI_Cr_CysC), simplified MDRD (MDRD) and China MDRD equations. The EPI_Cr_CysC equation was used as the standard and the precision and accuracy of the other six equations were compared and analyzed. Results A total of 403 CKD participants were enrolled in the study, with 228 male patients and a mean age of (54.9±18.4) years. The main primary diseases were chronic glomerulonephritis (43.7%) and diabetic nephropathy (13.2%). The median concentration of serum creatinine and cystatin C were 117.5 (69.7, 242.4) μmol/L and 1.80 (1.13, 3.31) mg/L, respectively. The median values of Ccr_BSA, eCcr_BSA, MDRD, China MDRD, EPI_Cr, EPI_CysC and EPI_Cr_CysC equations were 50.8 (21.1, 96.2), 51.9 (23.3, 93.2), 53.6 (23.0, 97.4), 52.2 (22.4, 94.1), 53.2 (22.1, 97.3), 35.1 (15.4, 67.0) and 49.1 (22.8, 82.3) ml?min-1?(1.73 m2)-1, respectively. There was well agreement among MDRD, China MDRD and EPI_Cr equations, while there were large differences between equations derived from CysC (EPI_Cr_CysC and EPI_CysC) and equations derived only from creatinine (EPI_Cr, MDRD, China MDRD, eCcr_BSA, Ccr_BSA equations). Compared with EPI_Cr_CysC equation (the reference equation), EPI_Cr equation showed the highest accuracy [percentage of other eGFR equation calculations that were ＞30% of the reference equation calculations (1-P30), 30.8%] while Ccr_BSA equation showed the lowest (1-P30, 42.4%). EPI_CysC equation showed the highest precision [inter-quartile range (IQR) of the difference, 11.7 ml?min-1?(1.73 m2)-1] while Ccr_BSA equation showed the lowest [IQR of the difference, 22.8 ml?min-1?(1.73 m2)-1]. Conclusions The agreement among equations derived only from creatinine is better; while it exhibits some differences between equations with cystatin C and equations derived only from creatinine. The accuracy of EPI_Cr equation is second only to EPI_Cr_CysC equation and it is currently the most suitable eGFR equation for clinical popularization of renal glomerular function assessment.     

Prediction of glomerular filtration rate in renal transplant recipients: cystatin C or Modification of Diet in Renal Disease equation?

BACKGROUND: To overcome disadvantages of serum creatinine two strategies have been suggested to identify patients with reduced glomerular filtration rate (GFR). On the one hand, the Modification of Diet in Renal Disease (MDRD) equation is now recommended to classify the stage of chronic kidney disease. On the other hand, cystatin C (Cys C) has been investigated in numerous studies, finding a higher sensitivity than creatinine in detecting diminished GFR. To date, no comparison of both strategies in patients after renal transplantation has been performed. METHODS: One hundred and five consecutive renal transplant recipients underwent (99m)Tc-DTPA-- clearance measurement. Simultaneously, MDRD estimates were calculated and Cys C serum levels were determined. ROC analyses were performed at different decision points from 20 to 70 mL/min/1.73 m(2). RESULTS: Although the area under the curve did not differ significantly between MDRD and Cys C within the tested GFR range, the AUC for Cys C tended to be higher when GFR exceeded 55 mL/min/1.73 m(2). A significantly higher diagnostic accuracy for Cys C compared with MDRD (p = 0.045 at 65 mL/min/1.73 m(2)) was found when investigating the subgroup of patients with well-functioning grafts (GFR>40 mL/min/1.73 m(2)). CONCLUSION: MDRD equation is equivalent to Cys C measurement in renal transplant recipients. As availability of MDRD is superior to Cys C, we recommend GFR estimation using the MDRD equation. Nevertheless, Cys C may serve as a confirmation test of high MDRD estimates in patients with well-functioning grafts because of superior accuracy in these patients.     

MDRD Equations for Estimation of GFR in Renal Transplant Recipients

After renal transplantation monitoring and detection of slight-to-moderate changes in GFR is a prerequisite for an optimal patient management. Recently, several equations to estimate GFR were developed and verified in the MDRD study cohort. However, little is known about the application of the MDRD formulas in the setting of renal transplantation. We prospectively conducted a study of the GFR estimates of the Cockcroft and Gault (C&G), MDRD6-, MDRD7 and the abbreviated MDRD (aMDRD) with the true GFR as measured by (99m)Tc-DTPA clearance in 95 consecutive patients 6.5, 5.3-7.7 years (mean, 95% CI) after renal transplantation. On average the DTPA clearance was 37.4, 34.4-40.4 mL/min/1.73 m(2), which differed significantly from estimates of GFR by C&G (52.6, 48.3-56.9 mL/min/1.73 m(2)), MDRD7 (44.8, 40.7-49.0 mL/min/1.73 m(2)), MDRD6 (43.8, 39.9-47.7 mL/min/1.73 m(2)) and aMDRD (46.6, 42.4-50.9 mL/min/1.73 m(2)). Bias was lowest for MDRD6 (6.4 mL/min/1.73 m(2)) and highest for C&G (15.2 mL/min/1.73 m(2)). Precision was similar for MDRD7 and aMDRD (10.6 and 11.1 mL/min/1.73 m(2)) but significantly better for MDRD6 (8.6 mL/min/1.73 m(2); p < 0.035). Accuracy within 50% of real GFR was 55.8% for C&G, 83.2% for aMDRD, 87.4% for MDRD7 and 90.5% for MDRD6. MDRD equations perform significantly better than the commonly used C&G formula. Moreover, the MDRD6 equation provides the best diagnostic performance, and should therefore be preferred in renal transplant recipients.     

Chronic kidney disease stage in renal transplantation classification using cystatin C and creatinine-based equations.

BACKGROUND: Current clinical guidelines recommend that renal transplant recipients (RTRs) be classified into chronic kidney disease (CKD) stage using a creatinine-based estimate of glomerular filtration rate (GFR). However, creatinine-based equations are inaccurate in RTRs leading to frequent CKD stage misclassification. It is not known whether the classification of CKD stage would be improved using a cystatin C-based estimate of GFR. METHODS: We measured (99m)Tc-DTPA GFR, cystatin C and creatinine in 198 stable RTRs. GFR was estimated using cystatin C-based equations (Filler, Le Bricon and Rule) and four creatinine-based equations. We determined the proportion, overall and by CKD stage, that were classified correctly by each equation as compared to the (99m)Tc-DTPA GFR. RESULTS: The Filler equation correctly classified 76% of patients compared to only 65% with the abbreviated modification of diet in renal disease (MDRD) equation and 69% with the Cockcroft-Gault equation. In CKD stages two and four, the Filler equation correctly classified 77% and 60% of patients whereas the abbreviated MDRD equation correctly classified 46% and 93% of patients. The area under the curve by receiver operating curve analysis for overall stage classification was uniformly poor for all equations (0.52-0.56). CONCLUSIONS: The cystatin C-based Filler and Le Bricon GFR estimates classified slightly more patients into the correct CKD stage than the standard creatinine-based equations in stable RTRs although the overall diagnostic accuracies were similar. The differences are modest and prospective studies will be needed to determine if the adoption of these equations for classification would lead to improved recognition of CKD complications or patient care.     

CKD-EPI方程对基于简化MDRD方程的慢性肾脏病患者分期的影响

目的 研究CKD-EPI方程对基于简化MDRD方程的慢性肾脏病（CKD）患者分期的影响。 方法 选择2008年6月至2009年9月在我院肾内科就诊的CKD患者450例,分别用简化MDRD方程和CKD-EPI方程估测GFR（eGFR）。用Bland-Altman曲线对二方程计算的eGFR进行一致性检验。根据eGFR对CKD患者分期,对基于不同方程的CKD患者的分期情况进行Kappa检验。 结果 简化MDRD方程和CKD-EPI方程估测eGFR的一致性好,但CKD-EPI-eGFR较MDRD-eGFR平均高出约2.4 ml·（min）-1·（1.73 m2）-1。简化MDRD方程和CKD-EPI方程在CKD1、2、3A、3B、4 和5期符合率分别为97.10%（n=67）,80.77%（n=105）,60.86%（n=48）,87.69%（n=57）,90.38%（n=47）和98.18%（n=54）。Kappa检验提示2方程对CKD患者分期的一致性极好[Kappa值0.913（95%CI：0.881~0.945）]。然而,若依据CKD-EPI方程结果,仍须将由简化MDRD方程分类至60～89 ml·（min）-1·（1.73 m2）-1及45～59 ml·（min）-1·（1.73 m2）-1两组中的19.23%（n=25）及39.24%（n=31）的患者进行再次分类,且均被归为更高eGFR等级。 结论 CKD-EPI方程可“上调”基于简化MDRD方程的CKD 2期～3A期患者的分期等级,纠正了简化MDRD方程对CKD的过度诊断。     

The treatment of tacrolimus in primary IgA nephropathy with mild or moderate renal injury: a randomized controlled study

Objective To investigate the efficacy and safety of immunosuppressive therapy (Tacrolimus or CTX) in primary IgA nephropathy (IgAN) with mild or moderate renal dysfunction. Methods Thirty-six primary IgAN patients diagnosed by renal biopsy, with mild or moderate renal dysfunction[30 ml•min-1•(1.73m2)-1≤eGFR＜90 ml•min-1•(1.73m2)-1, proteinuria＞1.0 g/24 h] were recruited in this randomized controlled trial. All the patients were assigned into steroid therapy alone, steroid combined with CTX (CTX group) and steroid combined with tacrolimus (tacrolimus group). Results The 24-hour proteinuria at baseline were (1.91±0.81) g/24 h, (2.42±1.46) g/24 h, (2.57±1.87) g/24 h in steroid group, CTX group and tacrolimus group respectively. Compared with baseline, it was significantly decreased in steroid group at 3 months [(0.90±0.75) g/24 h, P＜0.05], 6 months [(0.76±0.73) g/24 h, P＜0.05] and 12 months [(0.35±0.35) g/24 h, P＜0.05], in CTX group at 3 months [(1.40±1.24) g/24 h, P＜0.05], 6 months [(0.87±0.83) g/24 h, P＜0.05] and 12 months [(0.68±0.70) g/24 h, P＜0.05], and in FK506 group at 3 months [(1.10±1.33) g/24 h, P＜0.05], 6 months [(0.78±0.69) g/24 h, P＜0.05] and 12 months [(0.69±0.82) g/24 h, P＜0.05]. At 6 months, serum creatinine were decreased in steroid alone [(111.72±31.23) μmol/L vs (121.17±36.51) μmol/L, P＜0.05] and in CTX group [(111.33±22.76) μmol/L vs (124.33±35.51) μmol/L, P＜0.05], while no significant difference was detected in tacrolimus group. At 12 months, there was no significant difference in terms of serum creatinine in all three groups. Besides, there was no significant difference in terms of eGFR (CKD-EPI) in all three groups. One case presented hyperglycemia and one case had liver dysfunction during the treatment in steroid group. Two cases had hyperglycemia, one case had impaired glucose tolerance and one case had liver dysfunction in the tacrolimus group. Conclusions Steroid along, steroid combined with tacrolimus or combined with CTX are efficient in reducing urine protein in the treatment of primary IgAN with mild or moderate renal dysfunction without inducing increased serum creatinine. Given the occurrence of hyperglycemia during the treatment with steroid combined with tacrolimus, it is important to monitor tacrolimus concentration during the treatment.