Chronic kidney disease in renal transplant recipients

The aim of the present study was to investigate the utility in renal transplant patients of the guidelines for the diagnosis and classification of chronic kidney disease (CKD) based on the estimated glomerular filtration rate (GFR) elaborated by the Kidney Disease Outcomes Quality Initiative (K/DOQI) of the National Kidney Foundation. PATIENTS AND METHODS: Four hundred forty-seven cadaveric kidney transplants performed between 1980 and 1994 with graft function at 12 months were included in the study. The GFR was calculated according to the MDRD equation. RESULTS: The mean GFR at 12 months was 54.5 +/- 20.3 mL/min/1.73 m(2): 23 patients (5.1%) had a GFR > or =90 mL/min/1.73 m(2); 136 patients (30.6%), 60-89; 246 (54.7%), 30-59; 35 patients (7.8%), 15-29; and 7 patients (1.6%), GFR <15. Similar distribution of CKD stages was observed at 5 and 10 years. Unadjusted graft survival at 10 years was better among patients with a higher GFR at 12 months: 87% in patients with GFR >90 mL/min/1.73 m(2); 83% of GFR 60-89 mL/min/1.73 m(2); 63%, GFR 30-59 mL/min/1.73 m(2); and 23%, GFR <30 mL/min/1.73 m(2) (P < .001). The association between GFR and graft survival persisted when adjusted by the age and gender of the recipients and donors, time on dialysis, body mass index, immunosuppression, delayed graft function, rejection, and HLA mismatches. The prevalence of complications, such as anemia, hypertension, dyslipidemias, and number of drugs increased as GFR declined. CONCLUSIONS: More than 60% of recipients presented chronic kidney disease. GFR was a predictive factor for graft survival at 10 years. The classification of renal transplant patients by CKD stages may help to identify patients with increased risk of graft loss and also to design strategies to improve outcomes.     

Critical prospective appraisal of renal morphology and function in children undergoing shockwave lithotripsy and percutaneous nephrolithotomy

PURPOSE: To assess the effect of shockwave lithotripsy (SWL) and percutaneous nephrolithotomy (PCNL) on renal morphology and function in children undergoing therapy for upper-tract urolithiasis. PATIENTS AND METHODS: Fourteen patients less than 13 years of age with renal or upper-ureteral calculi who were found suitable for primary SWL or PCNL were evaluated for alteration of renal morphology and function after treatment. Of the 18 renal units treated, SWL and PCNL were performed in 9 units each. The average stone size was 880.2 mm2 (range 110-3800 mm2; median 660 mm2). All children underwent ultrasonic estimation of renal length and parenchymal thickness, 99m technetium dimercaptosuccinic acid (DMSA) and 99m Tc-ethylene dicystine (EDC) scintigraphy, and glomerular filtration rate (GFR) estimation prior to intervention and at 3 and 6 months of follow-up. RESULTS: Extracorporeal lithotripsy achieved complete clearance in 8 renal units (88%), requiring an average of 6333 shockwaves and an average of 2.2 sessions per renal unit. The efficiency quotient was 42. Percutaneous surgery likewise achieved complete stone clearance in 88% of renal units, with three units requiring more than one tract. Mixed calcium oxalate monohydrate and dihydrate accounted for the majority of the stones. The mean preintervention GFR was 78.3 +/- 14.6 mL/min/1.73 m2 (median 82.5 mL/min/1.73 m2; range 54-98.6 mL/min/1.73 m2), whereas the mean GFR at 3 months was 78.95 +/- 14.4 mL/min/1.73 m2 (median 78.95 mL/min/1.73 m2; range 52-98 mL/min/1.73 m2). A marginal improvement of an average of 0.65 mL/min was noted. Split function EDC scans demonstrated improved drainage in five cases after intervention; the rest were unchanged. Preintervention DMSA scans revealed renal cortical scars in three children. None of the renal units had developed fresh scars at follow-up scans. None of the children developed new-onset hypertension, proteinuria, or alteration in renal size. CONCLUSION: In the present study, pediatric SWL and PCNL were not found to cause adverse renal morphologic or functional alteration. Stone clearance resulted in marginally improved function and better drainage.     

Rapid communication: chronic renal insufficiency after laparoscopic partial nephrectomy and radical nephrectomy for pathologic t1a lesions

PURPOSE: To report the prevalence of new-onset renal insufficiency in patients undergoing laparoscopic partial nephrectomy (LPN) as compared to laparoscopic radical nephrectomy (LRN) for pathologic T1a lesions. PATIENTS AND METHODS: Forty-eight patients and 37 patients with a normal contralateral kidney, preoperative creatinine (Cr) concentration <2 mg/dL, and tumors <4 cm in size underwent LPN and LRN, respectively. Glomerular filtration rate (GFR) was estimated using an abbreviated Modification of Diet in Renal Disease (MDRD) equation. Cr concentrations and GFR values were analyzed in patients undergoing LPN or LRN. Statistical analysis was performed with two-tailed t-test assuming unequal variances, to establish significance by P < 0.05. RESULTS: Preoperative Cr and GFR was equivalent in the LPN and LRN groups (0.9 mg/dL and 90 mL/min). At last follow-up (mean 205 and 233 days in the LPN and LRN groups, respectively) mean creatinine was 1.03 +/- 0.3 mg/dL v 1.4 mg/dL +/- 0.3 (P = 0.0002). Estimated GFR was 79 +/- 22 mL/min per 1.73 m2 v 55 +/- 14 mL/min per 1.73 m2 (range 31-91 mL/min per 1.73 m2; P < .0001) in the LPN and LRN groups, respectively. One patient in the LPN group and three patients in the LRN group had clinical renal insufficiency as defined by Cr > 2.0 mg/dL. Subclinical renal insufficiency (Cr < 2.0, but calculated GFR <60 mL/min per 1.73 m2) was present in 57% of the LRN patients v 15% of the LPN patients. CONCLUSIONS: LPN preserves renal function more effectively than LRN for pathologic T1a lesions. Subclinical renal insufficiency (GFR <60 mL/min per 1.73 m2) was present in the majority of patients undergoing radical nephrectomy in our series. Importantly, this series included the use of warm ischemia in all cases.     

Postoperative renal function after partial nephrectomy for renal cell carcinoma in patients with pre‐existing chronic kidney disease: A comparison with radical nephrectomy

We assessed whether adequately functioning parenchyma is preserved in patients with pre‐existing chronic kidney disease (CKD) after partial nephrectomy (PN) compared with those who underwent radical nephrectomy (RN). A total of 95 patients with pre‐existing CKD who underwent curative surgery for pathological T1a‐T2N0M0 renal cell carcinoma with a follow‐up period of 12 months or more were the subject of the present study. Of these, 51 patients underwent RN, and 44 PN. Renal function was assessed by using the estimated glomerular filtration rate (e‐GFR). We classified the subjects into two groups according to the preoperative e‐GFR: preoperative e‐GFR 45–59 mL/min/1.73 m² (68 patients); and 30–44 mL/min/1.73 m² (27 patients). In the former group, the probability of freedom from new onset of e‐GFR <45 mL/min/1.73 m² stemmed from the significant difference between the PN and RN groups (P = 0.006; PN: 2 years 64%; RN: 2 years 22%). In contrast, in the latter group, the probability of freedom from new onset of e‐GFR <30 mL/min/1.73 m² was not associated with a significant difference between PN and RN group (P = 0.80). Overall survival and the number of the patients who went on to develop end‐stage renal disease requiring renal replacement therapy between PN and RN were not significantly different in each group. Death from renal cell carcinoma was not noted in either group. PN could significantly prevent development to late‐stage CKD in patients with preoperative e‐GFR 45–59 mL/min/1.73 m² compared with RN. Patients with preoperative e‐GFR 30–44 mL/min/1.73 m² should be reviewed in a more strict study.     

Evolución de la función renal en pacientes con cáncer renal cT1 después de nefrectomía parcial y radical laparoscópica. Factores predictores de deterioro de función renal

Introduction and objectivesTo analyze the evolution of kidney function after laparoscopic partial nephrectomy (PN) and radical nephrectomy (RN) and to identify predictive factors for deterioration in kidney function.Material and methodRetrospective study of patients with two kidneys, glomerular filtration rate (GFR) > 60 mL/min/1.73 m², and single renal tumor cT1, treated in our center between 2005 and 2018.ResultsA total of 372 patients met the inclusion criteria for the study; 156 (41.9%) were treated by RN and 216 (58.1%) by PN. There was a difference of 26.75 mL/min/1.73 m² in GFR between RN and PN at discharge. Age > 60 years, postoperative complications (OR 2.97, p = 0.005) and RN (OR 10.03, p = 0.0001) were predictors of GFR<60 mL/min/1.73 m² at discharge. Only RN (OR 7.69, p = 0.0001) behaved as an independent prognostic factor for GFR<45 mL/min/1.73m2 at discharge. The median follow-up of the series was 57 (IQR 28-100) months. At the end of the follow-up period, nine (6%) patients treated with RN developed severe chronic kidney disease (CKD) and three (2%) developed end stage renal disease (ESRD). Age > 70 years, diabetes mellitus (DM) (HR 2.12, p = 0.001), arterial hypertension (AHT) (HR 1.73, p = 0.01) and RN (HR 2.88, p = 0.0001) behaved as independent predictors of GFR<60 mL/min/1.73 m². The independent predictors for GFR< 45 mL/min/1.73m2 were age >70 years, DM (HR 1.99 CI 95% 1.04-3.83, p = 0.04) and RN (HR 5.88 CI 95% 2.57-13.45, p = 0.0001).ConclusionsRN is a short- and long-term risk factor for CKD, although with a low probability of severe CKD or ESRD in patients with preoperative GFR > 60 mL/min/1.73 m². Age, DM and AHT contribute to worsening renal function during follow-up.     

Glomerular filtration rate after left renal vein division and reconstruction during infrarenal aortic aneurysm repair

OBJECTIVES: The study assessed the effect on postoperative renal function of left renal vein (LRV) division and reconstruction by direct reanastomosis or graft interposition during infrarenal abdominal aortic aneurysm (AAA) repair. METHODS: Between January 2001 and March 2006, 1189 patients underwent elective open repair of infrarenal AAAs. LRV division was performed in 15 (1.3%) and its reconstruction in all but one (LRV group), where the LRV was occluded. Patients' glomerular filtration rates (GFRs) were retrospectively estimated through postoperative day 4 by using the Cockcroft-Gault equation and compared with the GFRs of 56 controls undergoing AAA repair without LRV division (control group) randomly identified from a prospectively compiled database in a 4:1 ratio. Post hoc 1:1 case-matched analysis was also performed. Statistical analyses were performed as appropriate. RESULTS: Comparison of demographics and risk factors revealed no statistically significant differences between the two groups with the exception of the following: AAAs were larger in LRV group (71.4 +/- 17.1 mm vs 56.0 +/- 14.6 mm; P = .003) and preoperative GFR was lower in LRV group (65.3 +/- 19.0 mL/min/1.73 m(2) vs 82.8 +/- 22.3 mL/min/1.73 m(2); P = .009). Postoperatively, the trend of GFR with time did not differ between groups (P = .33). The variation of GFR at day 4 after surgery compared with preoperative values was not different either (5.6 +/- 12.6 mL/min/1.73 m(2) vs 1.0 +/- 15.5 mL/min/1.73 m(2); P = .67). A further 1:1 case-matched multivariate analysis of variance, matching patients and controls by AAA size and preoperative GFR, showed no difference in trend of GFR with time between groups (P = .15). Operative time was not significantly longer in LRV group (148.4 +/- 35.8 minutes vs 131.0 +/- 40.3 minutes; P = .07). No differences between groups were found for blood loss (585.7 +/- 264.2 mL vs 567.7 +/- 222.5 mL; P = .88), perioperative complications (5 vs 8; P = .12), or hospital length of stay (6.2 +/- 1.8 days vs 5.5 +/- 1.2 days; P = .10). A 6-month follow-up of renal function available in 12 patients of LRV group showed no significant decrease in GFR compared with postoperative values (70.8 +/- 24.8 mL/min/1.73 m(2) vs 69.1 +/- 23.5 mL/min/1.73 m(2); P = .86). At duplex scan, the reconstructed LRV could be insonated in nine of these 12 patients and all were patent. CONCLUSIONS: LRV division during AAA repair was associated with larger aneurysms and preoperative subclinical renal function impairment. In these patients, LRV reconstruction was associated with the maintenance of preoperative renal functional status without significantly lengthening of operative time or increasing the complications from surgery.     

Relationship between hematocrit and renal function in men and women

BACKGROUND: Anemia is a known complication of renal insufficiency, but the relationship between level of renal function and magnitude of reduction in hematocrit is not well defined. Men have higher hematocrit and absolute glomerular filtration rate (GFR) than women; however, it is unknown whether the level of clearance associated with decreased hematocrit is the same in men and women. METHODS: We conducted a cross-sectional study of 12,055 adult ambulatory patients. General linear models were used to analyze the relationship between hematocrit and Cockcroft-Gault equation estimated creatinine clearance (C(Cr); mL/min) and Modification of Diet in Renal Disease (MDRD) formula estimated the GFR indexed to body surface area (mL/min/1.73 m(2)). RESULTS: The hematocrit decreased progressively below estimated C(Cr) 60 mL/min in men and 40 mL/min in women. Compared with subjects with C(Cr)> 80 mL/min, men with C(Cr) 60 to 50 mL/min, 50 to 40 mL/min, 40 to 30 mL/min, 30 to 20 mL/min, and < or =20 mL/min had mean hematocrits that were lower by 1.0, 2.4, 3.7, 3.5, and 10.0%, respectively; the corresponding reductions in women with C(Cr) 40 to 30 mL/min, 30 to 20 mL/min, and < or =20 mL/min were 1.7, 2.9, and 6.3% (all P < 0.05). This between-sex difference diminished when renal function measurement was indexed to body size. Compared with subjects with GFR> 80 mL/min/1.73 m(2), men with GFR 50 to 40 mL/min/1.73 m(2), 40 to 30 mL/min/1.73 m(2), 30 to 20 mL/min/1.73 m(2), and < or =20 mL/min/1.73 m(2) had mean hematocrits that were lower by 2.0, 4.4, 5.3, and 9.4%; the corresponding reductions in women with GFR 50 to 40 mL/min/1.73 m(2), 40 to 30 mL/min/1.73 m(2), 30 to 20 mL/min/1.73 m(2) and < or =20 mL/min/1.73 m(2) were 0.6, 1.6, 3.8, and 5.3% (all P < 0.05). CONCLUSIONS: A decrease in hematocrit is apparent even among patients with mild to moderate renal insufficiency. At any given level of renal function below estimated C(Cr) 60 mL/min, men have a larger decrease in hematocrit than women.     

The management of renal artery atherosclerosis for renal salvage: does stenting help?

OBJECTIVE: The use of endovascular techniques to treat renal artery stenosis (RAS) has increased in recent years but remains controversial. The purpose of this study was to review the outcomes and durability of percutaneous transluminal angioplasty and stenting (PTA/S) for patients with RAS and decreasing renal function. METHODS: Between 1999 and 2004, 125 consecutive patients underwent angiography and intervention for renal salvage and formed the basis of this study. Inclusion criteria for this study included serum creatinine greater than 1.5 mg/dL, ischemic nephropathy, and high-grade RAS perfusing a single functioning kidney. Patients undergoing PTA/S for renovascular hypertension or fibromuscular dysplasia or in conjunction with endovascular stent grafting for aneurysm repair were excluded. The original angiographic imaging was evaluated for lesion grade and parenchymal kidney size. All medical records and noninvasive testing were reviewed. Preoperative and postoperative patient data were standardized and analyzed by using chi(2) tests for nominal values and t tests for continuous variables. The Modification of Diet in Renal Disease equation was used to estimate glomerular filtration rate (GFR), and univariate analysis was performed. RESULTS: Preoperative variables included the presence of coronary artery disease (93%), diabetes (44%), tobacco use (48%), and hypercholesterolemia (70%). RAS was suspected on the basis of preoperative duplex imaging or magnetic resonance angiography. Aortography and PTA/S were performed in 125 patients (mean age, 71 years; 59% male) with a mean baseline creatinine level of 2.2 mg/dL. There were two mortalities (1.6%) in the 30-day postoperative period, but there was no case of acute renal loss. Blood pressure decreased after PTA/S (151/79 mm Hg before vs 139/72 mm Hg after 1 month; P < .03). For all patients, the estimated GFR went from 33 +/- 12 mL . min(-1) . 1.73 m(-2) (mean +/- SD) to 37 +/- 19 mL . min(-1) . 1.73 m(-2) at 6 months (P = .10). Sixty-seven percent of treated patients had improvement (>10% increase in GFR) or stabilization of renal function. A rapid decline in GFR before intervention was correlated with improvement after PTA/S. Responders after PTA/S had a 27% decrease in GFR before intervention (44 +/- 13 mL . min(-1) . 1.73 m(-2) to 32 +/- 13 mL . min(-1) . 1.73 m(-2); P < .001) with a negative to positive slope change in GFR values. Ten patients underwent reintervention for in-stent restenosis. Cases without improvement in GFR after PTA/S were associated with eventual dialysis need (P = .01; mean follow-up, 19 months). Survival at 3 years was 76%, and dialysis-free survival was 63% as estimated by Kaplan-Meier analyses. CONCLUSIONS: Renal artery stenoses causing renal dysfunction can be safely treated via endovascular means. Rapidly decreasing renal function is associated with the response to renal artery angioplasty/stenting and helps identify patients for renal salvage.     

KDIGO Guidelines and Kidney Transplantation: Is the Cystatin‐C Based Recommendation Relevant?

The KDIGO guidelines propose a new approach to diagnose chronic kidney disease (CKD) based on estimated glomerular filtration rate (GFR). In patients with a GFR value comprised between 45 and 59 mL/min/1.73 m² as estimated by the CKD‐EPI creatinine equation (eGFR_creat), it is suggested to confirm the diagnosis with a second estimation using the CKD‐EPI cystatin C‐based equations (eGFR_cys/eGFR_creat‐cys). We sought to determine whether this new diagnostic strategy might extend to kidney transplant recipients (KTR) and help to identify those with decreased GFR. In 670 KTR for whom a measured GFR was available, we simulated the detection of CKD using the two‐steps approach recommended by the guidelines in comparison to the conventional approach relying on creatinine equation. One hundred forty‐five patients with no albuminuria had eGFR_creat between 45 and 59 mL/min/1.73 m². Among them, 23% had inulin clearance over 60 mL/min/1.73 m² and were thus incorrectly classified as CKD patients. When applying the Kidney Disease: Improving Global Outcomes (KDIGO) strategy, 138 patients were confirmed as having a GFR below 60 mL/min with eGFR_creat‐cys. However, 21% of them were misclassified in reference to measured GFR. Our data do no not support the use of cystatin C as a confirmatory test of stage 3 A CKD in KTR.     

Is the Chronic Kidney Disease Epidemiology Collaboration four‐level race equation better than the cystatin C equation?

Aim: To evaluate the Chronic Kidney Disease Epidemiology Collaboration (CKD‐EPI) four‐level race equation in the assessment of glomerular filtration rate (GFR) in Chinese people with chronic kidney disease (CKD), which was published in 2011, compared with the cystatin C‐based GFR estimation equation (CysC GFR) and the combination of CysC and serum creatinine equation (CysC‐Scr GFR). Methods: The CKD‐EPI four‐level race equation estimated GFR (CKD‐EPI GFR) was compared with the CysC GFR and CysC‐Scr GFR. Three equations were compared with body surface area (BSA) standardized GFR (sGFR), which was measured by ^99mTc‐DTPA renal dynamic imaging method in 111 CKD cases. Results: A statistically significant correlation was found between sGFR and CKD‐EPI GFR, CysC GFR and CysC‐Scr GFR. Three estimated GFR (eGFR) equations of 30% accuracy were 58.6%, 56.8% and 63.5%, respectively. Average deviations of eGFR from sGFR were 2.34, 1.19, and 1.32 (mL/min per 1.73 m²) (P > 0.05), respectively. There was no significant deviation in the CKD from stages 1 to 5 in CKD‐EPI GFR and CysC‐Scr GFR. However, when estimated by CysC GFR, the deviation was increased, with the value of 12.41 mL/min per 1.73 m² (P= 0.002) in CKD stage 5. Conclusion: Our results showed that in a Chinese population with CKD, CKD‐EPI GFR, CysC GFR and CysC‐Scr GFR of bias and overall accuracy of 30% were very similar. There was little advantage in adding Asian coefficient to modifying the CKD‐EPI equation. CysC GFR overestimated GFR in patients with CKD stages 4 and 5.     

Prevalence of decreased kidney function in Chinese adults aged 35 to 74 years

BACKGROUND: Chronic kidney disease (CKD) is a major public health burden in Western countries but little is known about its impact in developing countries. We estimated the prevalence and absolute burden of CKD in the general adult population in China. METHODS: A cross-sectional survey was conducted in a nationally representative sample of 15,540 Chinese adults aged 35 to 74 years in 2000 and 2001. Serum creatinine was measured using the modified kinetic Jaffe reaction method at a central laboratory calibrated to the Cleveland Clinic Foundation laboratory. Glomerular filtration rate (GFR) was estimated using the simplified equation developed by the Modification of Diet in Renal Disease study. CKD was defined as an estimated GFR <60 mL/min/1.73m2. RESULTS: Overall, the age-standardized prevalences of GFR 60 to 89, 30 to 59, and <30 mL/min/1.73m2 were 39.4%, 2.4%, and 0.14%, respectively, in Chinese adults aged 35 to 74 years. The overall prevalence of CKD (GFR <60 mL/min/1.73m2) was 2.53%, representing 11,966,653 persons (1.31% or 3,185,330 men and 3.82% or 8,781,323 women). The age-specific prevalence of CKD was 0.71%, 1.69%, 3.91%, and 8.14% among persons 35 to 44, 45 to 54, 55 to 64, and 65 to 74 years old, respectively. The age-standardized prevalence of CKD was similar in urban (2.60%) and rural (2.52%) residents but was higher in south China (3.05%) than in north China (1.78%) residents. CONCLUSION: Although the prevalence of CKD in China was relatively low, the population absolute burden is substantial. These data warrant a national program aimed at detection, prevention, and treatment of CKD in China.     

High plasma phosphate as a risk factor for decline in renal function and mortality in pre-dialysis patients.

BACKGROUND: Hyperphosphataemia is associated with increased mortality in patients with chronic kidney disease (CKD) stage IV or on dialysis. Furthermore, in animal studies, elevated plasma phosphate has been shown to be associated with an accelerated decline in renal function. The aim of this study was to determine the association of plasma phosphate with renal function loss and mortality in CKD stage IV-V pre-dialysis patients with GFR <20 ml/min/1.73 m(2). METHODS: Incident pre-dialysis patients were included between 1999 and 2001 in the multi-centre PREPARE study, and followed until 2003 or death. Rate of decline in renal function for each patient was calculated by linear regression using the Modification of Diet in Renal Disease (MDRD) formula to estimate GFR (eGFR). RESULTS: A total of 448 patients were included [mean (SD) age 60 (15) years, eGFR 13 (5.4) ml/min/1.73 m(2), decline in renal function 0.38 (0.95) ml/min/month]. Phosphate concentration at baseline was 4.71 (1.16) mg/dl, calcium 9.25 (0.77) mg/dl and calcium-phosphate product 43.5 (10.9) mg(2)/dl(2). For each mg/dl higher phosphate concentration, the mean (95% CI) decline in renal function increased with 0.154 (0.071-0.237) ml/min/month. After adjustment, this association remained [beta 0.178 (0.082-0.275)]. Seven percent of the patients died. Crude mortality risk was 1.25 (0.85-1.84) per mg/dl increase in phosphate, which increased to 1.62 (1.02-2.59) after adjustment. CONCLUSIONS: High plasma phosphate is an independent risk factor for a more rapid decline in renal function and a higher mortality during the pre-dialysis phase. Plasma phosphate within the normal range is likely of vital importance in pre-dialysis patients.     

Implication of CKD-EPI Equation to Estimate Glomerular Filtration Rate in Chinese Patients with Chronic Kidney Disease

Abstract

Objective: To evaluate the applicability of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation to estimate glomerular filtration rate (GFR) in Chinese patients of different stages of CKD. Methods: The CKD-EPI equation estimated GFR (eGFR) was compared with body surface area standardized GFR (sGFR), which was measured by diethylenetriaminepentaacetic acid renal dynamic imaging method in 142 CKD cases. Results: eGFR was positively correlated with sGFR (r = 0.838, p < 0.001). eGFR of 15%, 30%, and 50% accuracy were 31.0%, 57.7%, and 76.8%, respectively. Average deviation of eGFR from sGFR was ?0.92 ± 16.36 mL/min/1.73 m² (p = 0.506). There was no significant deviation in the CKD from stages 2 to 5. However, in CKD stage 1, the deviation was increased with the value of 13.36 ± 18.44 mL/min/1.73 m² (p = 0.023). Conclusion: CKD-EPI equation might be widely used in evaluation of Chinese CKD patients of different stages, with a less deviation and higher accuracy. However, in CKD stage 1, eGFR was higher than sGFR on average. It was suggested that eGFR might be overcorrected or overestimated. These results demonstrated that careful modification of CKD-EPI equation would be necessary in Chinese populations with CKD.     

Retarding progression of chronic renal disease: the neglected issue of residual proteinuria

BACKGROUND: Findings that early changes in proteinuria independently predict long-term glomular filtration rate (GFR) decline (Delta GFR) would highlight proteinuria as a major determinant of progression in chronic renal disease. METHODS: We investigated whether percent changes (3 months vs. baseline) in proteinuria (adjusted for concomitant changes in GFR) and residual proteinuria at 3 months, predicted Delta GFR [over a median (IQ range) follow up of 31.3 (24.5 to 50.3) months] in 273 patients with proteinuric chronic nephropathies enrolled in the Ramipril Efficacy In Nephropathy (REIN) study. RESULTS: Short-term changes and residual proteinuria (r = -0.23, P = 0.0001 for both) significantly correlated with Delta GFR and, at multivariate analyses, independently predicted Delta GFR (beta = -0.23, P = 0.0002; beta = -0.21, P = 0.0004, respectively). For comparable levels of residual proteinuria, patients with greater short-term reduction had slower Delta GFR (-0.28 +/- 0.04 mL/min/1.73 m2/ vs. -0.53 +/- 0.07 mL/min/1.73 m2/month, P = 0.04). On ramipril and conventional treatment, specular short-term changes in proteinuria (-18.2 +/- 3.5% vs. 24.2 +/- 6.7%, P < 0.0001, respectively) were associated with significantly different Delta GFRs. However, similar changes in proteinuria resulted in a difference in Delta GFR (ramipril, 0.39 +/- 0.07 mL/min/1.73 m2/month; conventional therapy, 0.74 +/- 0.11 mL/min/1.73 m2/month; P < 0.01) that was sevenfold higher (0.35 vs. 0.05 mL/min/1.73 m2/month) in patients with basal proteinuria > or =3 g/24 hours as compared to those with basal proteinuria 1 to 3 g/24 hours (ramipril, 0.25 +/- 0.06 mL/min/1.73 m2/month; conventional therapy, 0.30 +/- 0.07 mL/min/1.73 m2/month; P = NS). CONCLUSION: Regardless of blood pressure control and treatment randomization, short-term changes in proteinuria and residual proteinuria reliably predict long-term disease progression. Reducing proteinuria is renoprotective, particularly in nephrotic patients. As for arterial hypertension, proteinuria should be a specific target for renoprotective treatment.     

血清CysC、B2-MG评价慢性肾脏病患者早期肾功能损害

目的探讨血清半胱氨酸蛋白酶抑制剂C（CystC）、B2微球蛋白（胆-MG）在评价慢性肾脏病（CKD）患者早期肾功能损害中的临床价值。方法收集2008年2月至2009年1月问包头市中心医院。肾内科住院CKD患者116例,根据肾小球滤过率（GFR）,分为3组,即A组为肾功能正常组,GFR≥90ml·min-1。·（1．73m2）-1;B组为早期肾功能不全组,60ml·min-1。·（1．73m2）-1≤GFR〈90ml·min-1·（1．73m2）-1;C组为中晚期。肾功能不全组,GFR％60ml·min。·（1．73m2）～。测定不同肾功能时期CysC、132-MG、SCr、尿素氮（BUN）水平,各组间进行比较,并与GFR进行相关性比较,采用受试者工作特征曲线下面积,评价CysC、132-MG的可靠性。结果患者血清CysC、G2-MG、SCr、尿素氮（BUN）与GFR均呈显著相关（P〈0．01）,且以CysC与GFR的相关程度最密切,CysC、82-MG、SCr、尿素氮（BUN）受试者曲线下面积分别是0．989、0．983、0．877、0．873。结论CysC、胆-MG成为理想的反应GFR的内源性指标。通过联合检测血清CysC和B32-MG水平可以为评价GFR提供敏感、对早期诊断各种慢性肾脏病患者肾小球滤过功能的损害具有重要价值。     

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.     

Is cystatin C useful for the detection and the estimation of low glomerular filtration rate in heart transplant patients?

Although previously studied in patients with chronic kidney disease, there is less data for the use of cystatin C and cystatin C-based formulas in heart transplant recipients. The ability of creatinine and cystatin C to detect renal failure (glomerular filtration rate [GFR] below 60 mL/min/1.73 m(2)) in heart transplant patients has been compared. The accuracy and precision of a creatinine-based formula (Modification of Diet in Renal Disease [MDRD]) versus a cystatin C-based formula (Rule's formula) to estimate GFR have also been studied. GFR was measured using the (51)Cr-ethylenediamine tetraacetic acid tracer in 27 patients. There was no significant difference between GFR and the reciprocal of creatinine or cystatin C. Receiver operating characteristic curves for cystatin C and creatinine were similar. Both formulas were well correlated with the GFR. The bias of the cystatin C-based was significantly better than one of the MDRD formula, but the standard deviation appeared better for the MDRD formula (bias of +3.9 mL/min/1.73 m(2) versus +12 mL/min/1.73 m(2) and SD of 8.5 versus 11.6, respectively). Plasma cystatin C has no clear advantage over serum creatinine to detect renal failure in heart transplanted patients.     

Cardiovascular disease in early stages of chronic kidney disease in a Chinese population

Cardiovascular disease (CVD) is one of the most serious complications of kidney disease, yet studies of CVD in early stage of chronic kidney disease (CKD) in Asian patients are very limited. Therefore, this study determined the prevalence and the spectrum of CVD in individuals with early-stage CKD and compared them with data of individuals without CKD. Compared with individuals with estimated GFR (eGFR) >90 ml/min per 1.73 m2, the prevalence of myocardial infarction, stroke, and total CVD of individuals with eGFR 60 to 89 ml/min per 1.73 m2 was increased by 91.4, 71.7, and 67.6%, respectively. For individuals with eGFR 30 to 59 ml/min per 1.73 m2, the percentage was 105.2, 289.1, and 200.7%, respectively. For each eGFR category, stroke was more prevalent than myocardial infarction. Compared with individuals with eGFR >90 ml/min per 1.73 m2, participants with eGFR 60 to 89 and 30 to 59 ml/min per 1.73 m2 tended to have more cardiovascular risk factors, and there were strong unadjusted and adjusted associations between CVD with different stages of eGFR (eGFR >90 ml/min per 1.73 m2 as reference). This is the first report on the prevalence and the spectrum of CVD in early stages of CKD in a community-based Chinese population. The spectrum of CVD in this Chinese population is different from reports of Western countries. Individuals with subtle decreased renal function seem much more likely to have multiple cardiovascular risk factors and have higher prevalence of CVD than those without CKD.     

Performance of the modification of diet in renal disease and Cockcroft-Gault equations in the estimation of GFR in health and in chronic kidney disease

The performance of the Modification of Diet in Renal Disease (MDRD) and the Cockcroft-Gault (CG) equations as compared with measured (125)I-iothalamate GFR (iGFR) was analyzed in patients with chronic kidney disease (CKD) and in potential kidney donors. All outpatients (n = 1285) who underwent an iGFR between 1996 and 2003 were considered for analysis. Of these, 828 patients had CKD and 457 were potential kidney donors. Special emphasis was put on the calibration of the serum creatinine measurements. In CKD patients with GFR <60 ml/min per 1.73 m(2), the MDRD equation performed better than the CG formula with respect to bias (-0.5 versus 3.5 ml/min per 1.73 m(2), respectively) and accuracy within 30% (71 versus 60%, respectively) and 50% (89 versus 77%, respectively). Similar results are reported for 249 CKD patients with diabetes. In the kidney donor group, the MDRD equation significantly underestimated the measured GFR when compared with the CG formula, with a bias of -9.0 versus 1.9 ml/min per 1.73 m(2), respectively (P < 0.01), and both the MDRD and CG equations overestimated the strength of the association of GFR with measured serum creatinine. The present data add further validation of the MDRD equation in outpatients with moderate to advanced kidney disease as well as in those with diabetic nephropathy but suggest that its use is problematic in healthy individuals. This study also emphasizes the complexity of laboratory calibration of serum creatinine measurements, a determining factor when estimating GFR in both healthy individuals and CKD patients with preserved GFR.     

Beta-blockers for coronary heart disease in chronic kidney disease.

BACKGROUND: Limited data exist on whether the cardioprotective benefit of beta-blockers is modified by the presence of chronic kidney disease (CKD). METHODS: A post hoc analysis of the data from the Bezafibrate Infarction Prevention (BIP) study was performed. CKD was defined according to the Modification of Diet in Renal Disease (MDRD) equation as an estimated glomerular filtration rate (GFR) <60 mL/min/1.73 m(2). The Cox proportional hazard model, including adjustment for propensity score, was used to estimate the hazard ratios (HR) for the composite endpoint combining acute myocardial infarction (AMI) or sudden cardiac death (SCD). RESULTS: In this cohort of 3075 coronary heart disease (CHD) patients, 568 (18.5%) had CKD and 1185 (38.5%) were treated with beta-blockers. A total of 245 (43.1%) CKD patients received beta-blockers at baseline. The mean (+/- SD) estimated GFR in the CKD and non-CKD subgroups was 55 (+/- 4) and 73 (+/- 9) mL/min/1.73 m(2), respectively. After a median follow-up of 6.2 years, the crude incidence rates of AMI or SCD/1000 person years (PY) were 25.6, 21.9, 34.6 and 27.5 for the beta-blockers-/CKD-, beta-blockers+/CKD-, beta-blockers-/CKD+ and beta-blockers+/CKD+ groups, respectively. Compared to patients with beta-blockers-/CKD-, the adjusted HR of AMI or SCD was 0.87 (90% CI 0.71-1.06) for the beta-blockers+/CKD-, 1.35 (90% CI 1.05-1.73) for the beta-blockers-/CKD+ and 1.06 (90% CI 0.76-1.46) for the beta-blockers+/CKD+. CONCLUSIONS: These analyses suggest that the use of beta-blockers is associated with a reduction in event risk in patients with CHD regardless of the presence or absence of CKD.