oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Estimated Glomerular Filtration Rate Correlates Poorly with Four-Hour Creatinine Clearance in Critically Ill Patients with Acute Kidney Injury  [PDF]
Christopher J. Kirwan,Barbara J. Philips,Iain A. M. MacPhee
Critical Care Research and Practice , 2013, DOI: 10.1155/2013/406075
Abstract: Introduction. RIFLE and AKIN provide a standardised classification of acute kidney injury (AKI), but their categorical rather than continuous nature restricts their use to a research tool. A more accurate real-time description of renal function in AKI is needed, and some published data suggest that equations based on serum creatinine that estimate glomerular filtration rate (eGFR) can provide this. In addition, incorporating serum cystatin C concentration into estimates of GFR may improve their accuracy, but no eGFR equations are validated in critically ill patients with AKI. Aim. This study tests whether creatinine or cystatin-C-based eGFR equations, used in patients with CKD, offer an accurate representation of 4-hour creatinine clearance (4CrCl) in critically ill patients with AKI. Methods. Fifty-one critically ill patients with AKI were recruited. Thirty-seven met inclusion criteria, and the performance of eGFR equations was compared to 4CrCl. Results. eGFR equations were better than creatinine alone at predicting 4CrCl. Adding cystatin C to estimates did not improve the bias or add accuracy. The MDRD 7 eGFR had the best combination of correlation, bias, percentage error and accuracy. None were near acceptable standards quoted in patients with chronic kidney disease (CKD). Conclusions. eGFR equations are not sufficiently accurate for use in critically ill patients with AKI. Incorporating serum cystatin C does not improve estimates. eGFR should not be used to describe renal function in patients with AKI. Standards of accuracy for validating eGFR need to be set. 1. Introduction There are numerous and inconsistent definitions of acute kidney injury (AKI). The RIFLE criteria [1], which were then modified to the AKIN criteria [2], form the basis for classification of AKI; however, these classifications do not provide an indication for when and how to alter the management. Their categorical rather than continuous nature is an important limitation in their use as a research tool. A more accurate real time description of true renal function in patients with AKI is needed. In contrast, there are well-established techniques for measuring and categorizing renal function in chronic kidney disease (CKD). Glomerular filtration rate (GFR) is accepted as the best overall measure of kidney function [3, 4]. The gold standard for measurement of GFR is the urinary or plasma clearance of an ideal filtration marker, such as inulin, 51Cr-EDTA (51Cr-ethylenediaminetetra-acetic acid), DTPA (diethylene triamine penta-acetic acid), or iohexol. Measuring clearance with these
24-hour creatinine clearance reliability for estimation of glomerular filtration rate in different stages of chronic kidney disease  [cached]
El-Minshawy Osama,Saber Rafet,Osman Ashraf
Saudi Journal of Kidney Diseases and Transplantation , 2010,
Abstract: Glomerular Filtration Rate (GFR) is considered the best overall index of renal function currently used. Measurement of 24 hours urine/plasma creatinine ratio (UV/P) is usually used for estimation of GFR. However little is known about its accuracy in different stages of Chronic Kidney Disease (CKD) aim: is to evaluate performance of UV/P in classification of CKD by comparing it with isotopic GFR (iGFR). 136 patients with CKD were enrolled in this study 80 (59%) were males, 48 (35%) were diabetics. Mean age 46 ± 13. Creatinine Clearance (Cr.Cl) estimated by UV/P and Cockroft-Gault (CG) was done for all patients, iGFR was the reference value. Accuracy of UV/P was 10%, 31%, 49% within ± 10%, ± 30%, ± 50% error respectively, r 2 = 0.44. CG gave a better performance even when we restrict our analysis to diabetics only, the accuracy of CG was 19%, 47%, 72% in ± 10%, ± 30% and ± 50% errors respectively, r 2 = 0.63. Both equations gave poor classification of CKD. In conclusion, UV/P has poor accuracy in estimation of GFR, The accuracy worsened as kidney disease becomes more severe. We conclude 24 hours CrCl. is not good substitute for measurement of GFR in patients with CKD.
Cystatin C: can it be more reliable marker for estimation of glomerular filtration rate in children with reduced renal function?  [cached]
Nurdan Y?ld?z,Salim ?al??kan,Levent Kabasakal,Lale Sever
Turk Pediatri Ar?ivi , 2011,
Abstract: Aim: The aim of this study was to evaluate whether serum cystatin C is superior as a marker of glomerular filtration rate calculation in children with reduced renal functions.Material and Method: Serum cystatin C, creatinine and 99Tc-diethylenetriamene penta acetate (DTPA) clearance (GFRDTPA) were measured in 100 children (53 girls, 47 boys; mean age 8.4±5.1). Glomerular filtration rate was calculated by the Schwartz formula. Patients with DTPA clearance, accepted as the a gold standart, above 80 mL/dk/1.73m2 were included in group 1(n=64) and below 80 mL/dk/1.73m2 in group 2 (n=36). Receiver-operating characteristics analysis was performed to assess their diagnostic accuracy. Signed informed consents of the parents were obtained in all cases.Results: Serum cystatin C and creatinine were correlated with glomerular filtration rate in group 1 and 2. Diethylen etriamene penta acetate (DTPA) clearance was correlated with glomerular filtration rate in both groups, and with cystatin C in group 2. Receiver-operating characteristics analysis showed that the accuracy of cystatin C and glomerular filtration rate was similar. The area under curves were statistically significant but not different for cystatin C and glomerular filtration rate. Conclusions: Serum cystatin C may be useful but not superior to glomerular filtration rate calculated by Schwartz formula which is a simple and reliable method to estimate glomerular filtration rate in children with normal and decreased renal functions. (Turk Arch Ped 2011; 46: 118-23)
Serum Cystatin C in Estimating Glomerular Filtration Rate
Velibor abarkapa, Zoran Sto i , Mirjana eri , Ljiljana Vu urevi -Risti , Radmila eravica, Branislava Ilin i
Journal of Medical Biochemistry , 2008, DOI: 10.2478/v10011-007-0042-4
Abstract: Using serum cystatin C in estimating glomerular filtration rate (GFR) has in recent times been recommended. A number of simple formulas for calculating GFR have been derived specifically from serum cystatin C concentrations. The purpose of this study was to assess the significance of cystatin C and of the two most frequently applied of these formulas in estimating glomerular filtration rate compared to serum creatinine and its derived formulas for estimating glomerular filtration rate from creatinine concentrations. The study included 74 patients: 59 were in various stages of chronic renal insufficiency (divided into two subgroups: I with GFR ≥ 60 mL/min/1.73m2 and II with GFR<60 mL/min/1.73m2) and 15 on hemodialysis. A control group of 30 healthy participants was also included in the study. Serum values of cystatin C ranged from: 0.86 ± 0.16 mg/L in subgroup I, and 1.77 ± 0.79 mg/L in subgroup II, to 6.9 ± 1.83 mg/L in patients on hemodialysis. The correlation between the two formulas derived from cystatin C and the clearance of creatinine, as well as the Cockcroft and Gault's formula, was significant, while one of the formulas derived from cystatin C did not show a significant correlation with MDRD. It was concluded that serum cystatin C is a significant marker in estimating glomerular filtration rate, especially in the advanced stages of chronic renal insufficiency.
Proteinuria, 99mTc-DTPA Scintigraphy, Creatinine-, Cystatin- and Combined-Based Equations in the Assessment of Chronic Kidney Disease  [PDF]
Hernán Trimarchi,Alexis Muryan,Agostina Toscano,Diana Martino,Mariano Forrester,Vanesa Pomeranz,Fernando Lombi,Pablo Young,María Soledad Ra?a,Alejandra Karl,M. Alonso,Mariana Dicugno,Clara Fitzsimons
ISRN Nephrology , 2014, DOI: 10.1155/2014/430247
Abstract: Background. Precise estimation of the glomerular filtration rate (GFR) and the identification of markers of progression are important. We compared creatinine, cystatin, and combined CKD-EPI equations with scintigraphy to measure GFR and proteinuria as markers of progression. Methods. Cross-sectional, observational study including 300 subjects. CKD was classified by scintigraphy. Determinations. Creatinine, 24-hour creatinine clearance, cystatin, Hoek formula, and creatinine, cystatin, and combined CKD-EPI equations. Results. In the global assessment, creatinine CKD-EPI and combined CKD-EPI equations yielded the highest correlations with : ρ = 0.839, and ρ = 0.831, . Intergroup analysis versus : control G, creatinine clearance ρ = 0.414, P = 0.013; G3, combined CKD-EPI ρ = 0.5317, ; G4, Hoek ρ = 0.618, , combined CKD-EPI ρ = 0.4638, ; and G5, creatinine clearance ρ = 0.5414, , combined CKD-EPI ρ = 0.5288, . In the global assessment, proteinuria displayed the highest significant correlations with cystatin (ρ = 0.5433, ) and cystatin-based equations (Hoek: , ). When GFR < 60?mL/min: in stage 3, proteinuria-cystatin (ρ = 0.4341, ); proteinuria-Hoek (ρ = ?0.4105, ); in stage 4, proteinuria-cystatin (ρ = 0.4877, ); proteinuria-Hoek (ρ = ?0.4877, P = 0.0026). Conclusions. At every stage of GFR < 60?mL/min, cystatin-based equations displayed better correlations with . Proteinuria and cystatin-based equations showed strong associations and high degrees of correlation. 1. Introduction In clinical practice, it is critical to assess kidney function in a precise and accurate manner. Measurement of the glomerular filtration rate (GFR) is considered the best method that reflects kidney function, both in health and in disease [1]. The Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines, widely employed in clinical practice, stratify CKD into 5 stages according to the GFR estimated through the depuration of creatinine [2]. During the last decades, serum creatinine has been the most frequently employed marker to estimate GFR. The K/DOQI guidelines emphasize the necessity to assess GFR employing equations based on serum creatinine and not to rely on serum creatinine concentration alone [2]. The most commonly used creatinine-based formulae include Crockoft-Gault, adjusted to age, weight, and gender, and the Modification of Diet in Renal Disease (MDRD) and its variants, focused on estimating GFR [3]. Finally, Chronic Kidney Disease Epidemiology (CKD-EPI) equation, published in 2009 appears to be more exact than the previous ones in estimating GFR [1]. All these
Cystatin C and beta2-microglobulin: markers of glomerular filtration in critically ill children
José Herrero-Morín, Serafín Málaga, Nuria Fernández, Corsino Rey, María Diéguez, Gonzalo Solís, Andrés Concha, Alberto Medina
Critical Care , 2007, DOI: 10.1186/cc5923
Abstract: This was a prospective, observational study set in an eight-bed PICU. Twenty-five children were included. The inverses of serum creatinine, cystatin C, and B2M were correlated with creatinine clearance (CrC) using a 24-hour urine sample and CrC estimation by Schwartz formula (Schwartz). The diagnostic value of serum creatinine, cystatin C, and B2M to identify a glomerular filtration rate under 80 ml/minute per 1.73 m2 was evaluated using receiver operating characteristic (ROC) curve analysis.Mean age was 2.9 years (range, 0.1 to 13.9 years). CrC was less than 80 ml/minute per 1.73 m2 in 14 children, and Schwartz was less than 80 ml/minute per 1.73 m2 in 9 children. Correlations between inverse of B2M and CrC (r = 0.477) and between inverse of B2M and Schwartz (r = 0.697) were better than correlations between inverse of cystatin C and CrC (r = 0.390) or Schwartz (r = 0.586) and better than correlations between inverse of creatinine and CrC (r = 0.104) or Schwartz (r = 0.442). The ability of serum cystatin C and B2M to identify a CrC rate and a Schwartz CrC rate under 80 ml/minute per 1.73 m2 was better than that of creatinine (areas under the ROC curve: 0.851 and 0.792 for cystatin C, 0.802 and 0.799 for B2M, and 0.633 and 0.625 for creatinine).Serum cystatin C and B2M were confirmed as easy and useful markers, better than serum creatinine, to detect acute kidney injury in critically ill children.Glomerular filtration rate (GFR) is difficult to measure in clinical practice [1-4]. The ideal laboratory marker should be of endogen synthesis, regular production rate, eliminated only by glomerular filtration, and without tubular secretion or reabsorption [4-6]. Creatinine clearance (CrC) using a 24-hour urine sample and serum creatinine (Cr) are the most commonly used parameters to estimate GFR in clinical practice [2,4,5,7,8], although not the most accurate. However, there are limitations to their use. Cr could be affected by factors other than renal function (for exampl
Simple Cystatin C Formula for Estimation of Glomerular Filtration Rate in Overweight Patients with Diabetes Mellitus Type 2 and Chronic Kidney Disease  [PDF]
Sebastjan Bevc,Radovan Hojs,Robert Ekart,Matej Zavr nik,Maksimiljan Gorenjak,Ludvik Puklavec
Experimental Diabetes Research , 2012, DOI: 10.1155/2012/179849
Abstract: In clinical practice the glomerular filtration rate (GFR) is estimated from serum creatinine-based equations like the Cockcroft-Gault formula (C&G) and Modification of Diet in Renal Disease formula (MDRD). Recently, serum cystatin C-based equations, the newer creatinine formula (The Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI)), and equation that use both serum creatinine and cystatin C (CKD-EPI creatinine & cystatin formula) were proposed as new GFR markers. Present study compares serum creatinine-based equations, combined (including both serum creatinine and cystatin C) equation, and serum simple cystatin C formula (100/serum cystatin C) against 51CrEDTA clearance in 113 adult overweight Caucasians with diabetes mellitus type 2 (DM2) and chronic kidney disease (CKD). The results of present study demonstrated that the simple cystatin C formula could be a useful tool for the evaluation of renal function in overweight patients with DM2 and impaired kidney function in daily clinical practice in hospital and especially in outpatients. Despite the advantages of the simple cystatin C formula, cystatin C-based equations cannot completely replace the “gold standard” for estimation of the GFR in a population of DM2 patients with CKD, but may contribute to a more accurate selection of patients requiring such invasive and costly procedures.
HIV Viremia and T-Cell Activation Differentially Affect the Performance of Glomerular Filtration Rate Equations Based on Creatinine and Cystatin C  [PDF]
Bhavna Bhasin, Bryan Lau, Mohamed G. Atta, Derek M. Fine, Michelle M. Estrella, George J. Schwartz, Gregory M. Lucas
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082028
Abstract: Background Serum creatinine and cystatin C are used as markers of glomerular filtration rate (GFR). The performance of these GFR markers relative to exogenously measured GFR (mGFR) in HIV-positive individuals is not well established. Methods We assessed the performance of the chronic kidney disease epidemiology collaboration equations based on serum concentrations of creatinine (eGFRcr), cystatin C (eGFRcys) and both biomarkers combined (eGFRcr-cys) in 187 HIV-positive and 98 HIV-negative participants. Measured GFR was calculated by plasma iohexol clearance. Bias and accuracy were defined as the difference between eGFR and mGFR and the percentage of eGFR observations within 30% of mGFR, respectively. Activated CD4 and CD8 T-cells (CD38+ HLA-DR+) were measured by flow cytometry. Results The median mGFR was >100 ml/min/1.73 m2 in both groups. All equations tended to be less accurate in HIV-positive than in HIV-negative subjects, with eGFRcr-cys being the most accurate overall. In the HIV-positive group, eGFRcys was significantly less accurate and more biased than eGFRcr and eGFRcr_cys. Additionally eGFRcys bias and accuracy were strongly associated with use of antiretroviral therapy, HIV RNA suppression, and percentages of activated CD4 or CD8 T-cells. Hepatitis C seropositivity was associated with larger eGFRcys bias in both HIV-positive and HIV-negative groups. In contrast, eGFRcr accuracy and bias were not associated with HIV-related factors, T-cell activation, or hepatitis C. Conclusions The performance of eGFRcys relative to mGFR was strongly correlated with HIV treatment factors and markers of T-cell activation, which may limit its usefulness as a GFR marker in this population.
Reduced cystatin C-estimated GFR and increased creatinine-estimated GFR in comparison with iohexol-estimated GFR in a hyperthyroid patient: A case report
Malgorzata Karawajczyk, Mia Ramklint, Anders Larsson
Journal of Medical Case Reports , 2008, DOI: 10.1186/1752-1947-2-66
Abstract: We report an account of a hyperthyroid patient with a discrepancy between the GFR estimates from cystatin C and creatinine. The cystatin C concentration (1.36 mg/L) was higher and gave an estimated GFR which was lower (51 mL/min/1.73 m2), while the creatinine concentration was lower (36 μmol/L) and gave a corresponding creatinine-estimated GFR that was higher (145 mL/min/1.73 m2) than the iohexol-estimated GFR (121 mL/min/1.73 m2) during the hyperthyroid period. After thyroidectomy, the creatinine concentration was 36 μmol/L and creatinine-estimated GFR was calculated as 73 mL/min/1.73 m2, while the cystatin C concentration and cystatin C-calculated GFR was 0.78 mg/L and 114 mL/min/1.73 m2, respectively.In contrast to creatinine, cystatin C levels rose in the hyperthyroid state as compared to the euthyroid state. The cystatin C-estimated GFR was reduced compared to the iohexol-estimated GFR. This patient case shows that the hyperthyroid-associated changes in cystatin C levels are not due to changes in GFR. Thyroid function should thus be considered when both cystatin C and creatinine are used as markers of kidney function.Glomerular filtration rate (GFR) is generally accepted as the best overall indicator of renal function and is therefore an important marker for renal disease. Reduced GFR influences the clearance of many pharmaceuticals used today. In the last decades, serum or plasma creatinine has become the most commonly used marker for estimating GFR in clinical practice [1,2]. Despite common use, creatinine has serious limitations as a marker for renal function. GFR is often calculated from plasma creatinine using the Cockcroft-Gault [3] or Modification of Diet in Renal Disease (MDRD) study equations [4]. It is recommended that laboratories should report estimated GFR instead of only reporting the concentration of the analyte [5]. Creatinine is also influenced by factors such as age, gender, muscle mass, thyroid function and physical activity [6]. Cystatin C i
Simple Cystatin C Formula for Estimation of Glomerular Filtration Rate in Overweight Patients with Diabetes Mellitus Type 2 and Chronic Kidney Disease  [PDF]
Sebastjan Bevc,Radovan Hojs,Robert Ekart,Matej Zavr?nik,Maksimiljan Gorenjak,Ludvik Puklavec
Journal of Diabetes Research , 2012, DOI: 10.1155/2012/179849
Abstract: In clinical practice the glomerular filtration rate (GFR) is estimated from serum creatinine-based equations like the Cockcroft-Gault formula (C&G) and Modification of Diet in Renal Disease formula (MDRD). Recently, serum cystatin C-based equations, the newer creatinine formula (The Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI)), and equation that use both serum creatinine and cystatin C (CKD-EPI creatinine & cystatin formula) were proposed as new GFR markers. Present study compares serum creatinine-based equations, combined (including both serum creatinine and cystatin C) equation, and serum simple cystatin C formula (100/serum cystatin C) against 51CrEDTA clearance in 113 adult overweight Caucasians with diabetes mellitus type 2 (DM2) and chronic kidney disease (CKD). The results of present study demonstrated that the simple cystatin C formula could be a useful tool for the evaluation of renal function in overweight patients with DM2 and impaired kidney function in daily clinical practice in hospital and especially in outpatients. Despite the advantages of the simple cystatin C formula, cystatin C-based equations cannot completely replace the “gold standard” for estimation of the GFR in a population of DM2 patients with CKD, but may contribute to a more accurate selection of patients requiring such invasive and costly procedures. 1. Introduction Chronic kidney disease (CKD) is an important public health problem classified into stages according to the level of GFR. Therefore, estimation of the GFR is essential for the evaluation of patients with CKD and is useful tool to screen for chronic kidney disease also in high-risk groups as persons with diabetes mellitus. GFR estimation allows us to detect early impairment of kidney function, prevent further deterioration and complications, correct the dosage of drugs cleared by the kidney so as to avoid potential drug toxicity, and manage CKD patients. Recently, the National Kidney Disease Education Program (NKDEP) recommended reporting GFR values above 60?mL/min/1.73?m2 not as an exact number but simply as >60?mL/min/1.73?m2, and contrary for the values of 60?mL/min/1.73?m2 and below the exact numerical estimate should be reported [1]. For clinicians the GFR below 60?mL/min/1.73?m2 is very important. The values indicate the presence of CKD and represent an increased risk of impaired kidney function, progression to kidney failure, and premature death caused by cardiovascular events of patients with CKD [2, 3]. Over the last decades several different markers for estimation of GFR have been
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.