Application of MDRD and CKD-EPI equations in patients with peripheral arterial diseases / 中华肾脏病杂志

Objective To compare the performance of newly developed Chronic Kidney Disease Epideniology 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 reclassification 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.

Enfermedad renal crónica determinada mediante la creatinina sérica / Chronic kidney disease as measured by serum creatinine

La enfermedad renal crónica se relaciona con un mayor riesgo de enfermedad renal crónica terminal, de enfermedades cardiovasculares y de muerte, por lo que se requiere sudiagnóstico desde las primeras etapas de la enfermedad. Para ello, se disponen de un gran número de ecuaciones para estimar la tasa de filtración glomerular basadas en la concentración de creatinina sérica. Si bien la creatinina no es el analito ideal para estimar la filtración glomerular, ésta continuará empleándose hasta que haya una amplia disponibilidad en el medio de otros marcadores, como la cistatina C, por lo que el laboratorio clínico debe velar por la calidad analíticade los resultados y por lo tanto, debe determinar la creatinina a través de un método estandarizado frente a los procedimientos de medida de referencia. El objetivo de este módulo es revisar ladetección de la enfermedad renal crónica desde sus etapas iniciales, a partir de la creatinina sérica y de la estimación de la tasa de filtración glomerular.

Chronic kidney disease is associated with an increased risk of end-stage renal disease,cardiovascular diseases and death; hence, it is necessary to make a diagnosis in the early phasesof the disease. Many equations for estimating glomerular filtration rates are available for thispurpose, and are based on serum creatinine concentration. Although creatinine is not the idealanalyte to gauge glomerular filtration rate, it will be used until there is extensive availability of othermarkers, such as cystatin C. On these grounds, clinical laboratories must offer results with highstandards of quality control, and accordingly, they must measure serum creatinine with suitablemethods, previously standardized by reference measurement procedures. The aim of this moduleis to assess early diagnosis of chronic kidney disease through serum creatinine quantification andglomerular filtration rate estimation.

Comparative performance of the equations for estimating GFR in type 2 diabetic patients / 中华内分泌代谢杂志

Serum creatinine was determined by enzymatic method.99mTc-GFR was measured by 99mTc-DTPA dynamic renal imaging and considered as GFR marker in 210 males and 180 females with type 2 diabetes,eGFR was calculated by Cockcroft-Gault formula,MDRD equation7,abbreviated MDRD equation,modified MDRD equation for Chinese (c-7GFR4 and c-aGFR4),and CKD-EPI equation.They were analyzed by correlation,regression,Bland-Altman analysis and receiver operating characteristic (ROC) curve analysis.The correlation coefficients for Cockcroft-Gault formula,MDRD equation7,abbreviated MDRD equation,c-7GFR4,c-aGFR4,and CKD-EPI equation were 0.79,0.76,0.77,0.76,0.76,0.81 respectively.And the differences were-14.99,-18.85,-23.79,-25.85,-32.07,and-7.16,respectively.The area under ROC curves were 0.91,0.88,0.89,0.88,0.90,and 0.92,respeetively.Kappa values were 0.67、0.52、0.39、0.49、0.46、0.54respectively.The CKD-EPI equation seams to be the most accurate measurement among the six methods when the serum creatinine was determined by enzymatic method in Chinese type 2 diabetic patients.

Detección precoz de Enfermedad Renal Crónica / Early detection of Chronic Kidney Disease. Multidisciplinary document / Detecção precoce de doença renal Crônica

El aumento de la prevalencia de pacientes con Enfermedad Renal Crónica (ERC), la ha convertido en un problema de Salud Pública mundial, no sólo por el requerimiento de tratamiento sustitutivo renal, sino porque el desarrollo de enfermedad cardiovascular constituye la primera causa de muerte en estos pacientes. La creatinina plasmática (Crp) no siempre resulta un marcador precoz, pues su valor en sangre se eleva por encima del límite superior del intervalo de referencia cuando el Índice de Filtrado Glomerular (IFG) disminuye a la mitad. La medición del IFG con marcadores exógenos es el mejor indicador para evaluar la función renal (FR), aunque su uso en la práctica clínica se reserva para situaciones especiales. El Índice de depuración de creatinina (IDC) puede presentar errores por causa de una mala recolección de orina. Además, sobreestima el IFG debido a que la creatinina, además de ser excretada, se secreta a nivel tubular. La utilización de fórmulas asociadas a Crp está recomendada por la mayoría de las sociedades científicas. La ecuación MDRD-4 se adoptó por consenso "IFGe (mL/min/1,73 m²)= 186 x (Crp) -1.154 x (edad) -0.203 x (0,742 mujer) x (1,212 raza negra)". El factor inicial es 175 cuando el resultado de Crp es trazable a Espectrometría de Masa con Dilución Isotópica (EM-DI). Esta fórmula no es aplicable en casos de embarazadas, hospitalizados, menores de 18 o mayores de 70 años, amputados, etc. Dado que la medición de Crp es la mayor fuente de error para el cálculo de IFGe, el laboratorio debe validar su procedimiento analítico para determinar creatinina. El Error Total no debe superar el 8% para que no produzca un aumento mayor del 10% en la estimación del IFG. Para la detección de ERC se recomienda: 1) Estimar la VFG utilizando la ecuación MDRD-4 asociada a Crp (fuerza de recomendación C). 2) Informar valores de más de 60 mL/min/1,73 m² sólo como "mayor de 60" y los valores menores de 60, como el número exacto obtenido; 3) Excluir en sistemas con cálculos automáticos las situaciones que limitan el uso de la ecuación.

The increase in prevalence of patients with Chronic Kidney Disease (CKD) has turned it a worldwide public health problem not only due to its requirement of a kidney replaceable treatment, but also because cardiovascular disease is now the main cause of death among these patients. Plasma Creatinine (Crp) is not always an early marker, due to the fact that its blood levels exceed the highest limit of the reference range when the Glomerular Filtration Rate (GFR) decreases to a half. GFR measurement with exogenous markers is the best indicator to test renal function (RF), although its use in the clinical practice is only restricted to special situations. Creatinine Clearance (CC) may have errors caused by an inadequate urine collection. Moreover, it overestimates the GFR considering that creatinine is not only excreted but also secreted at the tubular level. The utilization of formulas associated to Crp is recommended by most of the Scientific Societies. The MDRD-4 equation has been adopted by consensus "eGFR (mL/min/1.73 m²)= 186 x (Crp) -1.154 x (age) -0.203 x (0.742 woman) x (1.212 black people)". When the creatinine results are traceable to isotope Dilution/Mass Spectrometry reference method, the initial factor is 175. This formula does not apply to pregnant women, hospitalized patients, people under 18 or older than 70 years old, amputees, etc. Given that the measurement of Crp is the biggest cause of error for the calculation of eGFR, the lab should validate the analytical procedure to determine creatinine. The Total Error should not exceed 8% in order not to yield an increase over 10% of GFR estimation. For CKD detection, it is recommended as follows: 1) Estimate the GFR using MDRD-4´s equation associated to Crp. (Strength of Recommendation C); 2) Report values over 60 mL/min/1.73 m² only as "over 60" and values under 60 as the exact number obtained; 3) Exclude from automatic calculation systems, situations that limit the use of the equation.

Modified MDRD equation in predicting glomerular filtration rate in patients with chronic kidney disease: An assessment of applicability / 第二军医大学学报

Objective: To evaluate the applicability of modified MDRD equation in predicting Glomerular filtration rate in patients with chronic kidney disease (CKD). Methods: Totally 481 CKD patients, who were diagnosed based on K/DOQI guideline from Jan. 2005 to Jan. 2007 in our hospital, were enrolled in this study. The sex, age, body weight and height of patients were recorded; the plasma creatinine, serum albumin and 99mTc-GFR (standardized by body surface area) were measured. GFRs were estimated by abbreviated MDRD equation and the modified MDRD equation separately. The bias, accuracy and precision of both equations were compared. Results: The estimated GFRs (eGFRs) by both equations were significantly correlated with the rGFR(P<0.01). Except for the slightly decreased precision, the modified MDRD equation showed great improvements in the 5%, 30%, and 50% accuracy and bias when compared with the original abbreviated MDRD equation(P<0.05). Compared with the original equation, the modified MDRD equation showed smaller bias in all stages of CKD except for stage 5(P<0.05). The modified MDRD equation also decreased the absolute bias and improved the 30% accuracy in stage 2 CKD (P<0.01). Conclusion: Compared with original equation, the modified MDRD equation has great advantages in predicting the total GFR and GFRs at different CKD stages. Currently it can be used in predicting the GFR of Chinese CKD patients.

Utilidad de las ecuaciones basadas en la concentración sérica de cistatina C en el estudio de la función renal / Usefulness of equations based on serum cystatin C concentration in the study of renal function

La creatinina sérica es un marcador poco sensible para identificar reducciones leves del índice de filtración glomerular (IFG); por ello resulta de gran importancia clínica disponer de métodos alternativos para estimar la función renal. Con este objetivo estudiamos la función renal de 41 pacientes -grupo completo y divididos según la creatinina sérica (menor o igual 1.2 mg/dl o mayores)- usando el clearance de creatinina modificado con cimetidina (Clcrc) como aproximación al IFG, las ecuaciones de Larsson y Hoek que incluyen el uso de cistatina C sérica y las tradicionales fórmulas de Cockroft-Gault y MDRD abreviada. En el grupo completo de pacientes y especialmente en aquellos con creatinina sérica menor o igual 1.2 mg/dl - con reducción de la función renal: Clcrc: 62.01 mas o menos 17.33 ml/min/1.73 m2-, las ecuaciones de Larsson y Hoek mostraron mejores correlaciones y menores diferencias promedio respecto a las fórmulas basadas en la creatinina sérica. La ecuación MDRD abreviada mostró buen rendimiento sólo en el grupo con evidente alteración de la función renal (creatinina sérica > 1.2 mg/dl). Concluimos que en pacientes con diferentes estadios de función renal, las fórmulas que emplean la cistatina C sérica detectan la reducción del IFG más precozmente respecto a aquellas basadas en la creatinina sérica.

Serum creatinine is an insensitive marker to identify early changes in glomerular filtration rate (GFR), for this reason alternative methods to estimate renal function result of great clinical importance. Forty-one patients were studied using creatinine clearance modified with cimetidina (Clcrc) as surrogate of GFR, cystatin C-based equations (i.e. Larsson and Hoek formulas), Cockroft-Gault and MDRD abbreviated equations. In the whole group, as well as in those patients with serum creatinine less than or equal to 1.2 mg/dl -but reduced renal function: Clcrc 62.01 more or less 17.33 ml/min/1.73 m2-, Larsson and Hoek equations showed higher correlations and lower bias than creatinine-based formulas. Abbreviated MDRD equation showed good performance just in those patients with evident alteration of renal function (serum creatinine > 1.2 mg/dl). We concluded that in patients with different stages of renal function, cystatin C-based equations detect reduction of renal function earlier than the serum creatinine-based formulas.