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Resistive index (RI) could provide more useful diagnostic and prognostic information for kidney disease than parenchymal thickness (PT) only. The aims of this study were to find the association between PT, glomerular filtration rate (GFR), and RI and their determination of renal function. B-mode and Doppler ultrasonography and standard biochemical laboratory testing (urea and creatinine) were performed among 75 participants (57.1 ± 10.6 years). We measured PT and RI and calculated GFR. The mean and standard deviation were 0.671 ± 0.041, 12.24 ± 1.98 mm, and 86.38 ± 15.96 mL/min/1.73 m 2 for RI, PT, and GFR, respectively. The mean RI in two subgroups with PT smaller or greater than 12.5 mm was RI 1 = 0.692 ± 0.038 or RI 2 = 0.648 ± 0.03 (P <0.0001). Strong inverse correlation between RI (y) and PT (x) presented by the linear regression equation: y = 0.744 + (-0.005932 x). By multiple regression, we show GFR and PT as predictors for increasing of RI (R 2 = 0.2063, βst = -0.0009176, P = 0.0012 and βst = -0.006003, P = 0.0078), respectively. Renal RI inversely strongly correlates with the PT and GFR. Renal PT and GFR are independent predictors for increasing of RI in general population.

Recently, a new approach was proposed to detect mild impairment in renal function: a reduced ratio between estimated glomerular filtration rate (eGFR) calculated by cystatin C and eGFR calculated by creatinine. We aimed to evaluate if this ratio is associated with aortic stenosis (AS) requiring surgery. We identified 336 patients that first participated in population surveys and later underwent surgery for AS (median age [interquartile range] 59.8 [10.3] years at survey and 68.3 [12.7] at surgery, 48% females). For each patient, two matched referents were allocated. Cystatin C and creatinine were determined in stored plasma. eGFR cystatin C and eGFR creatinine and their ratio were estimated. Conditional logistic regression analyses were used to estimate the risk (odds ratio (OR) with [95% confidence interval (CI)]) related to one (ln) standard deviation increase in the ratio between eGFR cystatin C and eGFR creatinine . A high ratio was associated with lower risk for AS requiring surgery (OR [95% CI]) (OR 0.84 [0.73-0.97]), especially in women (0.74 [0.60-0.92] vs. 0.93 [0.76-1.13] in men). After further stratification for coronary artery disease (CAD), the association remained in women with CAD but not in women without CAD (0.60 [0.44-0.83] and 0.89 [0.65-1.23], respectively). In conclusion, a high ratio between eGFR cystatin C and eGFR creatinine was associated with lower risk for surgery for AS, especially in women. Mild impairment of renal function is thus associated with future risk for AS requiring surgery.

Background: Current heart failure guidelines recommend target eplerenone dose of 50 mg/day. We have examined the effect of different eplerenone doses based on pre-specified renal function stratification in the Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF)., Methods and Results: In EMPHASIS-HF, the target dose of eplerenone/placebo was stratified at randomization according to estimated glomerular filtration rate (eGFR): 50 mg/day if eGFR ≥ 50 mL/min/1.73 m 2 and ≤ 25 mg/day if eGFR 30-49 mL/min/1.73 m 2 . Patients remained within these dose ranges during the trial (as per stratification). The primary outcome was a composite of heart failure hospitalization or cardiovascular mortality. Eplerenone was superior to placebo within each respective eGFR stratum [eplerenone vs. placebo in the eGFR ≥ 50 mL/min/1.73 m 2 stratum: hazard ratio (HR) 0.58, 95% confidence interval (CI) 0.45-0.74; and eplerenone vs. placebo in the eGFR 30-49 mL/min/1.73 m 2 stratum: HR 0.62, 95% CI 0.49-0.78; P interaction  = 0.89]. Despite receiving lower eplerenone doses, patients in the eGFR 30-49 mL/min/1.73 m 2 stratum more often had hyperkalaemia, renal failure events, and drug discontinuation., Conclusion: In EMPHASIS-HF the eplerenone dose was stratified according to renal function and the treatment effect was not influenced by renal function: 25 mg/day in patients with eGFR 30-49 mL/min/1.73 m 2 was as effective as 50 mg/day in patients with eGFR > =50 mL/min/1.73 m 2 . However, patients with impaired renal function experienced more adverse events, despite reveiving lower eplerenone doses. Current guidelines do not recommend tailoring the dose of eplereone according to renal function but the current data suggest they should., (© 2019 The Authors. European Journal of Heart Failure © 2019 European Society of Cardiology.)

Objective: Estimated glomerular filtration rate (eGFR) is calculated routinely using creatinine-based formulas, but their reliability in the elderly is limited. The aim of this study was to analyse the concordance between the BIS1 equation which is specific for the elderly, and the usual CKD-EPI and MDRD-IDMS in a large population over 70 years of age., Material and Methods: Retrospective cross-sectional study in which the eGFR was calculated using BIS1, CKD-EPI and MDRD-IDMS equations based on gender, age, and creatinine data of 85,089 subjects (58.5% women, mean age 78 years [IQR 73-83]).The following statistics were carried out: Wilcoxon test, Bland-Altman graphic analysis, study of the concordance using the intraclass correlation coefficient (ICC), and comparison tables for the classification of CKD., Results: The median of the eGFRs using BIS1 was 58mL/min/1.73m 2 (IQR 48-70), using CKD-EPI was 68mL/min/1.73m 2 (IQR 53-84), and using MDRD it was 68mL/min/1.73m 2 (IQR 53-82). The concordance between BIS1 and CKD-EPI (intraclass correlation coefficient =0.87) was found to be acceptable. It was lower with MDRD (intraclass correlation coefficient =0.81). A mean difference of 8mL/min/1.73m 2 (SD 2.6-18) was found BIS1 vs. CKD-EPI, and 10mL/min/1.73m 2 (SD 6-27) with BIS1 vs. MDRD, which was maintained when stratifying by gender and age groups., Conclusions: Despite the acceptable statistical agreement, the eGFR obtained with the BIS1 equation is not interchangeable with CKD-EPI or with MDRD-IDMS. The BIS1 equation gives lower values than CKD-EPI, and classifies patients into a higher level of CKD, mainly when the eGFR is above 30mL/min/1.73 m 2 ., (Copyright © 2019 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: Although several epidemiological studies have suggested that high serum uric acid (SUA) levels are related to a decline in kidney function, only a few studies have investigated using cystatin C to calculate estimated glomerular filtration rate (eGFR). We aimed to clarify the relationship between SUA levels and kidney function assessed by cystatin C in a Japanese general community population without chronic kidney disease (CKD)., Methods: We conducted a community-based cross-sectional study that included 1086 healthy participants, aged 40-74 years, without CKD and not undergoing treatment of hyperuricemia, who had participated in the baseline survey of the Kobe Orthopedic and Biomedical Epidemiological (KOBE) study. The preconditions for participation in this study were no past histories of cardiovascular disease or cancer, and not undergoing treatment for diabetes, hypertension, or dyslipidemia. We classified the participants into quartiles stratified by sex according to their SUA level and then examined the relationship with eGFR. The odds ratios for having a low eGFR, defined as the lowest quartile of eGFR (i.e., ≤78.4 mL/min/1. 73m 2 ) was estimated according to SUA quartiles (men, Q1 ≤ 5.0, Q2 5.1-5.9, Q3 6.0-6.6, and Q4 ≥ 6.7; women, Q1 ≤ 3.8, Q2 3.9-4.3, Q3 4.4-4.9, and Q4 ≥ 5.0 mg/dL) after adjustment for age, body mass index, systolic blood pressure, HbA1c, high and low density lipoprotein cholesterol, and smoking and drinking habits. The adjusted mean of each quartile was also calculated., Results: Multivariable-adjusted means of eGFR showed a graded decrease in higher SUA quartiles (men, Q1 90.5, Q2 88.0, Q3 83.5, and Q4 82.0; women, Q1 95.7, Q2 91.3, Q3 89.2, and Q4 86.7). In addition, the multivariable-adjusted odds ratios for having a lower eGFR (95% confidence interval) for each SUA quartile compared with Q1 was Q2 2.29 (0.98, 5.35), Q3 4.94 (2.04, 11.97), and Q4 8.01 (3.20, 20.04) for men, and was Q2 2.20 (1.12, 4.32), Q3 2.68 (1.39, 5.20), and Q4 4.96 (2.62, 9.41) for women., Conclusions: There was a graded inverse relationship between mild elevations in SUA levels and eGFR assessed by cystatin C in an apparently healthy Japanese population without CKD. This association was similar in both men and women.

Objective: There is a growing interest in the relationship between obesity and renal damage. The effect of obesity on renal function in children and adolescents has not been adequately investigated. In addition, there is no complete consensus on the reliability of various renal function parameters. The primary goal of this study was to evaluate renal function in obese children and adolescents using glomerular filtration rate (GFR), cystatin C, and creatinine (Cr)-derived formulas. We also compared classical GFR measurement methods with methods based on bioimpedance analysis-derived body cell mass (BCM)., Methods: We enrolled 108 obese and 46 healthy subjects aged 6-18 years. Serum cystatin C, serum Cr, 24-hour proteinuria, Cr clearance, and GFR were evaluated in both groups. Estimated GFR was measured with Cr-based, cystatin C-based, combined (cystatin C and Cr) and BCM-based formulae. Both actual and fat-free mass body surface areas (BSA) were used when required. Metabolic parameters (blood glucose, insulin, and lipids) were analyzed in the obese subjects. International Diabetes Federation criteria were used to identify metabolic syndrome (MetS)., Results: We did not detect statistically significant differences between the obese and control groups for mean Cr (p=0.658) and mean cystatin C (p=0.126). Mean cystatin C levels of MetS patients were significantly higher than those of non-MetS obese participants (p<0.001). Cr-based GFR measurements, BCM-based measurements and a combined Cr and cystatin C measurement showed a statistically significant increase in the GFR of obese subjects compared to controls (p=0.002 and p<0.001). This increase was negatively correlated with duration of obesity. Estimations based on actual or fat-free mass BSA did not differ either. Only the Filler equation showed a statistically significant decrease in eGFR in MetS patients. There were no statistically significant differences between the obese and control groups for proteinuria (p=0.994) and fat-free mass proteinuria (p=0.476)., Conclusion: We conclude that cystatin C could be used as an earlier biomarker than Cr in the detection of impaired renal function in obese children, especially those with MetS. Cr-based formulae reveal hyperfiltration as the first change in renal function. Decreasing eGFR seen in MetS patients with cystatin C-based formulae, but not Cr-based formulae, may represent the early stages of renal damage. Using fat-free mass or BCM for eGFR formulae in obese children seems to provide no additional information.

Background:  Haemodynamic alterations caused by acute pulmonary embolism (PE) may affect multi-organ function including kidneys. This multi-centre, multinational cohort study aimed to validate the prognostic significance of estimated glomerular filtration rate (eGFR) and its potential additive value to the current PE risk assessment algorithms., Methods:  The post hoc analysis of pooled prospective cohort studies: 2,845 consecutive patients (1,424 M/1,421 F, 66 ± 17 years) with confirmed acute PE and followed up for 180 days. We tested prognostic value of pre-specified eGFR level ≤60 mL/min/1.73 m 2 calculated on admission according to the Modification of Diet in Renal Disease study equation. The primary outcome was all-cause 30-day mortality; the secondary outcomes were PE-related mortality, 180-day all-cause mortality, bleeding and composite outcome (PE-related death, thrombolysis or embolectomy)., Results:  Two hundred and twenty-three patients (8%; 95% confidence interval [CI]: 7-9%) died within the first 30 days after the diagnosis. The eGFR on admission was significantly lower in non-survivors than in survivors (64 ± 34 vs. 75 ± 3 mL/min/1.73 m 2 , p  < 0.0001). Independent predictors for a fatal outcome included: cancer, systolic blood pressure, older age, hypoxia, eGFR, heart rate and coronary artery disease. The eGFR of ≤60 mL/min/1.73 m 2 independently predicted all-cause mortality (hazard ratio: 2.3; 95% CI: 1.7-3.0, p  < 0.0001), PE-related outcome and clinically relevant bleedings (odds ratio: 0.90 per 10 mL/min/1.73 m 2 , 95% CI: 0.85-0.95, p  = 0.0002). The eGFR assessment significantly improved prognostic models proposed by European guidelines with net re-classification improvement of 0.42 ( p  < 0.0001)., Conclusion:  The eGFR of ≤60 mL/min/1.73 m 2 not only independently predicted higher 30- and 180-day all-cause mortality and bleeding events, but when added to the current European Society of Cardiology risk stratification algorithm improved identification of both low- and high-risk patients. Therefore, eGFR calculation should be implemented in the risk assessment of acute PE., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)

Objectives: The aim of this study was to describe the variability in renal function markers in non-azotaemic and azotaemic cats, and also the rate of change in the markers., Methods: Plasma creatinine concentration and its reciprocal, glomerular filtration rate (GFR) and urine specific gravity (USG) were studied as markers of renal function in client-owned cats. GFR was determined using a corrected slope-intercept iohexol clearance method. Renal function testing was performed at baseline and a second time point. The within-population variability (coefficient of variation; CV%) was determined at the baseline time point. Within-individual variability (CV%) and rate of change over time were determined from the repeated measurements., Results: Twenty-nine cats were included in the study, of which five had azotaemic chronic kidney disease. The within-individual variability (CV%) in creatinine concentration was lower in azotaemic cats than in non-azotaemic cats (6.81% vs 8.82%), whereas the within-individual variability in GFR was higher in azotaemic cats (28.94% vs 19.98%). The within-population variability was greatest for USG (67.86% in azotaemic cats and 38.00% in non-azotaemic cats). There was a negative rate of change in creatinine concentration in azotaemic and non-azotaemic cats (-0.0265 and -0.0344 µmol/l/day, respectively) and a positive rate of change of GFR in azotaemic and non-azotaemic cats (0.0062 and 0.0028 ml/min/day, respectively)., Conclusions and Relevance: The within-individual variability data suggest creatinine concentration to be the more useful marker for serial monitoring of renal function in azotaemic cats. In contrast, in non-azotaemic cats, GFR is a more useful marker for serial monitoring of renal function. The majority of cats with azotaemic CKD did not have an appreciable decline in renal function during the study.

Objectives: To examine the hypothesis that the inflammatory state of aging is a risk factor for accelerated renal function (RF) decline using inflammatory biomarkers and RF measures collected over 9 years of follow-up in relatively healthy individuals enrolled in the Invecchiare in Chianti study., Design: Longitudinal., Setting: Community., Participants: Individuals aged 60 and older with baseline estimated glomerular filtration rate (eGFR) of 60 mL/min per 1.73 m 2 and greater and no diabetes mellitus (DM) (N = 687)., Measures: eGFR, as a proxy for RF, was determined using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation at baseline and 3-, 6-, and 9-year follow-up. Incident chronic kidney disease (CKD) was defined as new-onset eGFR less than 60 mL/min per 1.73 m 2 at each follow-up. Predictors included baseline and time-dependent inflammatory biomarkers: soluble tumor necrosis factor alpha receptors (sTNFα-R1 and -R2), interleukin (IL)-6, IL-18, IL-1β, IL-1 receptor antagonist, and high-sensitivity C-reactive protein., Results: Higher baseline sTNFα-R1 was significantly associated with lower eGFR over 9 years, independent of DM or blood pressure (baseline: β^ = -0.39, P = .001; 3-year: β^ = -0.26, P = .001; 6-year: β^ = -0.36, P = .001; 9-year: β^ = -0.47, P = .001). The rate of TNFα-R1 change was significantly associated with rate of eGFR change (β^ = -0.18, P = .001). Baseline sTNFα-R1 predicted incident CKD (per 1-standard deviation increment: 3-year: relative risk (RR) = 1.3, 95% confidence interval (CI) = 1.1-1.5; 6-year: RR = 1.5, 95% CI = 1.1-2.2; 9-year RR = 1.6, 95% CI = 1.1-2.2). Similar results were found for sTNFα-R2., Conclusion: Baseline TNFα-R levels and their rates of change were significantly associated with RF decline and incident CKD in older adults independent of DM or blood pressure., (© 2018, Copyright the Authors Journal compilation © 2018, The American Geriatrics Society.)

What Is Known and Objectives: Formulae estimating glomerular filtration rate (GFR) are frequently used to guide drug dosing. The objectives of this prospective single-center study were to evaluate agreement between these equations and measured creatinine clearance (CrCl) in non-critically ill surgery patients with normal kidney function and augmented renal clearance (ARC, CrCl ≥ 130 mL/min/1.73 m²), to determine predictors for disagreement, define a GFR estimator cut-off value identifying ARC and determine the ARC prevalence and duration in non-critically ill surgical patients., Methods: Hospitalized adult non-critically ill abdominal and trauma surgery patients were eligible for inclusion. Measured CrCl based on an 8-hour urinary collection (CrCl 8h ) was used as the primary method for determining kidney function. Agreement between equations and measured CrCl 8h was assessed in terms of precision, defined as a bias within ±10 mL/min/1.73 m². Predictors for disagreement were identified for the most precise estimator using an ordinal logistic regression model with negative bias, agreement and positive bias as outcome variables. A receiver operating characteristic (ROC) analysis was performed to identify an estimator cut-off predicting ARC, which was subsequently applied for the daily proportion of patients displaying ARC and ARC duration., Results and Discussion: During the study period (14/11/2013 - 13/05/2014), in 232 adult non-critically ill abdominal and trauma surgery patients, all estimators tend to underestimate CrCl 8h (mean bias ranging from 17 to 22 mL/min/1.73 m²), especially in patients displaying ARC (mean bias ranging from 44 to 56 mL/min/1.73 m²). eGFR CKD-EPI performed the best. Younger age and low ASA score independently predicted underestimation of CrCl 8h . Three different eGFR CKD-EPI cut-offs with decreasing sensitivity and increasing specificity (84, 95 and 112 mL/min/1.73 m²) identified, respectively, 65%, 44% and 14% patients displaying ARC. The median ARC duration was 4, 4 and 3 days, respectively., What Is New and Conclusion: In surgical patients, eGFR frequently underestimates measured CrCl, especially in young patients with low ASA score. eGFR cut-offs predicting ARC were identified., (© 2018 John Wiley & Sons Ltd.)

Background: While chronic kidney disease (CKD) is a growing public health concern in low- and middle-income countries, such as China, few studies have investigated the association between urbanization and the occurrence of CKD in those countries., Methods: We investigated the association between urbanization and estimated glomerular filtration rate (eGFR), an important CKD risk marker. Data came from the China Health and Nutrition Survey wave 2009, in which we collected fasting serum, individual and household data along with community level urbanization data, which was used to derive a study-specific urbanization measure, in 218 communities across nine provinces. A total of 3644 men and 4154 women participants aged 18 years or older were included in the analysis. Reduced renal function was defined as eGFR of less than 60 mL/min/1.73 m 2 measured using serum creatinine concentration (mg/dL)., Results: After adjusting for socio-demographic (e.g., age, education and household income), a sex-stratified multilevel logistic model revealed that living in a more urbanized community was associated with higher odds of reduced eGFR (odds ratio [OR] = 1.38 per one-standard deviation [SD] increase in the CHNS specific urbanization index, 95% confidence interval [CI] = 1.11-1.73 for men; OR = 1.35, 95% CI = 1.11-1.62 for women). After adjusting for behavioral variables (i.e., alcohol consumption, smoking, physical activity and diet), as well as obesity and cardiometabolic risk factors, the association was attenuated in men (OR = 1.25, 95% CI = 0.98-1.59), but remained statistically significant in women (OR = 1.24, 95% CI = 1.01-1.52)., Conclusion: Our findings suggest that living in an urban environment is linked with higher odds of reduced renal function independently of behavioral and cardiometabolic risk factors, which have been shown to increase along with urbanization.

Cardiorenal syndrome type 1 causes acute kidney injury but is poorly understood; animal models and diagnostic aids are lacking. Robust noninvasive measurements of glomerular filtration rate are required for injury models and clinical use. Several have been described but are untested in translational models and suffer from biologic interference. We developed a mouse model of cardiorenal syndrome and tested the novel near-infrared fluorophore ZW800-1 to assess renal and cardiac function. We performed murine cardiac arrest and cardiopulmonary resuscitation followed by transthoracic echocardiography, 2 and 24 h later. Transcutaneous fluorescence of ZW800-1 bolus dispersion and clearance was assessed with whole animal imaging and compared with glomerular filtration rate (GFR; inulin clearance), tubular cell death (using unbiased stereology), and serum creatinine. Correlation, Bland-Altman, and polar analyses were used to compare GFR with ZW800-1 clearance. Cardiac arrest and cardiopulmonary resuscitation caused reversible cardiac failure, halving fractional shortening of the left ventricle ( n = 12, P = 0.03). Acute kidney injury resulted with near-zero GFR and sixfold increase in serum creatinine 24 h later ( n = 16, P < 0.01). ZW800-1 biodistribution and clearance were exclusively renal. ZW800-1 t 1/2 and clearance correlated with GFR ( r = 0.92, n = 31, P < 0.01) and bolus time-dispersion curves demonstrated that ZW800-1 fluorescence dispersion correlated with left ventricular function ( P < 0.01) and bolus time-dispersion curves demonstrated that ZW800-1 fluorescence dispersion correlated with left ventricular function ( r < 0.01). Cardiac arrest and cardiopulmonary resuscitation lead to experimental cardiorenal syndrome type 1. ZW800-1, a small near-infrared fluorophore being developed for clinical intraoperative imaging, is favorable for evaluating cardiac and renal function noninvasively.P < 0.01). Cardiac arrest and cardiopulmonary resuscitation lead to experimental cardiorenal syndrome type 1. ZW800-1, a small near-infrared fluorophore being developed for clinical intraoperative imaging, is favorable for evaluating cardiac and renal function noninvasively., (Copyright © 2017 the American Physiological Society.)

Background: Accurately determining renal function is essential for clinical management of HIV patients. Classically, it has been evaluated by estimating glomerular filtration rate (eGFR) with the MDRD-equation, but today there is evidence that the new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation has greater diagnostic accuracy. To date, however, little information exists on patients with HIV-infection. This study aimed to evaluate eGFR by CKD-EPI vs. MDRD equations and to stratify renal function according to KDIGO guidelines., Methods: Cross-sectional, single center study including adult patients with HIV-infection., Results: Four thousand five hundred three patients with HIV-infection (864 women; 19%) were examined. Median age was 45 years (IQR 37-52), and median baseline creatinine was 0.93 mg/dL (IQR 0.82-1.05). A similar distribution of absolute measures of eGFR was found using both formulas (p = 0.548). Baseline median eGFR was 95.2 and 90.4 mL/min/1.73 m 2 for CKD-EPI and MDRD equations (p < 0.001), respectively. Of the 4503 measurements, 4109 (91.2%) agreed, with a kappa index of 0.803. MDRD classified 7.3% of patients as "mild reduced GFR" who were classified as "normal function" with CKD-EPI. Using CKD-EPI, it was possible to identify "normal function" (>90 mL/min/1.73 m 2 ) in 73% patients and "mild reduced GFR" (60-89 mL/min/1.73 m 2 ) in 24.3% of the patients, formerly classified as >60 mL/min/1.73 m 2 with MDRD., Conclusions: There was good correlation between CKD-EPI and MDRD. Estimating renal function using CKD-EPI equation allowed better staging of renal function and should be considered the method of choice. CKD-EPI identified a significant proportion of patients (24%) with mild reduced GFR (60-89 mL/min/1.73 m 2 ).

Background: Renal function, as quantified by the estimated glomerular filtration rate (eGFR), is a predictor of death in acute heart failure (AHF). It is unknown whether one of the clinically-available serum creatinine-based formulas to calculate eGFR is superior to the others for predicting mortality., Methods and Results: We quantified renal function using five different formulas (Cockroft-Gault, MDRD-4, MDRD-6, CKD-EPI in patients<70 years, and BIS-1 in patients≥70 years) in 1104 unselected AHF patients presenting to the emergency department and enrolled in a multicenter study. Two independent cardiologists adjudicated the diagnosis of AHF. The primary endpoint was the accuracy of the five eGFR equations to predict death as quantified by the time-dependent area under the receiver-operating characteristics curve (AUC). The secondary endpoint was the accuracy to predict all-cause readmissions and readmissions due to AHF. In a median follow-up of 374 days (IQR: 221 to 687 days), 445 patients (40.3%) died. eGFR as calculated by all equations was an independent predictor of mortality. The Cockcroft-Gault formula showed the highest prognostic accuracy (AUC 0.70 versus 0.65 for MDRD-4, 0.55 for MDRD-6, and 0.67 for the combined formula CKD-EPI/BIS-1, p<0.05). These findings were confirmed in patients with varying degrees of renal function and in three vulnerable subgroups: women, patients with severe left ventricular dysfunction, and the elderly. The prognostic accuracy for readmission was poor for all equations, with an AUC around 0.5., Conclusions: Calculating eGFR using the Cockcroft-Gault formula assesses the risk of mortality in patients with AHF more accurately than other commonly used formulas., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Glomerular filtration rate (GFR) is the gold standard to assess overall kidney function. However, traditional methods to evaluate GFR are cumbersome and time-consuming. In addition, serial blood or urine samples are required, with the associated stress for the experimental animals. A recent technique significantly reduces the investment in time and resources, minimizing the invasiveness and the animal stress, but being equally valid as the traditional approaches. The method measures transcutaneously renal function. Using an optical device and the exogenous renal marker fluorescein isothiocyanate (FITC)-sinistrin, this technique is capable of measuring the elimination kinetics of the marker through the skin. With neither blood nor urine samples nor the associated laboratory assays needed, the results of the transcutaneous measurement are almost instantaneously available. The method has been already validated in different species and successfully applied in several models of renal pathology. Moreover, due to its minimally invasive characteristics, it is suitable for sequential measurements within the same animal. Here is provided a detailed protocol to carry out the transcutaneous assessment of renal function in rodents.

Purpose: Creatinine clearance (Ccr) is used as a marker of renal function in cancer chemotherapy, but it is not correlated with glomerular filtration rate (GFR) after high-dose cisplatin treatment. In addition to Ccr, measured using 24-h urine collection (24-h Ccr) or Cockcroft-Gault formula (CGF), the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and the Japanese GFR estimation equation (the Japanese equation) have been recently developed to estimate GFR for predicting renal function. However, these equations remain to be evaluated, particularly in cancer patients treated with cisplatin. Therefore, we investigated the validity of these equations for predicting the GFR in cancer patients treated with cisplatin., Methods: GFR was measured by inulin clearance (Cin) in 50 cancer patients and compared with GFR estimated by the CKD-EPI equation, the Japanese equation, and Ccr estimated by CGF or measured by 24-h Ccr before the first and third cisplatin-containing chemotherapy cycles (considered pretreatment and posttreatment, respectively)., Results: Before treatment, the CKD-EPI and the Japanese equations estimated GFR with higher accuracy than Ccr. Posttreatment bias values for GFR estimation using the CKD-EPI and the Japanese equations were lower than those for Ccr. The CKD-EPI and the Japanese equations were also more precise than Ccr. However, for patients with low renal function, these equations still overestimated Cin., Conclusion: The CKD-EPI and the Japanese equations estimated GFR with lower bias and higher precision than Ccr pre- and postcisplatin treatment. This study is registered at UMIN: 000002167.

Background: Impaired renal function is associated with increased mortality among patients with implantable cardioverter-defibrillators (ICDs). The relationship between renal function at time of ICD generator replacement and subsequent appropriate ICD therapies is not known., Methods and Results: We identified 441 patients who underwent first ICD generator replacement between 2000 and 2011 and had serum creatinine measured within 30 days of their procedure. Patients were divided into tertiles based on estimated glomerular filtration rate (eGFR). Adjusted Cox proportional hazard and competing risk models were used to assess relationships between eGFR and subsequent mortality and appropriate ICD therapy. Median eGFR was 37.6, 59.3, and 84.8 mL/min/1.73 m(2) for tertiles 1-3, respectively. Five-year Kaplan-Meier survival probability was 34.8%, 61.4%, and 84.5% for tertiles 1-3, respectively (P < 0.001). After multivariable adjustment, compared to tertile 3, worse eGFR tertile was associated with increased mortality (HR 2.84, 95% CI [1.36-5.94] for tertile 2; HR 3.84, 95% CI [1.81-8.12] for tertile 1). At 5 years, 57.0%, 58.1%, and 60.2% of patients remained free of appropriate ICD therapy in tertiles 1-3, respectively (P = 0.82). After adjustment, eGFR tertile was not associated with future appropriate ICD therapy. Results were unchanged in an adjusted competing risk model accounting for death., Conclusions: At time of first ICD generator replacement, lower eGFR is associated with higher mortality, but not with appropriate ICD therapies. The poorer survival of ICD patients with reduced eGFR does not appear to be influenced by arrhythmia status, and there is no clear proarrhythmic effect of renal dysfunction, even after accounting for the competing risk of death., (© 2014 Wiley Periodicals, Inc.)

Background: The current glomerular filtration rate (GFR) equation (CKiD) may be less accurate in adolescents and children with higher GFR., Methods: This was a retrospective study (n = 161, 247 (99)mTc DTPA-GFRs). Six equations were evaluated for bias, accuracy, and low GFR diagnosis: (1) CKiD; (2) historic center; (3) Hoste(age); (4) Hoste(height); (5) modified Pottel; (6) Gao. Children with ≥ vs. <90 ml/min/1.73 m(2)) and < vs. ≥16 years were compared. Two adult equations were evaluated in children ≥16 years., Results: Most equations underestimated GFR by 1-14 % in the higher GFR group, least so for Hoste(age). In the low GFR group, Hoste(age) and historic center overestimated GFR significantly more than CKiD (p < 0.05). Accuracy (within 30 % GFR) was similar across equations and GFR subgroups (66-86 %). In the ≥16 years group, CKiD underestimated GFR by ∼10 %, vs. ∼3 % for Hoste(height). Accuracy was 5-10 % lower in the older group and most equations were more sensitive than specific for detecting low GFR; this discrepancy was less for the Hoste equations. Adult equations were highly inaccurate., Conclusions: GFR estimation in older children and with higher GFR is suboptimal. The Hoste(height) may be an alternative GFR estimation method; Hoste(age) may allow for height-independent GFR estimation in patients with normal GFR.

Background: Chronic kidney disease is an important concern in preventive medicine, but the rate of decline in renal function in healthy population is not well defined. The purpose of this study was to determine reference values for the estimated glomerular filtration rate (eGFR) and rate of decline of eGFR in healthy subjects and to evaluate factors associated with this decline using a large cohort in Japan., Methods: Retrospective cross-sectional and longitudinal studies were performed with healthy subjects aged ≥18 years old who received a medical checkup. Reference values for eGFR were obtained using a nonparametric method and those for decline of eGFR were calculated by mixed model analysis. Relationships of eGFR decline rate with baseline variables were examined using a linear least-squares method., Results: In the cross-sectional study, reference values for eGFR were obtained by gender and age in 72,521 healthy subjects. The mean (±SD) eGFR was 83.7±14.7 ml/min/1.73 m2. In the longitudinal study, reference values for eGFR decline rate were obtained by gender, age, and renal stage in 45,586 healthy subjects. In the same renal stage, there was little difference in the rate of decline regardless of age. The decline in eGFR depended on the renal stage and was strongly related to baseline eGFR, with a faster decline with a higher baseline eGFR and a slower decline with a lower baseline eGFR. The mean (±SD) eGFR decline rate was ‒1.07±0.42 ml/min/1.73 m2/year (‒1.29±0.41%/year) in subjects with a mean eGFR of 81.5±11.6 ml/min/1.73 m2., Conclusions: The present study clarified for the first time the reference values for the rate of eGFR decline stratified by gender, age, and renal stage in healthy subjects. The rate of eGFR decline depended mainly on baseline eGFR, but not on age, with a slower decline with a lower baseline eGFR.

Practical Relevance: Routinely used markers of renal function in clinical practice include urea and creatinine. However, these are insensitive markers, particularly in the early stages of kidney disease. Measurement of glomerular filtration rate (GFR) is regarded as the most sensitive index of functioning renal mass. It may be useful for feline patients in varying clinical scenarios; for example, where a more accurate measurement of renal function may aid diagnosis, to enable response to therapeutic interventions to be more closely monitored, or to evaluate renal function prior to the use of nephrotoxic or renally cleared drugs., Clinical Challenges: Traditional methods of measuring GFR, such as renal clearance or multisample plasma clearance techniques, are generally impractical for clinical use. Limited sampling and single sample plasma clearance methods using the filtration marker iohexol have been validated in cats. These have the advantages of reduced stress to cats associated with repeated sampling and reduced costs of analysis, and therefore offer greater clinical utility. Attempts to develop an estimated GFR (eGFR) formula similar to that used in human patients have been made in cats, although currently an accurate and reliable formula is not available., Audience: This review presents the basis for the theoretical understanding and practical measurement of GFR for any veterinary practitioner wishing to obtain a more accurate and sensitive assessment of renal function than routinely used markers provide., Evidence Base: The review draws evidence from peer-reviewed publications, the author's PhD thesis and also clinical experience., (© ISFM and AAFP 2014.)

In the clinical context of the patients with liver cirrhosis, accurate evaluation of the renal function is potentially crucial. Indeed, it can lead to early diagnosis of both acute kidney injury and chronic kidney disease and to reliable characterization of the renal status of the patient before performing a liver transplantation. Despite some limitations, the assay of serum creatinine (SCr) is universally used to estimate glomerular filtration rate (GFR) because of its wide availability, its simplicity and because it is inexpensive. Nevertheless, several reports show that the value of this assay to estimate GFR is strongly challenged in cirrhotic patients, especially in patients with liver failure and/or severely impaired renal function. This has led to seek new alternatives to estimate more reliably the GFR in these patients. Although the reference methods, based on the utilization of exogenous markers, allow measuring GFR and thereby constitute the "gold standard" to evaluate renal function, they are not feasible in routine clinical practice. Several studies have shown that a cystatin C (CysC) based formula perform better than the SCr-based estimates in cirrhotic patients and the estimation of GFR by these formulas could therefore lead to optimize the management of the patients. A new estimate based on CysC has been recently developed using a large number of patients and the first results regarding the evaluation of its performance are promising, making this new formula the best candidate for a reference estimate of the renal function in cirrhotic patients.

Background: Urban migration is associated with an increased risk of hypertension, obesity and diabetes in Indian migrants. This study assessed the relationship between internal migration and renal function in the Hyderabad arm of the Indian Migration Study., Methods: We assessed 841 subjects; urban non-migrants (n = 158), urban migrants (n = 424) and rural non-migrants (n = 259). Muscle mass was ascertained from DXA scanning. We derived urban life years for urban migrants and rural non-migrants. Multivariable linear regression was used to examine the association between tertiles of urban life years and 4-variable MDRD eGFR using Stata 11., Results: Mean eGFR was lower in urban non-migrants and urban migrants compared to rural non-migrants. The prevalence of CKD 3-5 was higher in the rural non-migrant population (5.0%) than in the urban non-migrant populations (2.5%) due to a negatively skewed distribution of eGFR in rural non-migrants. As urban life years increased, eGFR declined (p = 0.008) though there was no obvious dose response effect. After adjustment for muscle mass, the association was attenuated and the trend was consistent with chance (p = 0.08). Further adjustment for vascular risk factors weakened the association to a small degree (p = 0.11)., Conclusions: The high prevalence of reduced eGFR in rural areas requires further research. Urbanization was associated with reduced eGFR. This association appears mostly to be due to higher muscle mass with a small contribution from adverse vascular disease risk factors.

Background: Instead of scaling glomerular filtration rate (GFR) to a body surface area of 1.73 m(2), it has been suggested to scale GFR to extracellular fluid volume (ECV). The ratio GFR/ECV has physiological meaning in that it indicates how often 'that which is to be regulated' (i.e. ECV) comes into contact with the 'regulator' (i.e. the kidneys)., Aim: The aim of the present study was as follows: to analyse two published calculation methods for determining ECV and GFR/ECV; to develop a new simple and accurate formula for determining ECV; and to compare and evaluate these methods., Materials and Methods: GFR was determined as (51)Cr-EDTA clearance. The study comprised 128 individuals (35 women, 66 men and 27 children) with a full (51)Cr-EDTA plasma concentration curve, determined from injection until 4-5 h p.i. Reference values for GFR and ECV were calculated from the full curve. One-pool approximations C/(1) and V(1) were calculated using only the final-slope curve. Four calculation methods were compared: simple one-pool values; GFR/ECV according to Peters and colleagues; ECV according to Brøchner-Mortensen (BM); and ECV according to a new method (JBM): y=2x-1, where x=Cl(1)/Cl and y=V(1)/ECV., Results: The new JBM method is accurate and can be explained theoretically. BM has a slight bias for high renal function. The Peters method had bias in our data. GFR/ECV had better precision than ECV alone, especially for BM and JBM, which were within -4% to +7% of the reference values (95% limits of agreement in adults)., Conclusion: GFR/ECV can be precisely determined, especially with the BM and JBM methods. Expressing GFR/ECV in unit %/h gives a simple interpretation. Normal ranges for GFR/ECV need to be established.

Purpose: Renal function is monitored during chemotherapy because chemotherapeutic drugs are excreted by the kidneys and are potentially nephrotoxic. Doses are adjusted according to the glomerular filtration rate (GFR), i.e. the more reduced the GFR, the lower the treatment dose. Plasma clearance of (51)Cr-EDTA is a reliable indicator of GFR before and during treatment with potentially nephrotoxic drugs, but its measurement is costly. GFR can also be estimated using an algorithm that converts plasma creatinine concentration to GFR, e.g. the MDRD equation. The aim of this investigation was to evaluate the reliability of estimated GFR (eGFR) in detecting changes in GFR as assessed by the MDRD equation in cancer patients treated with nephrotoxic chemotherapeutic drugs., Methods: We included all patients from the Department of Oncology undergoing chemotherapy who were referred to the Department of Nuclear Medicine for measurement of GFR by the (51)Cr-EDTA plasma clearance technique at least four times during the study period of 12 months. The eGFR was calculated from plasma creatinine concentration and the MDRD formula. GFR was determined by the (51)Cr-EDTA plasma clearance method., Results: In 48 patients with a mean age of 47 years, GFR decreased from 86 to 73 ml/min/1.73 m(2) (mean values, p < 0.002) from the first to the last measurement, whereas plasma creatinine concentration and eGFR remained unchanged. In 13 patients (27 %) the finding of a decreased GFR led to adjustment of the dose of the chemotherapy drug. Eight of the 13 patients with decreased GFR also had a reduced eGFR but five patients had a normal eGFR. These five patients would have been treated with the nephrotoxic drug at a dose that was too high., Conclusion: Neither creatinine plasma concentration nor eGFR (MDRD) can be recommended as a replacement for measurement of GFR with the (51)Cr-EDTA plasma clearance method in patients treated with nephrotoxic cytostatic drugs.

Purpose: The relative effectiveness of partial vs radical nephrectomy remains unclear in light of the recent phase 3 European Organization for the Research and Treatment of Cancer trial. We performed a systematic review and meta-analysis of partial vs radical nephrectomy for localized renal tumors, considering all cause and cancer specific mortality, and severe chronic kidney disease., Materials and Methods: Cochrane Central Register of Controlled Trials, MEDLINE®, EMBASE®, Scopus and Web of Science® were searched for sporadic renal tumors that were surgically treated with partial or radical nephrectomy. Generic inverse variance with fixed effects models were used to determine the pooled HR for each outcome., Results: Data from 21, 21 and 9 studies were pooled for all cause and cancer specific mortality, and severe chronic kidney disease, respectively. Overall 31,729 (77%) and 9,281 patients (23%) underwent radical and partial nephrectomy, respectively. According to pooled estimates partial nephrectomy correlated with a 19% risk reduction in all cause mortality (HR 0.81, p < 0.0001), a 29% risk reduction in cancer specific mortality (HR 0.71, p = 0.0002) and a 61% risk reduction in severe chronic kidney disease (HR 0.39, p < 0.0001). However, the pooled estimate of cancer specific mortality for partial nephrectomy was limited by the lack of robustness in consistent findings on sensitivity and subgroup analyses., Conclusions: Our findings suggest that partial nephrectomy confers a survival advantage and a lower risk of severe chronic kidney disease after surgery for localized renal tumors. However, the results should be evaluated in the context of the low quality of the existing evidence and the significant heterogeneity across studies. Future research should use higher quality evidence to clearly demonstrate that partial nephrectomy confers superior survival and renal function., (Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Background: Renal function is an important predictor of mortality in patients with myocardial infarction (MI), but changes in the impact over time have not been well described.We examined the importance of renal function by estimated GFR (eGFR) and se-creatinine as an independent long-term prognostic factor., Methods: Prospective follow-up of 6653 consecutive MI patients screened for entry in the Trandolapril Cardiac Evaluation (TRACE) study. The patients were analysed by Kaplan-Meier survival analysis, landmark analysis and Cox proportional hazard models. Outcome measure was all-cause mortality., Results: An eGFR below 60 ml per minute per 1.73 m2, consistent with chronic renal disease, was present in 42% of the patients. We divided the patients into 4 groups according to eGFR. Overall, Cox proportional-hazards models showed that eGFR was a significant prognostic factor in the two groups with the lowest eGFR, hazard ratio 1,72 (confidence interval (CI) 1,56-1,91) in the group with the lowest eGFR. Using the eGFR group with normal renal function as reference, we observed an incremental rise in hazard ratio. We divided the follow-up period in 2-year intervals. Landmark analysis showed that eGFR at the time of screening continued to show prognostic effect until 16 years of follow-up. By multivariable Cox regression analysis, the prognostic effect of eGFR persisted for 12 years and of se-creatinine for 10 years. When comparing the lowest group of eGFR with the group with normal eGFR, prognostic significance was present in the entire period of follow-up with a hazard ratio between 1,97 (CI 1,65-2,35) and 1,35 (CI 0,99-1,84) in the 2-year periods., Conclusions: One estimate of renal function is a strong and independent long-term prognostic factor for 10-12 years following a MI.

Methods for measurement of glomerular filtration rate (GFR) (clearance in plasma, urine or both of an « exogenous » tracer, usually radio labeled) often are considered impractical from a clinical standpoint. Alternate methods proposed to estimate the GFR are based on plasma levels of « endogenous » tracers (creatinine, cystatin C). These methods are so imprecise that they provide little if any true reassurance with regards to warnings and recommended GFR values for the use of iodinated and gadolinium based contrast agents., (Copyright © 2011 Elsevier Masson SAS and Éditions françaises de radiologie. All rights reserved.)

Background/aims: Adults with congenital heart disease exhibit a 3-fold higher mortality in the presence of chronic kidney disease, hence assessment of renal function is crucial in this patient population. Formulas for the estimation of glomerular filtration rate (GFR) have not been evaluated in this patient population. Therefore, this study compares different markers and equations for the estimation of renal function in adults with congenital heart disease., Methods: Renal function was assessed in 102 patients using the Modification of Diet in Renal Disease (MDRD) equation, the simplified MDRD equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and the Cockcroft-Gault formula. Additionally, symmetrical dimethylarginine (SDMA) was measured. Those parameters were compared to cystatin C-derived GFR using the Larsson equation., Results: GFR estimates using the original MDRD (r = 0.465, p < 0.001) and the CKD-EPI equation (r = 0.462, p < 0.001) showed a similar strong correlation with the cystatin C-based eGFR equation, while eGFR using the simplified MDRD equation showed a slightly weaker correlation (r = 0.439, p < 0.001). The Cockcroft-Gault formula showed no correlation at all to the cystatin C-based eGFR (r = 0.144, p = 0.17). The strongest correlation was observed for SDMA and cystatin C-based eGFR (r = -0.552, p < 0.001)., Conclusion: GFR in adults with congenital heart disease should be estimated using the original MDRD or the CKD-EPI formula. SDMA seems to be a promising marker of renal function for this patient group., (Copyright © 2010 S. Karger AG, Basel.)

Chronic kidney disease is one of the most common disorders in dogs and cats. The plasma urea nitrogen (P-UN) and creatinine (P-Cre) concentrations are not sufficiently sensitive for early diagnosis of renal dysfunction. Although urine and plasma clearance methods allow earlier detection of reductions in the GFR, it is difficult to estimate a mildly reduced GFR from the values obtained by these methods, as they are also affected by physiological factors, such as body weight (BW) and age. The present study is a retrospective survey designed to assess the factors that affect markers of kidney function and to revaluate the clinical utility of the markers, including P-UN, P-Cre and GFR determined by plasma iohexol clearance (PCio) in dogs and cats. The P-UN, P-Cre and PCio values in dogs and the P-Cre and PCio values in cats were significantly correlated with BW (P<0.001). PCio in smaller dogs (≤ 15.0 kg) was significantly and inversely correlated with age. In smaller dogs, increase of P-UN alone might warrant a suspicion of a decreased GFR, but in contrast, P-Cre may be inefficient for detecting renal dysfunction or determining the severity of CKD compared with that in larger dogs (≥ 15.1 kg). P-Cre in larger dogs correlated better with PCio than in smaller dogs, suggesting that P-Cre in larger dogs was a more sensitive marker of reduced GFR.

Background: Renal disease is one of the major complications in Fabry disease, an X-linked lysosomal storage disease due to deficiency of the enzyme alpha-galactosidase A. The aim of our study was to determine the value of creatinine-, cystatin C- and beta-trace-based formulas for the estimation of glomerular filtration rate (eGFR) in Fabry patients. For comparison, the gold standard method (125)I-labelled iothalamate/(131)I-labelled hippuran [measured GFR (mGFR)] was used., Methods: GFR was estimated by using 11 different formulas based on creatinine, cystatin C and beta-trace protein. Accuracy and precision, detection of early decline of renal function and follow-up of renal function by eGFR was compared to mGFR., Results: One hundred and thirty-six GFR measurements and plasma samples were available from 36 (20 male) Fabry patients, treated with agalsidase alpha or beta with a median follow-up of 3.1 (range 1.5-5.2) years. Median mGFR was 97.3 (15.5-148.6) ml/min/1.73 m(2) in males and 84.4 (23.0-131.0) ml/min/1.73 m(2) in females at the start of follow-up., Conclusions: Although none of the investigated endogenous markers proved to be an equivalent substitute for mGFR in Fabry patients, the Stevens equation, a creatinine- and cystatin C-based formula, most closely approximated the mGFR. When a creatinine-based formula is preferred, considering that there is no standardized method available for cystatin C, the abbreviated Modification of Diet in Renal Disease (aMDRD) and the recently developed Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas had the best performance. In male Fabry patients, the aMDRD may overestimate GFR, especially in the higher ranges. In these cases, CKD-EPI may perform better.

Chronic kidney disease affects millions of Americans. Many drugs are eliminated from the body by the kidneys. As renal function declines due to the disease, drugs that are normally eliminated by the kidneys can accumulate, potentially leading to toxicity. Assessing kidney function in patients is essential in determining the appropriate dose of medications to achieve the desired clinical outcome while minimizing the potential for toxicity.

Aims: To measure the glomerular filtration rate (GFR) in adults and children with cystic fibrosis (CF) using a radio-isotope technique as the gold standard and to compare this to serum creatinine based equations, serum cystatin C levels and tobramycin clearance, and to determine which method correlates most closely with measured GFR in this population., (Crown Copyright (c) 2010. Published by Elsevier B.V. All rights reserved.)

The chronic kidney disease (CKD) is a polysymptomatic syndrome resulting from the reduction of active nephrons. It is estimated that the disease affects from 4.7-20% of adults. According to the actual knowledge, glomerular filtration rate (GFR) less than 60 ml/min/1.73 m2 is a significant risk factor for the cardiovascular diseases. The aim of our study was to assess the frequency of using the serum creatinine level and the estimated GFR (eGFR) as the indices of renal function in clinical practice. The study was performed amongst physicians working in non-academic departments of internal disease in the region of lubelskie voivodeships in 2008. An anonymous questionnaire of own composition consisting of 18 open and closed questions was used. The questions concerned the use of eGFR and serum creatinine level in everyday practice. 162 physicians were asked to fill the questionnaire, the percent of positive answers was 27.78% which is 45 questionnaires. The best parameter in evaluation of renal function, according to the asked physicians, was serum creatinine level (49% of all answers), eGFR (47%) and serum urea level or microalbuminuria (4%). Despite the actual recommendations, the serum creatinine level still remains the most popular routine parameter used to evaluate renal function. It seems that the knowledge concerning the diagnosing of CKD and the prophylaxis of its progression among physicians is insufficient. It concerns mainly physicians with no special training, working rather in profiled than in general medicine departments. Therefore, current educational programs concerning preventing and early diagnosis of CKD should be destinated mainly to these groups of physicians.

Background: the Modification of Diet in Renal Disease (MDRD) method of renal function estimation has not been extensively assessed in elderly patients. We needed to assess which renal function estimate was most suited for drug dose estimation in our population., Method: we compared MDRD with an optimised version of the Cockcroft-Gault (CG(opt)) method in a hospital population, using gentamicin clearance as a baseline., Results: MDRD overestimated gentamicin clearance by 29% (P < 0.001, n = 68), while CG(opt) underestimated by 10% (P < 0.01). Overestimation by MDRD increased with increasing age. This was 12%, 26% and 69% in age groups <65, 65-80 and >80 years respectively (P < 0.001). CG(opt) underestimated renal function by -5%, -16% and -4% respectively (P = NS). Bias and precision of renal function estimations for the three age groups were less for CG(opt) than for MDRD. Age significantly influenced MDRD overestimation in this population (P = 0.037)., Conclusion: MDRD overestimated renal function as age increased. While CG(opt) underestimated renal function, this was of a smaller magnitude, consistent across age, and thus better suited for dose calculation, especially in the elderly. Larger-scale studies using gold standard markers of renal function estimation are urgently needed to determine the accuracy of MDRD in elderly hospitalised patients.

Common blood and marrow transplantation (BMT) eligibility criteria include a minimum glomerular filtration rate (GFR) that may vary by regimen intensity. GFR is often estimated by measurement of creatinine clearance in a 24-hour urine collection (24-hr CrCl), an inconvenient and error-prone method that overestimates GFR. The study objectives were to determine which of 6 GFR calculations: Cockroft-Gault (CG), modified CG (mCG), Modification of Diet in Renal Disease 1 (MDRD1), MDRD2, Jelliffe, and Wright, consistently underestimated measured 24-hr CrCl pre-BMT. We retrospectively analyzed 98 consecutive allogeneic (n = 48) or autologous (n = 50) adult BMT patients from January 2006 to April 2007. All 6 formulas were significantly (P < .001) correlated with 24-hr CrCl with R = 0.64 (Wright), 0.63 (CG), 0.61 (mCG), 0.61 (Jelliffe), 0.54 (MDRD2), and 0.50 (MDRD1). When compared to the measured 24-hr CrCl, MDRD2 consistently underestimated it in the highest proportion of patients (66%, P < .001), compared with MDRD1 (65%, P < .001), Jelliffe (61%, P = NS), mCG (55%, P = NS), Wright (34%, P < .001), and CG (34%, P = .001). Measured 24-hr CrCl, pre-BMT serum Cr, and all 6 equations were not predictive of renal regimen-related toxicity (RRT) post-BMT. The Wright and CG formulas are closest to, but overestimate 24-hr CrCl in 66% of patients. In comparison, MDRD2 consistently underestimates 24-hr CrCl in 66%. Although MDRD2 is the most conservative formula, all 6 formulas gave reasonable estimates of GFR and any of the 6 equations can replace the measured 24-hr CrCl. Larger analyses and transplantation of patients with GFR <50 mL/min may better define subgroups at risk for renal RRT.

Objective: This longitudinal study evaluated renal function and acute kidney injury (AKI) over time in US agriculturalworkers. Methods:We followed Florida agricultural workers from January 2020 to August 2022, collecting blood and urine preworkday and postworkday during five visits. Results: Preworkday estimated glomerular filtration rate function in all participants was lower in summers but relatively consistent over time. In participants who worked almost exclusively in fernery operations (piece-rate compensation), we observed a high incidence of postworkday AKI in 2020 (21%) that increased to 43% by the end of the study. In comparison, 11% of nursery workers (hourly compensation) had AKI, and this rate was fairly stable. Conclusion:AKI risk over time differs according to the type of agricultural work. Piece rate workers who are incentivized to forgo rest breaks and hydration to earn higher wages demonstrate steadily increasing rates of AKI. [ABSTRACT FROM AUTHOR]

Aims: To compare the accuracy of renal assessment in patients with cancer using radioisotope glomerular filtration rate (GFR), urine collection for creatinine clearance, Cockroft-Gault, Modification of Diet in Renal Disease (MDRD) and Wright formulae., Materials and Methods: Measurements of isotope GFR from 367 patients were compared with estimates from the described methods (Cockroft-Gault, MDRD, Wright). An analysis including a further 252 patients with an isotope GFR < or = 50 ml/min was also carried out., Results: The Wright formula was the most accurate form of estimating renal function for the first study group. The formulae were similar in accuracy in the second study group., Conclusions: The Wright formula is the most accurate form of estimation of renal function in comparison with the isotope GFR for cancer patients. When there is a large proportion of patients with a low isotope GFR (< or = 50 ml/min), the formulae have similar accuracy.

Background: The National Kidney Foundation's practice guidelines for chronic kidney disease recommend using the Modification of Diet in Renal Disease (MDRD) equation for calculating the estimated glomerular filtration rate (GFR)., Objective: The purpose of this article was to compare the use of this estimated GFR with estimated creatinine clearance (CrCl) calculated using the Cockcroft-Gault equation (CG(CrCl)-Eq) in the dosing of drugs requiring adjustments in elderly patients with declining renal function. Existing as well as new serum creatinine assay standards were used., Methods: A PubMed literature search for all English-language articles published before November 2007 was conducted using the terms estimated glomerular filtration, GFR, modified diet in renal disease, MDRD, creatinine clearance, CrCl, drug dosing adjustment, renal impairment, human, and elderly. Mathematical comparisons of the age, race, and sex factors for these 2 equations (CG(CrCl)-Eq and MDRD) were performed, as well as a simulation of resulting values from these equations using various combinations of age, weight, and sex factors., Results: None of the articles identified found that the use of the MDRD equation in the elderly was better than the CG(CrCl)-Eq for estimating renal drug elimination. Substantial mathematical differences are inherent in these 2 prediction equations that make any clinical comparison quite difficult. Implementation of new creatinine assay standards will further confuse the use of these 2 equations for estimating GFR and for dosage adjustments in elderly patients with renal insufficiency., Conclusions: Although an MDRD equation may be useful for estimating GFR, the CG(CrCl)-Eq should still be used for drug dosage adjustments. The CG(CrCl)-Eq may require a slight "adjustment factor" to be applied using serum creatinine values measured by newly established assay procedures.

In the present study we evaluated two commonly used iodinated contrast agents, iohexol and iodixanol, as potential markers of impaired renal function. A reversed phase LC-MS method has been developed in order to separate and quantify the two substances. The assay was linear between 0.02 and 9.7 micromol/L for iohexol and between 0.4 and 49.3 micromol/L for iodixanol (r(2) > 0.998). The recovery during sample preparation ranged from 89.1 to 112.4%. The intra- and inter-assay RSD values were 3.06-13.6% for iohexol and 4.32-12.7% for iodixanol. The validated method was subsequently applied to 17 patients scheduled for angiographic procedure displaying normal and impaired renal function. A mixture of iohexol and iodixanol was intra-arterially injected and their corresponding plasma levels were determined periodically over a 24h period following administration. The elimination of both contrast agents followed by the LC-MS approach allowed us to discriminate between patients with normal and impaired renal function at 4, 8 and 24h after administration. Our preliminary results support the predictive value of iohexol and/or iodixanol clearance in a clinical environment to screen and identify patients at risk of developing CIN.