Measuring GFR: A Systematic Review Soveri, Inga, MD, PhD; Berg, Ulla B., MD, PhD; Björk, Jonas, PhD ...
American journal of kidney diseases,
2014, Letnik:
64, Številka:
3
Journal Article
Recenzirano
Background No comprehensive systematic review of the accuracy of glomerular filtration rate (GFR) measurement methods using renal inulin clearance as reference has been published. Study Design ...Systematic review with meta-analysis of cross-sectional diagnostic studies. Setting & Population Published original studies and systematic reviews in any population. Selection Criteria for Studies Index and reference measurements conducted within 48 hours; at least 15 participants studied; GFR markers measured in plasma or urine; plasma clearance calculation algorithm verified in another study; tubular secretion of creatinine had not been blocked by medicines. Index Tests Endogenous creatinine clearance; renal or plasma clearance of chromium 51−labeled ethylenediaminetetraacetic acid (51 Cr-EDTA), diethylenetriaminepentaacetic acid (DTPA), iohexol, and iothalamate; and plasma clearance of inulin. Reference Test Renal inulin clearance measured under continuous inulin infusion and urine collection. Results Mean bias < 10%, median bias < 5%, the proportion of errors in the index measurements that did not exceed 30% (P30 ) ≥ 80%, and P10 ≥ 50% were set as requirements for sufficient accuracy. Based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach, the quality of evidence across studies was rated for each index method. Renal clearance of iothalamate measured GFR with sufficient accuracy (strong evidence). Renal and plasma clearance of51 Cr-EDTA and plasma clearance of iohexol were sufficiently accurate to measure GFR (moderately strong evidence). Renal clearance of DTPA, renal clearance of iohexol, and plasma clearance of inulin had sufficient accuracy (limited evidence). Endogenous creatinine clearance was an inaccurate method (strong evidence), as was plasma clearance of DTPA (limited evidence). The evidence to determine the accuracy of plasma iothalamate clearance was insufficient. With the exception of plasma clearance of inulin, only renal clearance methods had P30 > 90%. Limitations The included studies were few and most were old and small, which may limit generalizability. Requirements for sufficient accuracy may depend on clinical setting. Conclusions At least moderately strong evidence suggests that renal clearance of51 Cr-EDTA or iothalamate and plasma clearance of51 Cr-EDTA or iohexol are sufficiently accurate methods to measure GFR.
Racializing Affect Berg, Ulla D.; Ramos-Zayas, Ana Y.
Current anthropology,
10/2015, Letnik:
56, Številka:
5
Journal Article
Recenzirano
Despite the recent boom in scholarly works on affect from a range of disciplines, scant attention has been paid to the intersection of affect and racialization processes, either historically or in ...contemporary contexts. This paper situates the diachronic articulation of race and affect—particularly in terms of the historical everyday lives and the political, economic, and material contexts of populations from Latin American and Caribbean backgrounds—in anthropological studies of “racialization” and the “affective turn.” Drawing on a broad reading of both scientific and popular constructions of affect among Latin American and US Latino populations, we propose the concept of “racialized affect” to account for the contradictions embedded in the study of race and affect, both separately and at their intersections. We highlight what we see as the two cornerstones of our theoretical intervention: on the one hand, a conception of “liable affect” results in a simplified, undermined subjectivity of populations racialized as Other, and, on the other hand, a conception of “empowering affect” perpetuates the privileged and nuanced affective subjectivity frequently reserved for whites in the United States and for self-styled “whitened” elites in Latin America.
Recent social science research has highlighted the chaos imposed by detention and deportation policies on migrant families and communities. This paper expands on these discussions by examining the ...role of transnational family dynamics as people experience detention, deportation, reintegration and/or remigration. Analysing five exemplary cases of indigenous Ecuadorian families drawn from a larger sample, we highlight the reconfigurations of transnational social relations resulting from these cycles of (im)mobility. We argue that transnational family support structures play a crucial role in the reconfiguration of families affected by deportation by combining material and emotional support and healing with social control. Our findings suggest that the social, emotional, and economic effects of deportation over time are shaped both by family and community contexts of reception and by migrants’ own gender, class, life‐course stage, time spent in the United States, and migration experiences. These findings allow us to conclude that deportation is a heterogeneous social and temporal process that does not impact families uniformly but in fact unfolds in diverse ways within family situations where social relationships, gender roles, care arrangements, and social expectations for the most part are already profoundly transnationalised and reconfigured by migration.
Background. To ensure that potential kidney donors have no renal impairment, it is extremely important to have accurate methods for evaluating the glomerular filtration rate (GFR). The golden ...standard, clearance of inulin, has been used in the present study. The aim was to evaluate the effects of age and sex on renal function and present reference data. Methods. A total of 122 potential kidney donors, 62 females, aged 21–67 years, were investigated with the GFR and effective renal plasma flow (ERPF) determined by clearances of inulin and para-amino hippurate. Results. The mean ± SD GFR and ERPF were 105 ± 13 and 545 ± 108 ml/min/1.73 m2, respectively, and we found no difference between the males and females. When relating GFR and ERPF to age, however, a significant decline was found in GFR and ERPF in males, but not in females in the age range of 20–50 years. GFR fell by a mean of 8.7 ml/min/1.73 m2 and ERPF by 90 ml/min/1.73 m2 per decade in male donors. Conclusion. With adequate methods for determining GFR and ERPF, a clear difference in the effect of age was seen between the sexes. Males showed a significant decrease between 20 and 50 years of age, which was not seen in females. Females seem to be protected in the pre-menopausal period probably by oestrogens. These results confirm clinically those found in rats.
Aim
The Cockcroft‐Gault (CG) creatinine‐based equation is still used to estimate glomerular filtration rate (eGFR) for drug dosage adjustment. Incorrect eGFR may lead to hazardous over‐ or ...underdosing.
Methods
In a cross‐sectional analysis, CG was validated against measured GFR (mGFR) in 14 804 participants and compared with the Modification‐of‐Diet‐in‐Renal‐Diseases (MDRD), Chronic‐Kidney‐Disease‐Epidemiology (CKD‐EPI), Lund‐Malmö‐Revised (LMR) and European‐Kidney‐Function‐Consortium (EKFC) equations. Validation focused on bias, imprecision and accuracy (percentage of estimates within ±30% of mGFR, P30), overall and stratified for mGFR, age and body mass index at mGFR <60 mL/min, as well as classification in mGFR stages.
Results
The CG equation performed worse than the other equations, overall and in mGFR, age and BMI subgroups in terms of bias (systematic overestimation), imprecision and accuracy except for patients ≥65 years where bias and P30 were similar to MDRD and CKD‐EPI, but worse than LMR and EKFC. In subjects with mGFR <60 mL/min and at BMI 18.5‐25 kg/m2, all equations performed similarly, and for BMI < 18.5 kg/m2 CG and LMR had the best results though all equations had poor P30‐accuracy. At BMI ≥ 25 kg/m2 the bias of the CG increased with increasing BMI (+17.2 mL/min at BMI ≥ 40 kg/m2). The four more recent equations also classified mGFR stages better than CG.
Conclusions
The CG equation showed poor ability to estimate GFR overall and in analyses stratified for mGFR, age and BMI. CG was inferior to correctly classify the patients in the mGFR staging compared to more recent creatinine‐based equations.
How the kidney prevents urinary excretion of plasma proteins continues to be debated. Here, using unfixed whole-mount mouse kidneys, we show that fluorescent-tagged proteins and neutral dextrans ...permeate into the glomerular basement membrane (GBM), in general agreement with Ogston’s 1958 equation describing how permeation into gels is related to molecular size. Electron-microscopic analyses of kidneys fixed seconds to hours after injecting gold-tagged albumin, negatively charged gold nanoparticles, and stable oligoclusters of gold nanoparticles show that permeation into the lamina densa of the GBM is size-sensitive. Nanoparticles comparable in size with IgG dimers do not permeate into it. IgG monomer-sized particles permeate to some extent. Albumin-sized particles permeate extensively into the lamina densa. Particles traversing the lamina densa tend to accumulate upstream of the podocyte glycocalyx that spans the slit, but none are observed upstream of the slit diaphragm. At low concentrations, ovalbumin-sized nanoparticles reach the primary filtrate, are captured by proximal tubule cells, and are endocytosed. At higher concentrations, tubular capture is saturated, and they reach the urine. In mousemodels of Pierson’s or Alport’s proteinuric syndromes resulting from defects in GBM structural proteins (laminin β2 or collagen α3 IV), the GBM is irregularly swollen, the lamina densa is absent, and permeation is increased. Our observations indicate that size-dependent permeation into the lamina densa of the GBM and the podocyte glycocalyx, together with saturable tubular capture, determines which macromolecules reach the urine without the need to invoke direct size selection by the slit diaphragm.
Aim
We have previously found well‐maintained renal function in children with new‐onset chronic liver disease. In this study, we investigated their renal function during long‐term follow‐up of the ...disease.
Methods
In a study of 289 children with chronic liver disease, renal function was investigated as glomerular filtration rate (GFR) measured as clearance of inulin or iohexol. Yearly change in GFR was calculated based on a linear mixed model. The data were analysed with regard to different subgroups of liver disease and with regard to the outcome.
Results
The initially well‐preserved renal function remained so in most patients during the observation period, even in children with progressive liver disease leading to decompensation. The greatest fall in GFR occurred in patients with initial hyperfiltration. Cholestasis seemed to have a nephroprotective effect.
Conclusion
Chronic liver disease in childhood seems to have less impact on renal function than believed earlier, at least as long as the liver function remains compensated. Regular renal check‐ups remain an essential tool for optimal patient care. Hyperfiltration seems to predict decline in renal function. Otherwise no further reliable prognostic markers were found in patients whose liver disease was not decompensated.
ABSTRACT
Background
A new Chronic Kidney Disease Epidemiology Collaboration equation without the race variable has been recently proposed (CKD-EPIAS). This equation has neither been validated outside ...USA nor compared with the new European Kidney Function Consortium (EKFC) and Lund-Malmö Revised (LMREV) equations, developed in European cohorts.
Methods
Standardized creatinine and measured glomerular filtration rate (GFR) from the European EKFC cohorts (n = 13 856 including 6031 individuals in the external validation cohort), from France (n = 4429, including 964 Black Europeans), from Brazil (n = 100) and from Africa (n = 508) were used to test the performances of the equations. A matched analysis between White Europeans and Black Africans or Black Europeans was performed.
Results
In White Europeans (n = 9496), both the EKFC and LMREV equations outperformed CKD-EPIAS (bias of –0.6 and –3.2, respectively versus 5.0 mL/min/1.73 m², and accuracy within 30% of 86.9 and 87.4, respectively, versus 80.9%). In Black Europeans and Black Africans, the best performance was observed with the EKFC equation using a specific Q-value (= concentration of serum creatinine in healthy males and females). These results were confirmed in matched analyses, which showed that serum creatinine concentrations were different in White Europeans, Black Europeans and Black Africans for the same measured GFR, age, sex and body mass index. Creatinine differences were more relevant in males.
Conclusion
In a European and African cohort, the performances of CKD-EPIAS remain suboptimal. The EKFC equation, using usual or dedicated population-specific Q-values, presents the best performance in the whole age range in the European and African populations included in this study.
Graphical Abstract
Graphical Abstract
The current Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend the use of the bedside creatinine-based Chronic Kidney Disease in Children (CKiD) equation to estimate glomerular ...filtration rate (GFR) in children and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation in adults. However, this approach causes implausible changes in estimated GFR (eGFR) at the transition from pediatric to adult care. We investigated the performance of the KDIGO strategy and various creatinine-based eGFR equations in a cross-sectional dataset of 5,764 subjects (age 10-30 years), using directly measured GFR (mGFR) as reference. We also evaluated longitudinal GFR slopes in 136 subjects who transitioned to adult care. Implausible changes in eGFR resulted from the large overestimation (bias=+21 mL/min/1.73m2) and poor precision of the CKD-EPI equation in the 18-20 year age group, compared to CKiD in the 16-18 year age group (bias=-2.7 mL/min/1.73m2), resulting in a mean change of 23 mL/min/1.73m2 at the transition to adult care. Averaging the CKiD and CKD-EPI estimates in young adults only partially mitigated this issue. The Full Age Spectrum equation (with and without height), the Lund-Malmö Revised equation, and an age-dependent weighted average of CKiD and CKD-EPI resulted in much smaller changes in eGFR at the transition (change of 0.6, -2.1, -0.9 and -1.8 mL/min/1.73m2, respectively). The longitudinal analysis revealed a significant difference in average GFR slope between mGFR and the KDIGO strategy (-2.2 vs. +2.9 mL/min/1.73 m2/year), which was not observed with the other approaches. These results suggest that the KDIGO recommendation for GFR estimation at the pediatric-adult care transition should be revisited.
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