Estimated glomerular filtration rate in clinical practice: Consensus positioning of the Brazilian Society of Nephrology (SBN) and Brazilian Society of Clinical Pathology and Laboratory Medicine (SBPC/ML) / Estimativa da taxa de filtração glomerular na prática clínica: posicionamento consensual da Sociedade Brasileira de Nefrologia (SBN) e Sociedade Brasileira de Patologia Clínica e Medicina Laboratorial (SBPC/ML)

ABSTRACT Chronic kidney disease (CKD) represents one of today's main public health problems. Serum creatinine measurement and estimation of the glomerular filtration rate (GFR) are the main tools for evaluating renal function. There are several equations to estimate GFR, and CKD-EPI equation (Chronic Kidney Disease - Epidemiology) is the most recommended one. There are still some controversies regarding serum creatinine measurement and GFR estimation, since several factors can interfere in this process. An important recent change was the removal of the correction for race from the equations for estimating GFR, which overestimated kidney function, and consequently delayed the implementation of treatments such as dialysis and kidney transplantation. In this consensus document from the Brazilian Societies of Nephrology and Clinical Pathology and Laboratory Medicine, the main concepts related to the assessment of renal function are reviewed, as well as possible existing controversies and recommendations for estimating GFR in clinical practice.

RESUMO A doença renal crônica (DRC) representa um dos principais problemas de saúde pública da atualidade. A dosagem da creatinina sérica e a estimativa da taxa de filtração glomerular (TFG) são as principais ferramentas para avaliação da função renal. Para a estimativa da TFG, existem diversas equações, sendo a mais recomendada a CKD-EPI (Chronic Kidney Disease - Epidemiology). Existem ainda algumas controvérsias com relação à dosagem da creatinina sérica e da estimativa da TFG, uma vez que vários fatores podem interferir nesse processo. Uma importante mudança recente foi a retirada da correção por raça das equações para estimativa da TFG, que superestimavam a função renal, e consequentemente retardavam a implementação de tratamentos como diálise e transplante renal. Neste documento de consenso da Sociedade Brasileira de Nefrologia e Sociedade Brasileira de Patologia Clínica e Medicina Laboratorial são revisados os principais conceitos relacionados à avaliação da função renal, possíveis controvérsias existentes e recomendações para a estimativa da TFG na prática clínica.

The role of podocyte injury in the pathogenesis of Fabry disease nephropathy / O papel da injúria podocitária na patogênese da nefropatia da doença de Fabry

Abstract Renal involvement is one of the most severe morbidities of Fabry disease (FD), a multisystemic lysosomal storage disease with an X-linked inheritance pattern. It results from pathogenic variants in the GLA gene (Xq22.2), which encodes the production of alpha-galactosidase A (α-Gal), responsible for glycosphingolipid metabolism. Insufficient activity of this lysosomal enzyme generates deposits of unprocessed intermediate substrates, especially globotriaosylceramide (Gb3) and derivatives, triggering cellular injury and subsequently, multiple organ dysfunction, including chronic nephropathy. Kidney injury in FD is classically attributed to Gb3 deposits in renal cells, with podocytes being the main target of the pathological process, in which structural and functional alterations are established early and severely. This configures a typical hereditary metabolic podocytopathy, whose clinical manifestations are proteinuria and progressive renal failure. Although late clinical outcomes and morphological changes are well established in this nephropathy, the molecular mechanisms that trigger and accelerate podocyte injury have not yet been fully elucidated. Podocytes are highly specialized and differentiated cells that cover the outer surface of glomerular capillaries, playing a crucial role in preserving the structure and function of the glomerular filtration barrier. They are frequent targets of injury in many nephropathies. Furthermore, dysfunction and depletion of glomerular podocytes are essential events implicated in the pathogenesis of chronic kidney disease progression. We will review the biology of podocytes and their crucial role in regulating the glomerular filtration barrier, analyzing the main pathogenic pathways involved in podocyte injury, especially related to FD nephropathy.

Resumo O acometimento renal é uma das mais severas morbidades da doença de Fabry (DF), enfermidade multissistêmica de depósito lisossômico com padrão de herança ligada ao cromossomo X, decorrente de variantes patogênicas do gene GLA (Xq22.2), que codifica a produção de alfa-galactosidase A (α-Gal), responsável pelo metabolismo de glicoesfingolipídeos. A atividade insuficiente dessa enzima lisossômica gera depósitos de substratos intermediários não processados, especialmente do globotriaosilceramida (Gb3) e derivados, desencadeando injúria celular e, posteriormente, disfunção de múltiplos órgãos, incluindo a nefropatia crônica. A lesão renal na DF é classicamente atribuída aos depósitos de Gb3 nas células renais, sendo os podócitos o alvo principal do processo patológico, nos quais as alterações estruturais e funcionais são instaladas de forma precoce e severa, configurando uma podocitopatia metabólica hereditária típica, cujas manifestações clínicas são proteinúria e falência renal progressiva. Embora os desfechos clínicos tardios e as alterações morfológicas estejam bem estabelecidos nessa nefropatia, os mecanismos moleculares que deflagram e aceleram a injúria podocitária ainda não estão completamente elucidados. Podócitos são células altamente especializadas e diferenciadas que revestem a superfície externa dos capilares glomerulares, desempenhando papel essencial na preservação da estrutura e função da barreira de filtração glomerular, sendo alvos frequentes de injúria em muitas nefropatias. A disfunção e depleção dos podócitos glomerulares são, além disso, eventos cruciais implicados na patogênese da progressão da doença renal crônica. Revisaremos a biologia dos podócitos e seu papel na regulação da barreira de filtração glomerular, analisando as principais vias patogênicas envolvidas na lesão podocitária, especialmente relacionadas à nefropatia da DF.

Renal deficit and associated factors in children born with low birth weight / Déficit renal e fatores associados em crianças nascidas com baixo peso

ABSTRACT Introduction: Kidney problems may be due to low birth weight alone or may occur in association with other conditions. The objective this study was to evaluate the association between maternal and birth characteristics, anthropometric measurements, and kidney function deficit in low birth weight infants. Methods: Cross-sectional study with children who were born weighing < 2500 grams and were under outpatient follow-up. Maternal factors investigated were prenatal care and presence of hypertension, diabetes, and infection during pregnancy. The children's variables were sex, gestational age, birth weight, Apgar score, use of nephrotoxic medications, age, body weight at the time of evaluation, height, and serum creatinine and cystatin C dosages. The glomerular filtration rate (GFR) was estimated with the combined Zapittelli equation. Multivariate logistic regression model was used for identification of associated factors, with renal function deficit (GFR < 60 mL/min/1.73 m2) as the dependent variable. Results: Of the 154 children evaluated, 34.42% had kidney function deficit. Most of them had a gestational age > 32 weeks (56.6%), a mean birth weight of 1439.7 grams, and mean estimated GFR of 46.9 ± 9.3 mL/min/1.73 m2. There was a significant association of GFR < 60 mL/min/1.73 m2 with children's current weight and use of nephrotoxic drugs. Discussion: Children born with low birth weight had a high prevalence of kidney function deficit and current normal weight was a protective factor while the use of nephrotoxic drugs during perinatal period increased the chance of kidney deficit. These findings reinforce the need to evaluate the kidney function in these children, especially those who use nephrotoxic drugs.

RESUMO Introdução: Problemas renais podem ser devido apenas ao baixo peso ao nascer ou podem ocorrer em associação com outras condições. O objetivo deste estudo foi avaliar a associação entre características maternas e de nascimento, medidas antropométricas e déficit da função renal em bebês de baixo peso ao nascer. Métodos: Estudo transversal com crianças que nasceram com peso < 2500 gramas e estavam sob acompanhamento ambulatorial. Os fatores maternos investigados foram cuidados pré-natal e presença de hipertensão, diabetes e infecção durante a gravidez. As variáveis das crianças foram sexo, idade gestacional, peso ao nascer, índice Apgar, uso de medicamentos nefrotóxicos, idade, peso corporal no momento da avaliação, altura e dosagens séricas de creatinina e cistatina C. A taxa de filtração glomerular (TFG) foi estimada com a equação combinada de Zapittelli. Utilizou-se um modelo de regressão logística multivariada para identificação de fatores associados, com déficit da função renal (TFG < 60 mL/min/1,73 m2) como variável dependente. Resultados: Das 154 crianças avaliadas, 34,42% apresentaram déficit da função renal. A maioria tinha idade gestacional > 32 semanas (56,6%), peso médio ao nascer de 1439,7 gramas, e TFG média estimada de 46,9 ± 9,3 mL/min/1,73 m2. Houve uma associação significativa da TFG < 60 mL/min/1,73 m2 com o peso atual das crianças e o uso de medicamentos nefrotóxicos. Discussão: Crianças nascidas com baixo peso apresentaram alta prevalência de déficit da função renal e o peso atual normal foi um fator de proteção, enquanto o uso de medicamentos nefrotóxicos durante o período perinatal aumentou a chance de déficit renal. Estes achados reforçam a necessidade de avaliar a função renal destas crianças, especialmente aquelas que usam medicamentos nefrotóxicos.

Effects of renal ROI and depth calibrated by 99Tc m-DMSA renal imaging on GFR measurement of the injured-kidney in infants with congenital hydronephrosis / 中华核医学与分子影像杂志

Objective:To investigate the application value of 99Tc m-dimercaptosuccinic acid (DMSA) renal static imaging to correct renal ROI and renal depth in measurement of glomerular filtration rate (GFR) of the injured-kidney in infants with congenital hydronephrosis. Methods:From January 2022 to November 2022, 30 infants with congenital hydronephrosis (25 males, 5 females, age 3.0(1.0, 5.5) months) in Nuclear Medicine Department of the Second Hospital of Shanxi Medical University were prospectively included. Sixty kidneys were divided into 3 groups according to the degree of hydronephrosis: normal group (7 left kidneys and 12 right kidneys), mild hydronephrosis group (10 left kidneys and 12 right kidneys) and moderate to severe hydronephrosis group (13 left kidneys and 6 right kidneys). The patients received 99Tc m-diethylenetriamine penta-acetic acid (DTPA) diuretic renal dynamic imaging and 99Tc m-DMSA renal static imaging within 3 days, and bilateral renal lateral acquisition was performed at the end of the imaging. The depths (cm) of kidneys measured based on the lateral image and Tonnesen′s formula were compared. The single kidney GFR (ml·min -1·1.73 m -2) measured after the renal ROI corrected, or renal depth corrected, or renal ROI-depth corrected by renal static imaging (aGFR single, dGFR single, adGFR single) was compared with that measured by Gates method (gGFR single). The one-way analysis of variance, the least significant difference- t test and Dunnett- t test were used for data analysis. Results:In different hydronephrosis groups, renal depths measured by dynamic imaging, static imaging and Tonnesen formulas were significantly different ( F values: 38.07-59.63, t values: 2.53-15.17, all P<0.05). There were no significant differences in renal depth between the two kinds of imaging in the normal group ( F values: 34.89, 54.30, both P<0.05; t values: 0.65, 1.60, both P>0.05). aGFR single of all groups were smaller than gGFR single, but the values were similar, and were not significantly different in normal kidneys ( F values: 3.02, 5.51, both P<0.05; t values: 0.12, 0.53, both P>0.05), while those in abnormal kidneys (left kidneys: 43.27±8.84 vs 46.19±7.88, F=9.75, t=2.18, both P<0.05; right kidneys: 39.87±10.25 vs 42.94±10.28, F=10.32, t=2.04, both P<0.05) and in mild (48.58±10.94 vs 51.08±11.44, F=10.34, t=2.04, both P<0.05), moderate to severe (34.41±8.84 vs 37.62±8.84, F=19.97, t=3.41, both P<0.05) hydronephrosis groups were different. The dGFR single was significantly higher than gGFR single in 3 (normal, mild, moderate to severe) hydronephrosis groups ( t values: 3.82, 3.39, 3.81, all P<0.01). adGFR single was between aGFR single and dGFR single, and adGFR single were significantly different from gGFR single in normal right kidneys, in abnormal kidneys and in mild and moderate to severe hydronephrosis groups ( t values: 2.25-3.12, all P<0.05). Conclusions:Renal static imaging corrected ROI can improve the accuracy of GFR measurement of the affected kidney, especially for children with moderate and severe congenital hydronephrosis. However, the GFR corrected for renal depth or ROI-depth are significantly different from the true GFR. The lateral kidney depth measured by static imaging is more accurate than that measured by dynamic imaging.

Predictive Value of Serum Albumin Levels for Coronary Artery Calcification in Patients with Early Chronic Kidney Disease / 中山大学学报(医学科学版)

ObjectiveTo explore the correlation between serum albumin levels and coronary artery calcification （CAC） in patients with early-stage chronic kidney disease （CKD）， as well as the value of serum albumin levels in predicting the incidence and severity of CAC. MethodsThe study included 391 early-stage CKD patients who underwent coronary computed tomography angiography （CTA） at Sun Yat-sen Memorial Hospital of Sun Yat-sen University between January 2019 and December 2022. Demographic and biochemistry data， as well as the coronary CTA results， were collected. Based on the coronary artery calcification score （CACS）， all patients were divided into non-CAC group （CACS=0， n=184） and CAC group （CACS>0， n=207）. All patients were further divided into 3 groups based on the serum albumin levels： group A （serum albumin levels<35 g/L， n=30）， group B （35 g/L≤ serum albumin levels< 40 g/L， n=198） and group C （serum albumin levels≥ 40 g/L， n=163）. Univariate and multivariate binary logistic regression analyses were conducted to investigate the association between serum albumin levels and CAC in early-stage CKD patients. Differences in CAC among groups were analyzed by using post-hoc multiple comparisons and ordinal logistic regression model analysis. ResultsPatients with CAC had significantly lower serum albumin levels than those without CAC （P<0.05）. There was a negative correlation between serum albumin levels and CACS in early-stage CKD patients （P<0.01）， as serum albumin decreased in levels， CAC increased in severity. ConclusionsOur study shows that early-stage CKD patients with lower serum albumin levels have a higher incidence of CAC. Low serum albumin level is an independent risk factor for CAC progression.

Research progress of cardiac structure and function in patients with diabetic nephropathy / 中国基层医药

Diabetic nephropathy (DN) is a common microvascular complication of diabetes mellitus. Cardiovascular disease often occurs in patients with DN. Patients with DN often experience changes in cardiac structure and function as proteinuria increases, glomerular filtration rate decreases, and blood creatinine levels increase, leading to the occurrence of cardiovascular disease. Additionally, inflammatory factors play a crucial role in cardiac structure and function. Understanding the pathological and physiological effects of inflammation on diabetic nephropathy-related cardiovascular disease and clarifying the relationship between cardiac structure and function in patients with DN are crucial for effective prevention and treatment of DN.

Effect of preoperative metabolic syndrome on early function of renal allografts in kidney transplant recipients / 器官移植

Objective To evaluate the effect of preoperative metabolic syndrome on early function of renal allografts in allogeneic kidney transplant recipients. Methods Clinical data of 117 kidney transplant recipients were retrospectively analyzed. According to the renal allograft function, they were divided into the delayed graft function (DGF) group (n=29) and non-DGF group (n=88). Relevant risk factors of DGF in recipients undergoing allogeneic kidney transplantation were assessed by univariate and multivariate regression analyses. The effect of preoperative metabolic syndrome on early function of renal allografts was analyzed. Results Among 117 kidney transplant recipients, 47 cases were complicated with preoperative metabolic syndrome, and 29 cases developed postoperative DGF. In the DGF group, 83% of the recipients were complicated with preoperative metabolic syndrome, higher than 74% in the non-DGF group (P<0.05). Univariate analysis showed that the body mass index (BMI) and terminal serum creatinine (Scr) level of the donors, and BMI, blood glucose level, triglyceride level and the proportion of preoperative metabolic syndrome of the recipients in the DGF group were higher than those in the non-DGF group (all P<0.05). Multivariate logistic regression analysis revealed that high Scr levels of the donors, high hemoglobin levels of the recipients and preoperative metabolic syndrome of the recipients were the independent risk factors for DGF after kidney transplantation (all P<0.05). Conclusions Preoperative metabolic syndrome is an independent risk factor for DGF in allogeneic kidney transplant recipients. Corresponding measures should be taken to lower the incidence of DGF and other metabolic complications.

Validação das equações para estimativa da filtração glomerular ajustáveis por raça/cor em adultos de Vitória, Espírito Santo, Brasil / Validation of glomerular filtration estimation equations adjustable by race/colour in adults from Vitória, Espírito Santo, Brazil

Resumo A avaliação da função renal é feita por meio da taxa de filtração glomerular (TFG), que pode ser determinada pelo clearance de creatinina (CrCl) e é dependente da coleta urinária de 24 horas (h), o que dificulta o seu uso na atenção primária. As equações que estimam a TFG a partir da creatinina sérica tornam o exame mais acessível, contudo, os seus ajustes por raça/cor têm sido questionados em populações miscigenadas. Para verificar a concordância entre o ClCr e a TFG estimada por fórmulas (Modification of Diet in Renal Disease [MDRD-4] e Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]), com ou sem ajuste por raça/cor, foram utilizados dados de subestudo da Pesquisa Nacional de Saúde (PNS) com inclusão de 272 adultos de Vitória, Espírito Santo, que fizeram coleta urinária de 24h. Adotou-se análise de variância (ANOVA) e método de Bland-Altman. Houve concordância adequada entre o ClCr e as equações, mas o ajuste por raça/cor diminui a acurácia destas últimas. No fator raça/cor, houve semelhança entre grupos para o ClCr (p=0,21) sugerindo não haver diferença no metabolismo da creatinina em função da cor da pele. Conclui-se que MDRD-4 e CKD-EPI apresentam desempenho satisfatório na avaliação da função renal, não sendo recomendado o uso de correções para raça/cor.

Abstract The assessment of renal function is performed using the glomerular filtration rate (GFR) whose measurement by creatinine clearance (ClCr) and is dependent on a 24-hour urine sample, hindering it use in primary healthcare. The equations that estimate GFR from serum creatinine make the test more accessible, however, their adjustments by race/color have been questioned in mixed populations. To test the agreement between CrCl and GFR estimated by formulas (Modification of Diet in Renal Disease [MDRD-4] and Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]), with or without adjusting for race/color, data were used from a sub-study of the National Health Survey (NHS) including 272 adults from Vitória/Espírito Santo who underwent a 24-hour urinary sampling. Analysis of variance (ANOVA) and the Bland-Altman method were adopted. There was adequate agreement between ClCr and equations, but the adjustment by race/color decreases the accuracy of both equations. In the race/color factor, there was similarity between groups for CrCl (p=0.21), suggesting that there is no difference in creatinine metabolism induced by skin color. It is concluded that MDRD and CKD-EPI equations perform satisfactorily in the evaluation of renal function, and the use of corrections for race/color is not recommended.

Different methods for assessing glomerular filtration rate in the elderly

SUMMARY OBJECTIVE: The objective of this study was to identify the best method to replace cystatin C in the evaluation of glomerular filtration in the elderly. METHODS: Individuals over 60 years of age from a primary care center were studied. Blood was collected to determine creatinine and cystatin C and 24-h urine. Three methods were compared to determine glomerular filtration: Creatinine clearance, Cocroft-Gault, modification of diet in renal disease, and Collaboration Epidemiology of Chronic Kidney Disease based on creatinine, considering as a reference the determination of glomerular filtration using the cystatin-based Chronic Kidney Disease Epidemiology Collaboration equation. The statistical methods used were linear regression, Bland-Altman curve, and receiver operating characteristic. RESULTS: A total of 180 elderly people were evaluated, but 14 patients were lost from the sample, resulting in a total of 166 patients. The average age of patients was 66.9±6.1 years, and 69.8% were females. Regarding the number of patients eligible for the study, there were 12 black, 108 brown, and 46 white, 42.77% hypertensive, and 38.3% diabetic. Glomerular filtration was less than 60 mL/min in 22.28% of patients. Regarding the evaluation of the different equations, the correlation coefficient was lower for creatinine clearance and progressively higher for Cocroft-Gault, modification of diet in renal disease, and Collaboration Epidemiology of Chronic Kidney Disease based on creatinine. The Bland-Altman diagram and the receiver operating characteristic curve showed similar performance to the correlation coefficient for the different equations evaluated. CONCLUSION: Collaboration Epidemiology of Chronic Kidney Disease based on creatinine presented the best performance. Creatinine debug had the worst performance, which reinforces the idea that 24-h urine collection is unnecessary in these patients.

The influence of hemodialysis on intracranial pressure waveform in patients with chronic kidney disease: an observational study

ABSTRACT BACKGROUND: Among the complications related to chronic kidney disease (CKD), those of a neurological nature stand out, and for a better quality of life for patients, the diagnosis and treatment of these complications is fundamental. OBJECTIVES: This study aimed to assess the effect of hemodialysis on intracranial pressure waveform (ICPw) in patients with chronic kidney disease undergoing hemodialysis and those who are not yet undergoing substitutive therapy. DESIGN AND SETTING: An observational study was conducted in two stages at a kidney replacement therapy center in Brazil. The first was a longitudinal study and the second was a cross-sectional study. METHODS: Forty-two patients on hemodialysis were included in the first stage of the study. In the second stage, 226 participants were included. Of these, 186 were individuals with chronic kidney disease (who were not undergoing substitutive therapy), and 40 did not have the disease (control group). The participants' intracranial compliance was assessed using the non-invasive Brain4care method, and the results were compared between the groups. RESULTS: There was a significant difference between the hemodialysis and non-hemodialysis groups, with the former having better ICPw conditions. CONCLUSIONS: Hemodialysis influenced the improvement in ICPw, probably due to the decrease in the patients' extra-and intracellular volumes. Furthermore, ICPw monitoring can be a new parameter to consider when defining the moment to start substitutive therapy.

Effects of bariatric surgery on renal function: a retrospective cohort study comparing one-year outcomes between one-anastomosis gastric bypass and Roux-en-Y gastric bypass

ABSTRACT BACKGROUND: Evidence on the effect of one-anastomosis gastric bypass (OAGB) on renal function is limited. OBJECTIVE: To compare the evolution of estimated renal function observed 1 year after OAGB and Roux-en-Y gastric bypass (RYGB) in individuals with obesity. DESIGN AND SETTING: Observational, analytical, and retrospective cohort study. Tertiary-level university hospital. METHODS: This study used a prospectively collected database of individuals who consecutively underwent bariatric surgery. Renal function was assessed by calculating the estimated glomerular filtration rate (eGFR), according to the Chronic Kidney Disease Epidemiology Collaboration. The one-year variation in the eGFR was compared between the procedures. RESULTS: No significant differences in age, sex, obesity-associated conditions, or body mass index were observed among individuals who underwent either OAGB or RYGB. OAGB led to a significantly higher percentage of total (P = 0.007) and excess weight loss (P = 0.026). Both OAGB and RYGB led to significantly higher values of eGFR (103.9 ± 22 versus 116.1 ± 13.3; P = 0.007, and 102.4 ± 19 versus 113.2 ± 13.3; P < 0.001, respectively). The one-year variation in eGFR was 11 ± 16.2% after OAGB and 16.7 ± 26.3% after RYGB (P = 0.3). Younger age and lower baseline eGFR were independently associated with greater postoperative improvement in renal function (P < 0.001). CONCLUSION: Compared with RYGB, OAGB led to an equivalent improvement in renal function 1 year after the procedure, along with greater weight loss.

Comparison of plasma clearance of [51Cr]CrEDTA based on three, two and single samples to measure the glomerular filtration rate in patients with solid tumors: a prospective cross-sectional analysis

Abstract Objectives: [51Cr]CrEDTA is used to measure the Glomerular Filtration Rate (GFR) in different clinical conditions. However, there is no consensus on the ideal number of blood samples to be taken and at what time points to measure its clearance. This study aimed to compare Slope Intercept (SI) and Single-Sample (SS) methods for measuring GFR in patients with solid tumors, stratified by age, GFR, and Body Mass Index (BMI). Methods: 1,174 patients with cancer were enrolled in this prospective study. GFR was calculated by the SI method using blood samples drawn 2-, 4-, and 6-hours after [51Cr]CrEDTA injection (246-GFR). GFR was also measured using the SI method with samples at 2 and 4 hours (24-GFR) and at 4 and 6 hours (46-GFR), and SS methods according to Groth (4Gr-GFR) and Fleming (4Fl-GFR). Statistical analysis was performed to assess the accuracy, precision, and bias of the methods. Results: Mean 246-GFR was 79.2 ± 21.9 mL/min/1.73 m2. ANOVA indicated a significant difference between 4Gr-GFR and the reference 246-GFR. Bias was lower than 5 mL/min/1.73 m2 for all methods, except for SS methods in subgroups BMI > 40 kg/m2; GFR > 105 or < 45. Precision was adequate and accuracy of 30 % was above 98% for all methods, except for SS methods in subgroup GFR < 45. Conclusion: 46-GFR and 246-GFR have high agreement and may be used to evaluate kidney function in patients with solid tumors. Single-sample methods can be adopted in specific situations, for non-obese patients with expected normal GFR.

Comparação de fórmulas para cálculo da taxa de filtração glomerular estimada e seus limiares diagnósticos para doença renal crônica em pessoas idosas: um estudo transversal / Comparison of formulas for calculating estimated glomerular filtration rate and its diagnostic thresholds for chronic kidney disease in older adults: a cross-sectional study

Resumo Objetivo Avaliar e comparar as fórmulas CKD-EPI, BIS1 e MDRD e o limiar diagnóstico de 45 e 60 ml/min/1,73m2 em pacientes idosos. Método Estudo observacional do tipo transversal, de caráter descritivo e analítico. Foram incluídos pacientes atendidos em ambulatório de referência entre janeiro/2020 e junho/2022, com idade ≥65 anos. Foram excluídos pacientes com apenas uma dosagem de creatinina ou com alterações transitórias da TFG. Resultados Observou-se que entre o grupo de pacientes com idade entre 65-74 anos e 75-84 anos as estimativas da TFG feitas pela fórmula CKD-EPI foram superiores às fórmulas BIS1 e MDRD. Enquanto, no grupo de pacientes com 85-94 anos a CKD-EPI não apresentou diferença quando comparada com MDRD, permaneceu com estimativas maiores apenas quando comparada com a BIS1. Observamos maior dispersão entre CKD-EPI e BIS1, mostrando menor concordância entre essas fórmulas, confirmada pelo teste Kappa (76,7%) e a concordância quase perfeita entre CKD-EPI e MDRD. Conclusão A fórmula BIS1 apresentou melhor correlação da diminuição da TFGe conforme o avanço das faixas etárias, podendo-se relacionar com o processo de envelhecimento renal fisiológico, podendo ser uma ferramenta auxiliar na estimativa da TFG em idosos, auxiliando no diagnóstico mais preciso da DRC, assim como, no planejamento de intervenções que possam retardar a progressão da DRC e prever risco de mortalidade por doenças cardiovasculares.

Abstract Objective To evaluate and compare the CKD-EPI, BIS1 and MDRD formulas and diagnostic thresholds of 45 and 60 ml/min/1.73m2 in older patients. Method A cross-sectional, descriptive, analytical observational study was conducted. Patients aged ≥65 years treated at a referral outpatient clinic between January 2020 and June 2022, were assessed. Patients with only one creatinine level or with transient GFR abnormalities were excluded. Results The GFR estimates using the CKD-EPI formula were higher than both the BIS1 and MDRD formulas in patient groups aged 65-74 years and 75-84 years. In the group of patients aged 85-94 years, the CKD-EPI showed no difference when compared with the MDRD, yielding higher estimates only compared with the BIS1. Greater dispersion was found between the CKD-EPI and BIS1, showing less agreement between these formulas, as confirmed by the Kappa test (76.7%), while there was almost perfect agreement between the CKD-EPI and MDRD. Conclusion The BIS1 formula showed stronger correlation of the decrease in eGFR with advancing age, reflecting the physiological renal aging process and serving as a potentially useful tool for estimating GFR in older adults. The formula can help provide a more accurate diagnosis of CKD and aid planning of interventions to slow the progression of CKD and predict the risk of mortality from cardiovascular diseases.

Reduction of estimated glomerular filtration rate after COVID-19-associated acute kidney injury / Redução da taxa de filtração glomerular estimada após injúria renal aguda associada à COVID-19

ABSTRACT Introduction: Acute Kidney Injury (AKI), a frequent manifestation in COVID-19, can compromise kidney function in the long term. We evaluated renal function after hospital discharge of patients who developed AKI associated with COVID-19. Methods: This is an ambidirectional cohort. eGFR and microalbuminuria were reassessed after hospital discharge (T1) in patients who developed AKI due to COVID-19, comparing the values with hospitalization data (T0). P < 0.05 was considered statistically significant. Results: After an average of 16.3 ± 3.5 months, 20 patients were reassessed. There was a median reduction of 11.5 (IQR: -21; -2.1) mL/min/1.73m2 per year in eGFR. Forty-five percent of patients had CKD at T1, were older, and had been hospitalized longer; this correlated negatively with eGFR at T1. Microalbuminuria was positively correlated with CRP at T0 and with a drop in eGFR, as well as eGFR at admission with eGFR at T1. Conclusion: There was a significant reduction in eGFR after AKI due to COVID-19, being associated with age, length of hospital stay, CRP, and need for hemodialysis.

RESUMO Introdução: A Injúria Renal Aguda (IRA), uma manifestação frequente na COVID-19, pode comprometer a função renal em longo prazo. Avaliamos a função renal após a alta hospitalar de pacientes que desenvolveram IRA associada à COVID-19. Métodos: Esta é uma coorte ambidirecional. A TFGe e a microalbuminúria foram reavaliadas após a alta hospitalar (T1) em pacientes que desenvolveram IRA devido à COVID-19, comparando os valores com dados de hospitalização (T0). P < 0,05 foi considerado estatisticamente significativo. Resultados: Após uma média de 16,3 ± 3,5 meses, 20 pacientes foram reavaliados. Houve uma redução média de 11,5 (IIQ: -21; -2,1) mL/min/1,73m2 por ano na TFGe. Quarenta e cinco por cento dos pacientes apresentaram DRC no T1, eram mais velhos e haviam sido hospitalizados por mais tempo; isso se correlacionou negativamente com a TFGe no T1. A microalbuminúria foi positivamente correlacionada com a PCR no T0 e com uma queda na TFGe, assim como a TFGe na admissão com a TFGe no T1. Conclusão: Houve uma redução significativa na TFGe após IRA devido à COVID-19, sendo associada à idade, tempo de internação, PCR e necessidade de hemodiálise.

Frailty and chronic kidney disease: associations and implications / Fragilidade e doença renal crônica: associações e implicações

ABSTRACT Introduction: Frailty and its association with chronic kidney disease (CKD) has been established previously. The present study examined this association further by studying the distribution of frailty among groups defined by different stages of the disease. It also identified associated health deficits and explored their association with estimated glomerular filtration rate (eGFR) and urine albumin creatinine ratio (UACR). Methods: A cross-sectional survey was conducted on 90 non-dialysis dependent CKD Stage 1-4 patients, recruited in three stratified groups of 30 participants each based on the stage of disease. Frailty was assessed using Fried's frailty criteria and associated health deficits were recorded using a pre-determined list. Depression was screened using a 4-point depression scale. Results: 21.1% of the participants were frail and 43.3% were pre-frail. The proportion of frailty in CKD groups A (Stages 1 and 2), B (Stage 3a), and C (Stages 3b and 4) was 10%, 13.3%, and 40%, respectively. The association of health deficits including co-morbidities, physical parameters, mental status, daily activities, etc. with UACR, eGFR, and CKD stages was not statistically significant. Nearly one in two frail participants was depressed compared with 14% among non-frail participants. Conclusion: The skewed distribution of 21% frail subjects identified in our study indicates an association between frailty and advancing kidney disease. Frail individuals had a lower eGFR, higher UACR, were more likely to be depressed, and had higher count of health deficits and poorer performance on Barthel Index of Activities of Daily Living and WHOQOL. Early identification of depression would improve care in these patients.

RESUMO Introdução: Fragilidade e sua associação com DRC foram estabelecidas anteriormente. O presente estudo aprofundou esta associação, estudando distribuição da fragilidade entre grupos definidos por diferentes estágios da doença. Também identificou déficits de saúde associados e explorou sua associação com taxa de filtração glomerular estimada (TFGe) e relação albumina/creatinina urinária (RAC). Métodos: Realizou-se uma pesquisa transversal em 90 pacientes com DRC Estágios 1-4 não dependentes de diálise, recrutados em três grupos estratificados de 30 participantes cada, conforme estágio da doença. Avaliou-se fragilidade usando os critérios de fragilidade de Fried e registraram-se os déficits de saúde associados usando uma lista pré-determinada. A depressão foi verificada utilizando a escala de depressão de 4 pontos. Resultados: 21,1% dos participantes eram frágeis e 43,3% eram pré-frágeis. A proporção de fragilidade nos grupos de DRC A (Estágios 1 e 2), B (Estágio 3a), e C (Estágios 3b e 4) foi de 10%, 13,3%, 40% respectivamente. A associação de déficits de saúde, incluindo comorbidades, parâmetros físicos, estado mental, atividades diárias etc. com RAC, TFGe e estágios da DRC não foi estatisticamente significativa. Cerca de um em cada dois participantes frágeis estava depressivo comparados com 14% entre não frágeis. Conclusão: A distribuição enviesada de 21% dos indivíduos frágeis identificados em nosso estudo indica associação entre fragilidade e doença renal progressiva. Indivíduos frágeis apresentaram menor TFGe, maior RAC, eram mais propensos a depressão, tinham maior índice de déficits de saúde e desempenho inferior no Índice de Atividades da Vida Diária de Barthel e WHOQOL. A identificação precoce da depressão melhoraria o atendimento desses pacientes.

Maior Rigidez Arterial Prediz Doença Renal Crônica no Estudo de Coorte ELSA-Brasil / Higher Arterial Stiffness Predicts Chronic Kidney Disease in Adults: The ELSA-Brasil Cohort Study

Resumo Fundamento A rigidez arterial pode afetar diretamente os rins, que são perfundidos passivamente por alto fluxo. No entanto, determinar se a relação entre rigidez arterial e função renal depende das condições de diabetes e hipertensão é uma questão controversa. Objetivo Investigar a relação entre a rigidez arterial, por velocidade da onda de pulso carotídea-femoral (VOPcf), e a incidência de doença renal crônica (DRC) em indivíduos e verificar se essa associação está presente em indivíduos sem hipertensão e diabetes. Métodos Estudo longitudinal com 11.647 participantes do ELSA-Brasil acompanhados por quatro anos (2008/10-2012/14). A VOPcf basal foi agrupada por quartil, de acordo com pontos de corte específicos com relação a sexo. A presença de DRC foi verificada pela taxa de filtração glomerular (TFGe-CKD-EPI) < 60 ml/min/1,73 m2 e/ou relação albumina/creatinina ≥ 30 mg/g. Modelos de regressão logística foram executados para toda a coorte e uma subamostra livre de hipertensão e diabetes no início do estudo, após ajuste para idade, sexo, raça, escolaridade, tabagismo, relação colesterol/HDL, índice de massa corporal, diabetes, uso de anti-hipertensivos, pressão arterial sistólica, frequência cardíaca e doenças cardiovasculares. A significância estatística foi fixada em 5%. Resultados A chance de DRC foi de 42% (IC de 95%: 1,05;1,92) maior entre indivíduos no quartil superior da VOPcf. Entre os participantes normotensos e não diabéticos, os indivíduos do 2º, 3º e 4º quartis da VOPcf apresentaram maiores chances de desenvolver DRC, quando comparados aos do quartil inferior, sendo a magnitude dessa associação maior para aqueles do quartil superior (OR: 1,81 IC de 95%: 1,14;2,86). Conclusão A maior VOPcf aumentou as chances de DRC, e sugere que esse efeito é ainda maior em indivíduos sem diabetes e hipertensão.

Abstract Background Arterial stiffening can directly affect the kidneys, which are passively perfused by a high flow. However, whether the relation between arterial stiffness and renal function depends on diabetes and hypertension conditions, is a matter of debate. Objective To investigate the relationship between arterial stiffening by carotid-to-femoral pulse wave velocity (cfPWV) and chronic kidney disease (CKD) incidence in individuals and verify whether this association is present in individuals without hypertension and diabetes. Methods A longitudinal study of 11,647 participants of the ELSA-Brasil followed up for four years (2008/10-2012/14). Baseline cfPWV was grouped per quartile, according to sex-specific cut-offs. Presence of CKD was ascertained by glomerular filtration rate (eGFR-CKD-EPI) < 60 ml/min/1.73 m2 and/or albumin-to-creatinine ratio ≥ 30 mg/g. Logistic regression models were run for the whole cohort and a subsample free from hypertension and diabetes at baseline, after adjustment for age, sex, race, schooling, smoking, cholesterol/HDL ratio, body mass index, diabetes, use of antihypertensive, systolic blood pressure, heart rate, and cardiovascular disease. Statistical significance was set at 5%. Results The chance of CKD was 42% (CI 95%: 1.05;1.92) greater among individuals in the upper quartile of cfPWV. Among normotensive, non-diabetic participants, individuals in the 2nd, 3rd, and 4th quartiles of cfPWV presented greater chances of developing CKD, as compared to those in the lower quartile, and the magnitude of this association was the greatest for those in the upper quartile (OR: 1.81 CI 95%: 1.14;2.86). Conclusion Higher cfPWV increased the chances of CKD and suggests that this effect is even greater in individuals without diabetes and hypertension.

Association of proton pump inhibitors with renal dysfunction: a cross-sectional study

Background: Proton pump inhibitors are the most frequently prescribed class of medications for prescription and over-the-counter, and the data suggest that comorbidities, polypharmacy, self-medication, no clear indications and duration beyond the recommended guidelines PPIs use are associated with renal dysfunction. Aim was to study the proportion of renal dysfunction among patients using oral PPIs and determine the association between the duration of oral PPIs use and the severity of renal dysfunction. Methods: The data collection of 250 patients was done at the time of contact, which included demographic profiles, complete medical history, physical examination, and laboratory investigation in this study. For analysis, name of oral PPIs used, duration and dosage of oral PPIs therapy, laboratory values of serum blood urea, serum creatinine, eGFR, and serum electrolytes parameters have been considered. Results: Amongst 250 patients with PPIs used for a week, 23 patients showed mildly reduced kidney function (p=0.000), PPIs used for >1 to 2 weeks, 29 patients showed grade 2 kidney function (p=0.001), while PPIs used for >2-3 weeks only two patients showed grade 3 kidney function (p=0.44). Patients aged >50 years in all groups showed grade 2 renal function, regardless of the duration of PPIs use. Increasing age, males, rural, smoking, and alcoholics were the risk factors for renal dysfunction. PPIs use significantly impacts eGFR. Conclusions: Collectively, this study found a significant association between PPIs use and renal dysfunction. PPIs used for >2 weeks in elderly patients have shown a 4?fold increased risk of developing renal dysfunction.

Comparison of GFR measurement with a two-blood sample technique using [99mTc]Tc-DTPA vs. creatinine-based equations in potential kidney donors / Comparação da medição da TFG com uma técnica com duas amostras de sangue usando [99mTc]Tc-DTPA vs. equações baseadas em creatinina em potenciais doadores de rim

ABSTRACT Introduction: Accurate determination of glomerular filtration rate (GFR) is crucial for selection of kidney donors. Nuclear medicine methods are considered accurate in measuring GFR but are not always easily available. The four-variable Modification of Diet in Renal Disease (MDRD4), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Full Age Spectrum (FAS) formulas are common equations for estimating GFR and are recommended for initial assessment of kidney donors. The aim of this study was to evaluate the performance of these GFR estimation equations compared with technetium-99m diethylenetriaminepentaacetic acid ([99mTc]Tc-DTPA) clearance. Methods: We compared GFR estimation by [99mTc]Tc-DTPA clearance using a two-blood sample method with estimation by MDRD4, CKD-EPI, and FAS creatinine-based equations in a population of healthy potential kidney donors. Results: A total of 195 potential kidney donors (68.2% female; mean age 49 years, range 21-75 years) were included in this study. Mean [99mTc]Tc-DTPA measured GFR (mGFR) was 101.5 ± 19.1 mL/min/1.73 m2. All three equations underestimated the GFR value measured by [99mTc]Tc-DTPA (MDRD4: -11.5 ± 18.8 mL/min/1.73 m2; CKD-EPI: -5.0 ± 17.4 mL/min/1.73 m2; FAS: -8.3 ± 17.4 mL/min/1.73 m2). Accuracy within 30% and 10% of the measured GFR value was highest for CKD-EPI. Conclusion: The CKD-EPI equation showed better performance in estimating GFR in healthy potential kidney donors, proving to be a more accurate tool in the initial assessment of kidney donors. However, creatinine-based equations tended to underestimate kidney function. Therefore, GFR should be confirmed by another method in potential kidney donors.

RESUMO Introdução: Determinar precisamente a taxa de filtração glomerular (TFG) é crucial para seleção de doadores de rim. Métodos de medicina nuclear são considerados precisos na medição da TFG, mas nem sempre estão facilmente disponíveis. As fórmulas Modification of Diet in Renal Disease de 4 variáveis (MDRD4), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), e Full Age Spectrum (FAS) são equações comuns para estimar a TFG, sendo recomendadas para avaliação inicial dos doadores. Este estudo visou avaliar o desempenho destas equações de estimativa da TFG em comparação com o clearance do tecnécio-99m-ácido dietilenotriaminopentacético ([99mTc]Tc-DTPA). Métodos: Comparamos a TFG por clearance de [99mTc]Tc-DTPA usando um método com duas amostras de sangue com estimativa da TFG pelas equações MDRD4, CKD-EPI e FAS baseadas em creatinina em uma população de potenciais doadores saudáveis. Resultados: Incluiu-se 195 potenciais doadores de rim (68,2% mulheres; idade média de 49 anos, intervalo 21-75 anos). A TFG média medida por [99mTc]Tc-DTPA foi 101,5 ± 19,1 mL/min/1,73m2. As três equações subestimaram o valor da TFG medida por [99mTc]Tc-DTPA (MDRD4: -11,5 ± 18,8 mL/min/1,73 m2; CKD-EPI: -5,0 ± 17,4 mL/min/1,73 m2; FAS: -8,3 ± 17,4 mL/min/1,73 m2). A precisão dentro de 30% e 10% do valor da TFG medida foi maior para CKD-EPI. Conclusão: A equação CKD-EPI mostrou melhor desempenho na estimativa da TFG em potenciais doadores de rim saudáveis, revelando-se uma ferramenta mais precisa na avaliação inicial dos doadores. Entretanto, equações baseadas em creatinina tendem a subestimar a função renal. Portanto, a TFG deve ser confirmada por outro método em potenciais doadores.

Risk of renal damage associated with intravitreal anti-VEGF therapy for diabetic macular edema in routine clinical practice

Purpose: Vascular endothelial growth factor inhibitors (anti?VEGF) have been shown to be effective in the treatment of diabetic macular edema. However, there is little information about the systemic effects of intraocular administration of anti?VEGF drugs in patients with coexistent diabetic nephropathy because it can produce adverse renal effects. Methods: This retrospective cohort study analyzed the effect of intravitreal anti?VEGF drugs (bevacizumab, ranibizumab, or aflibercept) on eFGR and microalbuminuria (MicA) in patients with diabetic macular edema and nonproliferative retinopathy without chronic kidney disease (CKD). Results: Sixty?six patients were included, 54.5% male and 45.5% female, with a mean age of 66.70 ± 11.6 years. The mean follow?up of patients with antiangiogenic treatment was 42.5 ± 28.07 months, and the mean number of injections was 10.91 ± 7.54. In 12.1% of the cases, there was a worsening of the glomerular filtration rate (eFGR) and a 19.7% worsening of the microalbuminuria (MicA). The number of injections was not related to the worsening of the eFGR (P = 0.74) or the MicA (P = 0.239). No relationship was found between the type of drug and the deterioration of the GFR (P = 0.689) or the MicA (P = 0.53). Conclusions: Based on the results, there is a small proportion of patients with increase in MicA and the decrease in eFGR after anti?VEGF therapy, and these was no associated with the number of injection or the drug type. Ophthalmologists should be aware of renal damage in order to do a close monitoring of renal function and proteinuria after intravitreal administration of anti?VEGF mainly in hypertensive patients.

Factores asociados a la progresión acelerada de la enfermedad renal crónica en pacientes provenientes de la costa Caribe colombiana

Contexto: la enfermedad renal crónica (ERC) es un problema de salud pública mundial, con una prevalencia creciente y una carga sustancial sobre los sistemas de salud. Las características de los pacientes progresores rápidos junto con los factores que podrían predecir la progresión acelerada requieren una mayor exploración, sobre todo porque en Colombia no hay estudios publicados de este tipo. Objetivo: identificar los factores clínicos y sociodemográficos asociados con la progresión rápida de la ERC en una gran cohorte de pacientes de la costa norte colombiana. Metodología: este estudio observacional retrospectivo incluyó dos cohortes de pacientes de la costa norte colombiana con estadios de G1 a G4 sin diálisis. El seguimiento se realizó durante 18 meses (n = 14.420) y 24 meses (n = 10.042) y los pacientes se dividieron en progresores rápidos y progresores estables, según la pendiente de la tasa de filtración glomerular (TFGe) < -5 ml/min/1,73 m2/año o ≥ -5 mL/min/1,73 m2/año, respectivamente. Resultados: el 37,68 % de la cohorte se clasificó como progresión rápida a los 24 meses y el 28,41 % a los 18 meses. Se encontró un R2 = 0,77 en ambas cohortes para las mediciones de la TFGe, lo que indica una tendencia hacia una pérdida lineal. Además, la progresión acelerada se observó en pacientes más jóvenes y con valores más altos de tensión arterial diastólica. Conclusiones: en dos grandes cohortes de pacientes renales, aproximadamente 4 de cada 10 pacientes se clasificaron como progresores rápidos a los 24 meses de seguimiento y 3 de cada 10 a los 18 meses de seguimiento. Es importante identificar a los pacientes con mayor riesgo de progresión acelerada de la ERC en el corto plazo, para brindarles una atención personalizada y efectiva.

Background: Chronic Kidney Disease (CKD) is a global public health problem with increasing prevalence and a substantial burden on healthcare systems. The characteristics of rapid progressors and factors that may predict accelerated CKD progression require further exploration, especially since there are no published studies about this topic in Colombia. Purpose: To identify the clinical and sociodemographic factors associated with the rapid progression of CKD in a large cohort of Colombian patients. Methods: This retrospective observational study included two cohorts of G1 to G4 stage CKD patients without dialysis from the Colombian North Coast. Follow-up was conducted for 18 months (n=14,420) and 24 months (n=10,042). Patients were divided into rapid progressors and stable progressors based on the glomerular filtration rate (GFR) slope <−5 mL/min/1.73m2/year or ≥-5 mL/min/1.73 m2/year, respectively. Results: 37.68% of the cohort was classified as rapid progressors at 24 months and 28.41% at 18 months. An R2=0.77 was found in both cohorts for GFR measurements, indicating a linear trend toward loss. Furthermore, accelerated progression was observed in younger patients and those with higher diastolic blood pressure values. Conclusion: In two large cohorts of renal patients, approximately 4 out of 10 patients were classified as rapid progressors at 24 months of follow-up and 3 out of 10 at 18 months of follow-up. It is important to identify patients at higher risk of accelerated CKD progression in the short term to provide them with personalized and effective care.