Sensibilidad y especificidad de la presión de pulso ampliada como prueba diagnóstica de IRC estadio K/DOQI III-b / Sensitivity and specificity of increased pulse pressure as a diagnostic test for K/DOQI III-b

Resumen Introducción: La presión de pulso ampliada (PPA) se asocia a un filtrado glomerular calculado ≤ 60/mL/minuto/1.73 m2, por lo que puede ser útil como prueba diagnóstica para identificar a personas con insuficiencia renal crónica (IRC) estadio K/DOQI III-b. Objetivo: Determinar la utilidad de la PPA como prueba diagnóstica de IRC estadio K/DOQI III-b. Método: Estudio de prueba diagnóstica que incluyó a pacientes adultos sin comorbilidades, registrados en la Cohorte de Trabajadores de la Salud. Se utilizó la fórmula CKD-EPI para calcular la filtración glomerular. Se determinó la presión de pulso restando la presión arterial diastólica a la presión arterial sistólica. Se calculó sensibilidad, especificidad, valor predictivo positivo, valor predictivo negativo y prevalencia. Se elaboró una curva ROC para determinar el área bajo la curva. Resultados: Se incluyeron 6215 pacientes. Se observó que una PPA ≥ 50 mm Hg tuvo sensibilidad de 74 %, especificidad de 70 %, valor predictivo positivo de 1 %, valor predictivo negativo de 100 % y prevalencia de 1 %. El punto de inflexión en la curva ROC para identificar IRC K/DOQI III-b fue de 0.71. Conclusión: La PPA ≥ 50 mm Hg es útil como prueba diagnóstica para identificar a personas con IRC estadio K/DOQI III-b.

Abstract Introduction: Increased pulse pressure (IPP) is associated an estimated glomerular filtration ≤ 60/mL/min/1.73 m2; thus, it can be useful as a diagnostic test to identify people with K/DOQI stage III-b chronic kidney disease (CKD). Objective: To determine the usefulness of IPP as a diagnostic test for K/DOQI stage III-b CKD. Method: Diagnostic test study that included adult patients without comorbidities, registered in the Health Workers Cohort. The CKD-EPI formula was used to calculate glomerular filtration. Pulse pressure was determined by subtracting diastolic from systolic blood pressure. Sensitivity, specificity, positive predictive value, negative predictive value and prevalence were calculated using standard formulas. A ROC curve was generated to determine the area under the curve. Results: A total of 6,215 patients were included. An IPP ≥ 50 mmHg was observed to have a sensitivity of 74 %, specificity of 70 %, positive predictive value of 1 %, negative predictive value of 100 % and a prevalence of 1 %. The inflection point in the ROC curve to identify K/DOQI III-b CKD was 0.71. Conclusion: An IPP ≥ 50 mmHg is useful as a diagnostic test to identify people with K/DOQI stage III-b CKD.

Usefulness of Kidney Donor Profile Index (KDPI) to predict graft survival in a South Brazilian Cohort / Utilidade do Índice de Perfil de Doadores de Rins (KDPI) para prever a sobrevida do enxerto em uma coorte do Sul do Brasil

Abstract Introduction: Kidney Donor Profile Index (KDPI) has been incorporated in the United States to improve the kidney transplant allocation system. Objectives: To evaluate deceased kidney donors' profile using KDPI and compare to the previous United Network for Organ Sharing (UNOS) definition of expanded criteria donors (ECD) and assess the KDPI applicability to predict five-year graft survival and renal function in our sample. Methods: Retrospective cohort of 589 kidney transplants from deceased donors performed from January 2009 to May 2013 with follow-up until May 2018. Results: In 589 kidney transplants, 36.6% of donors were classified as ECD and 28.8% had KDPI ≥ 85%. Mean KDPI was 63.1 (95%CI: 60.8-65.3). There was an overlap of standard and ECD in KDPI between 60 and 95 and a significantly lower death-censored graft survival in KDPI ≥ 85% (78.6%); KDPI 0-20: 89.8%, KDPI 21-59: 91.6%, and KDPI 60-84: 83.0%; p = 0.006. The AUC-ROC was 0.577 (95%CI: 0.514-0.641; p = 0.027). Renal function at 5 years was significantly lower according to the incremental KDPI (p < 0.002). KDPI (HR 1.011; 95%CI 1.001-1.020; p = 0.008), donor-specific antibodies (HR 2.77; 95%CI 1.69-4.54; p < 0.001), acute rejection episode (HR 1.73; 95%CI 1.04-2.86; p = 0.034) were independent and significant risk factors for death-censored graft loss at 5 years. Conclusion: In our study, 36.6% were classified as ECD and 28.8% had KDPI ≥ 85%. KDPI score showed a moderate power to predict graft survival at 5 years. Renal function was significantly lower in patients with higher KDPI.

Resumo Introdução: O Índice de Perfil de Doadores de Rins (KDPI) foi adotado nos Estados Unidos para melhorar o sistema de alocação de transplantes renais. Objetivos: avaliar o perfil dos doadores de rim falecidos usando o KDPI e comparar com a definição anterior do United Network for Organ Sharing (UNOS) de doadores de critérios expandidos (DCE) e avaliar a aplicabilidade do KDPI para prever a sobrevida do enxerto em cinco anos e a função renal em nossa amostra. Métodos: Coorte retrospectiva de 589 transplantes renais de doadores falecidos, realizada de janeiro de 2009 a maio de 2013, com acompanhamento até maio de 2018. Resultados: Em 589 transplantes renais, 36,6% dos doadores foram classificados como DCE e 28,8% apresentaram KDPI ≥ 85%. O KDPI médio foi de 63,1 (IC 95%: 60,8-65,3). Houve uma sobreposição de padrão e DCE no KDPI entre 60 e 95 e uma sobrevida do enxerto censurada por óbito significativamente menor no KDPI ≥ 85% (78,6%); KDPI 0-20: 89,8%, KDPI 21-59: 91,6% e KDPI 60-84: 83,0%; p = 0,006. A ASC-ROC foi de 0,577 (IC 95%: 0,514-0,641; p = 0,027). A função renal aos 5 anos foi significativamente menor de acordo com o aumento do KDPI (p <0,002). KDPI (HR 1.011; 95% CI 1.001-1.020; p = 0.008), anticorpos específicos contra doadores (HR 2,77; 95% CI 1,69-4,54; p <0,001), episódio de rejeição aguda (HR 1,73; 95% CI 1,04-2,86; p = 0,034) foram fatores de risco independentes e significativos para perda do enxerto censurada por óbito em 5 anos. Conclusão: Em nosso estudo, 36,6% foram classificados como DCE e 28,8% apresentaram KDPI ≥ 85%. O escore KDPI mostrou potencial moderado para prever a sobrevida do enxerto em 5 anos. A função renal foi significativamente menor nos pacientes com maior KDPI.

Rare inherited kidney diseases: an evolving field in Nephrology / Doenças renais hereditárias raras: um campo em evolução na Nefrologia

Abstract There are more than 150 different rare genetic kidney diseases. They can be classified according to diagnostic findings as (i) disorders of growth and structure, (ii) glomerular diseases, (iii) tubular, and (iv) metabolic diseases. In recent years, there has been a shift of paradigm in this field. Molecular testing has become more accessible, our understanding of the underlying pathophysiologic mechanisms of these diseases has evolved, and new therapeutic strategies have become more available. Therefore, the role of nephrologists has progressively shifted from a mere spectator to an active player, part of a multidisciplinary team in the diagnosis and treatment of these disorders. This article provides an overview of the recent advances in rare hereditary kidney disorders by discussing the genetic aspects, clinical manifestations, diagnostic, and therapeutic approaches of some of these disorders, named familial focal and segmental glomerulosclerosis, tuberous sclerosis complex, Fabry nephropathy, and MYH-9 related disorder.

Resumo As doenças renais genéticas raras compreendem mais de 150 desordens. Elas podem ser classificadas segundo achados diagnósticos como (i) distúrbios do crescimento e estrutura, (ii) doenças glomerulares, (iii) tubulares e (iv) metabólicas. Nos últimos anos, houve uma mudança de paradigma nesse campo. Os testes moleculares tornaram-se mais acessíveis, nossa compreensão sobre os mecanismos fisiopatológicos subjacentes a essas doenças evoluiu e novas estratégias terapêuticas foram propostas. Portanto, o papel do nefrologista mudou progressivamente de mero espectador a participante ativo, parte de uma equipe multidisciplinar, no diagnóstico e tratamento desses distúrbios. O presente artigo oferece um panorama geral dos recentes avanços a respeito dos distúrbios renais hereditários raros, discutindo aspectos genéticos, manifestações clínicas e abordagens diagnósticas e terapêuticas de alguns desses distúrbios, mais especificamente a glomeruloesclerose segmentar e focal familiar, complexo da esclerose tuberosa, nefropatia de Fabry e doença relacionada ao MYH9.

Kidney transplantation with donors in severe acute kidney injury. Should we use these organs? Retrospective Case Series / Transplante renal com doadores em lesão renal aguda severa. Devemos utilizar esses órgãos? Série de casos retrospectiva

ABSTRACT Introduction: The number of incident and prevalent patients on dialysis has increased, as well as the number of candidates for renal transplantation in Brazil, without a proportional increase in the number of organ donors. The use of expanded kidneys, as to renal function, may be an alternative to increase the supply of organs. Objective: to discuss the feasibility of using expanded kidneys for renal function, which are in severe acute renal injury. Methods: All cases of renal transplantation of deceased donors performed at the Hospital das Clínicas de Botucatu of UNESP, from January 2010 to June 2018, totaling 732 cases were evaluated. Cases with final donor creatinine greater than 6 mg/dL were selected. Results: four patients were selected, of whom all donors were in severe acute kidney injury (AKI). These donors presented rhabdomyolysis as a probable cause of severe AKI, were young, with no comorbidities and had decreased urinary volume in the last 24 hours. The clinical evolution of all the recipients was satisfactory, with a glomerular filtration rate after transplantation ranging from 48 to 98 mL/min/1.73 m2. Conclusion: this series of cases shows the possibility of using renal donors in severe AKI, provided the following are respected: donor age, rhabdomyolysis as the cause of AKI, and implantation-favorable biopsy findings. Additional studies with better designs, larger numbers of patients and longer follow-up times are needed.

RESUMO Introdução: O número de pacientes incidentes e prevalentes em diálise tem aumentado, assim como o número de candidatos ao transplante renal no Brasil, sem um aumento proporcional do número de doadores de órgãos. O uso de rins expandidos, quanto à função renal, pode ser uma alternativa para aumentar a oferta de órgãos. Objetivo: discutir a viabilidade do uso de rins expandidos quanto à função renal, que estejam em lesão renal aguda severa. Métodos: foram avaliados todos os casos de transplante renal de doador falecido realizados no Hospital das Clínicas de Botucatu da UNESP, de janeiro de 2010 a junho de 2018, totalizando 732 casos. Selecionou-se os casos com creatinina final do doador maior do que 6 mg/dL. Resultados: quatro pacientes foram selecionados, dos quais todos os doadores estavam em lesão renal aguda (LRA) severa. Esses doadores apresentavam rabdomiólise como provável causa de LRA severa, eram jovens, sem comorbidades e apresentavam diminuição de volume urinário nas últimas 24 horas. A evolução clínica de todos os receptores foi satisfatória, com taxa de filtração glomerular após o transplante variando entre 48 a 98 mL/min/1,73m2. Conclusão: essa série de casos mostra a possibilidade de utilização de doadores renais em LRA severa, desde que respeitadas as condições seguintes: idade do doador, rabdomiólise como causa de LRA e achados de biópsia favoráveis à implantação. Estudos adicionais com melhores desenhos, maior número de pacientes e maiores tempos de seguimento são necessários.

Hepatitis C in Hemodialysis Units: diagnosis and therapeutic approach / Hepatite C nas Unidades de Hemodiálise: diagnóstico e abordagem terapêutica

Abstract According to data from the last census of the Brazilian Society of Nephrology (SBN), the prevalence of hepatitis C virus (HCV) in Brazilian hemodialysis units (HU) is 3.3%, about three times higher than what is reported for the Brazilian general population. Often, professionals working in HU are faced with clinical situations that require rapid HCV diagnosis in order to avoid horizontal transmission within the units. On the other hand, thanks to the development of new antiviral drugs, the cure of patients with HCV, both in the general population and in patients with chronic kidney disease and the disease eradication, appear to be very feasible objectives to be achieved in the near future . In this scenario, SBN and the Brazilian Society of Hepatology present in this review article a proposal to approach HCV within HUs.

Resumo De acordo com os dados do último censo da Sociedade Brasileira de Nefrologia (SBN), a prevalência de portadores do vírus da hepatite C (HCV) nas unidades de hemodiálise (UH) no Brasil é de 3,3%, cerca de três vezes maior do que é observado na população geral brasileira. Muitas vezes, os profissionais que trabalham nas UH deparam-se com situações clínicas que demandam rápido diagnóstico do HCV, a fim de evitar uma transmissão horizontal dentro das unidades. Por outro lado, a cura dos pacientes portadores do HCV, tanto na população geral como na portadora de doença renal crônica e a erradicação da doença, em virtude do desenvolvimento de novas drogas antivirais, parecem ser objetivos bastante factíveis, a ser alcançados em futuro próximo. Nesse cenário, a SBN e a Sociedade Brasileira de Hepatologia apresentam neste artigo de revisão uma proposta de abordagem do HCV dentro das UH.

Zinc alpha 2 glycoprotein as an early biomarker of diabetic nephropathy in patients with type 2 diabetes mellitus / Zinco-alfa2-glicoproteina (ZAG) como biomarcador precoce de nefropatia diabética em pacientes com diabetes mellitus tipo 2

Abstract Introduction: Although microalbuminuria remains the gold standard for early detection of diabetic nephropathy (DN), it is not a sufficiently accurate predictor of DN risk. Thus, new biomarkers that would help to predict DN risk earlier and possibly prevent the occurrence of end-stage kidney disease are being investigated. Objective: To investigate the role of zinc-alpha-2-glycoprotein (ZAG) as an early marker of DN in type 2 diabetic (T2DM) patients. Methods: 88 persons were included and classified into 4 groups: Control group (group I), composed of normal healthy volunteers, and three patient groups with type 2 diabetes mellitus divided into: normo-albuminuria group (group II), subdivided into normal eGFR subgroup and increased eGFR subgroup > 120 mL/min/1.73m2), microalbuminuria group (group III), and macroalbuminuria group (group IV). All subjects were submitted to urine analysis, blood glucose levels, HbA1c, liver function tests, serum creatinine, uric acid, lipid profile and calculation of eGFR, urinary albumin creatinine ratio (UACR), and measurement of urinary and serum ZAG. Results: The levels of serum and urine ZAG were higher in patients with T2DM compared to control subjects and a statistically significant difference among studied groups regarding serum and urinary ZAG was found. Urine ZAG levels were positively correlated with UACR. Both ZAG levels were negatively correlated with eGFR. Urine ZAG levels in the eGFR ˃ 120 mL/min/1.73m2 subgroup were higher than that in the normal eGFR subgroup. Conclusion: These findings suggest that urine and serum ZAG might be useful as early biomarkers for detection of DN in T2DM patients, detectable earlier than microalbuminuria.

Resumo Introdução: Embora a microalbuminúria continue sendo o padrão ouro para a detecção precoce da nefropatia diabética (ND), ela não é um preditor suficientemente preciso do risco de ND. Assim, novos biomarcadores para prever mais precocemente o risco de ND e possivelmente evitar a ocorrência de doença renal terminal estão sendo investigados. Objetivo: Investigar a zinco-alfa2-glicoproteína (ZAG) como marcador precoce de ND em pacientes com debates mellitus tipo 2 (DM2). Métodos: Os 88 indivíduos incluídos foram divididos em quatro grupos: grupo controle (Grupo I), composto por voluntários saudáveis normais; e três grupos de pacientes com DM2 assim divididos: grupo normoalbuminúria (Grupo II), subdivididos em TFG normal e TFG > 120 mL/min/1,73 m2), grupo microalbuminúria (Grupo III) e grupo macroalbuminúria (Grupo IV). Todos foram submetidos a urinálise e exames para determinar glicemia, HbA1c, função hepática, creatinina sérica, ácido úrico, perfil lipídico, cálculo da TFG, relação albumina/creatinina (RAC) e dosagem urinária e sérica de ZAG. Resultados: Os níveis séricos e urinários de ZAG foram mais elevados nos pacientes com DM2 em comparação aos controles. Foi identificada diferença estatisticamente significativa entre os grupos estudados em relação aos níveis séricos e urinários de ZAG. Os níveis urinários de ZAG foram positivamente correlacionados com a RAC. Ambos os níveis de ZAG foram negativamente correlacionados com TFG. Os níveis urinários de ZAG no subgrupo com TFG ˃ 120 mL/min/1,73m2 foram maiores do que no subgrupo com TFG normal. Conclusão: Constatamos que a ZAG sérica e urinária pode ser um útil biomarcador precoce para detecção de ND em pacientes com DM2, sendo detectável mais precocemente que microalbuminúria.

The natural history of solitary post-nephrectomy kidney in a pediatric population

ABSTRACT Introduction: Children with a solitary post-nephrectomy kidney (SNK) are at potential risk of developing kidney disease later in life. In response to the global decline in the number of nephrons, adaptive mechanisms lead to renal injury. The aim of this study was to determine the prevalence and time of onset of high blood pressure (HBP), proteinuria, glomerular filtration rate (GFR) disruption and renal tubular acidosis (RTA) in children with SNK. Materials and methods: After obtaining the approval from our institution's ethics committee, we reviewed the medical records of patients under 18 years of age who underwent unilateral nephrectomy between January 2005 and December 2015 in three university hospitals. Results: We identified 43 patients, 35 (81.4%) cases of unilateral nephrectomy (UNP) were due to a non-oncologic pathology and Wilm's tumor was identified in 8 (18.6%) cases. In patients with non-oncologic disease, 9.3% developed de novo hypertension, with an average time of onset of 7.1 years, 25% developed proteinuria de novo, with an average time of onset of 2.2 years. For GFR, 21.8% presented deterioration of the GFR in an average time of 3.4 years. Ten (43.5%) patients developed some type of de novo renal injury after UNP. Patients with oncologic disease developed the conditions slowly and none of them developed proteinuria. Conclusions: Taking into account the high rate of long term postoperative renal injury, it can be considered that nephrectomy does not prevent this disease. The follow-up of children with SNK requires a multidisciplinary approach and long-term surveillance to detect renal injury.

Reserva funcional renal: concepto y aplicabilidad potencial en la práctica clínica / Renal functional reserve: concept and potential application in clinical practice

Renal functional reserve (RFR) is the capacity of the kidney to increase its glomerular filtration rate (GFR) in response to physiological or pathological stimuli. The most commonly used stimuli to assess this reserve are an oral load of proteins of animal origin, amino acid infusions, dopamine, glucagon or combinations of them. RFR is calculated as the difference between stimulated and baseline GFR. Vegetarians have lower baseline GFR than the general population and an increased RFR. Subjects with only one kidney and those suffering from chronic nephropathies usually have a reduced or absent RFR despite having normal basal GFR. Quantification of RFR may be useful to detect subclinical renal damage, physiological conditions that reduce baseline GFR, evaluation of potential donors for kidney transplantation, suspected hyperfiltration, detection of renal lability against acute injuries or pregnancy and the evaluation after an acute renal injury when renal function seems to be recovered and residual subclinical damage is suspected.

Preoperative proteinuria is associated with increased rates of acute kidney injury after partial nephrectomy

ABSTRACT Purpose We investigated the association between preoperative proteinuria and early postoperative renal function after robotic partial nephrectomy (RPN). Patients and Methods We retrospectively reviewed 1121 consecutive RPN cases at a single academic center from 2006 to 2016. Patients without pre-existing CKD (eGFR≥60 mL/min/1.73m2) who had a urinalysis within 1-month prior to RPN were included. The cohort was categorized by the presence or absence of preoperative proteinuria (trace or greater (≥1+) urine dipstick), and groups were compared in terms of clinical and functional outcomes. The incidence of acute kidney injury (AKI) was assessed using RIFLE criteria. Univariate and multivariable models were used to identify factors associated with postoperative AKI. Results Of 947 patients, 97 (10.5%) had preoperative proteinuria. Characteristics associated with preoperative proteinuria included non-white race (p<0.01), preoperative diabetes (p<0.01) and hypertension (HTN) (p<0.01), higher ASA (p<0.01), higher BMI (p<0.01), and higher Charlson score (p<0.01). The incidence of AKI was higher in patients with preoperative proteinuria (10.3% vs. 4.6%, p=0.01). The median eGFR preservation measured within one month after surgery was lower (83.6% vs. 91%, p=0.04) in those with proteinuria; however, there were no significant differences by 3 months after surgery or last follow-up visit. Independent predictors of AKI were high BMI (p<0.01), longer ischemia time (p<0.01), and preoperative proteinuria (p=0.04). Conclusion Preoperative proteinuria by urine dipstick is an independent predictor of postoperative AKI after RPN. This test may be used to identify patients, especially those without overt CKD, who are at increased risk for developing AKI after RPN.

Evaluation of the royal free hospital cirrhosis glomerular filtration rate formula in hispanic patients with cirrhosis: an external validation

Abstract Background and Aims Glomerular filtration rate (GFR) measurement in patients with liver cirrhosis (LC) is the ideal method for adequate evaluation of kidney function. However, it is invasive, costly, and not widely accessible. Moreover, GFR estimation in patients with cirrhosis has been inaccurate. The aim of the present study was to evaluate and validate the recently described Royal Free Hospital (RFH) formula in a Hispanic cohort of patients with LC and compare it with other formulas, including the CKD-EPI cystatin C equation. Methods GFR was measured through the renal clearance of Tc-99m DTPA; it was cross-sectionally evaluated and compared with GFRs that were estimated utilizing the following formulas: RFH, Cockcroft-Gault, 6-variable Modification of Diet in Renal Disease-6, CKD-EPI cystatin C, CKD-EPI Creatinine, and CKD-EPI Cystatin C-Creatinine. Results We included 76 patients (53% women). The mean measured GFR in the entire cohort was 64 ml/min/1.73m2; 54% of the patients had a GFR < 60 ml/min/1.73 m2 at the time of evaluation. The RFH formula and the CKD-EPI cystatin C formula showed the best performance, with a p30 of 62% and 59%, respectively. All formulas performed poorly when GFR was < 60 ml/min/1.73 m2. Conclusions The RFH formula showed a better performance than the other formulas based on serum creatinine in a Hispanic population with LC. There was no difference in performance between the RFH formula and the CKD-EPI cystatin C formula.

Performance of the equations to estimate the glomerular filtration rate in Mexican patients receiving kidney transplantation / Desempeño de las ecuaciones para estimar la tasa de filtración glomerular en pacientes mexicanos receptores de trasplante renal

Abstract Introduction: The management of kidney transplant recipients requires glomerular filtration rate (GFR) monitoring, which is an indicator of graft primary function and patient survival. Objective: To evaluate the performance of different creatinine or cystatin-based formulas in the estimation of glomerular filtration rate in Mexican patients receiving kidney transplantation. Method: 30 transplant recipients were included, in whom the glomerular filtration rate was measured by means of iothalamate, and was also calculated using seven equations based on cystatin or creatinine. Results: The formula with the best performance was the one proposed by the chronic kidney disease epidemiology collaboration (CKD-EPI), with a bias of −2.4 mL/min/1.73 m2: and an accuracy of 9.6; 96.7 % of patients were within 30 % of the measured GFR. The second best formula was the modification of diet in renal disease (MDRD) equation. Cystatin-based equations showed a poor performance. Conclusions: Our study suggests that, in Mexican patients receiving kidney transplantations, the best equations to estimate GFR are the CKD-EPI and MDRD equations.

Cistatina C: marcador de laboratorio precoz de enfermedad renal en pacientes con depranocitosis / Cystatin C: early laboratory marker of renal disease In sickle cell disease

La enfermedad renal en el paciente con drepanocitosis es una consecuencia de su complejo proceso fisiopatológico, por lo que es importante disponer de un grupo de parámetros de laboratorio que, junto a la evaluación clínica, permita determinar de forma precoz la presencia de esta complicación. La cistatina C ha demostrado ser uno de los parámetros que con mayor exactitud aporta evidencia temprana de daño renal en este grupo de pacientes y al mismo tiempo constituye un posible indicador de pronóstico de gran importancia(AU)

Renal disease in patients with sickle cell disease is a consequence of its complex pathophysiological process, so it is important to have a set of laboratory parameters that, together with the clinical evaluation, allow the early detection of this complication. Cystatin C has been shown to be one of the parameters that provides, with greater accuracy, early evidence of kidney damage in this group of patients and at the same time constitutes a possible indicator of prognosis of great importance(AU)

Dietary intake of non-dialysis chronic kidney disease patients: the PROGREDIR study. A cross-sectional study

ABSTRACT BACKGROUND: Despite evidence that diet is very important in relation to chronic kidney disease (CKD) progression, studies in this field are scarce and have focused only on some specific nutrients. We evaluated the energy, macronutrient and micronutrient intakes and dietary patterns of non-dialysis CKD participants in the PROGREDIR study. DESIGN AND SETTING: Cross-sectional study; CKD cohort, São Paulo, Brazil. METHODS: Baseline data on 454 participants in the PROGREDIR study were analyzed. Dietary intake was evaluated through a food frequency questionnaire. Dietary patterns were derived through principal component analysis. Energy and protein intakes were compared with National Kidney Foundation recommendations. Linear regression analysis was performed between energy and nutrient intakes and estimated glomerular filtration rate (eGFR), and between sociodemographic and clinical variables and dietary patterns. RESULTS: Median energy and protein intakes were 25.0 kcal/kg and 1.1 g/kg, respectively. In linear regression, protein intake (β = -3.67; P = 0.07) was related to eGFR. Three dietary patterns (snack, mixed and traditional) were retained. The snack pattern was directly associated with male gender (β = 0.27; P = 0.006) and inversely with diabetes (β = -0.23; P = 0.02). The traditional pattern was directly associated with male gender (β = 0.27; P = 0.007) and schooling (β = 0.40; P < 0.001) and inversely with age (β = -0.01; P = 0.001) and hypertension (β = -0.34; P = 0.05). CONCLUSIONS: We identified low energy and high protein intake in this population. Protein intake was inversely related to eGFR. Dietary patterns were associated with age, gender, schooling level, hypertension and diabetes.

Abdominal obesity and reduction of glomerular filtration

SUMMARY The objective was to evaluate the association between nutritional status and the glomerular filtration rate (GFR) in remaining quilombolas. Cross-sectional study carried out on 32 remaining quilombola communities in the municipality of Alcântara-MA. The nutritional indicators (IN) used were: body mass index (BMI); Waist circumference (WC); Waist-to-hip ratio (WHR); Waist-to-height ratio (WHtR); conicity index (CI) and estimated visceral adipose tissue (VAT). GFR was estimated from the CKD-EPI creatinine-cystatin C formula. The Shapiro Wilk test was used to evaluate the normality of the quantitative variables. In order to compare the second IN sex, the chi-square test was applied. The Anova or Kruskal-Wallis tests were used to verify the association between IN and GFR. Of the 1,526 remaining quilombolas studied, 89.5% were black or brown, 51.2% were women, 88.6% belonged to economic classes D and E and 61.2% were farmers or fishermen. Clinical investigation revealed 29.2% of hypertensive patients, 8.5% of diabetics and 3.1% with reduced GFR. The BMI revealed 45.6% of the remaining quilombolas with excess weight. When compared to men, women presented a higher prevalence of overweight by BMI (56.6% vs 33.8%, p <0.001) and abdominal obesity CC (52.3% vs 4.3%), WHR (76,5% vs 5.8%), WHtR (82.3% vs 48.9%) and VAT (27.1% vs 14.5%) (p <0.001). Comparing the means of IN according to the GFR, it was observed that the higher the mean value of the IN lower the GFR (p <0.05). The GFR reduced with increasing mean values of nutritional indicators of abdominal obesity, regardless of sex.

RESUMO O objetivo foi avaliar a associação entre o estado nutricional e a taxa de filtração glomerular (TFG) em remanescentes quilombolas. Estudo transversal, realizado em 32 comunidades remanescentes de quilombolas, no município de Alcântara - MA. Os indicadores nutricionais (IN) utilizados foram: índice de massa corporal (IMC); circunferência da cintura (CC); relação cintura-quadril (RCQ); relação cintura-estatura (RCEst); índice de conicidade (Índice C) e tecido adiposo visceral estimado (TAVe). A TFG foi estimada a partir da fórmula do CKD-EPI creatinina-cistatina C. O teste Shapiro Wilk foi utilizado para avaliar a normalidade das variáveis quantitativas. Para comparar os IN segundo sexo foi aplicado o teste qui-quadrado. Os testes Anova ou Kruskal-Wallis foram usados para verificar a associação entre os IN e a TFG. Dos 1.526 remanescentes quilombolas estudados, 89,5% eram da cor preta ou parda, 51,2% eram mulheres, 88,6% pertenciam às classes econômicas D e E e 61,2% eram lavradores ou pescadores. A investigação clínica revelou 29,2% de hipertensos, 8,5% de diabéticos e 3,1% com TFG reduzida. O IMC revelou 45,6% dos remanescentes quilombolas com excesso de peso. Quando comparadas aos homens, as mulheres apresentaram maior prevalência de excesso de peso pelo IMC (56,6% vs. 33,8%; p <0,001) e obesidade abdominal CC (52,3% vs. 4,3%), RCQ (76,5% vs. 5,8%), RCEst (82,3% vs. 48,9%) e TAVe (27,1% vs. 14,5%) (p<0,001). Comparando as médias dos IN segundo a TFG observou-se que, quanto maior o valor médio dos IN, menor a TFG (p<0,05). A TFG foi reduzida com o aumento dos valores médios dos indicadores nutricionais de obesidade abdominal, independentemente do sexo.

Nephrometry scores and perioperative outcomes following robotic partial nephrectomy

ABSTRACT Objectives: Based on imaging features, nephrometry scoring systems have been conceived to create a standardized and reproducible way to characterize renal tumor anatomy. However, less is known about which of these individual measures are important with regard to clinically relevant perioperative outcomes such as ischemia time (IT), estimated blood loss (EBL), length of hospital stay (LOS), and change in estimated glomerular filtration rate (eGFR) after robotic partial nephrectomy (PN). We aimed to assess the utility of the RENAL and PADUA scores, their subscales, and C-index for predicting these outcomes. Materials and Methods: We analyzed imaging studies from 283 patients who underwent robotic PN between 2008 and 2014 to assign nephrometry scores (NS): PADUA, RENAL and C-index. Univariate linear regression was used to assess whether the NS or any of their subscales were associated with EBL or IT. Multivariable linear regression and linear regression models were created to assess LOS and eGFR. Results: The three NS were significantly associated with EBL, IT, LOS, and eGFR at 12 months after surgery. All subscales with the exception of anterior/posterior were significantly associated with EBL and IT. Collecting system, renal rim location, renal sinus, exophytic/endophytic, and nearness to collecting system were significant predictors for LOS. Only renal rim location, renal sinus invasion and polar location were significantly associated with eGFR at 12 months. Conclusions: Tumor size and depth are important characteristics for predicting robotic PN outcomes and thus could be used individually as a simplified way to report tumors features for research and patient counseling purposes.

Arterial stiffness and 25-hydroxyvitamin D levels in chronic kidney disease patients

Summary Objective: Arterial stiffness refers to arterial wall rigidity, particularly developing in central vessels. Arterial stiffness increases in early stage chronic kidney disease (CKD), and it is a strong predictor of cardiovascular and all cause mortality. Vitamin D has beneficial effects on blood pressure, vascular endothelial function and arterial stiffness. 25-hydroxyvitamin D (25(OH)D) deficiency is quite common worldwide and in the CKD population. We aimed to evaluate the prevalence of 25(OH)D deficiency and its relation with arterial stiffness in CKD. Method: Our study included 101 patients (51 male, 50 female), with stages 3B-5 CKD not on dialysis. A single-cuff arteriograph device (Mobil-O-Graph) was used to evaluate arterial stiffness parameters of pulse wave velocity (PWV) and augmentation index (Alx@75). The patients were divided into two groups: group I vitamin D non-deficient [25(OH)D > 15 ng/mL] and group II vitamin D deficient [25(OH)D ≤ 15 ng/mL]. Results: Overall, the mean 25(OH)D level was 14.1±7.9 ng/mL and 70 patients (69.4%) were vitamin D deficient. The mean Alx@75 value was significantly higher in group II (28.6±10.8% vs. 23.3±13.5%, p=0.038). PWV was higher in group II, but the difference was not significant. Group II exhibited significantly lower serum albumin (p<0.001), hemoglobin (p=0.005), calcium (p=0.041) and estimated glomerular filtration rate (eGFR) (p=0.041), but significantly higher 24-hour proteinuria (p=0.011) and more females (p=0.006). Vitamin D was negatively correlated with Alx@75 augmentation pressure, parathyroid hormone, proteinuria and body mass index, and positively correlated with albumin, hemoglobin, eGFR, calcium and transferrin. 25(OH)D was independently associated with Alx@75 (beta=-0.469, p=0.001) and albumin (beta=0.447, p=0.002). Conclusion: In CKD patients 25(OH)D deficiency was common, particularly in females. Level of 25(OH)D was independently associated with Alx@75.

Do We Need to Personalize Renal Function Assessment in the Stratification of Patients Undergoing Cardiac Surgery? / É Necessário Personalizar a Avaliação da Função Renal na Estratificação de Pacientes Submetidos à Cirurgia Cardíaca?

Abstract Background: Renal dysfunction is an independent predictor of morbidity and mortality in cardiac surgery. For a better assessment of renal function, calculation of creatinine clearance (CC) may be necessary. Objective: To objectively evaluate whether CC is a better risk predictor than serum creatinine (SC) in patients undergoing cardiac surgery. Methods: Analysis of 3,285 patients registered in a prospective, consecutive and mandatory manner in the Sao Paulo Registry of Cardiovascular Surgery (REPLICCAR) between November 2013 and January 2015. Values of SC, CC (Cockcroft-Gault) and EuroSCORE II were obtained. Association analysis of SC and CC with morbidity and mortality was performed by calibration and discrimination tests. Independent multivariate models with SC and CC were generated by multiple logistic regression to predict morbidity and mortality following cardiac surgery. Results: Despite the association between SC and mortality, it did not calibrate properly the risk groups. There was an association between CC and mortality with good calibration of risk groups. In mortality risk prediction, SC was uncalibrated with values > 1.35 mg /dL (p < 0.001). The ROC curve showed that CC is better than SC in predicting both morbidity and mortality risk. In the multivariate model without CC, SC was the only predictor of morbidity, whereas in the model without SC, CC was not only a mortality predictor, but also the only morbidity predictor. Conclusion: Compared with SC, CC is a better parameter of renal function in risk stratification of patients undergoing cardiac surgery.

Resumo Fundamentos: Disfunção renal é preditor independente de morbimortalidade após cirurgia cardíaca. Para uma melhor avaliação da função renal, o cálculo do clearance de creatinina (CC) pode ser necessário. Objetivo: Avaliar objetivamente se o CC é melhor que a creatinina sérica (CS) para predizer risco nos pacientes submetidos à cirurgia cardíaca. Métodos: Análise em 3285 pacientes do Registro Paulista de Cirurgia Cardiovascular (REPLICCAR) incluídos de forma prospectiva, consecutiva e mandatória entre novembro de 2013 e janeiro de 2015. Foram obtidos valores de CS, CC (Cockcroft-Gault) e do EuroSCORE II. Análise de associações da CS e do CC com morbimortalidade foi realizada mediante testes de calibração e discriminação. Por regressão logística múltipla, foram criados modelos multivariados independentes com CS e com CC para predição de risco de morbimortalidade após cirurgia cardíaca. Resultados: Apesar da associação entre a CS e morbimortalidade, essa não calibrou adequadamente os grupos de risco. Houve associação entre o CC e morbimortalidade com boa calibração dos grupos de risco. Na predição do risco de mortalidade, a CS ficou descalibrada com valores >1,35 mg/dL (p < 0,001). A curva ROC revelou que o CC é superior à CS na predição de risco de morbimortalidade. No modelo multivariado sem CC, a CS foi a única preditora de morbidade, enquanto que no modelo sem a CS, o CC foi preditor de mortalidade e o único preditor de morbidade. Conclusão: Para avaliação da função renal, o CC é superior que a CS na estratificação de risco dos pacientes submetidos a cirurgia cardíaca.

Characterization of an experimental model of progressive renal disease in rats

ABSTRACT PURPOSE: To characterize an experimental model of progressive renal disease induced by different degrees of nephrectomy in rats. METHODS: Eighty male Wistar rats were divided into four experimental groups (n=20/group): sham surgery (control group), progressive degrees of nephrectomy leading to mild uremia (group 1), moderate uremia (group 2) and severe uremia (group 3). Ten animals of each group were followed for two or four weeks. At the end, blood and 24-hour urine samples were collected to determine renal function parameters. Urine output and water and food intake were daily monitored. RESULTS: In rats of group 1, serum levels of creatinine and urea and microalbuminuria were increased, while reduced creatinine clearance (p<0.05, compared with control group), without changing blood pressure. Animals of group 2 had more accentuated alterations: increases in urinary output, blood pressure, serum concentrations of urea, creatinine, sodium, potassium, and in microalbuminuria, and reduction of creatinine clearance (p<0.05). Group 3 exhibited even more increased serum concentrations of urea, creatinine, sodium and potassium, blood pressure and microalbuminuria, and decreased creatinine clearance (p<0.05) in comparison with control group and unilateral nephrectomy. CONCLUSION: Progressive nephrectomy in rats seems to be useful to study the physiopathology of chronic kidney disease and its mechanisms of progression.

The role of oxidative stress in streptozotocin-induced diabetic nephropathy in rats

ABSTRACT Objective The objective of this study was to evaluate the role of oxidative stress in an experimental model of streptozotocin-induced diabetic nephropathy in rats. Materials and methods Wistar, adult, male rats were used in the study. Animals were divided in the following groups: Citrate (control, citrate buffer 0.01M, pH 4.2 was administrated intravenously - i.v - in the caudal vein), Uninephrectomy+Citrate (left uninephrectomy-20 days before the study), DM (streptozotocin, 65 mg/kg, i.v, on the 20th day of the study), Uninephrectomy+DM. Physiological parameters (water and food intake, body weight, blood glucose, kidney weight, and relative kidney weight); renal function (creatinine clearance), urine albumin (immunodiffusion method); oxidative metabolites (urinary peroxides, thiobarbituric acid reactive substances, and thiols in renal tissue), and kidney histology were evaluated. Results Polyphagia, polydipsia, hyperglycemia, and reduced body weight were observed in diabetic rats. Renal function was reduced in diabetic groups (creatinine clearance, p < 0.05). Uninephrectomy potentiated urine albumin and increased kidney weight and relative kidney weight in diabetic animals (p < 0.05). Urinary peroxides and thiobarbituric acid reactive substances were increased, and the reduction in thiol levels demonstrated endogenous substrate consumption in diabetic groups (p < 0.05). The histological analysis revealed moderate lesions of diabetic nephropathy. Conclusion This study confirms lipid peroxidation and intense consumption of the antioxidant defense system in diabetic rats. The association of hyperglycemia and uninephrectomy resulted in additional renal injury, demonstrating that the model is adequate for the study of diabetic nephropathy.

Evaluation of creatinine-based and cystatin C-based equations for estimation of glomerular filtration rate in type 1 diabetic patients

ABSTRACT Objective Several formulas based in different biomarkers may be used to estimate glomerular filtration rate (GRF). However, all of them have some limitations, and it is very important to evaluate their performances in different groups of patients. Therefore, we compared GFR, as estimated by creatinine-based and cystatin C-based equations, according to albuminuria, in type 1 diabetes (T1DM), in an observational case-control study. Subjects and methods T1DM patients were classified according to albuminuria: normoalbuminuric (n = 63), microalbuminuric (n = 30), macroalbuminuric (n = 32). GFR was calculated using creatinine-based and cystatin C-based (aMDRD, CKD-EPIcr, CKD-EPIcys, MacIsaac, Tan and CKD-EPIcrcys) equations. Spearman Correlation was used to evaluate the correlation of GFR estimated by the formulas with albuminuria. ROC curves were constructed to compare AUCs of GFR estimated by equations, in reference to macroalbuminuria. Sensibility, specificity and accuracy were calculated for a cut-off < 60 mL/min/1.73 m2. Results GFR estimated by creatinine-based and cystatin C-based equations significantly differed among normoalbuminuric, microalbuminuric and macroalbuminuric patients. Spearman correlation and AUCs of GFR estimated by creatinine-based and cystatin C-based formulas were very similar to each other, though cystatin C-based equations presented better correlation with albuminuria and higher AUCs than the creatinine-based ones, and the best accuracy to detect macroalbuminuric patients. Conclusion Although GFR estimated by all creatinine-based and cystatin C-based equations permitted the differentiation between T1DM patients, according to albuminuria, cystatin C-based equations presented best accuracy to detect macroalbuminuria in T1DM patients and should be considered in the clinical routine in order to increase the possibility of early diagnostic of chronic renal disease.