Association between Sodium Intake and Urinary Fractional Albumin and Immunoglobulin G Excretion in Chronic Nondialytic Renal Disease: A Prospective Longitudinal Study.

BACKGROUND/AIMS: Previous studies reported that fractional clearance of urinary proteins is better than total proteinuria in predicting chronic kidney disease (CKD) progression. However, the role of sodium in the fractional excretion of proteins has not been established. We aimed to evaluate the association between sodium intake and fractional albumin and immunoglobulin G (IgG) excretion in nondialytic CKD. METHODS: We did a longitudinal, observational, and prospective study that included CKD patients aged 18-80. Included patients performed basal routine laboratory evaluations, urinary sodium excretion, and fractional albumin and IgG excretion that were repeated after 6-month of follow-up. RESULTS: We evaluated 84 patients, mean age 55 ± 15.6 years, 40 women, and 74 whites. The change of estimated sodium intake had an association with the change of fractional albumin (R = 0.54; p < 0.001) and IgG (R = 0.56; p < 0.001) excretion in univariate analysis (increases in sodium intake were paralleled by increases in albumin and IgG excretion fractions). This association was maintained in a multiple generalized linear model even after adjusting for age and for changes in blood pressure, urinary potassium, protein intake, and blood glucose. CONCLUSION: In CKD patients, changes in estimated sodium intake were associated with changes in the fractional albumin and IgG excretion regardless of confounding factors. Findings of this study support the idea that reducing salt intake, and consequently, albumin and IgG fractional excretions could help to slow CKD progression. This hypothesis must be tested in long-term interventional studies.

Comparison of different methods of erythrocyte dysmorphism analysis to determine the origin of hematuria.

BACKGROUND/AIMS: There is disagreement regarding the performance of conventional optical microscopy to assess the origin of hematuria. The aim of this study was to determine the optimal cutoff point for dysmorphic cells in order to detect glomerular hematuria by optical and phase-contrast microscopy. METHODS: In total, 131 urine samples (66 from patients with glomerulopathies and 65 from nephrolithiasis patients) were evaluated in a blinded fashion. The percentages of doughnut cells and acanthocytes were verified by optical and phase-contrast microscopy. A total of 131 patients were randomly allocated to the derivation (n = 73) and validation (n = 58) groups. Receiver-operating characteristic (ROC) curves were plotted to check the discriminatory power of each group and the best cutoff points were determined by the Youden index in the derivation group and subsequently tested in the validation group. RESULTS: All areas under the ROC curve (AUCs) were statistically significant using both methods (conventional optical and phase-contrast microscopy) and both groups (derivation and validation). AUCs did not differ between different glomerulopathies. The best cutoff point to determine the glomerular origin of hematuria by total dysmorphic cells was 22% using an optical conventional microscope and 40% by phase-contrast microscopy. CONCLUSION: We determined the best cutoff points to interpret erythrocyte dysmorphism and demonstrated that it is possible to discriminate the origin of hematuria by evaluating erythrocyte dysmorphism in urinalysis using either an optical or a phase-contrast microscope.

Avaliação dos diferentes métodos de análise do dismorfismo eritrocitário, assim como a quantificação da proteinúria e a albuminúria na determinação da origem de hematúria / Evaluation of the different methods of analysis of dymorphic erythrocyte, as will as the quantification of proteinuria and albuminuriain in the determination of the origem of hematuria

Há discordância na literatura quanto à necessidade da realização da microscopia de fase para avaliação da origem da hematúria (glomerular ou não glomerular), isso mostra a necessidade de mais estudos para validar as modalidades de avaliação morfológica da hematúria. Os objetivos deste trabalho foram determinar o melhor ponto de corte da porcentagem dos diferentes padrões de células dismórficas na detecção da hematúria glomerular pelo microscópio óptico convencional e contraste de fase, verificar se a presença de proteinúria ou albuminúria pode auxiliar no diagnóstico da origem da hematúria e determinar o melhor ponto de corte para este parâmetro. Foram avaliadas de maneira cega 131 amostras de urina sendo 66 amostras de portadores de glomerulopatias e 65 amostras dos portadores de litíase renal da Faculdade de Medicina de Botucatu. Utilizaram-se amostras isoladas com densidade >1007 e com mais de 5 hemácias por campo de grande aumento. Verificou-se a presença e a porcentagem de codócitos e acantócitos tanto em microscópio óptico convencional com sedimento fresco e fixado submetidos à coloração de Papanicolaou e Panótico rápido LB e sedimento urinário fresco avaliado em microscópio de contraste de fase, além de determinar o índice de proteinúria e o índice de albuminúria. Os resultados desses métodos foram comparados entre si. Realizou-se regressão linear e diagrama de Bland-Altman das hemácias dismórficas para comparar os diferentes métodos. Curvas ROC foram traçadas para determinar a área sob a curva (ASC) e o melhor ponto de corte (PC) foi determinado pela maior soma de sensibilidade e especificidade. Nesse ponto foram calculadas a sensibilidade (S) e especificidade (Es), Valor Preditivo Positivo (VPP) e Valor Preditivo Negativo (VPN)...

There is disagreement over the literature regarding the performance of phase microscopy to assess the origin f hematuria (glomerular or nonglomerular). This shows the need for further investigation in order to validate the best form of morphological evaluation of hematuria. The aims of this study were to determine the optimal cutoff point percentage for different patterns of dysmorphic cells in the detection of glomerular hematuria by conventional optical microscopy and phase contrast microscopy, to verify whether the presence of proteinuria or albuminuria may assist in the diagnosis of hematuria and also to establish an optimal cutoff point for this parameter. One hundred thirty-one urine samples were blinded evaluated at the Faculdade de Medicina de Botucatu, 66 samples of patients with glomerulopathies and 65 samples of patients with nephrolithiasis. Isolated samples with density greater than 1007 and with more than 5 erythrocytes per high-power field were used. The presence and percentage of codocytes and acanthocytes were verified by conventional optical microscopy using fresh and fixed urinary sediment subjected to Papanicolaou and Panótico Rápido LB staining and fresh urinary sediment was evaluated by phase contrast microscopy. Proteinuria and albuminuria rates were determined. The results of these methods were compared using linear regression analysis and Bland-Altman diagram of dysmorphic red blood cells. ROC curve plots were generated to determine the area under the ROC curve (AUC) and also an optimal cutoff point with the highest sum of sensitivity and specificity. At this point, it was possible to calculate sensitivity (TPR) and specificity (ES), positive predictive value (PPV) and negative predictive value (NPV)...