Comparison of Urinary Protein/Creatinine Ratio as an Alternative to 24-h Proteinuria in Lupus Nephritis: TUNARI Study.

BACKGROUND: Lupus nephritis (LN) occurs in approximately 50% of people with systemic lupus erythematosus (SLE). The 24-h proteinuria (gold standard) is measured among other tests for the control and monitoring of LN activity. This study investigates the use of the protein/creatinine ratio (PCR) as an alternative for the detection of proteinuria and its accuracy compared to the gold standard in a predominantly non-white population. METHODS: This was a prospective study conducted in Salvador, Brazil, between December 2021 and May 2022. We invited adult patients diagnosed with SLE and LN, regardless of their disease activity. The estimation of the PCR and 24-h proteinuria was performed using conventional methods. The analysis used was Spearman's r correlation coefficient (rs), coefficient of determination (r2), and concordance by the Bland-Altman method. A specific sensitivity was measured by the ROC curve with its respective cut-off by the Youden Index. RESULTS: We compared 112 samples of 75 patients with LN, with a mean age of 34.5 ± 11.8 years. Of these patients, 85% were women, 87.9% were non-white. A high degree of correlation was observed between PCR with 24-h proteinuria (rs = 0.77 and r2 = 0.59). The ROC analysis shows an area under the curve of 0.92 and the cut-off point calculated by the Youden Index was 0.78 with a sensitivity of 90.0% and specificity of 82%. However, the Bland-Altman graph indicated decreasing concordance as the degree of proteinuria increased, despite showing concordance at high levels of proteinuria. CONCLUSION: The PCR shows high sensitivity to follow-up patients with LN when compared with 24-h proteinuria. Our findings suggest that PCR is a useful parameter for the evaluating and monitoring patients in complete remission. However, in cases of partial remission, the utility of PCR is limited.

Evaluation of angiogenic factors (PlGF and sFlt-1) in pre-eclampsia diagnosis / Avaliação dos fatores angiogênicos (PlGF e sFlt-1) no diagnóstico de pré-eclâmpsia

Abstract Objective: Recent observations support the hypothesis that an imbalance between angiogenic factors has a fundamental role in the pathogenesis of pre-eclampsia and is responsible for the clinical manifestations of the disease. The goal of the present study was to evaluate the sensitivity, specificity, and the best accuracy level of Soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), and sFlt-1/PlGF ratio in maternal serum and protein/creatinine ratio in urine sample to define the best cutoff point of these tests to discriminate between the patients with gestational hypertension and the patients with pre-eclampsia, to evaluate the possibility of using them as diagnostic methods. Methods: A prospective longitudinal study was performed, and blood samples were collected from 95 pregnant patients with hypertension to measure serum concentrations of biomarkers sFlt-1 and PlGF. Urine samples were collected for protein screening. Significance was set as p < 0.05. Results: The sFlt-1/PlGF ratio demonstrated a sensitivity of 57.5% and a specificity of 60% using 50.4 as a cutoff point. The test that showed the best accuracy in the diagnosis of pre-eclampsia was protein/creatinine ratio, with a sensitivity of 78.9% and a specificity of 70% using 0.4 as a cutoff point and showing an area under the receiver operating characteristic curve of 0.80 (p < 0.001). Conclusion: No studied laboratory test proved to be fairly accurate for the diagnosis of pre-eclampsia, except for the protein/creatinine ratio. The evidence is insufficient to recommend biomarkers sFlt-1 and PlGF to be used for the diagnosis of pre-eclampsia.

Resumo Objetivo: Pesquisas recentes sustentam a hipótese de que um desequilíbrio entre fatores angiogênicos desempenhe um papel fundamental na patogênese da pré-eclâmpsia e seja responsável pelas manifestações clínicas da doença. O objetivo do presente estudo foi avaliar a sensibilidade, a especificidade e o nível de melhor acurácia do Fator semelhante a tirosina quinase 1 (sFlt-1), Fator de crescimento placentário (PlGF), e relação sFlt-1/PlGF no soro materno e relação proteína/creatinina em amostra de urina e definir o melhor ponto de corte desses testes para distinguir pacientes com hipertensão gestacional daquelas com pré-eclâmpsia, a fim de avaliar a possibilidade de utilizá-los como métodos diagnósticos. Métodos: Foi realizado um estudo prospectivo longitudinal e foram coletadas amostras de sangue de 95 gestantes com hipertensão arterial para dosar as concentrações séricas dos biomarcadores sFlt-1 e PlGF. Amostras de urina foram coletadas para pesquisa de proteinúria. Foram consideradas significativas as diferenças com p < 0,05. Resultados: A relação sFlt-1/PlGF demonstrou sensibilidade de 57,5% e especificidade de 60% utilizando 50,4 como ponto de corte. O teste que apresentou a melhor acurácia no diagnóstico de pré-eclâmpsia foi a relação proteína/creatinina, com sensibilidade de 78,9% e especificidade de 70%, utilizando 0,4 como ponto de corte e demostrando uma área sob a curva receiver operating characteristic (ROC, na sigla em inglês) de 0,80 (p < 0,001). Conclusão: Nenhum método de rastreamento isolado se mostrou com boa acurácia para o diagnóstico de pré-eclâmpsia, exceto a relação proteína/creatinina. As evidências são insuficientes para recomendar os biomarcadores sFlt-1 e PlGF como diagnóstico de pré-eclâmpsia.

Assessment of renal functions and lesions in dogs with serological diagnosis of canine visceral leishmaniasis

Background: Visceral leishmaniasis is a complex vector-borne disease caused by the protozoan Leishmania infantum. In urban centers of South America, where this zoonotic cycle occurs, dogs seem to be the main reservoirs and infection sources. Animals with canine visceral leishmaniasis (CVL) may have a wide clinical spectrum, and dogs are usually classified as asymptomatic, oligosymptomatic, and symptomatic. Several organs are affected in canine CVL, and renal involvement is often a determining factor in dog prognosis. Nevertheless, serum markers are slow to indicate loss of renal function. The aim of this study was to evaluate kidney impairment in dogs diagnosed with CVL. Materials, Methods & Results: Blood and urine samples were collected from 45 dogs from Barra Mansa-RJ, and used for urinalysis, urine protein/creatinine (UPC) ratio, and serum concentrations of urea and creatinine. The animals were classified as symptomatic (42.2%), oligosymptomatic (37.8%), and asymptomatic (20.0%). Some alterations were found in the urine samples; pale-yellow color in 17.8%, low specific gravity in 6.7%, turbidity in 51.1%, proteinuria in 80%, occult blood in 46.7%, bilirubin in 8.89%, and glucose in 6.7% of the samples. According to the UPC ratio, 60% of dogs were proteinuric, and UPC > 2.0 was high in symptomatic dogs. Azotemia was observed only in three dogs with CVL. Discussion: The majority of dogs presented one or more symptoms of CVL, as expected in an endemic area from Brazil. Pale-yellow urine was observed in some samples, and this change, when accompanied by the decreased urine specific gravity in dogs with CVL, suggests some degree of kidney disease. The presence of epithelial and red blood cells, leukocytes, bacteria, suspended mucus, and phosphate crystals that precipitate in alkaline urines could be associated, to some degree, with the urine turbidity found in the present study. The alkaline urine identified in some dogs could be related to...

Cocientes urinarios Proteína-Creatinina y Albúmina-Creatinina en pacientes con lupus eritematoso sistémico / Urinary Protein/Creatinine ratio and Albumin/Creatinine ratio in patients with systemic lupus erythematosus / Quocientes urinários Proteína-Creatinina e Albumina- Creatinina em pacientes com lúpus eritematoso sistêmico

El objetivo del trabajo consistió en analizar las correlaciones entre: cociente Proteína/Creatinina en la primera orina de la mañana y Proteinuria de 24 horas (P/C-P24h); y cociente Albúmina/Creatinina en la primera orina de la mañana y Albuminuria de 24 horas (A/C-A24h) en pacientes con Lupus Eritematoso Sistémico y también evaluar la influencia del Clearance de Creatinina (ClCr) sobre la correlación P/C-P24h. Fue un estudio observacional, transversal y prospectivo. Se estudiaron 80 muestras de 52 pacientes lúpicos ambulatorios, entre marzo de 2013 y agosto de 2014. Se evaluaron mediante coeficiente de correlación de Spearman (CCS), las correlaciones P/C-P24h y A/C-A24h en distintos rangos de proteinuria y la influencia del ClCr sobre P/C-P24h. Para P/C-P24h cuando P24h<300 mg/24h CCS=0,6169 (n=52); cuando P24h≥300 mg/ 24h CCS=0,7461 (n=28). Para P/C-P24h en pacientes con ClCr<60 mL/ min CCS=0,9016 (n=12), y con ClCr>60 mL/min CCS=0,8689 (n=66). Para A/C-A24h a P24h<300 mg/24h CCS=0,8082 (n=37). Todos con p<0,0001. Este estudio mostró buena correlación P/C-P24h para P24h≥300 mg/24h y A/C-A24h para P24h<300 mg/24h. No se observó influencia del ClCr en la correlación P/C-P24h. Estos resultados sumados a los obtenidos por otros autores apoyan el uso del cociente A/C a P24h<300 mg/24h y P/C a P24h≥300 mg/24h para el seguimiento del compromiso renal en pacientes con Lupus Eritematoso Sistémico utilizando la primera orina de la mañana.

The objective of the present work was to analyze the correlation between: protein/creatinine ratio in first-morning urine and 24-hour urine protein (P/C-P24h), and albumin/creatinine ratio in first-morning urine and 24-hour urine albumin (A/C-A24h) in patients with Systemic Lupus Erythematosus, and to evaluate the influence of creatinine clearance (CrCl) on the P/C-P24h correlation.It was a prospective cross-sectional study in which 80 samples of 52 outpatients with lupus were studied between March 2013 and August 2014. They were evaluated by Spearman Correlation Coefficient (CCS), the P/C-P24h and A/C-A24h correlations in different ranges of proteinuria and the influence of ClCr on P/C-P24h.This study showed a good correlation P/C-P24h for P24h≥300 mg/24h and A/C-A24h for P24h<300 mg/24h. No influence of ClCr in the P/C-P24h correlation was observed. These results and those obtained by other authors support the use of the A/C to P24h<300 mg/24h ratio and P/C to P24h≥300 mg/24h ratio to monitor renal involvement in patients with systemic lupus erythematosus using the first-morning urine.

O objetivo do trabalho foi analisar as correlações entre quociente Proteína/Creatinina na primeira urina da manhã e Proteinúria de 24 horas (P/C-P24h); e quociente Albumina/Creatinina na primeira urina da manhã e Albuminuria de 24 horas (A/C-A24h) em paciêntes com Lupus Eritematoso Sistêmico e também avaliar a influência do Clearance de Creatinina (ClCr) sobre a correlação P/C-P24h. Foi um estudo observacional transversal e prospectivo. Foram estudadas 80 amostras de 52 pacientes ambulatórios com lúpus, entre março de 2013 e agosto de 2014. Avaliaram-se através do coeficiente de correlação de Spearman (CCS), as correlações P/C-P24h e A/C-A24h em diferentes níveis de proteinúria e a influência do ClCr sob P/C-P24h. Para P/C-P24h quando P24h<300 mg/24h CCS=0,6169 (n=52); quando P24h≥300 mg/24h CCS=0,7461 (n=28). Para P/C-P24h em pacientes com ClCr<60 mL/min CCS=0,9016 (n=12), e com ClCr>60mL/min CCS=0,8689 (n=66). Para A/C-A24h a P24h<300 mg/24h CCS=0,8082 (n=37). Em todos os casos, p<0,0001. Este estudo mostrou boa correlação P/C-P24h para P24h≥300 mg/24h y A/C-A24h para P24h<300 mg/24h. Não foi observada influência do ClCr na correlação P/C-P24h. Estes resultados, somados aos obtidos por outros autores, apoiam o uso do quociente A/C a P24h<300 mg/24h e P/C a P24h≥300 mg/24h para o seguimento do compromisso renal em pacientes com Lúpus Eritematoso Sistêmico utilizando a primeira urina da manhã.

Correlación entre cociente proteína/creatinina y proteinuria de 24 horas en pacientes con enfermedad renal / Correlation between protein/creatinine ratio and 24-hour urine protein in patients with kidney disease / CorrelaþÒo entre quociente proteína/creatinina e proteinuria de 24 horas em paciente com doenþa renal

La cuantificación de la proteinuria en orina de 24 horas se utiliza con frecuencia para el diagnóstico y la terapéutica en pacientes con enfermedad renal crónica (ERC). Sin embargo, muchas veces se pierde precisión debido a lo complicado que resulta para el paciente la recolección de la muestra. Se ha desarrollado el cociente proteína/creatinina (P/C) en orina esporádica como alternativa diagnóstica, razón por la cual el objetivo del presente estudio fue determinar si el cociente P/C se correlaciona con la proteinuria en 24 horas (ProtU24h), en pacientes con ERC que asistieron al Centro UNILIME UC, Valencia-Venezuela. El estudio fue correlacional, de campo y transversal. La muestra fue de tipo intencional, no probabilística, constituida por 120 pacientes que cumplieron con los criterios de inclusión, a quienes se les determinó la depuración de creatinina, proteinuria en orina de 24 horas y el índice P/C en la segunda orina, entre los meses de abril y septiembre de 2013. Se establecieron correlaciones entre las variables. La ProtU24h correlacionó significativamente con el cociente P/C (r=0,855; p=0,000) en proteinurias menores de 3500 mg/24 horas, y adicionalmente dicho cociente tiene la capacidad de detectar elevadas concentraciones de ProtU24h. El presente estudio demuestra que el cociente P/C en orina esporádica es útil en proteinurias inferiores al rango nefrótico, lo que supone simplificación de la recolección de la muestra y podría suponer una disminución del gasto sanitario.(AU)

Quantification of proteinuria in 24-hour urine is frequently used for diagnosis and therapy in patients with chronic kidney disease (CKD); however, accuracy is often lost due to how complicated it is for the patient to collect the sample. Researchers have developed the protein/creatinine ratio (P/C) in sporadic urine as a diagnostic alternative. The objective of this study was to determine if the P/C correlates with proteinuria in 24 hours (ProtU24h) in CKD patients who attended UNILIME UC Center, Valencia-Venezuela. This was a correlational field study. The sample was not probabilistic; it was constituted by 120 patients who met the inclusion criteria and were determined creatinine clearance and proteinuria in 24-hour urine, and P/C ratio in the second urine sample,from April to September 2013. Correlations between variables were established. The ProtU24h correlated significantly with the P/C (r=0.855 ; p=0.000) in proteinuria lower than 3500 mg/24 hours. Additionally, said quotient has the ability to detect high concentrations of ProtU24h. The present study shows that the P/C in sporadic urine is useful in proteinuria lower than the nephrotic range, which simplifies collection of the sample and could lead to a reduction in health expenditure.(AU)

A quantificaþÒo da proteinúria na urina de 24 horas é frequentemente utilizada para diagnóstico e terapia em pacientes com doenþa renal cr¶nica (DRC). Porém, muitas vezes, é perdida a precisÒo devido a que, para o paciente, é difícil a coleta da amostra de urina. Foi desenvolvido o quociente proteína / creatinina (P/C) na urina esporádica como um diagnóstico alternativo, razÒo pela qual o objetivo desse estudo foi determinar se o quociente P/C se correlaciona com a proteinúria em 24 horas (ProtU24h), em pacientes com DRC que frequentaram o Centro de UNILIME UC, Valencia-Venezuela. O estudo foi correlacional, de campo e transversal. A amostra foi de tipo intencional, nÒo probabilística, composta de 120 pacientes que cumpriram os critérios de inclusÒo, aos quais lhes determinaram a depuraþÒo da creatinina, proteinúria em urina de 24 horas e o índice P/C na segunda urina, entre abril e setembro de 2013. As correlaþ§es entre as variáveis foram estabelecidas. A ProtU24h se correlacionou significativamente com o quociente P/C (r=0,855; p=0,000) em proteinúrias menores de 3500 mg/24 horas, e além disso tal quociente tem a capacidade de detectar concentraþ§es elevadas de ProtU24h. O estudo presente demonstra que o quociente P/C na urina esporádica é útil em proteinúrias inferiores ao intervalo nefrótico, representando simplificaþÒo da coleta da amostra e poderia fazer supor uma reduþÒo das despesas em saúde.(AU)

Correlación entre el cociente proteinuria/creatininuria en una orina al azar y la proteinuria de 24 horas

Introducción: la cuantificación de proteínas en orina es un estudio que evalúa la afectación renal por ciertas enfermedades. Su medición puede realizarse también a través del cociente proteinuria/creatininuria. Objetivo: determinar la correlación entre el cociente proteinuria/creatininuria y la proteinuria de 24 horas. Metodología: se realizó un estudio descriptivo observacional, prospectivo con componente analítico de corte transverso, de muestreo no probabilístico. Se incluyó a 60 pacientes con factores de riesgo de padecer enfermedad renal crónica, que acudieron al Hospital Nacional (Itauguá) en el año 2014. Todos se realizaron análisis de orina de 24 horas y de una muestra de orina al azar para estimar el cociente proteinuria/creatininuria. Resultados: se observó que existe una correlación muy significativa (r= 0,9 p < 0,001) entre los valores del cociente de proteinuria/creatininuria en una orina al azar y la proteinuria de 24 horas, con una sensibilidad 94,1% (IC95% 79-100), especificidad 100% (IC95% 98-100%), valor predictivo positivo 100% (IC95% 96-100) y valor predictivo negativo 97,7% (IC95% 92-100). Conclusiones: el cociente proteinuria/creatininuria es útil para detectar proteinuria en rango no nefrótico.

Introduction: The quantification of proteins in urine is a study that evaluates kidney involvement in some diseases. The measurement can be made through the urine protein-creatinine ratio. Objective: To determine the correlation between the urine protein-creatinine ratio and 24-hour urine protein. Methodology: A cross-sectional prospective observational descriptive study with analytical component and non-probabilistic sampling was performed. Sixty patients who had risk factors of chronic renal disease and attended the National Hospital (Itauguá) in 2014 were included. Twenty four-hour urine and a random urine sample were analyzed to estimate the protein-creatinine ratio. Results: A very significant correlation (r= 0.9 p < 0.001) was observed between the values of the protein-creatinine ratio in a random urine and 24-hour urine protein with a sensitivity of 94.1% (IC95% 79-100), specificity of 100% (IC95% 98-100%), positive predictive value of 100% (IC95% 96-100) and negative predictive value of 97.7% (IC95% 92-100). Conclusion: The protein-creatinine ratio is useful to detect proteinuria in a non-nephrotic range.

Avaliação da relação proteína-creatinina urinária em gatos com doença renal crônica / Evaluation of urinary protein-creatinine ratio in cats with chronic kidney disease

Doença renal crônica (DRC) é a forma mais comum de doença renal em gatos. Vários fatores têm sido citados como importantes na progressão da doença, dentre eles a proteinúria. A relação proteína-creatinina (RPC) urinária em uma única amostra de urina apresenta boa correlação com a perda de proteína urinária em 24 horas. O objetivo dessa investigação foi determinar a RPC urinária em gatos com DRC adquirida naturalmente. A determinação da RPC foi realizada em nove gatos saudáveis (Grupo I) e em trinta gatos com DRC (Grupo II). Os gatos do Grupo I apresentaram RPC de 0,16±0,10 e os gatos do Grupo II apresentaram RPC de 0,53± 0,59. No Grupo II encontrou-se correlação positiva e significante da RPC com o nível de creatinina sérica. Os resultados deste estudo demonstram que a RPC urinária em gatos com DRC é bastante variável e que, à semelhança do que já havia sido previamente descrito, aproximadamente um terço dos gatos com DRC são considerados proteinúricos segundo critérios estabelecidos pela literatura (RPC urinária >0,4).

Chronic renal disease (CRD) is the most common form of renal disease in cats. Several factors contribute to disease progression. Proteinuria is an important marker of renal disease progression. The protein-creatinine ratio in a single urine sample correlates well with urinary protein loss in 24 hours. The aim of this investigation was to determine the urine protein-creatinine (UPC) ratio in cats with natural acquired chronic renal disease. The UPC ratio was performed in nine clinically normal cats and in 30 cats with chronic renal disease. Mean UPC ratio in normal cats was 0.16±0.10, and mean UPC ratio in the cats with chronic renal disease was 0.53± 0.59. In the group with renal disease there was positive correlation between UPC ratio and serum creatinine levels. The results obtained from this study demonstrate that UPC ratio in cats with CRD is variable and that, in accordance to what has previously been described, approximately one third of the cats with CRD are considered proteinuric according to the criteria established in literature (UPC ratio > 0.4).