Twenty-four-hour proteinuria levels are associated with adverse pregnancy outcomes among women with CKD.

Background: Proteinuria is commonly measured to assess the renal status of chronic kidney disease (CKD) patients before the 20th week of gestation during pregnancy. High levels of proteiuria have been associated with adverse pregnancy outcomes. However, researchers have not clearly determined what baseline proteinuria levels would be associated with adverse pregnancy outcomes. This study aimed to analyse associations between proteinuria levels and adverse pregnancy outcomes among CKD patients treated with or without steroids/immunosuppressive therapy in early pregnancy. Methods: This retrospective study included the clinical information of 557 pregnant patients with CKD from 1 January 2009 to 31 December 2021. A multivariable logistic regression analysis was conducted to evaluate the risk of adverse pregnancy outcomes across various proteinuria ranges, which were further stratified by whether the patients were receiving steroids/immunosuppressive therapy. Results: (i) Proteinuria was assessed on 24-h urine collection. The median (quartile) baseline proteinuria levels were 0.83 g (0.20, 1.92) and 0.25 g (0.06, 0.80) in the steroids/immunosuppressive therapy and therapy-free groups, respectively. (ii) CKD patients with adverse pregnancy outcomes had significantly higher proteinuria levels in the first trimester than patients without adverse pregnancy outcomes. (iii) The risk of adverse pregnancy outcomes increased with increasing baseline proteinuria levels (P < .001). (iv) In the early-pregnancy steroids/immunosuppressive therapy group, the risk of severe preeclampsia was higher in patients with higher baseline proteinuria levels (P < .007) [odds ratio (OR) 30.86 for proteinuria ≥5.00 g/24 h]; in the therapy-free group, the risks of severe preeclampsia, very-low-birth-weight infants, early preterm birth and foetal-neonatal death were higher in patients with higher baseline proteinuria levels (OR 53.16 for proteinuria ≥5.00 g/24 h; OR 37.83 for proteinuria ≥5.00 g/24 h; OR 15.30 for proteinuria ≥5.00 g/24 h; and OR 18.83 for proteinuria ≥5.00 g/24 h, respectively; P < .001, P < .001, P < .001 and P = .006, respectively). Conclusions: As shown in the present study, a baseline 24-h proteinuria level >1.00 g was associated with adverse maternal outcomes. Furthermore, a 24-h proteinuria level >2.00 g increased the incidence of adverse foetal events among CKD patients.

Spot urine protein-to-creatinine ratio as a diagnostic test in pre-eclampsia: A gold standard?

OBJECTIVE: To determine the diagnostic accuracy and optimal threshold of the spot protein-to-creatinine ratio (PCR) compared to the gold standard, 24-hour proteinuria (24HP) in patients with suspected pre-eclampsia. METHODS: A prospective observational study was performed from June 2015 to May 2017 consisting of patients hospitalized for suspected pre-eclampsia in a tertiary care referral center. To compare the two diagnostic tests, a spot urine sample was obtained to perform the PCR before starting the collection of the 24HP. Only patients who had both tests were analyzed. RESULTS: In total, 148 patients (216 samples) were included. The two tests were highly correlated (r=0.80, P<0.001). The receiver operating characteristic curve analysis and the area under the curve (AUC=0.92) highlighted the accuracy of PCR in diagnosing significant proteinuria and thus pre-eclampsia. The optimal cut-off using the Liu method was 56.9 mg/mmol (sensitivity=79.3%, specificity=91.5%). CONCLUSION: The results suggest that PCR could replace 24HP when diagnosing proteinuria in pre-eclampsia. Moreover, it is a simple test, easy to realize and standardize, and cheap with no need for systematic hospitalization. The best cut-off should be chosen by thinking about the risks for adverse maternal and/or fetal outcomes. The test may help to optimize medical care in pre-eclampsia worldwide.

An unresolved issue: The relationship between spot urine protein-to-creatinine ratio and 24-hour proteinuria.

OBJECTIVE: To investigate the relationship between spot urine protein-to-creatinine (sP/Cr) ratio and 24-h protein excretion in patients with different diagnoses. METHODS: This retrospective study analysed data from the medical records of patients admitted for24-h proteinuria determination who also had sP/Cr ratio data for the same day. RESULTS: A total of 1222 urine samples obtained from 694 adult outpatients were analysed. The mean ± SD age of the patients was 53.6 ± 15.9 years. The mean ± SD 24-h proteinuria and sP/Cr were 1.7 ± 2.4 g/day and 1.8 ± 2.4, respectively. The correlation between the sP/Cr and 24-h protein excretion was high (R2 = 0.89). The sP/Cr ratio accounted for 72% of the variability in 24-h proteinuria in the entire study population. Areas under the curve for 24-h proteinuria at 0.3 g/day, 1.0 g/day and 3.0 g/day were 0.940, 0.966, and 0.949, respectively. The mean + 2SD limits of agreement were between +2.99 and -2.73 g/day according to the Bland Altman analysis. CONCLUSION: This current study found a clinically unacceptable deviation between 24-h proteinuria and sP/Cr ratio. Therefore, the sP/Cr ratio cannot replace 24-h proteinuria. A new method using spot urine protein and creatinine values that is able to minimize under or over estimation is still warranted.

[Spot urinary protein to creatinine ratio: Which role in preeclampsia diagnosis?]. / Rapport protéinurie/créatininurie : quelle place dans le diagnostic de la pré-éclampsie ?

Preeclampsia remains a serious and feared complication of pregnancy. Its diagnosis is confirmed upon detection of hypertension and significant proteinuria starting from 20 weeks of gestation. The 24-hour urine collection is considered to be the gold standard test for quantitative diagnosis of proteinuria despite its downsides. Recent studies have brought into question its accuracy during pregnancy as complete samples are hard to get, but above all, as this time consuming procedure often delays treatment and may preclude optimal management. Several publications looked at the spot urinary protein to creatinine ratio (PCR) as a replacement to the 24-hour urine collection. Largely used outside pregnancy, this fast and less invasive test seems a compelling alternative. In this paper, data from previous meta-analysis and guidelines have been reviewed in an attempt to clarify the role of the PCR in clinical practice and elaborate an algorithm in case of suspicion of preeclampsia. Thus, this test seems a valid "rule-out test" when using the optimal threshold of 30mg/mmol. Higher values require a 24-hour urine collection for confirmation.

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.