1. The urine protein/creatinine ratio as a reliable indicator of 24-h urine protein excretion across different levels of renal function and proteinuria: the TUNARI prospective study.
- Author
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Gutiérrez-Peredo, Gabriel, Montaño-Castellón, Iris, Gutiérrez-Peredo, Andrea, Lopes, Marcelo, Tapioca, Fernanda, Guimaraes, Maria, Montaño-Castellón, Sony, Guedes, Sammara, da Costa, Fernanda, Mattoso, Ricardo, Filho, José, Norris, Keith, de Almeida, Antonio, and Lopes, Antonio
- Subjects
24-h urine protein ,Nephrology ,Proteinuria creatinine ratio ,Renal function ,Humans ,Proteinuria ,Female ,Male ,Cross-Sectional Studies ,Creatinine ,Adult ,Middle Aged ,Prospective Studies ,Sensitivity and Specificity ,ROC Curve ,Kidney ,Glomerular Filtration Rate - Abstract
BACKGROUND: The 24-h urine protein (24-hUP) excretion is the gold standard for evaluating proteinuria. This study aimed to evaluate the diagnostic efficacy of protein/creatinine ratio (PCR) for estimating 24-hUP at various levels of renal function and proteinuria levels. METHODS: A cross-sectional study was conducted between December 2021 and December 2023 in Salvador, Bahia-Brazil, as an extension of previously published data from the TUNARI study. The study included 217 samples from 152 patients with various levels of renal function and proteinuria. PCR in isolated samples and 24-hUP were determined conventionally within a 24-h timeframe. Patients were classified into three groups according to the level of renal function (Group 1 = 10 to 60 mL/min) and level of proteinuria ( 3.5 g/day). The data were analyzed using the Spearman correlation (rs), coefficient of determination (r2), Bland-Altman plots and receiver operating characteristic (ROC) curve. Likelihood ratios, positive (LR +), and negative (LR-) were derived from the sensitivity and specificity of PCR. RESULTS: Mean age was 41.5 ± 15.7 years, 61.8% were women, 36.8% Black and 52% Mixed-race. Glomerulopathies constituted 80.3%; 46.1% with lupus nephritis. Of the total urine samples, we observed a high correlation between PCR in the total sample of 24-hUP sample (rs = 0.86, p 0.3-3.5 g/day, the sensitivity was 64.1%, the specificity was 84.6%, and the AUC was 0.76 (95% CI = 0.67; 0.84), PCR detected all cases > 3.5 g/day. CONCLUSIONS: PCR is a suitable measure to be used as an indicator of 24-hUP at different levels of renal function, but may have limitations at higher levels of proteinuria. Analysis of PCR by proteinuria level found that agreement as well as sensitivity decreases at higher levels, but it maintains good specificity and is able to identify nephrotic range proteinuria.
- Published
- 2024