Yanjie Huang1, Xiaoqing Yang2, Yanan Zhang3, Shangsai Yue3, Xiaofeng Mei2, Liangliang Bi2, Wensheng Zhai3, Xianqing Ren3, Ying Ding4, Shusheng Zhang5, Zhifen Deng5, Yuan Sun6. 1. Department of Pediatrics, Henan University of Chinese Medicine, 156 Jinshui East Road, Zhengzhou, Henan, 450046, China. huangyanjie69@hotmail.com. 2. Department of Pediatrics, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, Henan, China. 3. Department of Pediatrics, Henan University of Chinese Medicine, 156 Jinshui East Road, Zhengzhou, Henan, 450046, China. 4. Department of Pediatrics, Henan University of Chinese Medicine, 156 Jinshui East Road, Zhengzhou, Henan, 450046, China. Dingying3236@sina.com. 5. College of chemistry and Molecular Engineer, Zhengzhou University, Zhengzhou, Henan, China. 6. Department of Anesthesia, Stanford University School of Medicine, Palo Alto Veterans Institute for Research, Stanford, CA, USA.
Abstract
BACKGROUND: The purpose of this study was to evaluate the correlation and consistency between urine protein/creatinine ratio (UPCR) and 24-h urine protein (24HUPr) in children, and to determine cutoff values of UPCR relative to 24HUPr at 100 mg/m2/d (≥ 100 mg/m2/d as pathological proteinuria) and 1000 mg/m2/d (≥ 1000 mg/m2/d as nephrotic-range proteinuria). METHODS: Three hundred sixty-six children were enrolled, including 81 controls, 109 with Henoch-Schönlein purpura nephritis, 167 with nephrotic syndrome, 5 with IgA nephropathy, and 4 with lupus nephritis. Patients were divided into three groups: normal group; non-nephrotic-range proteinuria group; nephrotic-range proteinuria group. The cutoff values of UPCR in predicting the different levels of proteinuria were determined using ROC curve analysis. RESULTS: UPCR was positively correlated with 24HUPr (r = 0.915, p < 0.01). Bland-Altman diagrams showed that UPCR and 24HUPr had good consistency, and > 95% spots of UPCR and 24HUPr were within 95% confidence intervals. Relative to 24HUPr at 100 mg/m2/d, the cutoff value of UPCR (0.18 g/g Cr) had the highest sensitivity (94%) and specificity (98.8%) which is close to 0.2 g/g Cr as proposed by the American College of Rheumatology. Relative to 24HUPr at 1000 mg/m2/d, the cutoff value of UPCR (2.09 g/g Cr) had the highest sensitivity (92.1%) and specificity (92.1%) which is close to the 2.0 g/g Cr proposed in KDIGO guidelines. CONCLUSIONS: UPCR showed strong correlation and consistency with 24HUPr for evaluating levels of proteinuria in children. UPCR < 0.2 g/g Cr can be considered a criterion for normal-range proteinuria. Instead of 24HUPr ≥ 1000 mg/m2/d, UPCR ≥ 2.0 g/g Cr can be considered a criterion for nephrotic-range proteinuria or nephrotic syndrome in children.
BACKGROUND: The purpose of this study was to evaluate the correlation and consistency between urine protein/creatinine ratio (UPCR) and 24-h urine protein (24HUPr) in children, and to determine cutoff values of UPCR relative to 24HUPr at 100 mg/m2/d (≥ 100 mg/m2/d as pathological proteinuria) and 1000 mg/m2/d (≥ 1000 mg/m2/d as nephrotic-range proteinuria). METHODS: Three hundred sixty-six children were enrolled, including 81 controls, 109 with Henoch-Schönlein purpura nephritis, 167 with nephrotic syndrome, 5 with IgA nephropathy, and 4 with lupus nephritis. Patients were divided into three groups: normal group; non-nephrotic-range proteinuria group; nephrotic-range proteinuria group. The cutoff values of UPCR in predicting the different levels of proteinuria were determined using ROC curve analysis. RESULTS: UPCR was positively correlated with 24HUPr (r = 0.915, p < 0.01). Bland-Altman diagrams showed that UPCR and 24HUPr had good consistency, and > 95% spots of UPCR and 24HUPr were within 95% confidence intervals. Relative to 24HUPr at 100 mg/m2/d, the cutoff value of UPCR (0.18 g/g Cr) had the highest sensitivity (94%) and specificity (98.8%) which is close to 0.2 g/g Cr as proposed by the American College of Rheumatology. Relative to 24HUPr at 1000 mg/m2/d, the cutoff value of UPCR (2.09 g/g Cr) had the highest sensitivity (92.1%) and specificity (92.1%) which is close to the 2.0 g/g Cr proposed in KDIGO guidelines. CONCLUSIONS: UPCR showed strong correlation and consistency with 24HUPr for evaluating levels of proteinuria in children. UPCR < 0.2 g/g Cr can be considered a criterion for normal-range proteinuria. Instead of 24HUPr ≥ 1000 mg/m2/d, UPCR ≥ 2.0 g/g Cr can be considered a criterion for nephrotic-range proteinuria or nephrotic syndrome in children.