Child Kidney Dis.  2021 Dec;25(2):78-83. 10.3339/jkspn.2021.25.2.78.

Spot Urine Uric Acid to Creatinine Ratio used in the Estimation of Hyperuricosuria in the Young Korean Population

• Choi H
• Namgoong M

• KMID: 2524509
• DOI: http://doi.org/10.3339/jkspn.2021.25.2.78

Abstract

Background
Uric acid levels in urine are measured using urine specimens 24 hours or by uric acid glomerular filtration rate (UAGFR) with spot urine, which additionally requires a blood sample. This study aimed to investigate whether urinary uric acid creatinine ratio (UUACr) obtained by spot urine alone could be recognized as a substitute for UAGFR value, and hyperuricosuria can be screened by UUACr. UUACr is known to vary with age and regional differences. This study focused on the reference value of each value in Korean young populations. Method: We enrolled Korean subjects 1–20 years with normal kidney function, from a single hospital, classified into 5 age groups, 1–5 years, 6–8 years, 9–12 years, 13–15 years, and 16–20 years. We checked spot urine uric acid, creatinine and serum uric acid, creatinine levels on the same day from February 2014 to December 2018. We measured the average of UAGFR and UUACr in each groups. The UUACr cut-off value of the upper 2 standard deviation (SD) of UAGFR were taken.
Results
The upper 2 SD of UUACr (mg/mg) and UAGFR (mg/dL) were determined in all age groups. UUACr decreased with grown up (P=0.000), but UAGFR were not statistically different among the groups. UUACr and UAGFR were not significantly different by gender. UUACr and UAGFR were positively correlated; UUACr cut-off value of upper 2 SD UAGFR (0.54 mg/dL) was 0.65 mg/mg in total age.
Conclusions
UUACr could potentially be used to screen for hyperuricosuria.

Keyword

Child; Glomerular filtration rate; Uric acid

Figure

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  Fig. 1. Study population.

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  Fig. 2. Correlation between urinary uric acid creatinine ratio (UUACr) and urinary uric acid GFR (UAGFR) in all age groups (R=0.602). P=0.0000, y=0.2351+0.15 x, y=UAGFR, x=UUACr.

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  Fig. 3. Receiver operating characteristic (ROC) curves analysis for UAGFR (mg/dL) (x-axis) versus UUACr (mg/mg) (y-axis); ability of UUACr to discriminate between children with and without hyperuricosuria; area under the ROC curve (AUC) statistic represents the probability of correctly classifying children with and without hyperuricosuria, (a) Total age group, (b) 1-20 age;. CI, confidence interval; UAGFR, urine uric acid glomerular filtration rate; UUACr, urine uric acid creatinine ratio.

Reference

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