LAUSR

Underexcretion of uric acid is the dominant mechanism leading to hyperuricemia [1] and the 24-hour urinary uric acid excretion is an important measurement. However, it is inconvenient due to accurate timing and complete collection of the specimen.The aim of this study was to investigate the relationship between serum uric acid to creatinine ratio (sUACR) and 24-hour urinary uric acid excretion in gout patients.A total of 110 gout patients fulfilling 2015 ACR/EULAR classification criteria from Guangdong Second Provincial General Hospital from January 2019 to January 2021 were retrospectively enrolled in this study. Patients were divided into underexcretion group (<3600 μmol/24h) and non-underexcretion group (≥3600 μmol/24h). The correlation between sUACR and 24-hour urinary uric acid excretion was analyzed by the Pearson’s correlations analysis. Receiver operation characteristic (ROC) curves were performed to assess the utility of sUACR for discriminating between underexcretion group and non-underexcretion group. Furthermore, the risk factors of uric acid underexcretion were evaluated using binary logistic regression analysis.sUACR in the underexcretion group was significantly lower than the non-underexcretion group (p=0.0001). Besides, sUACR was positively correlated with 24-hour urinary uric acid excretion (r=0.4833, p<0.0001). Furthermore, ROC suggested that the area under the curve (AUC) of sUACR was 0.728, which was higher that of serum uric acid and creatinine. The optimal cutoff point of sUACR was 5.2312, with a sensitivity and specificity of 71.9% and 67.9%. Logistic analysis results revealed that decreased sUACR (<5.2312) was an independent risk factor of underexcretion of uric acid (OR =5.510, 95% CI: 1.952-15.550, P=0.001).sUACR is lower in gout patients with underexcretion of uric acid and may serve as a useful and convenient marker of assessing underexcretion of uric acid in gout patients.[1]Perez-Ruiz F, Calabozo M, Erauskin GG, Ruibal A, Herrero-Beites AM. Renal underexcretion of uric acid is present in patients with apparent high urinary uric acid output. Arthritis Rheum 2002; 47: 610–13.Figure 1.A. Comparison of serum uric acid to creatinine ratio between underexcretion group and non-underexcretion group. B. Correlation between serum uric acid to creatinine ratio and 24h uric acid excretion.None declared.