Estimated excretion and clearance of uric acid as optimal surrogate indices for daily urinary uric acid excretion.

This article focuses on identifying simple and accurate indices for assessing daily uric acid excretion (Eua) and clearance (Cua) in patients with gout or hyperuricaemia, using spot urine samples as practical alternatives to the standard 24-hour urine collection. Analyzing data from 739 indoor workers aged 20–65 years in the multicenter RICE-U study, the researchers found that estimated uric acid clearance (eCua) and estimated uric acid excretion (eEua)—calculated by multiplying the uric acid-to-creatinine clearance ratios from spot urine by the estimated glomerular filtration rate (eGFR)—showed the strongest correlations with 24-hour Cua and Eua, respectively. Compared to 60-minute urine collection methods, eCua and eEua demonstrated lower error, bias, and higher accuracy, suggesting their suitability for routine clinical use due to convenience and reliability. The study emphasizes that while spot urine indices cannot fully replace 24-hour collections due to physiological fluctuations, eCua and eEua offer practical, non-invasive tools for monitoring renal uric acid handling in outpatient settings.