Estimation of 24-hour urinary sodium excretion using spot urine sample in the adult population in shandong, china

Abstract This study assessed the reliability of equations for estimating 24-hour urinary sodium excretion using first-time morning urine samples. In this study, a total of 2078 residents of Shandong Province in 2019 and 2024 were randomised, and three equations for estimating 24-HUNa were fitted using morning urine samples and 24-hour urine samples from 1454 participants (46.6 ± 13.4 years old), and the three equations as well as equations developed by other researchers were were validated. In the validation group, estimated 24-HUNa was significantly correlated with measured 24-HUNa values. There was no significant difference between the estimated 24-HUNa and the measured 24-HUNa for the three equations fitted in this study, whereas there was a significant difference between the estimated 24-HUNa and the measured 24-HUNa values using Kawasaki and Tanaka et al. In the Bland-Altman analyses, the agreement between measured and estimated 24-HUNa values for the six equations was more than 2500 mg / 24 hours. All equations showed a tendency to underestimate or overestimate 24-HUNa between different levels of actual 24-HUNa values, hypertension status, and age groups. None of the equations tested in this study could estimate an individual's 24-HUNa from a single SU. The SMASH equation fitted in this study was superior to those of other researchers in assessing population-level 24-HUNa excretion in Shandong Province.