To develop and validation of the new estimation methods for 24-h urinary sodium excretion by using spot urine for Chinese urban and rural residents.Design and Method:
Three populations were involved in this study. 100 healthy participants were enrolled in this study (Xishan population) and they all collected each spot urine sample and mixed finally as the 24-hour urine samples according to the study design and protocol. Data from previous researches were also used in this study, including Prospective Urban Rural Epidemiology study – China urine validation trial population (PURE-China urine trial population) and Application of prevention and treatment technique in community for noncommunicable diseases (Dexing population), for which these two researches were both collected the morning urine and 24-hour urine samples. The validation analysis conducted through correlation, bias distribution, residual analysis and Bland-Altman plots to assess the accuracy and the applicability of New methods in Chinese residents. Compared with the estimation by Kawasaki, INTERSALT, and Tanaka formula.Results:
Second morning urine New method: Male: PrCRE24h = 9.39 × weight (kg)-3.567 × height (cm)-4.683 × age +1498.014 Female: PrCRE24h = 8.09 × weight (kg)+4.417 × height (cm)-1.906 × age -159.528 e-24-h USE = 2.41 × PrUCr24h × (NaSMU / CrSMU)0.461Results:
New method underestimated the mean value of 24-h USE about 273 mg/day, which was better for population level estimation. Furthermore, the accuracy of estimation at individual level also was not improved through bias distribution analysis. With the similar effect of K method, New method showed a dispersed randomly Bland-Altman plot and indicated a relative accuracy. Although the gap between estimation values and real measured values was the least by using New method (Estimated – Measured), the bias of individual estimated values were all big no matter which methods used.Conclusions:
The estimation for 24-h USE by using spot urine through New methods did not showed a good accuracy at individual level and could be an alternative for 24-h USE estimation at population level to evaluate the salt intake in given population.