Zhang Xin, Liao Hang, Ye Runyu, Li Xinran, Gou Qiling, Zhang Zhipeng, Shi Rufeng, Meng Qingtao, Zhuoma Zewong, Zhang Hengyu, Chen Xiaoping
Department of Cardiology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People's Republic of China.
Luohuo County Health Bureau, Ganzi Tibetan Autonomous Prefecture, Luhuo, Sichuan Province, People's Republic of China.
J Clin Hypertens (Greenwich). 2021 Aug;23(8):1588-1598. doi: 10.1111/jch.14312. Epub 2021 Jul 1.
Twenty-four-hour urine collection is the gold standard method for the evaluation of salt intake, but it is often impractical in large-scale investigations, especially in resource-poor areas. Methods for the estimation of 24-hour urinary sodium excretion (USE) using a spot urine sample have been established, but have not been validated in Chinese Tibetans. Therefore, the authors aimed to evaluate the Kawasaki, Tanaka, and the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT) formulas for the prediction of 24-hour USE in Chinese Tibetan adults. The authors analyzed the bias, correlation, agreements between estimated values and measured values, and the relative and absolute differences and misclassification at the individual level for the three methods in 323 Tibetan participants from the Ganzi Tibetan Autonomous Prefecture of Sichuan Province, China. The mean biases between the measured values and the estimated 24-hour USE using the Kawasaki, Tanaka, and INTERSALT methods were 5.4 mmol/day (95% confidence interval [CI]: 0.8-10.1 mmol/day), -40.8 mmol/day (95% CI: -44.6 to -36.9 mmol/day), and -57.1 mmol/day (95% CI: -61.9 to -52.4 mmol/day), respectively. The Pearson correlation coefficients for the relationships between the measured values and the estimated 24-hour USE were 0.43 (Kawasaki), 0.38 (Tanaka), and 0.27 (INTERSALT), respectively (all p < .01). The intraclass correlation coefficients showed similar patterns to the correlation data: 0.47 for Kawasaki, 0.40 for Tanaka, and 0.27 for INTERSALT (all p < .01). The upper and lower limits of agreement between the measured values and the estimated 24-hour USE were -92.6 and 81.8 mmol/day for the Kawasaki method, -28.5 and 110.0 mmol/day for the Tanaka method, and -28.4 and 142.7 mmol/day for the INTERSALT method. Compared with the other two methods, the percentage of individuals that were misclassified by using the Kawasaki method was 48.2%, while those for the Tanaka and INTERSAL methods was 72.1% and 75.5%, respectively. However, when an individual's salt intake was higher than 12.8 g/day, the misclassification rates of the Kawasaki, Tanaka, and INTERSALT methods were 20%, 90%, and 97.5%, respectively. Thus, the authors found that the Kawasaki equation may have performed better than the other equations at Chinese Tibetan population level assessment, but none of these equations are suitable for use or perform well at the individual level. A more accurate method of using a spot urine sample to evaluate individual 24-hour USE for Tibetans is needed.
24小时尿样收集是评估盐摄入量的金标准方法，但在大规模调查中往往不切实际，尤其是在资源匮乏地区。利用随机尿样估算24小时尿钠排泄量（USE）的方法已经确立，但尚未在中国藏族人群中得到验证。因此，作者旨在评估川崎公式、田中公式以及盐、其他因素与血压国际合作研究（INTERSALT）公式对中国藏族成年人24小时USE的预测能力。作者分析了来自中国四川省甘孜藏族自治州的323名藏族参与者中，这三种方法在个体水平上的偏差、相关性、估计值与测量值之间的一致性，以及相对和绝对差异及错误分类情况。使用川崎公式、田中公式和INTERSALT公式估算的24小时USE与测量值之间的平均偏差分别为5.4 mmol/天（95%置信区间[CI]：0.8 - 10.1 mmol/天）、 - 40.8 mmol/天（95% CI： - 44.6至 - 36.9 mmol/天）和 - 57.1 mmol/天（95% CI： - 61.9至 - 52.4 mmol/天）。测量值与估算的24小时USE之间关系的Pearson相关系数分别为0.43（川崎公式）、0.38（田中公式）和0.27（INTERSALT公式）（均p <.01）。组内相关系数显示出与相关数据相似的模式：川崎公式为0.47，田中公式为0.40，INTERSALT公式为0.27（均p <.01）。川崎公式测量值与估算的24小时USE之间的一致性界限上下限分别为 - 92.6和81.8 mmol/天，田中公式为 - 28.5和110.0 mmol/天，INTERSALT公式为 - 28.4和142.7 mmol/天。与其他两种方法相比，使用川崎公式错误分类的个体百分比为48.2%，而田中公式和INTERSALT公式分别为72.1%和75.5%。然而，当个体盐摄入量高于12.8 g/天时，川崎公式、田中公式和INTERSALT公式的错误分类率分别为20%、90%和97.5%。因此作者发现，在对中国藏族人群水平的评估中，川崎公式可能比其他公式表现更好，但这些公式在个体水平上均不适用或表现不佳。需要一种更准确的利用随机尿样评估藏族个体24小时USE的方法。
