Epidemiological analysis on chronic kidney disease in Asian population after standardization of creatinine measurement

对于慢性肾脏病(CKD)的诊断和分期，用肾小球滤过率(GFR)评价肾功能是必不可少的。估计的GFR可以通过血肌酐(Cr)、年龄和性别来计算，因此用可靠的Cr值来评估GFR是很重要的。在这项在韩国、台湾、泰国和日本进行的国际合作研究中，我们用Jaffe方法分析了合作中心的Cr值，并在日本的一个中心实验室进行了标准化的Cr值。台湾的CR值与日本的标准值几乎相同，而韩国的CR值约为0。2 mg/dL较高，显示了铬测量方法标准化的意义。与高加索人相比，无论遗传、饮食和生活方式相似，亚洲人对MDRD方程的种族系数存在争议。在这项研究中，我们用菊粉清除法测量了200名韩国患者、200名台湾患者和60名泰国患者的GFR，并比较了日本GFR和MDRD方程在不同种族中的准确性。日本的GFR公式在韩语中显示出更好的准确性，但在台语中则不然。台湾人的肌肉量排泄率高于日本人和韩国人，这说明不同的身体肌肉质量在不同的民族系数中起主要作用。基于标准化的肌酸值和可靠的日本GFR方程，我们对爱知县约10万名健康体检者进行了CKD患病率分析。无论是男性还是女性，以及所有年龄段，爱知县的蛋白尿阳性率都高于全国调查。爱知县低GFR<60mL/min/1.73m2的患病率为8.6%，低于全国调查的10.6%，这可能是由于爱知县不同的生命统计因素所致。

For Chronic Kidney Disease(CKD) diagnosis and staging, is essential to evaluate kidney function by glomerular filtration rate(GFR). Estimated GFR could be calculated by serum creatinine(Cr), age and gender, therefore it is important to evaluate GFR by reliable Cr values. In this international collaborative study in Korea, Taiwan, Thailand and Japan, we analyzed Cr values measured in collaborative centers by Jaffe method and standardized Cr values in a central laboratory in Japan. Cr values in Taiwan were almost identical to Japanese standardized one, while those in Korea exhibited approximately 0. 2mg/dL higher values, which revealed a significance of standardization of Cr measurement methods.There is a controversy in ethnic coefficient for MDRD equation among Asians, regardless of similar genetics, food and lifestyle compared to Caucasian. In this study, we measured GFR by inulin clearance with an uniform protocol in 200 Korean, 200 Taiwanese and 60 Thai patients, and compare accuracies of Japanese GFR and MDRD equations in individual ethnics. Japanese GFR equations revealed better accuracy in Korean but not in Taiwanese. Cr excretion rate, a marker of body muscle mass, was greater in Taiwanese compared to Japanese and Korean, which suggest that different body muscle mass plays a major role in different ethnic coefficient.Based on standardized Cr values and reliable Japanese GFR equation, we conducted CKD prevalence analysis among approximately 100, 000 health-check subjects in Aichi prefecture. Positive rates of proteinuria were greater in Aichi than in the national survey, in both male and female, and in all age groups. Prevalence of low GFR less than 60 mL/min/1. 73m2 was 8. 6% in Aichi prefecture, which was smaller than 10. 6% in the national survey, provably due to different vital statics in Aichi prefecture.