基于广义估计方程评估尿液混匀程度对慢性肾脏病患者24 h尿蛋白定量的影响

Effect of urine mixing degree on 24-hour urinary total protein in patients with chronic kidney disease based on generalized estimating equation

目的 探讨尿液标本的混匀程度对慢性肾脏病(chronic kidney disease, CKD)患者24 h尿蛋白定量(24-hour urinary total protein, 24 h UTP)的影响。方法 选择2023年10月1日至2023年12月31日在复旦大学附属中山医院须完善24 h UTP的住院CKD患者30例。使用5 L集尿桶留取患者24 h尿液。尿液留取完成后,静置1 h,按体积分成上、中、下三等份,并分别取样,定义为直接采样组;采用磁力搅棒器充分混匀尿液标本,再次按上述三等分方法取样,定义为混匀采样组。采用广义估计方程比较混匀操作前后和不同采样位置的尿蛋白浓度差异。结果 广义估计方程统计结果显示,控制变量“采样位置”后,直接采样组和混匀采样组的尿蛋白浓度差异无统计学意义;控制变量“混匀方式”后,不同采样位置的尿液蛋白浓度差异无统计学意义。校正年龄、性别、估算肾小球滤过率(estimated glomerular filtration rate, eGFR)等协变量后,控制变量“采样位置”或“混匀方式”后,两采样组尿蛋白浓度或不同采样位置的尿蛋白浓度差异均无统计学意义。结论 规范留取的24 h尿液中尿蛋白分布相对均匀。总尿液采集完成后,1 h内可直接从原尿液任意层面提取临检标本,该标本的尿蛋白浓度乘以尿量可反映24 h UTP。

Objective To explore the effect of urine mixing degree on 24-hour urinary total protein(24 h UTP)in patients with chronic kidney disease(CKD).Methods From October 1,2023 to December 31,2023,30 hospitalized patients who needed to complete 24 h UTP testing in Zhongshan Hospital,Fudan University were selected.A 5 L unified container was used to collect urine for 24 hours. After collection and one hour’s standing, the urine sample was divided into upper, middle, and lower equal partsaccording to volume, which was defined as direct-sampling group. Then, the urine samples were fully mixed with a magnetic stirrerand sampled again according to the above-mentioned three-equal sampling method, which was defined as mixed-sampling group.The generalized estimating equation was used to compare the urinary protein concentration before and after mixing and at differentsampling location. Results The results of generalized estimating equation showed that after controlling the variable “samplingposition”, there was no significant difference in urinary protein concentration between the direct-sampling group and the mixedsamplinggroup. After controlling the variable “mixing method”, there was still no significant difference in urinary protein concentrationat different sampling positions. After adjusting the covariates such as age, gender, and estimated glomerular filtration rate (eGFR), theresults were consistent. Conclusions With standard protocol, the entire 24-hour urine sample is a relatively even-distributed solution.After the total urine collection is completed, the temporary sample can be directly extracted from any level of the original urine within1 hour, and the urine protein concentration of the sample multiplied by the urine volume can reflect the 24 h UTR.