Leong Amanda, Ekinci Elif Ilhan, Nguyen Cattram, Milne Michele, Hachem Mariam, Dobson Matthew, MacIsaac Richard J, Jerums George
Austin Health Endocrine Centre, Heidelberg Repatriation Hospital, PO BOX 5444, Melbourne, Victoria, 3081, Australia.
Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia.
BMC Nephrol. 2017 Dec 6;18(1):355. doi: 10.1186/s12882-017-0767-3.
Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease in the Western world. Early and accurate identification of DKD offers the best chance of slowing the progression of kidney disease. An important method for evaluating risk of progressive DKD is abnormal albumin excretion rate (AER). Due to the high variability in AER, most guidelines recommend the use of more than or equal to two out of three AER measurements within a 3- to 6-month period to categorise AER. There are recognised limitations of using AER as a marker of DKD because one quarter of patients with type 2 diabetes may develop kidney disease without an increase in albuminuria and spontaneous regression of albuminuria occurs frequently. Nevertheless, it is important to investigate the long-term intra-individual variability of AER in participants with type 2 diabetes.
Consecutive AER measurements (median 19 per subject) were performed in 497 participants with type 2 diabetes from 1999 to 2012 (mean follow-up 7.9 ± 3 years). Baseline clinical characteristics were collected to determine associations with AER variability. Participants were categorised as having normo-, micro- or macroalbuminuria according to their initial three AER measurements. Participants were then categorised into four patterns of AER trajectories: persistent, intermittent, progressing and regressing. Coefficients of variation were used to measure intra-individual AER variability.
The median coefficient of variation of AER was 53.3%, 76.0% and 67.0% for subjects with normo-, micro- or macroalbuminuria at baseline. The coefficient of variation of AER was 37.7%, 66% and 94.8% for subjects with persistent, intermittent and progressing normoalbuminuria; 43%, 70.6%, 86.1% and 82.3% for subjects with persistent, intermittent, progressing and regressing microalbuminuria; and 55.2%, 67% and 82.4% for subjects with persistent, intermittent and regressing macroalbuminuria, respectively.
High long-term variability of AER suggests that two out of three AER measurements may not always be adequate for the optimal categorisation and prediction of AER.
糖尿病肾病（DKD）是西方世界终末期肾病的主要病因。早期准确识别DKD为减缓肾病进展提供了最佳机会。评估DKD进展风险的一种重要方法是异常白蛋白排泄率（AER）。由于AER变异性高，大多数指南建议在3至6个月内使用三次AER测量中的至少两次来对AER进行分类。将AER用作DKD标志物存在公认的局限性，因为四分之一的2型糖尿病患者可能在无蛋白尿增加的情况下发生肾病，且蛋白尿的自发缓解经常发生。然而，研究2型糖尿病参与者中AER的长期个体内变异性很重要。
1999年至2012年对497名2型糖尿病参与者进行了连续的AER测量（每位受试者中位数为19次）（平均随访7.9±3年）。收集基线临床特征以确定与AER变异性的关联。根据最初的三次AER测量，将参与者分类为正常白蛋白尿、微量白蛋白尿或大量白蛋白尿。然后将参与者分为四种AER轨迹模式：持续、间歇、进展和消退。变异系数用于测量个体内AER变异性。
基线时正常白蛋白尿、微量白蛋白尿或大量白蛋白尿受试者的AER变异系数中位数分别为53.3%、76.0%和67.0%。持续、间歇和进展性正常白蛋白尿受试者的AER变异系数分别为37.7%、66%和94.8%；持续性、间歇性、进展性和消退性微量白蛋白尿受试者的AER变异系数分别为43%、70.6%、86.1%和82.3%；持续性、间歇性和消退性大量白蛋白尿受试者的AER变异系数分别为55.2%、67%和82.4%。
AER的高长期变异性表明，三次AER测量中的两次可能并不总是足以对AER进行最佳分类和预测。
