Consecutive first-morning urine samples to measure change in the albumin-to-creatinine ratio: a pilot study of a home urine collection protocol.
Consecutive first-morning urine samples to measure change in the albumin-to-creatinine ratio: a pilot study of a home urine collection protocol.
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DOI：
10.1186/s40697-016-0095-8
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发表时间：
2016
影响因子：
1.7
通讯作者：
Weir MA
中科院分区：
文献类型：
--
作者：
Sontrop JM;Garg AX;Li L;Gallo K;Schumann V;Winick-Ng J;Clark WF;Weir MA
建议多个第一次晨尿样本用于测量尿白蛋白与肌酐比值（ACR）;然而，这在社区研究中可能具有挑战性。本研究的目的是对家庭尿液收集方案进行试点测试，并检查ACR的平均值和方差如何随尿液收集次数和实验室分析时间而变化。这是一项前瞻性观察性初步研究。本研究在加拿大安大略省伦敦的伦敦健康科学中心进行（2012-2013年）。患者为患有慢性肾脏疾病的成人（平均估计肾小球滤过率，36 mL/min/1.73 m2）。参与者连续三天收集第一个早晨的20 mL尿液样本。这个过程在3个月后重复。由医院快递员提取样品，并在同一天分析ACR;在延迟24-48小时（在4 ℃下储存）和3-9个月（在-80 ℃下储存）后分析额外的等分试样。计算基线和3个月之间ACR百分比变化的几何平均值，并在单个样本和两个与三个连续样本的平均值之间进行比较。在入组的31例患者中，26例（83.9%）提交了所有6份尿液样本。基线时三个连续样本的ACR几何平均值为87、83和80 mg/mmol，从基线至3个月的相应百分比增加为15%（95%置信区间（CI），−9至46%）、33%（95% CI，10至59%）和22%（95% CI，−6至57%）。与基线和随访时的单次尿液采集相比，两次连续第一次晨尿样本的平均ACR值改善了样本方差，并将检测给定治疗效果所需的样本量减少了约30%。三份尿样的统计学效率没有进一步提高。当实验室分析延迟24-48小时时，结果相似，但延迟3-9个月导致ACR的系统性高估。我们的研究的普遍性是有限的，因为它的样本量小，并依赖于一个单一的城市中心的诊所为基础的人口。我们成功地使用了家庭尿液收集协议，以获得多个第一次晨尿样本的慢性肾脏疾病患者。通过对基线和随访时两个连续的第一次晨尿样本的ACR值取平均值，提高了统计效率。
Multiple first-morning urine samples are recommended for measuring the urine albumin-to-creatinine ratio (ACR); however, this can be challenging in community-based research. The objectives of the study are to pilot-test a home urine collection protocol and examine how the average and variance of ACR varied with the number of urine collections and time to laboratory analysis. This is a prospective observational pilot study. This study was conducted in London, Ontario, Canada at the London Health Sciences Centre (2012–2013). The patients were adults with chronic kidney disease (mean estimated glomerular filtration rate, 36 mL/min/1.73 m2). Participants collected a first-morning 20-mL urine sample on three consecutive days. This process was repeated after 3 months. Samples were picked up by hospital courier and analyzed for ACR on the same day; additional aliquots were analyzed after a delay of 24–48 h (stored at 4 °C) and 3–9 months (stored at –80 °C). The geometric mean of the percentage change in ACR between baseline and 3 months was calculated and compared between single samples and the average of two vs. three consecutive samples. Of 31 patients enrolled, 26 (83.9 %) submitted all six urine samples. The geometric mean of ACR for three consecutive samples at baseline was 87, 83, and 80 mg/mmol, and the corresponding percentage increase from baseline to 3 months was 15 % (95 % confidence interval (CI), −9 to 46 %), 33 % (95 % CI, 10 to 59 %), and 22 % (95 % CI, −6 to 57 %). Compared with single urine collections at baseline and follow-up, averaging ACR values from two consecutive first-morning urine samples improved the sample variance and reduced the required sample size to detect a given treatment effect by approximately 30 %. No further gain in statistical efficiency was achieved with three urine samples. Results were similar when the laboratory analysis was delayed by 24–48 h, but a delay of 3–9 months resulted in systematic overestimation of the ACR. Our study’s generalizability is limited by its small sample size and reliance on a clinic-based population from a single urban center. We successfully used a home urine collection protocol to obtain multiple first-morning urine samples in patients with chronic kidney disease. Statistical efficiency was improved by averaging ACR values from two consecutive first-morning urine samples at baseline and follow-up.