Background

This study aimed to test the hypothesis that reduced urinary excretions of neutrophil gelatinase-associated lipocalin (NGAL) predispose children to recurrence of febrile urinary tract infection (fUTI).

Methods

Subjects were 38 children diagnosed with fUTI. To examine risk factors for recurrence of fUTI, the subjects were divided into a non-recurrent group and a recurrent group according to the presence or absence of fUTI over 3 years since the first episode. We measured the urinary NGAL levels in patients with fUTI at the non-infected stage in addition to age-matched healthy control children.

Results

In a multiple logistic regression analysis, significant differences between the groups were not observed for age, sex, the prevalence of kidney scarring and bladder bowel dysfunction, urinary β2-microglobulin/creatinine (Cr) level, and serum levels of Cr and Cystatin C, while the recurrent group had significantly more cases with grade III or higher vesicoureteral reflux (p < 0.01). Furthermore, the urinary NGAL/Cr in the recurrent group (median, 3.60 μg/gCr) was significantly lower than that in the non-recurrent group (median, 16.47 μg/gCr; p < 0.01), and age-matched healthy control children (median, 14.14 μg/gCr; p < 0.05). The area under the receiver operating characteristic curve of NGAL/Cr was 0.86 for predicting recurrence of fUTI. A cut-off value of 11.59 μg/gCr had the best accuracy to predict recurrent fUTI yielding a specificity of 78% and a sensitivity of 93%.

Conclusions

Reduced levels of urinary NGAL, which protects against urinary infection, are a risk factor for recurrence of fUTI and could serve as a biomarker.

中文翻译：

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中性粒细胞明胶酶相关脂质运载蛋白的尿排泄减少是儿童发热性尿路感染复发的危险因素

背景

本研究旨在验证中性粒细胞明胶酶相关脂质运载蛋白 (NGAL) 尿排泄减少使儿童易患发热性尿路感染 (fUTI) 复发的假设。

方法

受试者是 38 名被诊断患有 fUTI 的儿童。为了检查 fUTI 复发的危险因素，根据自第一次发作后 3 年内是否存在 fUTI，将受试者分为非复发组和复发组。除了年龄匹配的健康对照儿童外，我们还测量了非感染期 fUTI 患者的尿 NGAL 水平。

结果

在多元逻辑回归分析中，在年龄、性别、肾脏瘢痕形成和膀胱肠功能障碍的发生率、尿 β2-微球蛋白/肌酐 (Cr) 水平以及血清 Cr 和 Cystatin C 水平方面未观察到组间的显着差异，而复发组出现Ⅲ级及以上膀胱输尿管反流的病例明显增多（p < 0.01）。此外，复发组的尿 NGAL/Cr（中位数，3.60 μg/gCr）显着低于非复发组（中位数，16.47 μg/gCr；p < 0.01）和年龄匹配的健康对照儿童（中位数，14.14 μg/gCr；p< 0.05)。预测 fUTI 复发的 NGAL/Cr 受试者工作特征曲线下面积为 0.86。11.59 μg/gCr 的临界值预测复发性 fUTI 的准确度最高，特异性为 78%，敏感性为 93%。

结论

尿 NGAL 水平降低，可防止尿路感染，是 fUTI 复发的危险因素，可作为生物标志物。