Supplementary Material for: Early Renal Ultrasound in Congenital Solitary Kidney May Help to Select Patients at Lower Risk of Associated Vesicoureteral Reflux

<b><i>Background:</i></b> Vesicoureteral reflux (VUR) may be associated with renal dysplasia and reduced renal length (RL). The diagnosis of VUR in children with congenital solitary functioning kidney (CSFK) identifies patients at risk of kidney injury but exposes to invasive procedures. <b><i>Objective:</i></b> We aimed to test the hypothesis that an RL &gt;2 standard deviation score (SDS) in the first months of life – reflecting renal hyperplasia – could identify CSFK patients with lower probability of presenting VUR. <b><i>Method:</i></b> We retrospectively selected 207 CSFK patients with prenatal diagnosis of CSFK and having undergone renal ultrasound (RUS) both at 0–3 and 10–13 months of life, renal scintigraphy, and cystourethrography/cysto­scintigraphy. We compared the cumulative proportion of an RL &gt;2 SDS by Kaplan-Meier analysis and evaluated the odds to present VUR of patients with an RL &gt;2 SDS both at the first and second RUS. <b><i>Results:</i></b> Overall, 3.3% of patients with VUR and 22.0% of patients without VUR presented an RL &gt;2 SDS at the first RUS (<i>p</i> = 0.02). At the second RUS, 53.3% of patients with VUR and 52.5% of patients without VUR presented an RL &gt;2 SDS (<i>p</i> = 0.93). Patients without VUR presented higher cumulative proportion of an RL &gt;2 SDS at 3 months of life than those with VUR (<i>p</i> = 0.02). This difference however disappeared at 11 and 13 months of age (<i>p</i> = 0.17 and <i>p</i> = 0.54, respectively). An RL &gt;2 SDS within 3 months of life presented an OR for VUR of 0.12 (95% CI: 0.02–0.92; <i>p</i> = 0.005), while an RL &gt;2 SDS at 12 months of life presented an OR for VUR of 0.96 (95% CI: 0.45–2.1; <i>p</i> = 0.93). <b><i>Conclusion:</i></b> Only an RUS made in the first months of life could identify CSFK patients at lower risk of presenting an associated VUR.

<b><i>背景：</i></b> 膀胱输尿管反流（Vesicoureteral Reflux, VUR）可伴发肾发育不良及肾长度（renal length, RL）缩短。针对先天性孤立功能肾（congenital solitary functioning kidney, CSFK）患儿，确诊VUR可识别存在肾损伤风险的患者，但同时也会使其面临侵入性操作暴露风险。<b><i>目的：</i></b> 本研究旨在验证下述假说：出生最初数月内肾长度超出2倍标准差评分（standard deviation score, SDS）——这一指标可反映肾脏增生情况——可识别出VUR发生概率更低的CSFK患者。<b><i>方法：</i></b> 本研究回顾性纳入207例经产前诊断为CSFK的患者，所有受试者均在出生后0~3月龄及10~13月龄分别接受肾脏超声（renal ultrasound, RUS）检查、肾闪烁显像检查，以及膀胱尿道造影/膀胱闪烁造影检查。我们通过Kaplan-Meier分析比较了肾长度超出2倍SDS的累积比例，并评估了在首次及第二次肾脏超声检查中肾长度超出2倍SDS的患者发生VUR的比值比。<b><i>结果：</i></b> 整体而言，首次肾脏超声检查中，VUR患者中3.3%存在肾长度超出2倍SDS的情况，无VUR患者中该比例为22.0%（<i>p</i> = 0.02）。第二次肾脏超声检查中，VUR患者与无VUR患者中肾长度超出2倍SDS的比例分别为53.3%与52.5%（<i>p</i> = 0.93）。出生3月龄时，无VUR患者的肾长度超出2倍SDS的累积比例显著高于VUR患者（<i>p</i> = 0.02）；但该差异在11月龄及13月龄时消失（分别为<i>p</i> = 0.17与<i>p</i> = 0.54）。出生3个月内肾长度超出2倍SDS的患者发生VUR的比值比为0.12（95%置信区间：0.02~0.92；<i>p</i> = 0.005），而12月龄时肾长度超出2倍SDS的患者发生VUR的比值比为0.96（95%置信区间：0.45~2.1；<i>p</i> = 0.93）。<b><i>结论：</i></b> 仅出生最初数月内完成的肾脏超声检查，可识别出VUR相关发病风险更低的CSFK患者。