BACKGROUND The correlation between complement activation and severity of hemolytic uremic syndrome related to Shiga toxin-producing Escherichia coli (STEC-HUS) has been examined in few studies, with conflicting results. We investigated whether C3 levels on admission are associated with worse acute outcomes. METHODS Demographic, clinical, and laboratory variables were compared between dialyzed and non-dialyzed patients and between those with or without extrarenal complications. Univariate and multivariate analyses were performed; odds ratio (OR) and 95% confidence interval (95%CI) were calculated. C3 concentrations were correlated with dialysis length (Spearman test) and ROC curves with area under the curves (AUC) were calculated to identify C3 concentrations able to discriminate patients with dialysis requirements and complicated course. RESULTS Among 49 children, 33 had normal and 16 had decreased C3 concentrations. Higher hemoglobin, lactic dehydrogenase, urea and creatinine and lower albumin, sodium, and C3 and C4 concentrations at admission were associated with dialysis requirement; only creatinine remained significant (p = 0.03, OR 2.1, 95%CI 1.34-2.7) by multivariate analysis. Patients with a complicated course presented higher leukocyte count, hemoglobin and lactic dehydrogenase and lower albumin, sodium, and C3 and C4. In the multivariate analysis, leukocyte count (p = 0.02, OR 2.6, 95%CI 1.4-4.3) and C3 concentration (p = 0.039, OR 1.7, 95%CI 1.1-2.73) were independently associated with a complicated disease. C3 levels correlated with dialysis length (r = - 0.42, p = 0.002); nevertheless, they were unable to discriminate dialysis requirement (AUC = 0.25, 95%CI 0.11-0.38) and extrarenal complications (AUC = 0.24, 95%CI 0.11-0.4). CONCLUSIONS Our study suggests that decreased C3 levels at admission are associated with a more complicated STEC-HUS episode.

中文翻译：

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志贺毒素相关的溶血性尿毒症综合征的C3水平和急性预后。

背景技术在少数研究中已经检查了补体激活与与志贺毒素生产大肠杆菌（STEC-HUS）有关的溶血性尿毒症综合征严重程度之间的相关性，但结果却相矛盾。我们调查了入院时C3水平是否与较差的急性预后相关。方法比较了透析患者和非透析患者以及有无肾外并发症的人口统计学，临床和实验室变量。进行单因素和多因素分析；计算比值比（OR）和95％置信区间（95％CI）。将C3浓度与透析时间（Spearman检验）相关联，并计算ROC曲线和曲线下面积（AUC），以识别能够区分透析需求和病程复杂的患者的C3浓度。结果在49名儿童中，有33名正常，而16名C3浓度降低。入院时血红蛋白，乳酸脱氢酶，尿素和肌酐较高，白蛋白，钠以及C3和C4浓度较低与透析需求有关。通过多变量分析，只有肌酐仍然显着（p = 0.03，或2.1，95％CI 1.34-2.7）。病程复杂的患者表现出较高的白细胞计数，血红蛋白和乳酸脱氢酶以及较低的白蛋白，钠以及C3和C4。在多变量分析中，白细胞计数（p = 0.02，OR 2.6，95％CI 1.4-4.3）和C3浓度（p = 0.039，OR 1.7，95％CI 1.1-2.73）与复杂疾病独立相关。C3水平与透析时间有关（r =-0.42，p = 0.002）；但是，他们无法区分透析要求（AUC = 0.25，95％CI 0.11-0。38）和肾外并发症（AUC = 0.24，95％CI 0.11-0.4）。结论我们的研究表明，入院时C3水平降低与STEC-HUS发作更为复杂有关。