Data_Sheet_2_Postoperative day 1 serum cystatin C level predicts postoperative delayed graft function after kidney transplantation.xlsx

BackgroundDelayed graft function (DGF) commonly occurs after kidney transplantation, but no clinical predictors for guiding post-transplant management are available.
Materials and methodsData including demographics, surgery, anesthesia, postoperative day 1 serum cystatin C (S-CysC) level, kidney functions, and postoperative complications in 603 kidney transplant recipients who met the enrollment criteria from January 2017 to December 2018 were collected and analyzed to form the Intention-To-Treat (ITT) set. All perioperative data were screened using the least absolute shrinkage and selection operator. The discrimination, calibration, and clinical effectiveness of the predictor were verified with area under curve (AUC), calibration plot, clinical decision curve, and impact curve. The predictor was trained in Per-Protocol set, validated in the ITT set, and its stability was further tested in the bootstrap resample data.
ResultPatients with DGF had significantly higher postoperative day 1 S-CysC level (4.2 ± 1.2 vs. 2.8 ± 0.9 mg/L; P < 0.001), serum creatinine level (821.1 ± 301.7 vs. 554.3 ± 223.2 μmol/L; P < 0.001) and dialysis postoperative (74 [82.2%] vs. 25 [5.9%]; P < 0.001) compared with patients without DGF. Among 41 potential predictors, S-CysC was the most effective in the parsimonious model, and its diagnostic cut-off value was 3.80 mg/L with the risk score (OR, 13.45; 95% CI, 8.02–22.57; P < 0.001). Its specificity and sensitivity indicated by AUC was 0.832 (95% CI, 0.779–0.884; P < 0.001) with well fit calibration. S-CysC yielded up to 50% of clinical benefit rate with 1:4 of cost/benefit ratio.
ConclusionThe postoperative day 1 S-CysC level predicts DGF and may be used as a predictor of DGF but warrants further study.

移植物功能延迟恢复（Delayed graft function, DGF）是肾移植术后常见并发症，但目前尚无可用的临床预测指标指导移植后管理。
材料与方法 收集2017年1月至2018年12月期间符合入组标准的603例肾移植受者的人口统计学资料、手术情况、麻醉情况、术后第1天血清胱抑素C（serum cystatin C, S-CysC）水平、肾功能及术后并发症等数据，经整理分析后形成意向性治疗（Intention-To-Treat, ITT）数据集。采用最小绝对收缩和选择算子（least absolute shrinkage and selection operator）对所有围手术期数据进行筛选。通过受试者工作特征曲线下面积（area under curve, AUC）、校准曲线、临床决策曲线以及影响曲线，验证该预测模型的区分度、校准度与临床有效性。本预测模型在符合方案集（Per-Protocol set）中训练，在ITT数据集中验证，并通过bootstrap重采样数据进一步检验其稳定性。
结果 与无DGF患者相比，DGF患者术后第1天S-CysC水平（4.2±1.2 vs 2.8±0.9 mg/L；P<0.001）、血清肌酐水平（821.1±301.7 vs 554.3±223.2 μmol/L；P<0.001）及术后透析比例（74例[82.2%] vs 25例[5.9%]；P<0.001）均显著升高。在41个潜在预测因子中，S-CysC是精简模型中效能最优的指标，其诊断截断值为3.80 mg/L，对应的比值比（odds ratio, OR）为13.45，95%置信区间（confidence interval, CI）为8.02~22.57（P<0.001）。该指标的AUC为0.832，95%置信区间为0.779~0.884（P<0.001），特异性与敏感度表现良好，且校准度拟合佳。S-CysC可带来最高达50%的临床获益率，对应成本效益比为1:4。
结论 术后第1天S-CysC水平可预测DGF，有望成为DGF的预测指标，但仍需开展进一步研究加以验证。