Supplementary Material for: Remote Ischemic Preconditioning Reduces the Risk of Contrast-Induced Nephropathy in Patients with Moderate Renal Impairment Undergoing Percutaneous Coronary Angiography: A Meta-Analysis

Background/Aims: This meta-analysis evaluated the effects of remote ischemic preconditioning (RIPC) on the risk of contrast-induced nephropathy (CIN) in patients undergoing percutaneous coronary intervention/coronary angiography (PCI/CA). Methods: PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases were searched for randomized controlled trials (RCTs) that assessed the effect of RIPC on CIN in patients undergoing PCI/CA. The main outcomes of interest were the incidence of CIN 48–72 h after CA, the levels of serum creatinine, cystatin C, neutrophil gelatinase-associated lipocalin, and estimated glomerular filtration rate (eGFR), mortality, and requirement of hemodialysis and rehospitalization. The analysis was conducted using the random-effect model due to the expected heterogeneity among different studies. Results: In total, 16 trials covering 2,048 patients were identified. By assessing the methodological quality of the included studies through the Cochrane risk of bias, we found that of the 16 RCTs, 3 had a low risk of bias, 6 a high, and 7 an unclear risk. The application of RIPC decreased the incidence of CIN (relative risk, RR, 0.50, 95% confidence interval, CI, 0.39–0.65; p < 0.001). Subgroup analyses showed that RIPC decreased the incidence of CIN in patients with eGFR <60 mL/min/1.73 m2 (RR 0.53, 95% CI 0.38–0.75; p < 0.001) but not in patients with eGRF ≥60 mL/min/1.73 m2 (RR 0.82, 95% CI 0.35–1.94; p = 0.66) at baseline. Furthermore, the increase in serum creatinine was significantly lower in patients with RIPC compared to control patients (standardized mean difference –1.41, 95% CI –2.46 to –0.35; p = 0.009). Conclusions: Based on 16 RCTs, this meta-analysis shows that RIPC can reduce the risk of CIN in patients with moderate renal impairment undergoing PCI/CA. However, this needs to be confirmed by further high-quality evidence.背景/目的：本荟萃分析评估了远程缺血预处理(remote ischemic preconditioning, RIPC)对接受经皮冠状动脉介入治疗/冠状动脉造影术(percutaneous coronary intervention/coronary angiography, PCI/CA)患者发生造影剂肾病(contrast-induced nephropathy, CIN)的风险影响。方法：检索PubMed、Embase及Cochrane对照试验中央注册库数据库，筛选评估RIPC对接受PCI/CA患者CIN影响的随机对照试验(randomized controlled trials, RCTs)。本研究关注的主要结局指标包括：造影术后48~72小时CIN发生率、血清肌酐水平、胱抑素C、中性粒细胞明胶酶相关脂质运载蛋白、估算肾小球滤过率(estimated glomerular filtration rate, eGFR)、死亡率以及血液透析需求与再住院率。由于纳入研究间存在预期异质性，本分析采用随机效应模型(random-effect model)进行统计分析。结果：共纳入16项试验，涉及2048例患者。通过Cochrane偏倚风险工具评估纳入研究的方法学质量，结果显示16项RCT中，3项偏倚风险较低，6项偏倚风险较高，7项偏倚风险尚不明确。应用RIPC可降低CIN发生率（相对危险度(relative risk, RR)=0.50，95%置信区间(confidence interval, CI)=0.39~0.65；p<0.001）。亚组分析显示，在基线估算肾小球滤过率(eGFR)<60 mL/min/1.73m²的患者中，RIPC可降低CIN发生率（RR=0.53，95%CI=0.38~0.75；p<0.001）；但在基线eGFR≥60 mL/min/1.73m²的患者中未观察到显著获益（RR=0.82，95%CI=0.35~1.94；p=0.66）。此外，与对照组相比，RIPC组患者的血清肌酐升高幅度显著更低（标准化均数差(standardized mean difference)=-1.41，95%CI=-2.46~-0.35；p=0.009）。结论：基于16项随机对照试验，本荟萃分析结果表明，远程缺血预处理(RIPC)可降低接受PCI/CA的中度肾功能损害患者的CIN风险，但该结论仍需进一步高质量研究证据予以验证。