Department of Internal Medicine, Al-Quds University, Jerusalem, State of Palestine.
Evidence-Based Practice Research Program, Mayo Clinic, Rochester, Minnesota.
Clin J Am Soc Nephrol. 2022 Jun;17(6):785-797. doi: 10.2215/CJN.14561121. Epub 2022 May 11.
AKI is classified as prerenal, intrinsic, and postrenal. Prerenal AKI and intrinsic AKI represent the most common causes for AKI in hospitalized patients. This study aimed to examine the accuracy of the fractional excretion of sodium for distinguishing intrinsic from prerenal AKI.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, the Cochrane Library, and Scopus for all available studies that met the criteria until December 31, 2021. We included studies that evaluated fractional excretion of sodium in differentiating AKI etiologies in adults, whereas studies that did not have sufficient data to extract a 2×2 table were excluded. We assessed the methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and extracted the diagnostic accuracy data for all included studies. We conducted a meta-analysis using the bivariate random effects model. We performed subgroup analysis to investigate sources of heterogeneity and the effect of the relevant confounders on fractional excretion of sodium accuracy.
We included 19 studies with 1287 patients. In a subset of 15 studies (872 patients) that used a threshold of 1%, the pooled sensitivity and specificity for differentiating intrinsic from prerenal AKI were 90% (95% confidence interval, 81% to 95%) and 82% (95% confidence interval, 70% to 90%), respectively. In a subgroup of six studies (511 patients) that included CKD or patients on diuretics, the pooled sensitivity and specificity were 83% (95% confidence interval, 64% to 93%) and 66% (95% confidence interval, 51% to 78%), respectively. In five studies with 238 patients on diuretics, the pooled sensitivity and specificity were 80% (95% confidence interval, 69% to 87%) and 54% (95% confidence interval, 31% to 75%), respectively. In eight studies with 264 oliguric patients with no history of CKD or diuretic therapy, the pooled sensitivity and specificity were 95% (95% confidence interval, 82% to 99%) and 91% (95% confidence interval, 83% to 95%), respectively.
Fractional excretion of sodium has a limited role for AKI differentiation in patients with a history of CKD or those on diuretic therapy. It is most valuable when oliguria is present.
急性肾损伤（AKI）可分为肾前性、肾性和肾后性。肾前性 AKI 和肾性 AKI 是住院患者 AKI 的最常见病因。本研究旨在评估钠排泄分数区分肾前性和肾性 AKI 的准确性。
设计、设置、参与者和测量：我们检索了 MEDLINE、Embase、Cochrane 对照试验中心注册库、Cochrane 图书馆和 Scopus，以获取截至 2021 年 12 月 31 日符合条件的所有可用研究。我们纳入了评估钠排泄分数在成人 AKI 病因鉴别中的研究，而那些没有足够数据提取 2×2 表格的研究则被排除。我们使用诊断准确性研究质量评估工具（QUADAS-2）评估方法学质量，并提取所有纳入研究的诊断准确性数据。我们使用双变量随机效应模型进行荟萃分析。我们进行了亚组分析，以探讨异质性的来源以及相关混杂因素对钠排泄分数准确性的影响。
我们纳入了 19 项研究，共纳入 1287 例患者。在使用 1%阈值的 15 项研究（872 例患者）的亚组中，区分肾前性和肾性 AKI 的汇总敏感性和特异性分别为 90%（95%置信区间，81%至 95%）和 82%（95%置信区间，70%至 90%）。在包括慢性肾脏病（CKD）或利尿剂使用者的 6 项研究（511 例患者）的亚组中，汇总敏感性和特异性分别为 83%（95%置信区间，64%至 93%）和 66%（95%置信区间，51%至 78%）。在 5 项使用利尿剂的 238 例利尿剂患者研究中，汇总敏感性和特异性分别为 80%（95%置信区间，69%至 87%）和 54%（95%置信区间，31%至 75%）。在 8 项无 CKD 或利尿剂治疗史的少尿患者（264 例）研究中，汇总敏感性和特异性分别为 95%（95%置信区间，82%至 99%）和 91%（95%置信区间，83%至 95%）。
在有 CKD 病史或正在使用利尿剂的患者中，钠排泄分数对 AKI 的鉴别作用有限。在出现少尿时，它最有价值。
