Department of Internal Medicine, Keimyung University School of Medicine, Daegu, South Korea.
Department of Internal Medicine, Bokwang Hospital, Daegu, South Korea.
PLoS One. 2021 Jun 24;16(6):e0253886. doi: 10.1371/journal.pone.0253886. eCollection 2021.
The low-salt diet is considered important for control of ascites in cirrhotic patients. To validate whether the spot urine sodium (Na)/potassium (K) ratio could replace 24-h urine Na (uNa) excretion in assessing low-salt diet compliance.
We prospectively studied 175 patients. 24-h urine collection and spot urine collection were performed. Subsequently, 24-h uNa, urine creatinine (uCr), and spot urine Na and K were assessed. A complete urine collection was confirmed based on 24-h uCr excretion levels of 15mg/kg/day for men and 10mg/kg/day for women. The area under the receiver operating characteristic (AUROC) curve analysis was performed to evaluate the feasibility of spot urine Na/K ratio in predicting 24-h uNa greater than 78mmol/day.
Out of 175 patients, 24-h urine samples were completely collected in 57 patients only. Moreover, urine samples were not completely collected in 118 patients because their 24-h uCr excretion level was less than the established criteria. In complete urine collection group, AUROC curve for spot urine Na/K ratio in predicting 24-h uNa greater than 78mmol/day was 0.874±0.051 (P<0.001). In the incomplete urine collection group, the AUROC was 0.832±0.039 (P<0.001). In complete urine collection group, the classical cutoff value greater than 1.0 of spot urine Na/K ratio showed 90.9% sensitivity and 56.0% specificity.
The spot urine Na/K ratio reflects 24-h uNa, but the AUROC value obtained in this study is lower than that of a previous study. Considered the large number of patients with incomplete urine collection, validating 24-h complete urine collection criteria is necessary.
低盐饮食被认为对控制肝硬化患者腹水很重要。为了验证即时尿钠（Na）/钾（K）比值是否可以代替 24 小时尿钠（uNa）排泄来评估低盐饮食的依从性。
我们前瞻性地研究了 175 例患者。进行 24 小时尿收集和即时尿收集。随后，评估 24 小时 uNa、尿肌酐（uCr）和即时尿 Na 和 K。根据男性 15mg/kg/天和女性 10mg/kg/天的 24 小时 uCr 排泄水平，确认完全尿收集。进行受试者工作特征（ROC）曲线下面积（AUROC）分析，以评估即时尿 Na/K 比值预测 24 小时 uNa 大于 78mmol/天的可行性。
在 175 例患者中，仅 57 例患者完全收集了 24 小时尿样。此外，118 例患者由于 24 小时 uCr 排泄水平低于既定标准，未完全收集尿样。在完全尿收集组中，即时尿 Na/K 比值预测 24 小时 uNa 大于 78mmol/天的 AUROC 曲线为 0.874±0.051（P<0.001）。在不完全尿收集组中，AUROC 为 0.832±0.039（P<0.001）。在完全尿收集组中，即时尿 Na/K 比值大于 1.0 的经典截断值显示出 90.9%的敏感性和 56.0%的特异性。
即时尿 Na/K 比值反映 24 小时 uNa，但本研究获得的 AUROC 值低于先前的研究。考虑到大量患者未完全收集尿液，有必要验证 24 小时完整尿液收集标准。
