Iwatani Hirotsugu, Kawabata Hiroaki, Sakaguchi Yusuke, Yamamoto Ryohei, Hamano Takayuki, Rakugi Hiromi, Isaka Yoshitaka
Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine, Suita, Japan.
Nephron. 2015;130(1):8-12. doi: 10.1159/000381859. Epub 2015 Apr 30.
BACKGROUND/AIMS: Tolvaptan, a vasopressin V2 receptor antagonist, promotes the excretion of electrolyte-free water. Patients with heart failure or liver cirrhosis, whose urine osmolarity is high due to increased vasopressin, show a good response to tolvaptan; however, it remains dubious whether tolvaptan is also effective in patients with low urine osmolarity due to decreased renal function. The aim of this study was to investigate whether urine osmolarity predicts the effect of tolvaptan in patients with decreased renal function.
In this retrospective, observational study, 17 overhydrated chronic kidney disease patients with heart failure or liver cirrhosis who were admitted to Osaka University Hospital were included. They were treated with sodium-excreting diuretics first, and then tolvaptan was added. The clinically relevant parameters were evaluated before and after the use of tolvaptan, and they, including urine osmolarity before use of tolvaptan, were compared between the responder group and the non-responder group. The definition of responder was based on the decrease of body weight by ≥5% in one week, which is a more rigorous indicator of the effectiveness of tolvaptan than the increase in urine output.
The parameter that showed a significant difference between the responder and non-responder groups was urine osmolarity before the use of tolvaptan. The cut-off point derived from the receiver operating characteristic (ROC) curve analysis was 279 mOsm/kg H2O, with sensitivity of 0.86 and specificity of 0.80.
In patients with decreased renal function, urine osmolarity before the use of tolvaptan predicted the effectiveness of diuretics in terms of body weight reduction.
背景/目的：托伐普坦是一种血管加压素V2受体拮抗剂，可促进无电解质水的排泄。心力衰竭或肝硬化患者因血管加压素增加导致尿渗透压升高，对托伐普坦反应良好；然而，对于肾功能减退导致尿渗透压降低的患者，托伐普坦是否也有效仍存在疑问。本研究的目的是探讨尿渗透压是否可预测托伐普坦对肾功能减退患者的疗效。
在这项回顾性观察研究中，纳入了17例因心力衰竭或肝硬化而水负荷过重的慢性肾脏病患者，这些患者入住大阪大学医院。首先用排钠利尿剂对他们进行治疗，然后加用托伐普坦。在使用托伐普坦前后评估临床相关参数，并在反应者组和无反应者组之间进行比较，包括使用托伐普坦前的尿渗透压。反应者的定义基于一周内体重下降≥5%，这是比尿量增加更严格的托伐普坦有效性指标。
反应者组和无反应者组之间显示出显著差异的参数是使用托伐普坦前的尿渗透压。通过受试者工作特征（ROC）曲线分析得出的截断点为279 mOsm/kg H2O，敏感性为0.86，特异性为0.80。
在肾功能减退的患者中,使用托伐普坦前的尿渗透压可预测利尿剂在减轻体重方面的有效性。
