title: Prediction of diuretic response to tolvaptan by a simple, readily available spot urine Na/K ratio.
abstract: BACKGROUND
  Tolvaptan is vasopressin type 2 receptor antagonist that inhibits water reabsorption. It is used in combination with standard diuretics to treat ascites unresponsive to standard diuretic therapy or hyponatremia because of liver cirrhosis. This study evaluated the effectiveness and safety of tolvaptan in clinical practice and aimed to determine the factors related to its effectiveness.
  
  
  METHODS
  Tolvaptan was administered to 88 consecutive cirrhotic patients with ascites unresponsive to standard diuretic therapy. An effective treatment response was a ≥2% reduction in body weight on day 7. The association of patient pretreatment characteristics with therapeutic effects was analyzed.
  
  
  RESULTS
  Mean weight reduction on day 7 of tolvaptan therapy was -2.9% ± 3.2%, and treatment was effective in 52% of patients. Multivariate analysis revealed that spot urine Na/K ratio ≥2.5 at baseline was the only factor independently related to therapeutic effect, with an odds ratio of 7.85 (95% confidence interval 2.64-23.40, p = 0.0002). Weight reduction percentage on day 7 was -4.0% ± 2.8% in patients with spot urine Na/K ≥2.5, which was significantly greater than the 0.7% ± 2.7% loss in those with urine Na/K < 2.5 (p < 0.05). A spot urine Na/K ratio ≥2.5 had a sensitivity of 85% and specificity of 60% for predicting effective treatment. No adverse events of treatment led to treatment discontinuation.
  
  
  CONCLUSIONS
  Baseline spot urine Na/K was predictive of an effective response to tolvaptan therapy. It is simple to perform and readily available and might serve as an indicator of optimal timing of tolvaptan administration in patients with inadequate response to conventional Na diuretic therapy.
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.|First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Komiyama
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kurosaki
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakanishi
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Itakura
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yasui
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Nobuharu
authors.initials: N
authors.lastname: Tamaki
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Takada
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Mayu
authors.initials: M
authors.lastname: Higuchi
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Gotou
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Youhei
authors.initials: Y
authors.lastname: Kubota
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Takaura
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Tsuguru
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Wann
authors.initials: W
authors.lastname: Oh
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Mao
authors.initials: M
authors.lastname: Okada
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, Yamanashi, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Enomoto
authors.affiliation: Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
authors.forename: Namiki
authors.initials: N
authors.lastname: Izumi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D065092:Antidiuretic Hormone Receptor Antagonists / Q000627:therapeutic use*; D001201:Ascites / Q000097:blood* / Q000188:drug therapy*; D001552:Benzazepines / Q000627:therapeutic use*; D001835:Body Weight / Q000187:drug effects; D004232:Diuretics / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000188:drug therapy; D008103:Liver Cirrhosis / Q000097:blood / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011188:Potassium / Q000652:urine*; D012964:Sodium / Q000652:urine*; D000077602:Tolvaptan; D016896:Treatment Outcome; D015431:Weight Loss
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines; D004232:Diuretics; D000077602:Tolvaptan; D012964:Sodium; D011188:Potassium