Evidence map›Paper›PMID 42544815›Full record

Trial reportClinical endocrinology2026

Serum Copeptin Rises After Tolvaptan for Hyponatraemia, but Does Not Predict Risk of Rapid Sodium Rise: Pre-Specified Secondary Analysis of the TVFR Trial.

Annabelle M Warren, Kay Weng Choy, Rudolf Hoermann, Nicholas Russell, Mathis Grossmann

Abstract readRandomized Controlled Trial
In one paragraph

Trial report in Clinical endocrinology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

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5 · Who and what money

Authors and funding

5 authors.

Annabelle M WarrenDepartment of Endocrinology, Austin Health, Heidelberg, Victoria, Australia.ORCID https://orcid.org/0000-0002-7287-6162
Kay Weng ChoyNorthern Pathology Victoria, Northern Health, Epping, Victoria, Australia.
Rudolf HoermannDepartment of Medicine, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia.
Nicholas RussellDepartment of Endocrinology, Austin Health, Heidelberg, Victoria, Australia.
Mathis GrossmannDepartment of Endocrinology, Austin Health, Heidelberg, Victoria, Australia.ORCID https://orcid.org/0000-0001-8261-3457

Funding

Endocrine Society of AustraliaNational Health and Medical Research Council APP2005300Otsuka Pharmaceutical IIT 156-419-00250
6 · The paper itself

Abstract

objectiveHyponatraemia is a common electrolyte disorder often driven by excess arginine vasopressin (AVP). Copeptin is a stable surrogate marker co-secreted with AVP. It is unclear whether treatment of hyponatraemia with tolvaptan, an AVP-V2 receptor antagonist, impacts copeptin. We aimed to assess the effects of tolvaptan on serum copeptin, compared to fluid restriction.

designPre-specified secondary analysis of an open-label randomised trial comparing tolvaptan or fluid restriction for 3 days. PATIENTS: Hospitalised patients with plasma sodium (pNa) 115-130 mmol/L at a single-centre tertiary hospital in Melbourne, Australia. MEASUREMENTS: Copeptin measured at baseline and completion (Day 4, or discharge if sooner).

resultsCopeptin results were available in 45/54 participants, randomised to tolvaptan (n = 25) or FR (n = 20). Mean baseline copeptin was 10.4 pmol/L. pNa increased in both groups, significantly more with tolvaptan as previously reported. Copeptin remained stable after FR, but significantly increased after tolvaptan (mean adjusted difference between groups over 3 days 8.4 pmol/L, 95% CI 2.1-14.6, p = 0.01). Baseline copeptin did not predict rapid sodium rise. The rise in copeptin after tolvaptan may represent an exaggerated response to osmolality rise in these patients ('reset osmostat'), or feedback mechanisms from AVP blockade.

conclusionTolvaptan increased serum copeptin compared to fluid restriction. Further research is required to determine if there is clinical utility for measuring copeptin in hyponatraemia before it is adopted into practice.

trial registrationACTRN12619001683123.

Indexed as

Antidiuretic Hormone Receptor AntagonistsGlycopeptidesHyponatremiaSodiumTolvaptanAgedArginine VasopressinBenzazepinesFemaleHumansMaleMiddle AgedAntidiuretic Hormone Receptor AntagonistsArginine VasopressinBenzazepinescopeptinsGlycopeptidesSodiumTolvaptanarginine vasopressin (AVP)copeptinhyponatremia (hyponatraemia)syndrome of inappropriate antidiuresis (SIAD, SIADH)tolvaptan

Identifiers

PMID42544815
PMCPMC13532165

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.