Protein Supplementation in Hyponatremia Due to the Syndrome of Inappropriate Antidiuresis

NCT ID: NCT06821802

Last Updated: 2025-07-10

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 70 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-04-14
• Study Completion Date: 2027-04-30

Brief Summary

The goal of this study is to assess the impact of protein supplementation on hyponatremia caused by the syndrome of inappropriate antidiuresis during hospitalization.

Detailed Description

Hyponatremia (plasma sodium <135 mmol/L) is the most common electrolyte disorder, affecting up to 30% of hospitalized patients. Chronic hyponatremia (>48 hours) is linked to longer hospital stays, higher costs, increased mortality, and morbidity (e.g., falls, fractures, cognitive deficits). The most common cause of euvolemic hyponatremia is syndrome of inappropriate antidiuresis (SIAD), characterized by excessive water retention due to dysregulated vasopressin activity. Treatment options include fluid restriction or increasing water excretion with AVP antagonists, SGLT2 inhibitors, or oral urea.

A recent trial showed that protein supplementation can induce osmotic diuresis and raise sodium levels similarly to oral urea, with better tolerability. Since protein supplementation is often used in hospitalized patients with malnutrition, this study aims to compare its acceptability to fluid restriction in hospitalized SIAD patients. This head-to-head superiority trial will randomize patients to receive either 80 g of dietary protein daily or fluid restriction (1000 mL/day) for up to 5 days. The hypothesis is that protein supplementation is significantly more acceptable to patients than fluid restriction, ultimately improving treatment outcomes.

Conditions

Hyponatremia; Syndrome of Inappropriate Antidiuresis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Protein Supplementation

80 g protein supplementation per day (two bottles, each containing 40 g protein)

Group Type: EXPERIMENTAL

Moltein PURE Protein Powder

Intervention Type: DIETARY_SUPPLEMENT

80 g protein supplementation per day (two bottles, each containing 40 g protein)

Fluid restriction

total daily fluid intake to a maximum of 1000 ml

Group Type: ACTIVE_COMPARATOR

Fluid restriction

Intervention Type: BEHAVIORAL

total daily fluid intake to a maximum of 1000 ml

Interventions

Moltein PURE Protein Powder

80 g protein supplementation per day (two bottles, each containing 40 g protein)

Intervention Type: DIETARY_SUPPLEMENT

Fluid restriction

total daily fluid intake to a maximum of 1000 ml

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Adult patients with confirmed SIAD during the hospital stay or at screening, defined by:
• Plasma sodium concentration <135 mmol/L
• Plasma osmolality <300 mOsm/kg
• Urine osmolality >100 mOsm/kg
• Urine sodium concentration >30 mmol/L
• Clinical euvolemia (no signs of hypovolemia or hypervolemia)

Exclusion Criteria

• Lactose intolerance, milk protein allergy, soy allergy, nuts allergy, or hypersensitivity to components of the protein supplement.
• Inborn metabolic disorders affecting carbohydrate, lipid, or protein metabolism.
• Severe symptomatic hyponatremia requiring 3% NaCl or intensive care.
• New (within the last five days) treatment with SGLT2 inhibitors, vaptans or oral urea
• Uncontrolled severe hypothyroidism (untreated)
• Uncontrolled adrenal insufficiency (morning cortisol <150nmol/l)
• eGFR <45 mL/min/1.73 m² (KDIGO G3b-5) or end-stage renal disease (dialysis)
• Severe hepatic impairment or advanced symptomatic liver disease defined as past or current hepatic encephalopathy, liver cirrhosis Child C, or decompensated (bleeding, jaundice, hepatorenal syndrome)
• Pregnancy, breastfeeding, or plans to become pregnant during the study.
• End-of-life care
• Lack of capacity or other reasons preventing from giving informed consent or following study procedures (e.g., due to language problems, psychological disorders, dementia, etc.)
• Treatment with thiazid diuretic (must be stopped at least 48 hours before inclusion)

• Type 1 diabetes or uncontrolled type 2 diabetes (HbA1c >8.0%)

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University Hospital, Basel, Switzerland

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Mirjam Christ-Crain, Prof. MD

Role: PRINCIPAL_INVESTIGATOR

Universitätsspital Basel

Locations

University Hospital Basel

Basel, , Switzerland

Site Status: RECRUITING

Countries

Switzerland

Central Contacts

Mirjam Christ-Crain, Prof. MD

Role: CONTACT

mirjam.christ-crain@usb.ch

+41 61 328 70 80

Cemile Bathelt

Role: CONTACT

cemile.bathelt@usb.ch

+41 61 556 54 07

Facility Contacts

Mirjam Christ-Crain

Role: primary

mirjam.christ-crain@usb.ch

+41 61 328 70 80

Other Identifiers

2024-02282; kt25ChristCrain2

Identifier Type: -

Identifier Source: org_study_id