HyponatremiaTREASURE-PITNCT07273630
Effect of Protein Supplementation and Fluid Restriction on Plasma Sodium Levels in Patients Undergoing Pituitary Surgery
A study testing Fluid restriction, Dietary protein supplementation and Standard post-operative care in people with Hyponatremia and Pituitary Surgery, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
Trial summary
The investigators are conducting this study to investigate new preventive measures for patients with low sodium levels (hyponatremia), which can occur after surgery on the pituitary gland. This hyponatremia is often caused by the syndrome of inappropriate antidiuresis (SIAD). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Hyponatremia, Pituitary Surgery
- What is being tested?
- Fluid restriction, Dietary protein supplementation and Standard post-operative care
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 282 participants
- Where
- 1 siteSwitzerland
- Study dates
- 20 Jan 2026to 1 Oct 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adult patients (aged 18 or older) undergoing trans-sphenoidal or trans-cranial surgery for sellar / suprasellar pathology
- No pre-existing AVP-deficiency and SIAD or other causes of hyponatremia
Who cannot join
- AVP deficiency diagnosed before surgery based on established criteria
- Other type of neurosurgery / intracranial pathology / pre-existing spontaneous CSF -rhinorrhea
- Traumatic brain injury or intracranial hemorrhage
- Systemic infection or other causes for systemic stress
- Lactose intolerance, milk protein allergy, soy allergy, nuts allergy or known hypersensitivity or allergy to one of the components of the protein supplementation
- Inborn metabolic disorders implying carbohydrate, lipid, or protein metabolism
Show all 12Show fewer
- Severe hepatic impairment (ALAT/ASAT >3x upper limit) or advanced symptomatic liver disease defined as past or current hepatic encephalopathy, liver cirrhosis Child C, or decompensated (bleeding, jaundice, hepatorenal syndrome)
- Reduction of eGFR <45 mL/min/1.73m² (KDIGO G3b, G4 and G5) or end stage renal disease (dialysis)
- Recently initiated (within the last 5 days) SGLT2 inhibitors, vaptans, or oral urea therapy
- Pregnancy or breastfeeding
- Lack of capacity or other reason preventing from giving informed consent or following study procedures.
- Post-Inclusion Exclusion criteria (day 3 post-surgery, i.e.,time of randomization): - AVP deficiency diagnosed on post-operative day 3
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Michelle Mueller contact
Switzerland1 site, 1 recruiting
- Recruiting
University Hospital Basel
Basel, 4031
Michelle Muelle, +41 61 32 85523, michelle.mueller@usb.ch
About this study
Official title: Effect of Protein Supplementation and Fluid Restriction on Plasma Sodium Levels in Patients Undergoing Pituitary Surgery - a Randomized Open-label Active-controlled Trial -
The investigators are conducting this study to investigate new preventive measures for patients with low sodium levels (hyponatremia), which can occur after surgery on the pituitary gland. This hyponatremia is often caused by the syndrome of inappropriate antidiuresis (SIAD). SIAD occurs when the pituitary gland secretes too much antidiuretic hormone. The antidiuretic hormone causes the kidneys to absorb more water. This dilutes the sodium in the blood and leads to hyponatremia. Low sodium levels are particularly common after pituitary surgery, as the procedure on the pituitary gland can lead to increased reactive secretion of antidiuretic hormone. At present, apart from educating patients about the symptoms of hyponatremia, there are no established standard measures for prevention after pituitary surgery. If hyponatremia is present, it is currently treated primarily by fluid restriction, which is not always pleasant or easy to adhere to. With this study, the investigators want to investigate whether protein supplementation or fluid restriction between day 4 and day 9 after surgery can serve as a preventive measure to stabilize sodium levels after pituitary surgery and improve the quality of life of patients.
Read the detailed description
Disturbances in water balance, often due to disturbed arginine vasopressin (AVP) secretion from pituitary stalk and/or posterior lobe damage/manipulation, are common complications following pituitary surgery. This can result in either AVP deficiency, causing polyuria and polydipsia, or AVP excess, leading to water retention and dilutional hyponatremia (syndrome of inappropriate antidiuresis, SIAD). SIAD affects up to 30% of patients, typically developing between days 4 and 14 post-surgery, with a peak around day 7. While usually mild, severe hyponatremia is a leading cause of hospital readmission. Management includes fluid restriction, oral urea, or, in severe cases, hypertonic saline and AVP receptor antagonists.
Non-medicinal preventive strategies, such as prophylactic fluid restriction, have demonstrated efficacy in reducing SIAD incidence and hospital readmissions, but the optimal protocol remains unestablished. Dietary protein supplementation has recently emerged as a potential novel intervention, leveraging osmotic diuresis from increased endogenous urea production derived from the physiological amino-acid metabolism to raise plasma sodium levels. However, no data in the postoperative setting are available
This study aims to compare protein supplementation and fluid restriction to standard care (no specific intervention) in preventing post-pituitary surgery hyponatremia. From days 4 to 9 post-surgery, participants will receive one of the three treatments: Treatment A: Patients will limit their total daily fluid intake to a maximum of 1000 ml Treatment B: Patients will consume an additional 80 grams of protein daily through two 150 ml protein drinks (40 grams of protein each, MOLTEIN PURE Drink, OMANDA) in various flavors. Treatment C: Patients will not receive specific instructions. They will follow standard post-operative care and serve as a control group.
- Conditions
- Hyponatremia, Pituitary Surgery
- Being tested
- Fluid restriction, Dietary protein supplementation, Standard post-operative care
- Keywords
- postoperative hyponatremia, hyponatremia, SIAD-related complications, protein supplementation, fluid restriction, Pituitary Surgery, Plasma Sodium Levels
- Medical subject headings
- Hyponatremia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fluid restrictionDietary supplement
Patients will limit their total daily fluid intake to a maximum of 1000 ml, including any liquids of their choice, such as water, milk, or juice.
Dietary protein supplementationDietary supplement
Patients will consume an additional 80 grams of protein daily through two 150 ml protein drinks (40 grams of protein each, MOLTEIN PURE Drink, OMANDA) in various flavors. They can distribute the drinks throughout the day and drink other fluids freely based on thirst.
Standard post-operative careDietary supplement
Patients will not receive specific instructions on protein supplementation or fluid restriction. They will follow standard post-operative care and drink or eat freely based on natural appetite and thirst.
| Study group | Role | What they receive |
|---|---|---|
| Limited fluid intake | Experimental | Patients will limit their total daily fluid intake Receives: Dietary Supplement: Fluid restriction |
| Additional protein | Experimental | Patients will consume additional protein daily Receives: Dietary Supplement: Dietary protein supplementation |
| No instructions | Active comparator | Patients will not receive specific instructions. Receives: Dietary Supplement: Standard post-operative care |
What is being measured
The primary outcome is the main question the study is designed to answer.
Odds ratio of treatment failure (intervention compared to standard of care)
The primary objective is to evaluate the effectiveness of fluid restriction (Treatment A), and dietary protein supplementation (Treatment B) compared to the current standard care with no specific intervention and no fluid management guidance (Treatment C) in preventing treatment failure, defined at day 9 as a decrease in plasma sodium by at least 4 mmol/lL from baseline, and hyponatremia (plasma sodium <135mmol/L) or a decrease of at least 1 point in the MoCa score compared to baseline.
Measured: 3 days post-surgery (time of randomization), and day 9 post-surgery.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Dec 2025
- Study start20 Jan 2026
- Primary completion1 Oct 2028 (estimated)
- Study completion1 Oct 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HyponatremiaStudies of the same condition, open and under way.
- More trials run by University Hospital, Basel, SwitzerlandThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 282 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Basel, Switzerland
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Mirjam Christ-Crain, Prof. Dr. med., Principal investigator, University Hospital Basel, Endocrinology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07273630
- Sponsor's protocol ID
- 2025-01549; kt25ChristCrain
- Other IDs
- 2025
- Acronym
- TREASURE-PIT
- Status last verified
- Feb 2026
- First submitted
- 14 Nov 2025
- Last updated
- 3 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 3 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Protein Supplementation and Fluid Restriction on Plasma Sodium Levels in Patients Undergoing Pituitary Surgery - a Randomized Open-label Active-controlled Trial -
- ClinicalTrials.gov ID
- NCT07273630
- Acronym / sponsor ID
- TREASURE-PIT / 2025-01549; kt25ChristCrain
- Conditions
- Hyponatremia, Pituitary Surgery
- Keywords
- postoperative hyponatremia, hyponatremia, SIAD-related complications, protein supplementation, fluid restriction, Pituitary Surgery, Plasma Sodium Levels
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 282 participants (estimated)
- Lead sponsor
- University Hospital, Basel, SwitzerlandUniversity, hospital or other
- Study start
- 20 Jan 2026 (actual)
- Primary completion
- 1 Oct 2028 (estimated)
- Study completion
- 1 Oct 2028 (estimated)
- First posted
- 9 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The investigators are conducting this study to investigate new preventive measures for patients with low sodium levels (hyponatremia), which can occur after surgery on the pituitary gland. This hyponatremia is often caused by the syndrome of inappropriate antidiuresis (SIAD). SIAD occurs when the pituitary gland secretes too much antidiuretic hormone. The antidiuretic hormone causes the kidneys to absorb more water. This dilutes the sodium in the blood and leads to hyponatremia. Low sodium levels are particularly common after pituitary surgery, as the procedure on the pituitary gland can lead to increased reactive secretion of antidiuretic hormone. At present, apart from educating patients about the symptoms of hyponatremia, there are no established standard measures for prevention after pituitary surgery. If hyponatremia is present, it is currently treated primarily by fluid restriction, which is not always pleasant or easy to adhere to. With this study, the investigators want to investigate whether protein supplementation or fluid restriction between day 4 and day 9 after surgery can serve as a preventive measure to stabilize sodium levels after pituitary surgery and improve the quality of life of patients.
Detailed description
Disturbances in water balance, often due to disturbed arginine vasopressin (AVP) secretion from pituitary stalk and/or posterior lobe damage/manipulation, are common complications following pituitary surgery. This can result in either AVP deficiency, causing polyuria and polydipsia, or AVP excess, leading to water retention and dilutional hyponatremia (syndrome of inappropriate antidiuresis, SIAD). SIAD affects up to 30% of patients, typically developing between days 4 and 14 post-surgery, with a peak around day 7. While usually mild, severe hyponatremia is a leading cause of hospital readmission. Management includes fluid restriction, oral urea, or, in severe cases, hypertonic saline and AVP receptor antagonists.
Non-medicinal preventive strategies, such as prophylactic fluid restriction, have demonstrated efficacy in reducing SIAD incidence and hospital readmissions, but the optimal protocol remains unestablished. Dietary protein supplementation has recently emerged as a potential novel intervention, leveraging osmotic diuresis from increased endogenous urea production derived from the physiological amino-acid metabolism to raise plasma sodium levels. However, no data in the postoperative setting are available
This study aims to compare protein supplementation and fluid restriction to standard care (no specific intervention) in preventing post-pituitary surgery hyponatremia. From days 4 to 9 post-surgery, participants will receive one of the three treatments: Treatment A: Patients will limit their total daily fluid intake to a maximum of 1000 ml Treatment B: Patients will consume an additional 80 grams of protein daily through two 150 ml protein drinks (40 grams of protein each, MOLTEIN PURE Drink, OMANDA) in various flavors. Treatment C: Patients will not receive specific instructions. They will follow standard post-operative care and serve as a control group.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Limited fluid intake | Experimental | Dietary Supplement: Fluid restrictionPatients will limit their total daily fluid intake |
| Additional protein | Experimental | Dietary Supplement: Dietary protein supplementationPatients will consume additional protein daily |
| No instructions | Active comparator | Dietary Supplement: Standard post-operative carePatients will not receive specific instructions. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Adult patients (aged 18 or older) undergoing trans-sphenoidal or trans-cranial surgery for sellar / suprasellar pathology
- No pre-existing AVP-deficiency and SIAD or other causes of hyponatremia
Key exclusion criteria (12 listed)
- AVP deficiency diagnosed before surgery based on established criteria
- Other type of neurosurgery / intracranial pathology / pre-existing spontaneous CSF -rhinorrhea
- Traumatic brain injury or intracranial hemorrhage
- Systemic infection or other causes for systemic stress
- Lactose intolerance, milk protein allergy, soy allergy, nuts allergy or known hypersensitivity or allergy to one of the components of the protein supplementation
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fluid restrictionPatients will limit their total daily fluid intake to a maximum of 1000 ml, including any liquids of their choice, such as water, milk, or juice. | Dietary supplement | Limited fluid intake |
| Dietary protein supplementationPatients will consume an additional 80 grams of protein daily through two 150 ml protein drinks (40 grams of protein each, MOLTEIN PURE Drink, OMANDA) in various flavors. They can distribute the drinks throughout the day and drink other fluids freely based on thirst. | Dietary supplement | Additional protein |
| Standard post-operative carePatients will not receive specific instructions on protein supplementation or fluid restriction. They will follow standard post-operative care and drink or eat freely based on natural appetite and thirst. | Dietary supplement | No instructions |
Primary outcome
Odds ratio of treatment failure (intervention compared to standard of care)
Time frame: 3 days post-surgery (time of randomization), and day 9 post-surgery.
The primary objective is to evaluate the effectiveness of fluid restriction (Treatment A), and dietary protein supplementation (Treatment B) compared to the current standard care with no specific intervention and no fluid management guidance (Treatment C) in preventing treatment failure, defined at day 9 as a decrease in plasma sodium by at least 4 mmol/lL from baseline, and hyponatremia (plasma sodium <135mmol/L) or a decrease of at least 1 point in the MoCa score compared to baseline.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Feb 2026.
- Individual participant dataSharing planned: Undecided
Related trials for Hyponatremia
RecruitingPhase 3
Systematic Use of DDAVP to Prevent Serum Sodium Overcorrection in Severe Hyponatremia
Hyponatremia
Enrolling by invitationObservational study
International Multi-center Retrospective Study of Patients With Serum Sodium ≤110 mmol/L to Determine the Relationship Between Osmotic Demyelination Syndrome (ODS) and Rapid Correction of Hyponatremia
Hyponatremia Symptomatic, Osmotic Demyelination Syndrome
Active, not recruitingObservational study
Samsca Post-marketing General Drug Use-results Survey in Patients With Hyponatremia in SIADH
Antidiuretic Hormone, Inappropriate Secretion
Recruiting
Urea for Treatment of Hyponatremia in Patients With SIAD Unresponsive to Fluid Restriction
SIAD - Syndrome of Inappropriate Antidiuresis
Active, not recruitingObservational study
Hyponatremia - Complications, Prognosis, Epidemiology in Finnish Tertiary Care
Hyponatremia, Osmotic Demyelination Syndrome
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Michelle Mueller contact
Mirjam Christ-Crain, Prof. Dr. med. principal investigator
University Hospital Basel, Endocrinology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Fluid restriction, Dietary protein supplementation and Standard post-operative care in people with Hyponatremia and Pituitary Surgery, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 3 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Mirjam Christ-Crain, Prof. Dr. med. (0041 61 328 70 80, Mirjam.Christ-Crain@usb.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Odds ratio of treatment failure (intervention compared to standard of care) (time frame: 3 days post-surgery (time of randomization), and day 9 post-surgery.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Feb 2026.