Water Load Test Value for Hyponatremia

Study Overview
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Brief Summary
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Acute water load test has been using to diagnose renal ability to excrete water for decades. Latest recommendations for the diagnosis of hyponatremia do not recommend performing such a test. The investigators aim at, retrospectively, study the value of acute water load test in patients suffering from a syndrome of inappropriate antidiuresis.

Official Title
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Water Load Test Value for Hyponatremia Due to a Syndrome of Inappropriate Antidiuresis (SIAD)

Conditions
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SIAD - Syndrome of Inappropriate Antidiuresis, Hyponatremia

Intervention / Treatment
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* Procedure: Acute water load test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ≥ 18 years old at the time of the test affiliated to a social insurance system water load test performed at the Renal and Metabolic Diseases Unit of the European George Pompidou Hospital, AP-HP, Paris, France between 01/01/2001 and 12/31/2019 Exclusion Criteria: hypernatremia and/or polyuria-polydipsia (diabetes insipidus) hyponatremia due to a tea and toast syndrome and/or a beer potomania hyponatremia due to a high (or normal) osmolality related to diabetes mellitus, hyperproteinemia and/or intoxication chronic kidney disease with an estimated glomerular filtration rate (eGFR) by the MDRD formula <60 mL/min/1.73m2 hyponatremia related to thiazides hyponatremia related to an hypovolemic status syndrome of inappropriate antidiuresis related to an endocrine disorder (such as hypothyroidism or adrenal insufficiency)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Water load test<br>Patients experiencing a syndrome of inappropriate antidiuresis who had an acute water load test | Procedure: Acute water load test<br>* The acute water load test consists in administering orally 20 mL/kg (of body weight) of water (ingested in less than 30 min) and then follow (during 4 to 6 hours) blood and urine parameters.<br>|
| Control group<br>Patients who had an acute water load test and who did not experience any water homeostasis anomalies | Procedure: Acute water load test<br>* The acute water load test consists in administering orally 20 mL/kg (of body weight) of water (ingested in less than 30 min) and then follow (during 4 to 6 hours) blood and urine parameters.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Natremia | Plasma sodium concentration (abnormal if <135mM) | any time after water load test from hour 2 to hour 6 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma osmolality | Plasma osmolality (abnormal if <280mOsm/kgH2O) | any time after water load test from hour 2 to hour 6 | 
| Excretion of water load | Ratio between the excreted water (in urine) volume and the ingested one | after water load test from hour 0 to hour 6 | 
| Urine osmolality | Minimum urine osmolality reached | any time after water load test from hour 2 to hour 6 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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hyponatremia, SIAD, water load test