Arginine Vasopressin Deficiency, Primary Polydipsia
Conditions
Keywords
diabetes insipidus, copeptin, oral urea
Brief summary
The aim of this study is to investigate whether oral urea stimulates copeptin release and, if so, whether it may provide a novel diagnostic test in the differentiation between AVP-D (Arginine vasopressin deficiency) and PP (primary polydipsia).
Detailed description
This study consists of two parts, including healthy adults (study part 1 - proof of concept) and adults with an established diagnosis of PP or AVP-D (study part 2 - pilot study). If the results of study part 1 suggest that oral urea is a potent stimulator of copeptin in healthy adults, study part 2 will be conducted, meaning that adults with an established diagnosis of PP or AVP-D will be included. If study part 1 demonstrates no relevant copeptin increase in response to oral urea, the study will be terminated thereafter and study part 2 will not be conducted.
Interventions
DIAGNOSTIC_TESTUrea
Diagnostic test with a single weight-adapted dose of oral urea dissolved in 200 ml water together with 5 g of lemon-lime flavor powder (containing maltodextrin and citric acid). The investigators will make use of the lemon-lime flavor to soften the bitter taste of urea. \- Dose calculation: 0.5 g urea/kg body weight (rounded to no decimal places), with a minimal dose of 30g and a maximal dose of 45g.
DIAGNOSTIC_TESTPlacebo
Diagnostic test with a single weight-adapted dose of placebo dissolved in 200 ml water together with 5 g of lemon-lime flavor powder (containing maltodextrin and citric acid). The placebo will contain a mixture of bitter herbal substances to mimic the taste of urea. \- Dose calculation: 22 ml of placebo containing 20 ml Ergytonyl®, 1 ml Carmol®, and 1 ml Bitter Liebe®.
Sponsors
University Hospital, Basel, Switzerland
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
DIAGNOSTIC
Masking
DOUBLE (Subject, Investigator)
Masking description
Study staff and participants are blinded upon the nature of each study visit. The preparation of the study medication or placebo will be performed by unblinded study staff who is otherwise not involved in the trial.
Intervention model description
double-blind, randomized, placebo-controlled cross-over proof-of-concept and pilot study
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
Healthy volunteers Inclusion Criteria: * Age ≥18 years * Healthy with no medication except hormonal contraception
Exclusion criteria
* Participation in a trial with investigational drugs within 30 days * Evidence of disordered drinking habits and diuresis defined as polyuria \>50ml/kg body weight/24h and polydipsia \>3l /24h * Known allergy towards components of the study drink * Pregnancy and breastfeeding * Intention to become pregnant during the study * Evidence of acute illness Patients Inclusion Criteria: * Age ≥ 18 years * Documented PP or AVP-D based on accepted diagnostic criteria, i.e., water deprivation test, hypertonic saline infusion test or arginine infusion test. Accordingly, patients must have evidence of disordered drinking habits and diuresis defined as polyuria \>50ml/kg body weight/24h and polydipsia \>3l /24h or must be on regular daily desmopressin medication
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Difference in maximal increase in copeptin levels in plasma (pmol/l) | up to 6 time assessment until 150 minutes after baseline | The difference in maximal increase in copeptin levels in plasma (pmol/l) within 150 minutes after oral intake of urea versus placebo, with the maximal increase being the difference between baseline copeptin values measured at the beginning of the test and maximal values measured between 30 and 150 minutes after ingestion. |
Countries
Switzerland
Outcome results
None listed