Elderly people are at a high risk for disturbances in water homeostasis, with both hypo- and hypernatremia being more common with increasing age. Several changes in the physiology of the ageing body are responsible for this predisposition towards hypo- and hypernatremia, including diminished thirst perception, decreasing kidney function, and altered body composition. In addition, age-related changes in AVP secretion have been suggested, but findings remain inconclusive. Possibly, this controversy is due to measurement challenges of AVP. Copeptin, a surrogate marker of AVP-release, is more stable and a reliable assay is commercially available. While copeptin stimulation and suppression has been studied in healthy volunteers, no study assessed possible changes in copeptin dynamics occurring with ageing. Therefore, the aim of this study is to investigate copeptin levels in hypo- and hyperosmolar states in generally healthy elderly adults compared to young controls. The investigators hypothesize that both the suppression and stimulation of copeptin is impaired and that the overall range of variation is diminished with increasing age. This is a monocentric open-labeled randomized controlled trial conducted at the university hospital Basel. All participants will be scheduled for a copeptin stimulation test using hypertonic saline infusion and a copeptin suppression test using water ingestion. The order of the two study visits will be randomized at study inclusion.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
32
Participants receive 10 ml/kg body weight of 3% saline infused over 1 hour. The aim is to stimulate copeptin release.
Participants ingest 20 ml/kg water over 1h. The aim is to suppress copeptin release.
University Hospital Basel
Basel, Canton of Basel-City, Switzerland
Range of Variation in Copeptin
The primary outcome is the range of variation in copeptin, i.e. difference of suppressed copeptin to the stimulated copeptin, in healthy elderly participants compared to young controls.
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in Copeptin upon stimulation and suppression
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Differences in total body water (L) measured by body impedance analysis
Time frame: at Baseline
Changes in cortisol (mmol/L)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Number of participants with treatment-related adverse events as assessed by CTCAE v5.0
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in blood pressure (mmHg)
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in heart rate
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in plasma sodium (mmol/L)
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in plasma potassium (mmol/L)
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in plasma chloride (mmol/L)
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in plasma osmolality (mOsm/kg)
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in estimated glomerular filtration rate (ml/kg/1.73m2)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in plasma glucose (mmol/L)
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in plasma urea (mmol/L)
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in plasma uric acid (umol/L)
Time frame: Baseline, 15 minutes, 30 minutes, 45 minutes, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in urine osmolality (mOsm/kg)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in urine sodium (mmol/L)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in urine potassium (mmol/L)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in urine chloride (mmol/L)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in urine urea (mmol/L)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in urine uric acid (umol/L)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in urine glucose (mmol/L)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
Changes in urine creatinine (umol/L)
Time frame: Baseline, 60 minutes, and 120 minutes both after saline administration and after water ingestion
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