Diabetes Insipidus, Primary Polydipsia
Conditions
Keywords
Copeptin, differential diagnosis of polyuria polydipsia syndrome, diabetes insipidus, compulsive water drinking, water deprivation test, Diabetes insipidus (central and nephrogenic)
Brief summary
Prospective evaluation of the novel biomarker copeptin in the differential diagnosis of diabetes insipidus against the standard diagnostic test methods.
Detailed description
Purpose of this study is to compare the overall diagnostic accuracy of the three following diagnostic test procedures in diabetes insipidus (central, nephrogenic) and primary polydipsia: a) classical water deprivation test alone, b) classical water deprivation test plus plasma copeptin cut-off levels, c) hypertonic saline infusion test plus plasma copeptin measurement. The investigators hypothesize that firstly b) and c) is better as a). Secondly the investigators hypothesize that c) is non-inferior to b).
Interventions
OTHERWater deprivation test
Classical water deprivation test alone
hypertonic saline infusion test plus plasma copeptin measurement
Sponsors
University Hospital, Basel, Switzerland
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
16 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Polyuria or/and Polydipsia or/and therapy with synthetic adenovirus proteinase (AVP) derivate * Urine osmolality \<800mOsm/kgH20
Exclusion criteria
* Polyuria due to diabetes mellitus * Hypokalemia * Hyperkalemia (\>5mmol/l) * Hypercalcemia * Kidney disease (min.: glomerular filtration rate (GFR) 60ml/min/1.73m2) * Pregnancy * Hyponatremia \>135mmol/L * Hypernatremia \>145mmol/L * Hypo- or hypervolemia * uncorrected adrenal or thyroidal deficiency * Cardia failure * Epilepsia * Uncontrolled hypertension
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Overall diagnostic accuracy | beginning and end of protocol, up to 9hours | Ratio of the number of correctly diagnosed patients to the number of all tested patients for the tests: * classical water deprivation test alone * classical water deprivation test plus plasma copeptin cut-off levels * hypertonic saline Infusion test plus plasma copeptin measurements |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Sensitivity, specificity, positive and negative predictive value | beginning and end of protocol, up to 9hours | each diagnostic test |
| post-hoc best copeptin cut-off optimising overall performance | beginning and end of protocol, up to 9hours | best copeptin cut-offs for differentiation between different diagnosis of polyuria-polydipsia syndrome |
| subjective burden as rated by patients on visual analogue scale | beginning, during and end of protocol, up to 9hours | water deprivation test and hypertonic saline Infusion test |
| Predictive value of specific anamnestic and clinical features | before tests | Evaluation of anamnestic and clinical features to test-independently predict final diagnosis of polyuria-polydipsia syndrome |
| Predictive value of absent bright spot in posterior pituitary enlargement | before or after tests | Evaluation of predictive value of absent bright spot in T1 weighted cranial MRI scans |
Countries
Switzerland
Outcome results
None listed