Comparison of Mannitol and Hypertonic Saline Tests for Diagnosing Polyuria-Polydipsia Syndrome to Find a Simpler and More Comfortable Method

What this Trial Is About

Researchers are evaluating a new diagnostic approach for polyuria-polydipsia syndrome PPS, a condition marked by excessive urination and fluid intake. The study compares a new test using mannitol infusion against the current standard hypertonic saline infusion test to see if it can diagnose the cause of PPS as accurately. The goal is to find a simpler, more comfortable, and patient-friendly diagnostic method that can better guide treatment decisions. Participants undergo both diagnostic tests in random order during this multicenter, randomized crossover trial. One test involves an intravenous infusion of mannitol over 30 minutes, while the other uses hypertonic saline given as a bolus followed by a slower infusion. Researchers compare the accuracy of each test and which test patients prefer. The study also looks at safety, tolerability, and explores additional clinical and lab measures to improve diagnosis. During the study, participants have blood samples taken to measure copeptin levels, a marker reflecting vasopressin hormone levels, after each test. Questionnaires assess patient test preference, quality of life, and psychological traits. Safety and symptom burden are monitored throughout. The main outcomes include diagnostic accuracy measured 10 weeks after baseline and patient preference one week after both tests. The total participation lasts about ten weeks from baseline to final follow-up.

Copeptin Measurement After Mannitol and Hypertonic Saline for the Diagnosis of Polyuria-polydipsia Syndrome