Challenges and unmet needs in diagnosing polyuria-polydipsia syndrome: National survey by the Italian Society of Endocrinology

Purpose: Symptoms and baseline laboratory results often fail to identify the underlying cause of polyuria-polydipsia syndrome (PPS). A copeptin-based approach has recently been proposed for the differential diagnosis in adults. Given the rarity and complexity of PPS, national endocrinology societies should provide guidance to minimize diagnostic delays and ensure patients receive the most accurate evaluation. Methods: The Hydro-Saline Club conducted a 22-question web-based survey targeting all endocrinologists registered with the Italian Society of Endocrinology in 2024. Data were collected from July 18 to September 22, 2024. Results: A total of 120 endocrinologists from 75% of Italian regions completed the survey. 60% worked in university hospitals, while the remainder worked in peripheral hospitals and outpatient clinics. Copeptin testing was available in 58.3% of facilities. However, a basal copeptin evaluation was infrequently requested in PPS, mainly due to assay availability (p < 0.001) and low confidence in results interpretation, which correlated with clinical experience (p = 0.007). The WDT remained the most used stimulation test, with preference driven by personal experience (p = 0.020) rather than facility type. Familiarity with each diagnostic test increased with use, and test choice was apparently not influenced by concerns over potential side effects or accuracy. Rather, the main barrier identified was the perceived caregiving burden associated with the diagnostic process, leading many clinicians to prefer a stepwise diagnostic approach. Conclusion: Endocrinological societies should promote awareness of novel, accurate diagnostic tools for PPS and support streamlined referral pathways to centers offering reliable, appropriate testing.