METHODS: This was a prospective study where 88 patients with polyuria-polydipsia syndrome were evaluated with a water deprivation test (WDT). Weight, urine osmolality, urine specific gravity, and plasma copeptin were collected at baseline, after 8 h, and at termination of the WDT when one of the following had been reached: (i) >3% weight reduction, (ii) urine specific gravity >1.017 or urine osmolality >600 mOsm/kg, or (iii) intolerable adverse symptoms.
RESULTS: Of 88 patients (57 women), 21 (24%) were diagnosed with central diabetes insipidus (cDI), 5 (6%) with nephrogenic DI (nDI), and 62 (71%) with primary polydipsia (PP). Median (interquartile range) copeptin at baseline was 1.7 (1.4-2.5) pmol/L in cDI, 22 (18-65) pmol/L in nDI, and 2.7 (2-4) pmol/L in PP. After 8 h of WDT, the highest copeptin in patients with cDI was 4.0 pmol/L. In patients with PP: (i) 41 had urine osmolality <600 mOsm/kg, 7 (17%) of these had copeptin >4.0 pmol/L, (ii) 21 had urine osmolality ≥600 mOsm/kg, 14 (67%) of these had copeptin >4.0 pmol/L.
CONCLUSIONS: Copeptin >4.0 pmol/L after an overnight WDT can be used to rule out cDI and copeptin ≥21 pmol/L at baseline to diagnose nDI. The diagnostic performance of copeptin in the context of the WDT is otherwise limited in the diagnostic work-up of patients with polyuria-polydipsia syndrome.
方法:这是一项前瞻性研究,对88例多尿多饮综合征患者进行了水剥夺试验(WDT)评估。重量,尿液渗透压,尿液比重,在基线时收集血浆和肽素,8小时后,并且在WDT终止时,达到以下一项:(i)重量减少>3%,(ii)尿比重>1.017或尿渗透压>600mOsm/kg,或(iii)难以忍受的不良症状。
结果:在88名患者(57名女性)中,21例(24%)被诊断为中心性尿崩症(cDI),5(6%)伴肾性DI(nDI),原发性烦渴(PP)为62(71%)。cDI中的中位数(四分位数范围)和肽素在基线时为1.7(1.4-2.5)pmol/L,22(18-65)pmol/L,和2.7(2-4)pmol/L的PP。经过8小时的WDT,cDI患者的和肽素最高为4.0pmol/L。在PP患者中:(i)41的尿渗透压<600mOsm/kg,其中7例(17%)与肽素>4.0pmol/L,(ii)21例尿液渗透压≥600mOsm/kg,其中14例(67%)的肽素>4.0pmol/L。
结论:和肽素>4.0pmol/L的WDT后可用于排除cDI和和肽素≥21pmol/L的基线诊断nDI。在WDT背景下,和肽素的诊断性能在多尿多饮综合征患者的诊断工作中受到限制。