Abstract：
OBJECTIVE: Plasma copeptin is a relatively new biomarker for evaluation of arginine vasopressin (AVP) secretion. The aim of this study was to test the diagnostic performance of copeptin in patients with polyuria-polydipsia syndrome.
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.
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.
摘要：
目的：血浆和肽素是评价精氨酸加压素（AVP）分泌的一种相对较新的生物标志物。这项研究的目的是测试和肽素在多尿多饮综合征患者中的诊断性能。
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。
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。
