Akbari Ayub, Sriperumbuduri Sriram, Mangalgi Shreepryia, Joshi Vijay, Sood Manish, Buh Amos, Biyani Mohan, McCudden Christopher, Hundemer Gregory L, Brown Pierre Antoine
Division of Nephrology, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
Kidney Research Centre, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
Kidney Med. 2025 Jan 15;7(3):100965. doi: 10.1016/j.xkme.2025.100965. eCollection 2025 Mar.
RATIONALE & OBJECTIVE: Arginine vasopressin (AVP) is an established driver of cyst growth in autosomal dominant polycystic kidney disease (ADPKD). Urine osmolality (osm) measures are surrogate markers of AVP activity. Both 24-hour and spot urine samples are used as indicators of AVP suppression. The agreement between these 2 measurements remains unclear.
A retrospective cohort study.
SETTING & STUDY POPULATION: Three hundred and forty-nine patients with ADPKD with 839 urine samples from a tertiary care center.
Patients with ADPKD with records of spot and 24-hour urine measurements.
Consecutive patients' data from January 2018 to March 2023 were extracted from the quality assurance database of The Ottawa Hospital Cystic Kidney Disease Clinic.
Discordance assessed at target urine osmolality of 250 and 270 mmol/kg. Agreement assessed by Bland-Altman plots. The percentage of patients with difference in osmolality between the 2 measures for cutoff points of > 50, > 100, >150, and > 200 mmol/kg was calculated.
The mean 24-hour urine osm was 364 mmol/kg, and the mean spot urine osm was 424 mosm/kg. Mean age of 46 years, 52% females, and 47 (13.5%) were on tolvaptan. Overall, in comparing spot urine osm to 24-hour urine osm, the discordance at 250 and 270 mmol/kg was 24% with poor agreement on Bland-Altman plots. The differences between the 2 measures at varying cutoff points were 53.9% at 50 mmol/kg, 35.8% at 100 mmol/kg, 24.1% at 150 mmol/kg, and 16.1% at 200 mmol/kg. Results were similar when only a single measurement from each patient was used for analysis.
Total of 29% of patients did not have concurrent spot urine osmolality and 24-hour urine osmolality. The study was conducted at a single center. Limited number of patients were on tolvaptan.
In adults with ADPKD, important differences exist between the 24-hour urine osmolality and spot urine osmolality that preclude interchangeable use. The method employed may impact clinical decision-making. More research is needed to determine, which urine osm should be used when assessing AVP suppression.
精氨酸加压素（AVP）是常染色体显性遗传性多囊肾病（ADPKD）囊肿生长的既定驱动因素。尿渗透压（osm）测量是AVP活性的替代标志物。24小时尿样和随机尿样均被用作AVP抑制的指标。这两种测量方法之间的一致性仍不明确。
一项回顾性队列研究。
来自一家三级医疗中心的349例ADPKD患者，共839份尿样。
有随机尿和24小时尿测量记录的ADPKD患者。
从渥太华医院囊性肾病诊所的质量保证数据库中提取2018年1月至2023年3月连续患者的数据。
在目标尿渗透压为250和270 mmol/kg时评估不一致性。通过Bland-Altman图评估一致性。计算两种测量方法之间渗透压差异>50、>100、>150和>200 mmol/kg时患者的百分比。
24小时尿渗透压平均值为364 mmol/kg，随机尿渗透压平均值为424 mosm/kg。平均年龄46岁，女性占52%，47例（13.5%）服用托伐普坦。总体而言，比较随机尿渗透压和24小时尿渗透压时，250和270 mmol/kg时的不一致率为24%，Bland-Altman图显示一致性较差。在不同的截断点，两种测量方法之间的差异在50 mmol/kg时为53.9%，100 mmol/kg时为35.8%，150 mmol/kg时为24.1%，200 mmol/kg时为16.1%。当仅使用每位患者的一次测量进行分析时，结果相似。
共有29%的患者没有同时进行随机尿渗透压和24小时尿渗透压测量。该研究在单一中心进行。服用托伐普坦的患者数量有限。
在成年ADPKD患者中，24小时尿渗透压和随机尿渗透压之间存在重要差异，无法互换使用。所采用的方法可能会影响临床决策。需要更多研究来确定在评估AVP抑制时应使用哪种尿渗透压。
