Arginine Vasopressin and Nocturnal Polyuria in Older Adults With Frequent Nighttime Voiding

Abstract

We determined in older adults whether frequent nighttime voiding is associated with urine overproduction at night or nocturnal polyuria (NP) and whether NP is associated with abnormalities of arginine vasopressin (AVP) blood levels and/or renal responsiveness to AVP. We used a convenience sample of adults 65 years and older in home and general clinical research center settings. A total of 45 participants completed the 3-day general clinical research center stay. We used 7-day voiding diaries to determine which participants had 2 or greater nighttime voids and NP, defined as 35% or greater of 24-hour urine output at night. Abnormalities in AVP release and secretion were determined by water deprivation testing and by twice daily blood AVP measurement. There was a strong positive association between the number of nighttime voids and the proportion of urine produced at night (r = 0.6, p <0.001). There was no association between NP and AVP blood levels or action. Participants with and without NP had similar maximum urine osmolality following water deprivation and exogenous AVP administration (mean 549 mOsm, range 422 to 713 and 547 mOsm, range 353 to 692, respectively). We found no association between NP and AVP abnormalities in this sample of older adults. Study participants had low maximal urine osmolality in response to fluid deprivation and exogenous vasopressin administration irrespective of whether they were identified as having NP.