Increase in 24-hour urine production/weight causes nocturnal polyuria due to impaired function of antidiuretic hormone in elderly men.

OBJECTIVE

The goals of the present study were to evaluate whether the different function of endogenous antidiuretic hormone (arginine vasopressin; AVP) results in the difference in 24-h production/weight and to make indexes of lifestyle advice for patients with nocturia due to nocturnal polyuria (NP).

METHODS

A total of 205 male patients over 50 years of age were enrolled in the study. Frequency volume chart and fluid intake (time and volume) were recorded under unconditioned status. All patients submitted single voided urine sample at 06.00 hours. Urinary AVP (uAVP), sodium (uNa), creatinine (uCr), and osmolarity were measured. Patients were divided into four groups according to 24-h urine production/weight as follows: 24-h production/weight >40, 24-h production/weight: more than 30 to 40, 24-h production/weight: more than 20 to 30, 24-h production/weight: 20 or less.

RESULTS

The data of 174 eligible patients were finally evaluated. Although there were no differences in uAVP/uCr and uNa/uCr among the groups, the nocturnal voided volume (NUV) increased with the increase in 24-h production/weight. Age, uAVP/uCr, 24-hr production/weight of more than 20 to 30, and 24-h production/weight of 20 or less were independent factors for NP. NUV did not correlate with 24-h drinking volume in any group.

CONCLUSIONS

Our data suggested that the increased 24-h urine production/weight was apparently a risk factor for NP. We attributed this phenomenon to deterioration of the function of AVP.