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Diagnosing Nocturnal Polyuria from a Single Nocturnal Urine Sample
Thomas F Monaghan1, Joseph G Verbalis2, Rebecca Haddad3
1Department of Urology, State University of New York Downstate Health Sciences University, Brooklyn, NY, USA.
European Urology Focus
|October 21, 2019
Summary
A single early morning urine sample can help diagnose nocturnal polyuria (NP). Higher volume and lower osmolality in this sample indicate NP, offering a simpler alternative to voiding diaries.
Area of Science:
- Urology
- Nephrology
- Sleep Medicine
Background:
- Nocturnal polyuria (NP) is characterized by increased urine production during early sleep hours.
- Diagnosing NP typically involves time-consuming voiding diaries.
Purpose of the Study:
- To assess the diagnostic value of a single early nocturnal urine sample for detecting NP.
- To establish urine volume and osmolality cutoffs for NP identification.
Main Methods:
- Analysis of 1 am urine samples from 176 nocturic participants.
- Stratification into NP (n=87) and non-NP (n=89) groups.
- Receiver operating characteristic curve analysis to determine optimal cutoffs.
Main Results:
- Individuals with NP had higher 1 am urine volume (cutoff ≥350ml) and lower osmolality (cutoff ≤314 mOsm/kg H2O).
- Combined criteria (volume ≥350ml or osmolality ≤314 mOsm/kg H2O) showed 85% sensitivity and 75% specificity for NP.
- High sensitivity and specificity were consistent across genders.
Conclusions:
- Early nocturnal urine volume and osmolality are effective predictors of NP.
- This method offers a potentially simpler diagnostic approach compared to voiding diaries.
- Further research is needed due to the study's post hoc design and sample size.
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