Why Do People Void At Night

Weiss J P1, Blaivas J2, De Rosa P3, Dayan L4, Smith M1

Research Type


Abstract Category


Abstract 113
Open Discussion ePosters
Scientific Open Discussion ePoster Session 7
Wednesday 29th August 2018
12:35 - 12:40 (ePoster Station 5)
Exhibition Hall
Quality of Life (QoL) Voiding Diary Nocturia Voiding Dysfunction
1. SUNY Downstate, Dept. of Urology, 2. Icahn School of Medicine at Mount Sinai, Dept. of Urology, 3. SUNY Downstate College of Medicine, 4. Institute for Bladder and Prostate Research

Paige De Rosa




Hypothesis / aims of study
Nocturia represents a significant source of bother to patients and can be detrimental to quality of life and sleep [1]. There are two possible reasons why patients have nocturia – they are awakened by an urge to void (primary nocturia voids or PNV) or they awaken for some other reason and then void before going back to sleep (secondary nocturia voids or SNV). Each of these categories may be subdivided into urgency voids and non-urgency voids. The aim of this study is to determine the relative contribution of each type of night-time voids in a large cohort of patients.
Study design, materials and methods
This is an IRB approved retrospective study of consecutive patients who completed the Lower Urinary Tract Symptoms Score and 24 hour paper bladder diary (24H BD). Clinical diagnoses were included as documented in the patient record. Day and night-time voids were distinguished by the bedtime and awake time as recorded on the diary. Each nocturnal void was designated as primary or secondary nocturia based on the following scheme derived from the Urge Perception Score (UPS).   Primary nocturia - was sub-divided into urgency voids (severe urge or desperate urge - UPS = 3 or 4) and non-urgency voids (mild urge or moderate urge - UPS = 1 or 2), secondary nocturia – (no urge – UPS = 0).
572 patients completed 1288 diaries included in the analysis, including 369 men and 203 women. Overall, 1586 bladder diaries were reviewed. 298 diaries were excluded because of inaccurate UPS scores or incompleteness. 338 patients completed 1 diary, 113 patients completed 2 diaries, 54 patients completed 3 diaries and 77 patients completed 3 or more diaries. 

2,793 night-time voids were analyzed. 214 voids (7.7%) were designated as secondary nocturia. 1629 voids (58.3%) were designated as non-urgency voids and 950 voids (34.0%) were designated as urgency voids.

The age of patients ranged from 6 - 100 years. The average patient age was 62, with a standard deviation of 18.2. 169 patients had a clinical diagnosis documented. Clinical diagnoses include Urethral Stricture, OAB, BPH with/without obstruction, Parkinson’s disease, Urge Incontinence, Male Stress Incontinence, Prostate Cancer, Polyuria, and Pelvic Organ Prolapse. The most common diagnosis was overactive bladder (OAB) with 49 patients, followed by BPH with 38 patients. The data is summarized in the figures below.
Interpretation of results
In this study, 7.7% of the time, patients had SNV. Because patients designated that these voids were not accompanied by any urge, we posit that at the time of these voids, patients awoke for a reason other than urination and voided out of habit before returning to sleep. Conversely, urgency voids during the night-time are in fact related to the urinary tract. We found the prevalence of primary nocturia with urgency voids to be 34.0% overall. However, the great majority of night-time voids (58.3%) were primary nocturia non-urgency voids. While we can conclude that patients awoke to urinate for the urgency voids, we cannot definitively attribute waking up at night to bladder-related causes for these non-urgency voids. The multi-factorial nature of nocturia suggests that elucidating the etiology of night-time voids will improve clinical management [2]. Given that primary nocturia non-urgency voids contributed over greater than one-half of total night-time voids, we must further investigate the etiology of these voids, with implications for appropriate and effective treatment.
Concluding message
Although the vast majority of patients in this series with nocturia were awakened by the desire to void (PNV) a subset were not (SNV). Further, voiding at night did not appear to be related to the bladder at all in some patients. It is important to make these distinctions about why people void at night because the diagnostic evaluation and treatment options may be completely different depending upon these factors.
Figure 1
Figure 2
  1. Ancoli-Israel, Sonia, et al. “The Effect of Nocturia on Sleep.” Sleep Medicine Reviews, vol. 15, no. 2, 2011, pp. 91–97., doi:10.1016/j.smrv.2010.03.002.
  2. Weiss, Jeffrey P., et al. “The Evaluation and Treatment of Nocturia: a Consensus Statement.” BJU International, vol. 108, no. 1, 2011, pp. 6–21., doi:10.1111/j.1464-410x.2011.10175.x.
Funding Institute for Bladder and Prostate Research Clinical Trial No Subjects Human Ethics Committee Western IRB Helsinki Yes Informed Consent No
29/11/2020 11:06:04