Reference values for the nocturnal bladder capacity index
- 29 September 2010
- journal article
- research article
- Published by Wiley in Neurourology and Urodynamics
- Vol. 30 (1), 52-57
- https://doi.org/10.1002/nau.20924
Abstract
Aims The Nocturnal Bladder Capacity Index (NBCi) has been reported to be useful in distinguishing between nocturia caused by low bladder capacity and nocturnal polyuria. This paper aims to calculate reference values for NBCi from an asymptomatic population by comparing these with NBCi values from patients with lower urinary tract symptoms (LUTS) to obtain an indication of the sensitivity with which the NBCi detects low nocturnal bladder capacity. This paper also compares the sensitivity of rounded and unrounded calculations of NBCi. Methods Computer processed 3‐day bladder diaries from 253 asymptomatic volunteers and 184 female patients with LUTS were analyzed. NBCi values were calculated from each diary using rounded and unrounded formulae. 90th and 95th centile NBCi cutoff values were obtained from frequency distributions. Results NBCi reference values from the asymptomatic group were 1.1 (unrounded) and 0.7 (rounded) for 90th centile, and 1.3 (unrounded) and 1.0 (rounded) for 95th centile. The use of the rounded formula gave identical NBCi values despite a large variation in Vn/Vmax ratios whereas unrounded NBCis varied continuously with Vn/Vmax ratios. The unrounded formula found significantly more elevated NBCis in the patient group. Conclusion We suggest that an unrounded NBCi of 1.3 be considered a cutoff point above which reduced nocturnal bladder capacity should be investigated as a cause of nocturia. Rounding the NBCi lead to an underestimation of elevated values in a population of female patients with LUTS. Neurourol. Urodynam. 30:52–57, 2011.Keywords
This publication has 11 references indexed in Scilit:
- Role of Bladder Capacity in Assessing the Effectiveness of Antimuscarinic Agents on Nocturia in Patients with Overactive BladdersTzu Chi Medical Journal, 2008
- Bladder diary measurements in asymptomatic males: Frequency, volume per void, and 24-Hr volumeNeurourology and Urodynamics, 2008
- The Utility of Amitryptiline in Female Overactive Bladder Patients with NocturiaKorean Journal of Urology, 2008
- Nocturia: Etiology, diagnosis, and treatmentNeurourology and Urodynamics, 2007
- Nocturia, nocturia indices and variables from frequency‐volume charts are significantly different in Asian and Caucasian men with lower urinary tract symptoms: a prospective comparison studyBJU International, 2007
- Bladder diary measurements in asymptomatic females: functional bladder capacity, frequency, and 24‐hr volumeNeurourology and Urodynamics, 2007
- Bladder diary patterns in detrusor overactivity and urodynamic stress incontinenceNeurourology and Urodynamics, 2007
- Nocturia and complementary indices: determination and quantification of the cause of nocturia by frequency-volume charts in women with lower urinary tract symptomsUrological Research, 2004
- Nocturia: When is it not related to overactive bladder?Current Urology Reports, 2003
- Evaluation of the etiology of nocturia in men: The nocturia and nocturnal bladder capacity indicesNeurourology and Urodynamics, 1999