- Email: [email protected]
Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?
+
MODEL
Journal of Pediatric Urology (xxxx) xxx xxx
a
Department of Pediatric Urology, Jichi Medical University, Children’s Medical Center Tochigi, Tochigi, Japan
Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence? Taiju Hyuga a,b,*, Shigeru Nakamura a, Shina Kawai a, Kazuya Tanabe a, Makiko Naka Mieno c, Hideo Nakai a
b
Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
c Department of Medical Informatics, Center for Information, Jichi Medical University, Tochigi, Japan
* Corresponding author. Department of Pediatric Urology, Jichi Medical University, Children’s Medical Center Tochigi, 3311-1, Yakushiji Shimotsuke-shi, Tochigi 329-0498 Japan. Tel.: þ81 285 44 2111. , Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), 811-1, Kimiidera, Wakayama 641-8509, Japan. Tel.: þ81 73 447 2300. [email protected] (T. Hyuga) Keywords Uroflowmetry; Reproducibility; Small voided volume; Curve
Abbreviations DUI, Daytime Urinary Incontinence; UFM, Uroflowmetry; ICCS, International Children’s Continence Society; VV, Voided Volume; OAB, Overactive Bladder; EMG, Electromyography Received 20 December 2018 Accepted 5 September 2019 Available online xxx
Summary Background A voided volume (VV) of <50% of the expected bladder capacity for age is considered small VV. It was recommended that a VV 50% of expected bladder capacity for age is required to assess uroflowmetry (UFM) curves because a small VV causes changes in UFM curve characteristics. However, no clear consensus has been reached on the criterion for evaluating UFM curve patterns. Objective The aim of the study was to evaluate the reproducibility and characteristics of UFM curve patterns in children with daytime urinary incontinence (DUI) and with a variety of VVs. Methods This study investigated 119 children (79 boys and 40 girls) with primary DUI who underwent UFM 3 times on the same day and were classified into two groups: small VV (<50% of expected bladder capacity for age) in 0e1 of the 3 UFM measurements (group 1; normal VV) or in 2e3 of the 3 UFM measurements (group 2; small VV). The authors then evaluated the agreement of UFM curve patterns among the 3 measurements, classifying complete, partial, or no agreement according to the number of identical curve patterns. The authors also evaluated the most characteristic patterns of UFM curve patterns for each group.
Summary table
Results Group 1 comprised 45 children, and group 2 comprised 74 children. Rates of complete agreement (group 1, 24/45; group 2, 30/74), partial agreement (group 1, 19/45; group 2, 35/74), and no agreement (group 1, 2/45; group 2, 9/74) did not differ significantly between groups (p Z 0.226). Bell curve patterns were significantly more common in group 1 than in group 2 (p Z 0.025). Frequency of the tower pattern was significantly higher in group 2 than in group 1 (p Z 0.006) (Summary table). Discussion No differences in agreement rates of UFM curve patterns were seen between two groups (small and normal VV). The authors thus suggest that UFM curve patterns can be validly assessed in children with DUI and with small VV. It was found that the bell pattern was significantly more common among children with normal VV, whereas the tower pattern was significantly more common among children with small VV. The tower pattern reflects an overactive bladder. The present results suggest that some children have DUI that is not attributable to urgency. Conclusion Reproducibility of UFM curve patterns might be properly assessed even in children with DUI and with small VV. This result suggests the presence of various pathological conditions other than the conditions with urgency underlying DUI.
Comparison of group 1 and 2 using several UFM curve patterns.
UFM curve patterns
Group 1 (n Z 45)
Group 2 (n Z 74)
P
Bell Tower Staccato Plateau Unclassified
29 5 7 2 2
32 25 5 3 9
0.025 0.006 0.122 0.918 0.159
UFM, uroflowmetry. https://doi.org/10.1016/j.jpurol.2019.09.008 1477-5131/ª 2019 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
+
MODEL
1.e2
T. Hyuga et al.
Introduction
Procedure for UFM
In children with daytime urinary incontinence (DUI), uroflowmetry (UFM) has been recommended as a minimally invasive standard examination to assess voiding status [1,2]. Uroflowmetry curve patterns have been reported as useful [2]. The International Children’s Continence Society (ICCS) recommends performing UFM twice in children and taking additional measurements when two measurements show different UFM curve patterns to improve accuracy and reliability when interpreting test results. A voided volume (VV) of <50% of the expected bladder capacity for age is considered small VV. A small VV causes changes in UFM curve characteristics. A VV 50% of expected bladder capacity for age is required to assess UFM curve patterns [3e5]. To the best of the authors’ knowledge, no study has been published on the reproducibility of consecutive UFM measurements in the same patient, and no clear consensus has been reached on the criterion for evaluating UFM curve patterns (50% of expected bladder capacity for age) [6]. Because Japanese children reportedly show small bladder capacities, expected bladder capacity for age in this population should be assessed using different criteria [7]. If UFM is performed 3 times in Japanese children with DUI, many of whom show a VV of <50% of expected bladder capacity for age, the value of UFM will be reduced. The authors therefore performed 3 consecutive UFM assessments in each child on the same day at their outpatient clinic to examine functional bladder capacity and the reproducibility of UFM curve patterns in Japanese children with DUI.
An uroflowmeter (Flowmaster; Medical Measurement Systems, Mississauga, ON, Canada) was used to perform UFM. In the outpatient clinic, the child drank 300 mL of water to promote sufficient urination. Uroflowmetry was then performed for 3 consecutive voiding episodes with a maximum desire to void on the same day. When children felt a maximum desire to void, they voided on their own volition. Residual urine was measured within 5 min after voiding.
Materials and methods Patients Among 330 children (197 boys and 133 girls) who presented to the Department of Pediatric Urology at Children’s Medical Center Tochigi, Jichi Medical University, between April 2008 and December 2015 with a chief complaint of primary DUI, 172 underwent UFM 3 times on the same day. Urinary incontinence meant involuntary intermittent leakage of urine. Secondary daytime DUI was reserved for those children who have had a previous dry period of >6 months. Otherwise, it was termed primary DUI [3]. The exclusion criteria comprised the following: secondary cases; presence of neurological abnormalities, such as spina bifida; history of urinary tract surgery for hypospadias or other conditions; a VV >300 mL or <20 mL, for the reasons described in the following section (see ‘Assessment of UFM curve pattern, parameters and reproducibility’); or performance of the UFM while receiving oral anticholinergic agents in consideration of the effect of these agents. After excluding these children, this study included 119 children with a complete set of 3 UFM measurements (79 boys and 40 girls with a total of 357 UFM measurements). The mean age of the participants was 8 years and 6 months (range: 5 years and 2 months to 12 years and 11 months).
Assessment of UFM curve pattern, parameters and reproducibility Automated objective patterning software developed in the Department of Urology at Kyoto University was used to analyze UFM curve patterns [8]. Because UFM curve patterns for a VV of <20 mL or >300 mL could not be analyzed using this software, children with UFM curve patterns based on these volumes were excluded. Uroflowmetry curve patterns were classified into 5 types: bell, tower, staccato, plateau, and intermittent. Austin et al. [3] revealed the shape of the 5 types of UFM curve patterns in this report. The UFM curve pattern shown by at least 2 of the 3 UFM measurements was defined as the UFM curve pattern for the child. Children showing 3 different UFM curve patterns were defined as unclassified. Regarding UFM parameters, the VV ratio was defined as the ratio of VV divided by the expected bladder capacity for age (30 þ age in years 30), while the residual urine rate was used for the comparison of residual urine [3,9]. First, the authors verified the method of 3 consecutive UFMs (1st, 2nd, and 3rd UFM) on the same day. The authors investigated UFM parameters (VV, residual urine, and maximum flow rate) each time. Normal VV was defined as a VV 50% of expected bladder capacity for age, and small VV, as a VV of <50%. Children were then classified into two groups according to small VV: small VV identified in 0e1 of the 3 UFM measurements (group 1; normal VV) or small VV in 2e3 UFM measurements (group 2; small VV). Agreement of UFM curve patterns among the 3 UFM measurements was classified as follows: complete agreement, a state in which all 3 UFM curve patterns were identical; partial agreement, where 2 UFM curve patterns were identical; or no agreement, where none of the 3 UFM curve patterns were identical. The authors investigated whether agreement rates of UFM curve patterns would differ between the two groups of children with DUI. The most characteristic pattern of UFM curve patterns for each group was also determined. In addition, UFM parameters between two groups were compared.
Statistical analysis Statistical analyses were performed using the Chi-squared test and ManneWhitney U test. Values of P<0.05 were considered significant. Regarding analysis of UFM parameters (1st, 2nd, and 3rd UFM), the Student t-test and
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
+
MODEL
Uroflowmetry curve patterns in Japanese children Bonferroni correction were used, and values of P < 0.05/3 were considered significant.
Results All UFM curve patterns were of the same type in 54 children, and 2 UFM curve patterns were identical in 54 children. All UFM curve patterns were different in 11 children. Children with at least 1 of the 3 UFM curve patterns showing a different type from the others accounted for 54.6% (65/ 119). Uroflowmetry curve patterns were determined in 90.5% (108/119) of children as bell (n Z 61), tower (n Z 30), staccato (n Z 12), or plateau (n Z 5), but remained unclassified in 9.5% (11/119). In 26 cases (21.8%), the UFM curve pattern from the first UFM measurement differed from the curves in both the second and third measurements. For UFM parameters of 3 consecutive UFMs (1st, 2nd, and 3rd UFM), Bonferroni correction was used, and values of P < 0.05/3 were considered significant (Table 1). There were significant difference between the 1st and 3rd UFM measurement regarding VV and maximum flow rate and between the 2nd and 3rd UFM measurement regarding residual urine and maximum flow rate. Group 1 comprised 45 children, including 24 identified as having normal VV based on all 3 UFM measurements and 21 identified as having VV in 2 of 3 UFM measurements. Group 2 comprised 74 children, including 32 with small VV indicated by 2 UFM measurements and 42 indicated by all 3 measurements. Only 24 Japanese children (20.2%) had a VV 50% in all 3 UFM measurements. The mean age of group 1 was 101.6 21.9 months and that of group 2 was 102.4 18.5 months. There was no significant difference (P Z 0.831). Rates of complete, partial, and no agreement did not differ significantly between groups (P Z 0.226) (Table 2). Inclusion of children with small VV did not change the agreement rate for UFM curve patterns. Bell patterns were significantly more common in group 1 than in group 2 (P Z 0.025). The frequency of the bell
Table 1 UFM).
Results of UFM parameters (1st, 2nd, and 3rd
UFM parameters 1st UFM Voided volume (%) Residual urine (%) Maximum flow rate (ml/s)
Voided volume (%) Residual urine (%) Maximum flow rate (ml/s)
2nd UFM
3rd UFM
44.9 21.9
48.8 21.9
51.2 19.5
9.2 10.0
10.9 10.1
8.5 8.4
19.3 7.5
19.9 7.0
21.1 7.3
1.e3 pattern in all UFM patterns was decreased in group 2, whereas that of the tower pattern was significantly increased, compared with group 1 (P Z 0.006) (Table 3). The mean of UFM parameters were compared between two groups (Table 4). There were no significant differences between the two groups in residual urine and maximum flow rate.
Discussion The ICCS recommends taking additional measurements when 2 UFM measurements show different curves [10]. Considering this recommendation, UFM was introduced 3 times on the same day for many children with DUI in the authors’ clinic. Uroflowmetry curve patterns were determined based on the results of these 3 measurements. The authors determined whether the method of performing 3 consecutive UFMs on the same day could be properly evaluated because the children might be tired or hurried at the end of the day after performing 2 of the UFMs. The authors determined whether the children had inadequate urination gradually, especially in the 3rd UFM. As seen in Table 1, VV tended to be larger and residual urine (RU) tended to be smaller in the 3rd UFM, that is, the children had adequate urination. Therefore, the results of 3 consecutive UFMs on the same day can be properly evaluated. Bower et al. [11] performed UFM multiple times in healthy children without any lower urinary tract symptoms and divided UFM curve patterns into 3 types for analysis: bell, staccato, and intermittent patterns. The bell pattern was observed in 63% of children, whereas the staccato pattern was observed in 30%. They reported that UFM curve patterns did not change in a series of multiple UFM measurements. In the study of incontinent children, however, UFM curve patterns changed at least once in 55% of cases. Uroflowmetry curve patterns could be determined in 108 of the 119 children (90.5%) by selecting the predominant curve pattern to represent each case. In 21.8% of these cases, UFM curve patterns may have been misread if UFM had been performed only once. No differences in agreement rates of UFM curve patterns were seen between children with small and normal VV. The ICCS recommendations indicate that because UFM curve patterns change in children with a VV of <50% of expected bladder capacity for age, a VV 50% is required to assess UFM curve patterns [3e5]. However, no clear consensus has been reached on this criterion [6]. To the best of the authors’ knowledge, this is the first study comparing UFM
p (1st vs 2nd) p (1st vs 3rd) p (2nd vs 3rd)
Table 2
0.042
0.004
0.148
Reproducibility
Group 1 (n Z 45)
Group 2 (n Z 74)
0.134
0.496
0.014
0.183
<0.001
0.006
Complete agreement Partial agreement No agreement
24 19 2
30 35 9 Chi-squared P Z 0.226
UFM, uroflowmetry.
Results of reproducibility of UFM curve patterns.
UFM, uroflowmetry.
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
+
MODEL
1.e4
T. Hyuga et al.
Table 3 Comparison of group 1 and 2 using several UFM curve patterns. UFM curve pattern
Group 1 (n Z 45)
Group 2 (n Z 74)
P
Bell Tower Staccato Plateau Unclassified
29 5 7 2 2
32 25 5 3 9
0.025 0.006 0.122 0.918 0.159
UFM, uroflowmetry.
curve patterns in children with DUI under various conditions of expected bladder capacity for age. It was found that the rate of agreement of UFM curve patterns among the 3 measurements did not change even in children with small VV. The authors thus suggest that UFM curve patterns can be validly assessed in children with DUI and with small VV. Yang et al. [6] examined voiding patterns using home UFM devices multiple times in 38 children with DUI or nocturnal enuresis. They performed UFM measurements while the children were divided into those with a VV 50% of the expected bladder capacity for age and those with a VV of <50% [6]. In that study, only 34% of Taiwanese children included showed a VV 50%. The present study complied with ICCS standards for bladder capacity because standardization of the evaluation criteria was considered important. Consequently, this study included more children with DUI and with a VV of <50%, and only 24 Japanese children (20.2%) had a VV 50% in all 3 UFM measurements. No reports have compared UFM curve patterns between the clinic and home. However, no significant difference in bladder capacity has been reported between UFM in the clinic and a frequency volume chart [12]. The authors therefore performed UFM 3 times, in compliance with the ICCS standards. The characteristic UFM curve patterns between normal and small VV were different. It was found that the bell pattern was significantly more common among children with normal VV, whereas the tower pattern was significantly more common among children with small VV. The typical type of DUI in children is considered to be urge urinary incontinence with underlying overactive bladder (OAB). The tower pattern reflects an OAB, whereas the bell pattern reflects normal voiding [2,3,13]. However, the accuracy of UFM is not fully understood yet. Fuyama et al. [14] reported that a tower curve was observed in 25.6% of children with OAB and a bell-shaped curve in 74.4%.
Although children may not show urgency during UFM, the present results suggest that some children have DUI that is not attributable to urgency. In some articles, OAB was defined by various symptoms and conditions [3,13,14]. von Gontard et al. [15] reported that voiding postponement associated with bladder overactivity was related to behavioral problem [3]. Therefore, UFM curve findings were bell-shaped curve patterns [16]. Wenske et al. [17] reported that 86% of children with dysfunctional voiding have staccato or interrupted UFM curve patterns. There were some reports of UFM with electromyography (EMG) [18,19]. The key limitation of this study was the retrospective study design. In addition, this study targeted children with DUI and lacked a control group. The UFMs were performed at maximum desire to void, and the patients voided on their own volition. From this point, it may be difficult to create a reliable control group with small voiding volumes; it means to ask the people to void before they reach maximum desire to void if you expect them to have otherwise normal voiding volumes. In future, the authors intend to conduct a further study in which UFM is consecutively performed 3 times for healthy children. Furthermore, this study lacked EMG and urodynamic analysis. If UFM with EMG was used, the other children with dysfunctional voiding might have been revealed.
Conclusion The reproducibility of UFM curve patterns was confirmed even in children with DUI and with small VV. The study findings suggest that UFM curve patterns could also be assessed in these children. The bell pattern was observed in more than half (51.3%) of the children with DUI, and the frequency was higher in those with a VV 50% of expected functional bladder capacity for age. The children with DUI may not have an abnormal UFM. This result suggests the presence of various pathological conditions other than the conditions with urgency underlying DUI, and the practitioner should evaluate other several etiologies.
Author statements Acknowledgments None.
Ethical approval Table 4
UFM parameters between two groups.
UFM parameters
Group 1 (n Z 45)
Group 2 (n Z 74)
P
Voided volume (%) Residual urine (%) Maximum flow rate (ml/s)
65.2 14.0 9.1 5.8 21.7 6.7
38.1 9.7 9.8 7.4 19.1 6.6
<0.001 0.841 0.064
UFM, uroflowmetry.
This study was approved by the Ethics Committee of Jichi Medical University (A17-RE050). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required. The description document was posted on the authors’ department’s website, and the content of the study was published on their hospital.
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
+
MODEL
Uroflowmetry curve patterns in Japanese children
1.e5
Funding None declared.
[10]
Competing interests The authors declare that have no conflict of interest. [11]
References [1] Hoebeke P, Bower W, Combs A, De Jong T, Yang S. Diagnostic evaluation of children with daytime incontinence. J Urol 2010; 183:699e703. https://doi.org/10.1016/j.juro.2009.10.038. [2] Drzewiecki BA, Bauer SB. Urodynamic testing in children: indications, technique, interpretation and significance. J Urol 2011;186:1190e7. https: //doi.org/10.1016/j.juro.2011.02.2692. [3]) Austin PF, Bauer SB, Bower W, Chase J, Franco I, Hoebeke P, et al. The standardization of terminology of lower urinary tract function in children and adolescents: update report from the Standardization Committee of the International Children’s Continence Society. J Urol 2014;191:1863e5. https://doi.org/10.1016/j.juro.2014.01.110. e13. [4] Bauer SB, Nijman RJ, Drzewiecki BA, Sillen U, Hoebeke P, International Children’s Continence Society. International children’s continence society standardization report on urodynamic studies of the lower urinary tract in children. Neurourol Urodyn 2015;34:640e7. https://doi.org/10.1002/nau. 22783. [5] Dogan HS, Akpinar B, Gurocak S, Akata D, Bakkaloglu M, Tekgul S. Non-invasive evaluation of voiding function in asymptomatic primary school children. Pediatr Nephrol 2008; 23(7):1115e22. https://doi.org/10.1007/s00467-008-0776-3. [6] Yang SS, Wang CC, Chen YT. Home uroflowmetry for the evaluation of boys with urinary incontinence. J Urol 2003;169: 1505e7. [7] Hamano S, Yamanishi T, Igarashi T, Murakami S, Ito H. Evaluation of functional bladder capacity in Japanese children. Int J Urol 1999;6:226e8. [8] Kanematsu A, Tanaka S, Johnin K, Kawai S, Nakamura S, Imamura M, et al. A multi-center study of pediatric uroflowmetry data using patterning software. J Pediatr Urol 2013; 9:57e61. https://doi.org/10.1016/j.jpurol.2011.12.001. [9] Neveus T. The new International Children’s Continence Society’s terminology for the paediatric lower urinary tract- why it
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
has been set up and why we should use it. Pediatr Nephrol 2008;23(11):1931e2. https://doi.org/10.1007/s00467-0080865-3. Neveus T, von Gontard A, Hoebeke P, Hjalmas K, Bauer S, Bower W, et al. The standardization of terminology of lower urinary tract function in children and adolescents: report from the Standardisation Committee of the International Children’s Continence Society. J Urol 2006;176:314e24. Bower WF, Kwok B, Yeung CK. Variability in normative urine flow rates. J Urol 2004;171:2657e9. Maternik M, Chudzik I, Krzeminska K, Zurowska A. Evaluation of bladder capacity in children with lower urinary tract symptoms: comparison of 48-hour frequency/volume charts and uroflowmetry measurements. J Pediatir Urol 2016;12:214. https://doi.org/10.1016/j.jpurol.2016.04.004. e1-5. Van Batavia JP, Combs AJ. The role of non-invasive testing in evaluation and diagnosis of pediatric lower urinary tract dysfunction. Curr Urol Rep 2018;19(5):34. Fuyama M, Ikeda H, Oyake C, Onuki Y, Watanabe T, Isoyama K. Clinical features of, and association of bladder ultrasound and uroflowmetry with, overactive bladder recovery period in children. Pediatr Int 2018;60(6):569e75. https: //doi.org/10.1111/ped.13577. von Gontard A, Lettgen B, Olbing H, Heiken-Lowenau C, Gaebel E, Schmitz I. Behavioural problems in children with urge incontinence and voiding postponement: a comparison of a paediatric and child psychiatric sample. Br J Urol 1998; 81(Suppl 3):100e6. Lettgen B, von Gontard A, Olbing H, Heiken-Lowenau C, Gaebel E, Schmitz I. Urge incontinence and voiding postponement in children: somatic and psychosocial factors. Acta Paediatr 2002;91(9):978e84. Wenske S, Van Batavia JP, Combs AJ, Glassberg KI. Analysis of uroflow patterns in children with dysfunctional voiding. J Pediatr Urol 2014;10(2):250e4. https://doi.org/10.1016/j. jpurol.2013.10.010. Van Batavia JP, Combs AJ, Fast AM, Glassberg KI. Use of noninvasive uroflowmetry with simultaneous electromyography to monitor patient response to treatment for lower urinary tract conditions. J Pediatr Urol 2014;10(3):532e7. https: //doi.org/10.1016/j.jpurol.2013.11.015. Samjin B, Van Laecke E, Vande Walle J, Pascal A, Deschepper E, Renson C, et al. Uroflow measurement combined with electromyography testing of the pelvic floor in healthy children. Neurourol Urodyn 2019;38(1):231e8. https: //doi.org/10.1002/nau.23836.
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
MODEL
Journal of Pediatric Urology (xxxx) xxx xxx
a
Department of Pediatric Urology, Jichi Medical University, Children’s Medical Center Tochigi, Tochigi, Japan
Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence? Taiju Hyuga a,b,*, Shigeru Nakamura a, Shina Kawai a, Kazuya Tanabe a, Makiko Naka Mieno c, Hideo Nakai a
b
Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
c Department of Medical Informatics, Center for Information, Jichi Medical University, Tochigi, Japan
* Corresponding author. Department of Pediatric Urology, Jichi Medical University, Children’s Medical Center Tochigi, 3311-1, Yakushiji Shimotsuke-shi, Tochigi 329-0498 Japan. Tel.: þ81 285 44 2111. , Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), 811-1, Kimiidera, Wakayama 641-8509, Japan. Tel.: þ81 73 447 2300. [email protected] (T. Hyuga) Keywords Uroflowmetry; Reproducibility; Small voided volume; Curve
Abbreviations DUI, Daytime Urinary Incontinence; UFM, Uroflowmetry; ICCS, International Children’s Continence Society; VV, Voided Volume; OAB, Overactive Bladder; EMG, Electromyography Received 20 December 2018 Accepted 5 September 2019 Available online xxx
Summary Background A voided volume (VV) of <50% of the expected bladder capacity for age is considered small VV. It was recommended that a VV 50% of expected bladder capacity for age is required to assess uroflowmetry (UFM) curves because a small VV causes changes in UFM curve characteristics. However, no clear consensus has been reached on the criterion for evaluating UFM curve patterns. Objective The aim of the study was to evaluate the reproducibility and characteristics of UFM curve patterns in children with daytime urinary incontinence (DUI) and with a variety of VVs. Methods This study investigated 119 children (79 boys and 40 girls) with primary DUI who underwent UFM 3 times on the same day and were classified into two groups: small VV (<50% of expected bladder capacity for age) in 0e1 of the 3 UFM measurements (group 1; normal VV) or in 2e3 of the 3 UFM measurements (group 2; small VV). The authors then evaluated the agreement of UFM curve patterns among the 3 measurements, classifying complete, partial, or no agreement according to the number of identical curve patterns. The authors also evaluated the most characteristic patterns of UFM curve patterns for each group.
Summary table
Results Group 1 comprised 45 children, and group 2 comprised 74 children. Rates of complete agreement (group 1, 24/45; group 2, 30/74), partial agreement (group 1, 19/45; group 2, 35/74), and no agreement (group 1, 2/45; group 2, 9/74) did not differ significantly between groups (p Z 0.226). Bell curve patterns were significantly more common in group 1 than in group 2 (p Z 0.025). Frequency of the tower pattern was significantly higher in group 2 than in group 1 (p Z 0.006) (Summary table). Discussion No differences in agreement rates of UFM curve patterns were seen between two groups (small and normal VV). The authors thus suggest that UFM curve patterns can be validly assessed in children with DUI and with small VV. It was found that the bell pattern was significantly more common among children with normal VV, whereas the tower pattern was significantly more common among children with small VV. The tower pattern reflects an overactive bladder. The present results suggest that some children have DUI that is not attributable to urgency. Conclusion Reproducibility of UFM curve patterns might be properly assessed even in children with DUI and with small VV. This result suggests the presence of various pathological conditions other than the conditions with urgency underlying DUI.
Comparison of group 1 and 2 using several UFM curve patterns.
UFM curve patterns
Group 1 (n Z 45)
Group 2 (n Z 74)
P
Bell Tower Staccato Plateau Unclassified
29 5 7 2 2
32 25 5 3 9
0.025 0.006 0.122 0.918 0.159
UFM, uroflowmetry. https://doi.org/10.1016/j.jpurol.2019.09.008 1477-5131/ª 2019 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
+
MODEL
1.e2
T. Hyuga et al.
Introduction
Procedure for UFM
In children with daytime urinary incontinence (DUI), uroflowmetry (UFM) has been recommended as a minimally invasive standard examination to assess voiding status [1,2]. Uroflowmetry curve patterns have been reported as useful [2]. The International Children’s Continence Society (ICCS) recommends performing UFM twice in children and taking additional measurements when two measurements show different UFM curve patterns to improve accuracy and reliability when interpreting test results. A voided volume (VV) of <50% of the expected bladder capacity for age is considered small VV. A small VV causes changes in UFM curve characteristics. A VV 50% of expected bladder capacity for age is required to assess UFM curve patterns [3e5]. To the best of the authors’ knowledge, no study has been published on the reproducibility of consecutive UFM measurements in the same patient, and no clear consensus has been reached on the criterion for evaluating UFM curve patterns (50% of expected bladder capacity for age) [6]. Because Japanese children reportedly show small bladder capacities, expected bladder capacity for age in this population should be assessed using different criteria [7]. If UFM is performed 3 times in Japanese children with DUI, many of whom show a VV of <50% of expected bladder capacity for age, the value of UFM will be reduced. The authors therefore performed 3 consecutive UFM assessments in each child on the same day at their outpatient clinic to examine functional bladder capacity and the reproducibility of UFM curve patterns in Japanese children with DUI.
An uroflowmeter (Flowmaster; Medical Measurement Systems, Mississauga, ON, Canada) was used to perform UFM. In the outpatient clinic, the child drank 300 mL of water to promote sufficient urination. Uroflowmetry was then performed for 3 consecutive voiding episodes with a maximum desire to void on the same day. When children felt a maximum desire to void, they voided on their own volition. Residual urine was measured within 5 min after voiding.
Materials and methods Patients Among 330 children (197 boys and 133 girls) who presented to the Department of Pediatric Urology at Children’s Medical Center Tochigi, Jichi Medical University, between April 2008 and December 2015 with a chief complaint of primary DUI, 172 underwent UFM 3 times on the same day. Urinary incontinence meant involuntary intermittent leakage of urine. Secondary daytime DUI was reserved for those children who have had a previous dry period of >6 months. Otherwise, it was termed primary DUI [3]. The exclusion criteria comprised the following: secondary cases; presence of neurological abnormalities, such as spina bifida; history of urinary tract surgery for hypospadias or other conditions; a VV >300 mL or <20 mL, for the reasons described in the following section (see ‘Assessment of UFM curve pattern, parameters and reproducibility’); or performance of the UFM while receiving oral anticholinergic agents in consideration of the effect of these agents. After excluding these children, this study included 119 children with a complete set of 3 UFM measurements (79 boys and 40 girls with a total of 357 UFM measurements). The mean age of the participants was 8 years and 6 months (range: 5 years and 2 months to 12 years and 11 months).
Assessment of UFM curve pattern, parameters and reproducibility Automated objective patterning software developed in the Department of Urology at Kyoto University was used to analyze UFM curve patterns [8]. Because UFM curve patterns for a VV of <20 mL or >300 mL could not be analyzed using this software, children with UFM curve patterns based on these volumes were excluded. Uroflowmetry curve patterns were classified into 5 types: bell, tower, staccato, plateau, and intermittent. Austin et al. [3] revealed the shape of the 5 types of UFM curve patterns in this report. The UFM curve pattern shown by at least 2 of the 3 UFM measurements was defined as the UFM curve pattern for the child. Children showing 3 different UFM curve patterns were defined as unclassified. Regarding UFM parameters, the VV ratio was defined as the ratio of VV divided by the expected bladder capacity for age (30 þ age in years 30), while the residual urine rate was used for the comparison of residual urine [3,9]. First, the authors verified the method of 3 consecutive UFMs (1st, 2nd, and 3rd UFM) on the same day. The authors investigated UFM parameters (VV, residual urine, and maximum flow rate) each time. Normal VV was defined as a VV 50% of expected bladder capacity for age, and small VV, as a VV of <50%. Children were then classified into two groups according to small VV: small VV identified in 0e1 of the 3 UFM measurements (group 1; normal VV) or small VV in 2e3 UFM measurements (group 2; small VV). Agreement of UFM curve patterns among the 3 UFM measurements was classified as follows: complete agreement, a state in which all 3 UFM curve patterns were identical; partial agreement, where 2 UFM curve patterns were identical; or no agreement, where none of the 3 UFM curve patterns were identical. The authors investigated whether agreement rates of UFM curve patterns would differ between the two groups of children with DUI. The most characteristic pattern of UFM curve patterns for each group was also determined. In addition, UFM parameters between two groups were compared.
Statistical analysis Statistical analyses were performed using the Chi-squared test and ManneWhitney U test. Values of P<0.05 were considered significant. Regarding analysis of UFM parameters (1st, 2nd, and 3rd UFM), the Student t-test and
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
+
MODEL
Uroflowmetry curve patterns in Japanese children Bonferroni correction were used, and values of P < 0.05/3 were considered significant.
Results All UFM curve patterns were of the same type in 54 children, and 2 UFM curve patterns were identical in 54 children. All UFM curve patterns were different in 11 children. Children with at least 1 of the 3 UFM curve patterns showing a different type from the others accounted for 54.6% (65/ 119). Uroflowmetry curve patterns were determined in 90.5% (108/119) of children as bell (n Z 61), tower (n Z 30), staccato (n Z 12), or plateau (n Z 5), but remained unclassified in 9.5% (11/119). In 26 cases (21.8%), the UFM curve pattern from the first UFM measurement differed from the curves in both the second and third measurements. For UFM parameters of 3 consecutive UFMs (1st, 2nd, and 3rd UFM), Bonferroni correction was used, and values of P < 0.05/3 were considered significant (Table 1). There were significant difference between the 1st and 3rd UFM measurement regarding VV and maximum flow rate and between the 2nd and 3rd UFM measurement regarding residual urine and maximum flow rate. Group 1 comprised 45 children, including 24 identified as having normal VV based on all 3 UFM measurements and 21 identified as having VV in 2 of 3 UFM measurements. Group 2 comprised 74 children, including 32 with small VV indicated by 2 UFM measurements and 42 indicated by all 3 measurements. Only 24 Japanese children (20.2%) had a VV 50% in all 3 UFM measurements. The mean age of group 1 was 101.6 21.9 months and that of group 2 was 102.4 18.5 months. There was no significant difference (P Z 0.831). Rates of complete, partial, and no agreement did not differ significantly between groups (P Z 0.226) (Table 2). Inclusion of children with small VV did not change the agreement rate for UFM curve patterns. Bell patterns were significantly more common in group 1 than in group 2 (P Z 0.025). The frequency of the bell
Table 1 UFM).
Results of UFM parameters (1st, 2nd, and 3rd
UFM parameters 1st UFM Voided volume (%) Residual urine (%) Maximum flow rate (ml/s)
Voided volume (%) Residual urine (%) Maximum flow rate (ml/s)
2nd UFM
3rd UFM
44.9 21.9
48.8 21.9
51.2 19.5
9.2 10.0
10.9 10.1
8.5 8.4
19.3 7.5
19.9 7.0
21.1 7.3
1.e3 pattern in all UFM patterns was decreased in group 2, whereas that of the tower pattern was significantly increased, compared with group 1 (P Z 0.006) (Table 3). The mean of UFM parameters were compared between two groups (Table 4). There were no significant differences between the two groups in residual urine and maximum flow rate.
Discussion The ICCS recommends taking additional measurements when 2 UFM measurements show different curves [10]. Considering this recommendation, UFM was introduced 3 times on the same day for many children with DUI in the authors’ clinic. Uroflowmetry curve patterns were determined based on the results of these 3 measurements. The authors determined whether the method of performing 3 consecutive UFMs on the same day could be properly evaluated because the children might be tired or hurried at the end of the day after performing 2 of the UFMs. The authors determined whether the children had inadequate urination gradually, especially in the 3rd UFM. As seen in Table 1, VV tended to be larger and residual urine (RU) tended to be smaller in the 3rd UFM, that is, the children had adequate urination. Therefore, the results of 3 consecutive UFMs on the same day can be properly evaluated. Bower et al. [11] performed UFM multiple times in healthy children without any lower urinary tract symptoms and divided UFM curve patterns into 3 types for analysis: bell, staccato, and intermittent patterns. The bell pattern was observed in 63% of children, whereas the staccato pattern was observed in 30%. They reported that UFM curve patterns did not change in a series of multiple UFM measurements. In the study of incontinent children, however, UFM curve patterns changed at least once in 55% of cases. Uroflowmetry curve patterns could be determined in 108 of the 119 children (90.5%) by selecting the predominant curve pattern to represent each case. In 21.8% of these cases, UFM curve patterns may have been misread if UFM had been performed only once. No differences in agreement rates of UFM curve patterns were seen between children with small and normal VV. The ICCS recommendations indicate that because UFM curve patterns change in children with a VV of <50% of expected bladder capacity for age, a VV 50% is required to assess UFM curve patterns [3e5]. However, no clear consensus has been reached on this criterion [6]. To the best of the authors’ knowledge, this is the first study comparing UFM
p (1st vs 2nd) p (1st vs 3rd) p (2nd vs 3rd)
Table 2
0.042
0.004
0.148
Reproducibility
Group 1 (n Z 45)
Group 2 (n Z 74)
0.134
0.496
0.014
0.183
<0.001
0.006
Complete agreement Partial agreement No agreement
24 19 2
30 35 9 Chi-squared P Z 0.226
UFM, uroflowmetry.
Results of reproducibility of UFM curve patterns.
UFM, uroflowmetry.
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
+
MODEL
1.e4
T. Hyuga et al.
Table 3 Comparison of group 1 and 2 using several UFM curve patterns. UFM curve pattern
Group 1 (n Z 45)
Group 2 (n Z 74)
P
Bell Tower Staccato Plateau Unclassified
29 5 7 2 2
32 25 5 3 9
0.025 0.006 0.122 0.918 0.159
UFM, uroflowmetry.
curve patterns in children with DUI under various conditions of expected bladder capacity for age. It was found that the rate of agreement of UFM curve patterns among the 3 measurements did not change even in children with small VV. The authors thus suggest that UFM curve patterns can be validly assessed in children with DUI and with small VV. Yang et al. [6] examined voiding patterns using home UFM devices multiple times in 38 children with DUI or nocturnal enuresis. They performed UFM measurements while the children were divided into those with a VV 50% of the expected bladder capacity for age and those with a VV of <50% [6]. In that study, only 34% of Taiwanese children included showed a VV 50%. The present study complied with ICCS standards for bladder capacity because standardization of the evaluation criteria was considered important. Consequently, this study included more children with DUI and with a VV of <50%, and only 24 Japanese children (20.2%) had a VV 50% in all 3 UFM measurements. No reports have compared UFM curve patterns between the clinic and home. However, no significant difference in bladder capacity has been reported between UFM in the clinic and a frequency volume chart [12]. The authors therefore performed UFM 3 times, in compliance with the ICCS standards. The characteristic UFM curve patterns between normal and small VV were different. It was found that the bell pattern was significantly more common among children with normal VV, whereas the tower pattern was significantly more common among children with small VV. The typical type of DUI in children is considered to be urge urinary incontinence with underlying overactive bladder (OAB). The tower pattern reflects an OAB, whereas the bell pattern reflects normal voiding [2,3,13]. However, the accuracy of UFM is not fully understood yet. Fuyama et al. [14] reported that a tower curve was observed in 25.6% of children with OAB and a bell-shaped curve in 74.4%.
Although children may not show urgency during UFM, the present results suggest that some children have DUI that is not attributable to urgency. In some articles, OAB was defined by various symptoms and conditions [3,13,14]. von Gontard et al. [15] reported that voiding postponement associated with bladder overactivity was related to behavioral problem [3]. Therefore, UFM curve findings were bell-shaped curve patterns [16]. Wenske et al. [17] reported that 86% of children with dysfunctional voiding have staccato or interrupted UFM curve patterns. There were some reports of UFM with electromyography (EMG) [18,19]. The key limitation of this study was the retrospective study design. In addition, this study targeted children with DUI and lacked a control group. The UFMs were performed at maximum desire to void, and the patients voided on their own volition. From this point, it may be difficult to create a reliable control group with small voiding volumes; it means to ask the people to void before they reach maximum desire to void if you expect them to have otherwise normal voiding volumes. In future, the authors intend to conduct a further study in which UFM is consecutively performed 3 times for healthy children. Furthermore, this study lacked EMG and urodynamic analysis. If UFM with EMG was used, the other children with dysfunctional voiding might have been revealed.
Conclusion The reproducibility of UFM curve patterns was confirmed even in children with DUI and with small VV. The study findings suggest that UFM curve patterns could also be assessed in these children. The bell pattern was observed in more than half (51.3%) of the children with DUI, and the frequency was higher in those with a VV 50% of expected functional bladder capacity for age. The children with DUI may not have an abnormal UFM. This result suggests the presence of various pathological conditions other than the conditions with urgency underlying DUI, and the practitioner should evaluate other several etiologies.
Author statements Acknowledgments None.
Ethical approval Table 4
UFM parameters between two groups.
UFM parameters
Group 1 (n Z 45)
Group 2 (n Z 74)
P
Voided volume (%) Residual urine (%) Maximum flow rate (ml/s)
65.2 14.0 9.1 5.8 21.7 6.7
38.1 9.7 9.8 7.4 19.1 6.6
<0.001 0.841 0.064
UFM, uroflowmetry.
This study was approved by the Ethics Committee of Jichi Medical University (A17-RE050). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required. The description document was posted on the authors’ department’s website, and the content of the study was published on their hospital.
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008
+
MODEL
Uroflowmetry curve patterns in Japanese children
1.e5
Funding None declared.
[10]
Competing interests The authors declare that have no conflict of interest. [11]
References [1] Hoebeke P, Bower W, Combs A, De Jong T, Yang S. Diagnostic evaluation of children with daytime incontinence. J Urol 2010; 183:699e703. https://doi.org/10.1016/j.juro.2009.10.038. [2] Drzewiecki BA, Bauer SB. Urodynamic testing in children: indications, technique, interpretation and significance. J Urol 2011;186:1190e7. https: //doi.org/10.1016/j.juro.2011.02.2692. [3]) Austin PF, Bauer SB, Bower W, Chase J, Franco I, Hoebeke P, et al. The standardization of terminology of lower urinary tract function in children and adolescents: update report from the Standardization Committee of the International Children’s Continence Society. J Urol 2014;191:1863e5. https://doi.org/10.1016/j.juro.2014.01.110. e13. [4] Bauer SB, Nijman RJ, Drzewiecki BA, Sillen U, Hoebeke P, International Children’s Continence Society. International children’s continence society standardization report on urodynamic studies of the lower urinary tract in children. Neurourol Urodyn 2015;34:640e7. https://doi.org/10.1002/nau. 22783. [5] Dogan HS, Akpinar B, Gurocak S, Akata D, Bakkaloglu M, Tekgul S. Non-invasive evaluation of voiding function in asymptomatic primary school children. Pediatr Nephrol 2008; 23(7):1115e22. https://doi.org/10.1007/s00467-008-0776-3. [6] Yang SS, Wang CC, Chen YT. Home uroflowmetry for the evaluation of boys with urinary incontinence. J Urol 2003;169: 1505e7. [7] Hamano S, Yamanishi T, Igarashi T, Murakami S, Ito H. Evaluation of functional bladder capacity in Japanese children. Int J Urol 1999;6:226e8. [8] Kanematsu A, Tanaka S, Johnin K, Kawai S, Nakamura S, Imamura M, et al. A multi-center study of pediatric uroflowmetry data using patterning software. J Pediatr Urol 2013; 9:57e61. https://doi.org/10.1016/j.jpurol.2011.12.001. [9] Neveus T. The new International Children’s Continence Society’s terminology for the paediatric lower urinary tract- why it
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
has been set up and why we should use it. Pediatr Nephrol 2008;23(11):1931e2. https://doi.org/10.1007/s00467-0080865-3. Neveus T, von Gontard A, Hoebeke P, Hjalmas K, Bauer S, Bower W, et al. The standardization of terminology of lower urinary tract function in children and adolescents: report from the Standardisation Committee of the International Children’s Continence Society. J Urol 2006;176:314e24. Bower WF, Kwok B, Yeung CK. Variability in normative urine flow rates. J Urol 2004;171:2657e9. Maternik M, Chudzik I, Krzeminska K, Zurowska A. Evaluation of bladder capacity in children with lower urinary tract symptoms: comparison of 48-hour frequency/volume charts and uroflowmetry measurements. J Pediatir Urol 2016;12:214. https://doi.org/10.1016/j.jpurol.2016.04.004. e1-5. Van Batavia JP, Combs AJ. The role of non-invasive testing in evaluation and diagnosis of pediatric lower urinary tract dysfunction. Curr Urol Rep 2018;19(5):34. Fuyama M, Ikeda H, Oyake C, Onuki Y, Watanabe T, Isoyama K. Clinical features of, and association of bladder ultrasound and uroflowmetry with, overactive bladder recovery period in children. Pediatr Int 2018;60(6):569e75. https: //doi.org/10.1111/ped.13577. von Gontard A, Lettgen B, Olbing H, Heiken-Lowenau C, Gaebel E, Schmitz I. Behavioural problems in children with urge incontinence and voiding postponement: a comparison of a paediatric and child psychiatric sample. Br J Urol 1998; 81(Suppl 3):100e6. Lettgen B, von Gontard A, Olbing H, Heiken-Lowenau C, Gaebel E, Schmitz I. Urge incontinence and voiding postponement in children: somatic and psychosocial factors. Acta Paediatr 2002;91(9):978e84. Wenske S, Van Batavia JP, Combs AJ, Glassberg KI. Analysis of uroflow patterns in children with dysfunctional voiding. J Pediatr Urol 2014;10(2):250e4. https://doi.org/10.1016/j. jpurol.2013.10.010. Van Batavia JP, Combs AJ, Fast AM, Glassberg KI. Use of noninvasive uroflowmetry with simultaneous electromyography to monitor patient response to treatment for lower urinary tract conditions. J Pediatr Urol 2014;10(3):532e7. https: //doi.org/10.1016/j.jpurol.2013.11.015. Samjin B, Van Laecke E, Vande Walle J, Pascal A, Deschepper E, Renson C, et al. Uroflow measurement combined with electromyography testing of the pelvic floor in healthy children. Neurourol Urodyn 2019;38(1):231e8. https: //doi.org/10.1002/nau.23836.
Please cite this article as: Hyuga T et al., Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?, Journal of Pediatric Urology, https://doi.org/10.1016/j.jpurol.2019.09.008