EURURO Vol. 73 No. 1

E13 148

Letter to the Editor
Re: Alan D. Uren, Nikki Cotterill, Christopher Harding,
et al. Qualitative Exploration of the Patient Experience
of Underactive Bladder. Eur Urol 2017;72:402–7
Uren et al reported a remarkable initial exploration of
underactive bladder (UB) using a patient-reported outcome
(PRO). Although this is the first study to use a PRO for
exploration of UB and included subjects who had under-
gone a urodynamics study, there is a need for further
clarification for a better understanding of the study.
The terminology for UB still needs to be standardized
further and needs to be differentiated from detrusor
underactivity (DU) Considering the mixed and syn-
dromic clinical presentations of UB, it is necessary to
categorize DU etiologies in order to characterize UB . The
possible etiology categories for DU include neurogenic,
myogenic, iatrogenic, and idiopathic origins . Because of
the wide variance in symptomatic presentations according
to their origin, categorization is needed. Without this
categorization, the symptomatic presentation in this study
could be biased by the specific dominant etiology. For
example, nocturia was the most common frequent
symptom in this study; however, if the enrolled subjects
had a major disease that is a possible cause of nocturia, the
presentation of nocturia in the study cannot be general-
ized. Nocturia is the most common symptom among
elderly people , and subjects included in this study
could have experienced nocturia that was not really related
to UB. The main purpose of a PRO in this study was to
detect the most bothersome symptom. In general, urgency
or urge incontinence is the most bothersome symptom
which needs to be adopted differently according to the
baseline etiology.
Second, although the study presents novel results using a
PRO, a detailed description of the methodology, including
the structure of the questionnaires, is needed. While
developing the questionnaire, validation is needed to adopt
it as a PRO. To achieve its main purpose, a PRO usually
includes not only validity and reliability but also respon-
siveness. Although the measurement tool used in this study
was a part of a pioneer investigation, a further validated
measurement tool that considers responsiveness is needed.
The ultimate goal of a PRO in a clinical study is to determine
patient satisfaction after a specific treatment. Moreover, the
main purpose in using a PRO is to quantify responsiveness
among patients, and may be adopted differently according
to the country, disease, and socioeconomic circumstances
. Responsiveness includes two categories, an anchor-
based method and a distribution-based method, that need
to be considered after statistical validation. Hence, the
authors’ comments on the lack of requirement for the exact
representative sample means that the PRO cannot be
adopted in a future study considering responsiveness.
Furthermore, potential biases might arise from the semi-
structured interviews without bracketing or verification of
patients, and it would be better to describe this as a
limitation of the study.
In conclusion, this novel study could be refined in the
near future by categorizing possible UB etiologies and by
adopting a more statistically generated PRO.
Conflicts of interest: The authors have nothing to disclose.
Acknowledgments: This study was supported by Soonchunhyang
University Research Fund. The sponsor played a role in manuscript
preparation.
References
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ava ilable at
journal homepage:
DOI of original article: .
0302-2838/© 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.