EURURO Vol. 72 No. 3

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while the results are certainly thought-provoking, they
should be interpreted with this in mind.
In spite of these inherent drawbacks, the study gives us
unique new insights into the subjective experience of patients
with DU. It also provides an important framework for the
future development of a patient-reported UAB outcome
measure as promised by the authors. It is clear that a
concerted research effort is needed to improve our under-
standing of DU and UAB. For this, researchers must agree on
definitions and it will be important to distinguish between
subjective UAB and urodynamic DU. Recognizing that
symptoms of poor bladder emptying may be caused by
both obstruction and a lack of detrusor contraction, we
proposed an adjusted definition: Underactive bladder is the
subjective feeling of prolonged urination time, slow stream,
and hesitancy, which may or may not be associated with
poor bladder emptying and subsequent storage symptoms
in men and women without evidence of any outlet
obstruction . Meanwhile, a bladder contractility index of
<100 in men and a detrusor pressure at maximum flow of
<20 cm H2O in women used as thresholds by the authors
would represent reasonable definitions of urodynamic DU,
at least for research purposes.
Conflicts of interest: The authors have nothing to disclose.
References
[1]
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[2]
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[3]
[4]
[5]
[6]
Platinum Priority
Reply from Authors re: Mikkel Fode, Jens Sønksen.
Towards a [5_T D$DIFF ]Greater [6_TD$ DIFF]Understanding of [ 7_TD$D IFF]Underactive
[8_TD$DIFF]Bladder. Eur Urol 2017;72:408–9
Alan D. Uren Nikki Cotterill Christopher Harding
Christopher Hillary Christopher Chapple
Monique Klaver Dominique Bongaerts Zalmai Hakimi
Paul Abrams
a
[1_TD$DIFF]Bristol Urological Institute [9_TD$DIFF], Southmead Hospital, Bristol, UK; bDepartment
of Urology, Freeman Hospital, Newcastle, UK; c Department of Urology,
Royal Hallamshire Hospital, Sheffield, UK; d Astellas Pharma, Leiden,
The Netherlands
The editorial comments by Fode and Sønksen [1] on our
study [2] are most welcome and raise a number of
challenging issues. They are correct in suggesting that the
strands of our underactive bladder (UAB)/detrusor under-
activity (DU) research programme is work in progress.
Further work is ongoing to develop the ICIQ-UAB patient-
reported outcome measure, noninvasive methods of diag-
nosing DU, and a more precise way of defining DU.
For the modified definition proposed by Fode and
Sønksen, we would like to draw attention to the recently
published symptomatic definition proposed by the stan-
dardisation subcommittee of the International Continence
Society included in a recent book by Chapple et al [3]:
‘‘Underactive bladder is characterised by a slow urinary
stream, hesitancy and straining to void, with or without a
feeling of incomplete bladder emptying and dribbling, often
with storage symptoms’’. However, we would suggest that
the current proposed definition above, which we support at
this stage, is unlikely to be the definitive one in view of the
ongoing research efforts of many.
The editorial also raises further discussion as to how
closely linked DU is to what has become termed UAB. This
raises the question of whether all patients with a urodyna-
mically confirmed diagnosis of DU are considered to have
UAB, or only when such patients demonstrate symptoms
such as slow flow, hesitancy, and straining. Our qualitative
exploration of the reported symptoms [2] demonstrates that
in patients with confirmed DU, the actual subjective
reporting of symptoms associated with DU can be relatively
low. There are reasons why a patient may not volunteer
symptoms; for example, theymay have had symptoms for so
long that they have not noticed a deterioration over time.
Perhaps we can learn from the relationships between
overactive bladder (OAB) and detrusor overactivity (DO).
We see patients without OAB symptoms who demonstrate
involuntary detrusor contractions during urodynamics that
are characteristic of DO, but do not report urgency. We are
happy to accept such findings and report ‘‘asymptomatic
DO’’. Similarly, we see DU on voiding cystometry in patients
without voiding symptoms. Hence, we recommend that
DOIs of original articles: ,
.
* Corresponding author. Bristol Urological Institute, Learning and Re-
search Building, Southmead Hospital, Bristol BS10 5NB, UK.
Tel. +44 117 4147934.
E-mail address: (A.D. Uren).
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