Vol 13 No 04 July-August 2016 2784
FEMALE UROLOGY
Is There a Role for Urodynamic Study in Women with Urinary
Incontinence?
Elnaz Ayati,1 Zinat Ghanbari,2** Mohsen Ayati,3* Erfan Amini3, Maryam Deldar Pesikhani2
Purpose: To compare clinical and urodynamic study (UDS) findings in Iranian women with mixed or stress UI
(Urinary Incontinence).
Materials and methods: A total of 132 patients with either stress or mixed type of UI were enrolled. After accu-
rate examination, data regarding age, parity, mode of delivery and menopausal state were recorded. Furthermore
the presence and severity of UI was evaluated with empty bladder supine stress test (ESST) and cough test in su-
pine and standing positions in all patients. Eligible cases underwent UDS evaluation by an expert urologist using
a standardized protocol.
Results: Stress and mixed UI were found in 33 (25%) and 99 (75%) patients respectively. By considering clinical
evaluation as gold standard, sensitivity, specificity, positive and negative predictive value of urodynamic study
were 83.4%, 30.4%, 43.4% and 80% for detecting stress UI and 96.1%, 35.6%, 34.7%, 96.2% for detecting mixed
UI respectively. No correlation was noted between ESST or cough test results and Valsalva leak point pressure
(VLPP) values in patients with stress UI, however ESST was correlated with VLPP values in patients with mixed
UI.
Conclusion: Despite a relatively high sensitivity, the specificity was low and urodynamic evaluation seems to be
of limited value in the assessment of UI in female patients.
Key words: Female; Urinary incontinence; Urodynamics
INTRODUCTION
Urinary Incontinence (UI) is defined as the involun-
tary loss of urine and is associated with discomfort,
low self-esteem, and impaired quality of life(1). One
third of women of all ages report UI and the prevalence
of UI varies in different countries from 17 to 45%(2,3).
Differences in definitions, study characteristics and
target populations are the causes of this wide range(4).
UI is classified into three subtypes: stress, urgency, and
mixed UI. Stress UI (loss of urine on exertion such as
coughing, sneezing, lifting or laughing) is common in
premenopausal women(5), while urgency UI (loss of
urine with a strong desire to urinate) and mixed UI
(co-existing stress and urgency UI symptoms) become
prevalent in older women(5). It is important to determine
the type and severity of UI to consider the best treatment.
Both clinical signs and urodynamic findings are used
for UI diagnosis. Some investigators believe that
urodynamic evaluation is not needed at first eval-
uation as it is costly and associated with discom-
fort(6,7) while others believe that it provides neces-
sary information which helps accurate diagnosis(8).
As there are controversies regarding application of uro-
dynamic study (UDS) in patients with UI and its corre-
lation with subjective or objective measures of voiding
function, we designed this study to compare clinical and
UDS findings in Iranian women with mixed or stress UI.
MATERIALS AND METHODS
We conducted this cross-sectional study at our in-
stitution between August 2014 and August 2015. All
women with at least 3 month duration of stress or
mixed UI who were referred to our clinic were con-
sidered for enrollment. Questionnaire for Urinary
Incontinence Diagnosis (QUID), was applied to dis-
tinguish between stress and urgency UI(9). In patients
with mixed UI, those who had QUID urgency UI score
greater than stress UI score, were excluded from en-
rollment. Additional exclusion criteria were patient
age 18 years or younger, positive urine culture, api-
cal, posterior or anterior pelvic organ prolapse 1 cm or
greater (> stage 2), prior history of UI surgery, pelvic
surgery or radiation therapy and neurogenic bladder.
All participants were asked to fill informed consent
forms and institutional review board approved the study.
After accurate examination, data regarding age, par-
1 Department of obstetrics and gynecology, Tehran University of medical sciences, Tehran Iran.
2 Department of Pelvic Floor, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
3 Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
**Correspondence: Department of Pelvic Floor, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran,
Iran.
Tel:+982161192365. Mobile:+989121305814. E-mail: drz_ghanbari@yahoo.com.
*Correspondence: Uro-Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Tel:+982161192794. Mobile:+989121191522.
Received May 2016 Accepted August 2016
ity, mode of delivery and menopausal state were
recorded. Furthermore the presence and severi-
ty of UI was evaluated with both cough and emp-
ty bladder supine stress test (ESST) in all patients.
Included cases underwent UDS evaluation by an expert
urologist using a standardized protocol. Patients were
examined in supine position. Prior to the examination,
patients were asked to void and post-void residual urine
was measured. Urodynamic evaluation was performed
with a 6F dual-lumen vesical catheter and a 9F rectal
balloon catheter. Normal saline was infused at a rate
of 30mL/min. Valsalva leak point pressure (VLPP) and
cough leak point pressure were measured in cmH2O
and recorded. All measurements were performed in
both supine and standing positions. This study aimed
to compare urodynamic variables with clinical find-
ings to assess the correlation between UDS findings
and objective/subjective measures of voiding function.
All data were analyzed using SPSS software version
20 (SPSS Inc., Chicago, IL, USA). Student’s t test
and Chi square test were used to compare continu-
ous and categorical variables respectively. P value of
less than .05 was considered statistically significant.
RESULTS
A total of 132 patients with mean age of 51.8 ± 10.7
years ranging from 31 to 81 met inclusion criteria and
were considered for analysis. Stress and mixed UI were
found in 33 (25%) and 99 (75%) patients respectively.
Women with stress and mixed UI were comparable in
terms of age, body mass index and parity. Mean par-
ity was 3.6 ± 1.6 and 4.3 ± 2.3 in women with stress
and mixed UI respectively (p = .136). Among pa-
tients who presented with SUI, data on delivery mode
was available in 30 patients. Twenty one patients
had history of vaginal delivery, one patient had his-
tory of cesarean section and 8 patients had history of
both vaginal delivery and cesarean section. Frequen-
cy of vaginal delivery was similar in both groups and
we noted that the mode of delivery was not associat-
ed with incontinence type. Moreover rate of meno-
pause was 48.4% and 47.4% in the two study groups.
Among 33 patients with pure SUI, the diagnosis was
confirmed in 19 patients (57.6%) during UDS. More-
over UDS confirmed UI in 41 of 99 (41.4%) patients
who presented with mixed UI and predominant SUI.
By considering clinical evaluation as gold standard,
sensitivity, specificity, positive and negative predictive
values of urodynamic study were 83.4%, 30.4%, 43.4%
and 80% for detecting stress UI and 96.1%, 35.6%,
34.7%, 96.2% for detecting mixed UI respectively.
In a separate analysis we sub-classified study partici-
pants into three groups based on VLPP values (VLPP of
60 cmH2O or less, between 60 and 90 and > 90 cmH20).
Tables 1 and 2 show the frequency of patients with
positive ESST or cough test in each group. No correla-
tion was noted between ESST or cough test results and
VLPP values in patients with stress UI, however ESST
was correlated with VLPP values in patients with mixed
UI. To assess the effect of age on urodynamic param-
eters, we subclassified the study population into three
groups. Group 1 consisted of women younger than 45
years. In group 2 patients were between 45 and 60 and
group 3 comprised women older than 60. Mean VLPP
value was 133.8 ± 27.0, 144.2 ± 102.5 and 125.1±29.8 in
groups 1, 2 and 3, respectively. Applying Kruskal Wal-
lis test, no statistically significant difference was noted
in VLPP values between different age groups (p=0.606).
Cystometric capacity was normal in study participants
and did not differ between patients with stress and
mixed UI. Table 3 compares bladder volume at first
sensation, normal desire and strong desire between the
2 groups. As shown in Table 3 normal desire occurred
at higher bladder volumes in patients with stress UI
compared to those with mixed UI. Furthermore max-
Role of UDS in incontinence-Ayati et al.
Female Urology 2785
Table 1. Correlation between VLPP in the urodynamic study and ESST results in patients with stress or mixed urinary incontinence
VLPP Positive ESST Negative ESST P-value
Stress UI < 60 - -
60 - 90 0 2 .5
> 90 3 14
Mixed UI < 60 1 0
60 - 90 0 4 .02
> 90 6 32
Abbreviations: VLPP, Valsalva leak point pressure; ESST, Empty bladder leak point pressure; UI, Urinary incontinence
Abbreviations: VLPP, Valsalva leak point pressure; UI, Urinary incontinence
VLPP Positive cough test Negative cough test P-value
Stress UI < 60 0 0 .6
60 - 90 1 1
> 90 6 11
Mixed UI < 60 0 1 .7
60 - 90 1 3
> 90 12 24
Table 2. Correlation between VLPP in the urodynamic study and cough test results in patients with stress or mixed urinary incontinence
Vol 13 No 04 July-August 2016 2786
imal urine flow was comparable between the study
groups and not correlated with the results of ESST or
cough test. Urethral hypermobility was noted in 24 and
63 women with stress and mixed UI respectively. No
correlation was also noted between the occurrence of
urinary leakage during urodynamic evaluation and pres-
ence of urethral hypermobility in physical examination.
DISCUSSION
In this prospective study a large homogeneous group of
female patients with stress or mixed UI were included
and we noted that mixed UI is more prevalent compared
to stress UI. Our results are compatible with the results
of Digesu et al. In their study, 59% of women who were
referred to a referral center in Italy had mixed UI(10).
Mixed UI, comprises 29 to 61% of all types of inconti-
nence in the literature(11-13). Similarly in a study by Pan-
dey et al. among 202 women with UI, the most com-
mon type was found to be mixed UI (33.1%) followed
by stress UI (31.6%) and urgency UI (13.3%)(14). In
our study, mean bladder volumes at first sensation and
strong desire were not significantly different between the
two groups while mean normal desire was significantly
higher in patients with stress incontinence. Zaren et al.
evaluated 99 women who had undergone urodynamic
evaluation. Mixed, urgency and stress UI were reported
in 35%, 33.3% and 31.1% of their patients respectively.
They showed that mean bladder volumes at first sensa-
tion, normal desire and strong desire were significantly
different between the three groups(15). They also noted
that mean maximal flow (Q max) was not significantly
different between study groups. In the present study we
also noted that Q max was comparable between patients
with mixed UI and stress UI. Our results showed that
urodynamic findings are poorly correlated with clini-
cal findings. VLPP was not correlated with the results
obtained during clinical evaluation including ESST re-
sults in patients with stress UI, however VLPP was cor-
related with ESST findings in women with mixed UI.
In 1993, McGuire et al. introduced VLPP as a di-
agnostic test for stress UI(16). It should be considered
that VLPP measurement is not reliable in women who
are not able to produce enough intra-abdominal pres-
sure by Valsalva maneuver. Cough leak point pressure
(CLPP) measurement may be an alternative in these
patients. As proposed by McGuire et al., CLPP could
be measured as an adjunct to VLPP and when the pa-
tient is not capable of producing Valsalva maneuver.
CLPP was also not correlated with clinical findings
(data not shown). Frequency of hypermobility did
not differ between patients with mixed and stress UI.
Furthermore hypermobility, detected during physical
examination, was not correlated with VLPP values.
We showed that UDS has a low speci-
ficity and is of limited value in confirm-
ing the diagnosis of either mixed or stress UI.
Incontinence is a serious problem in women that affects
all aspects of life including physical, psychological and
social(17). Along with efforts to treat these patients, phy-
sicians attempt to standardize the evaluation of such
cases(15). History, physical examination, urinalysis and
cystourethroscopy are usually applied in evaluation
of patients with urinary incontinence. Applying UDS
in the assessment of women with UI is controversial.
UDS is costly and might be associated with patient
discomfort and serious adverse effects including uro-
sepsis. Since the etiology of UI can be determined
through clinical evaluation and considering the poor
correlation between urodynamic variables and clinical
findings, this modality seems to be of limited value in
evaluation of patients with UI especially in the absence
of a specific neurologic disorder. UDS has been con-
sidered as a useful modality in detecting occult stress
UI, nevertheless, in a recent study occult stress UI was
shown to be a poor urodynamic marker in predict-
ing the development of post-hysterectomy stress UI.
CONCLUSION
In this prospective study we showed that UDS varia-
bles are poorly correlated with patients’ symptoms and
clinical findings. Despite a relatively high sensitivity,
the specificity of urodynamic evaluation was low and it
seems to be of limited value in the assessment of UI in
female patients with no clear history of neurologic disor-
ders and might not change therapeutic approaches. Fur-
ther multi-center studies with larger sample size are nec-
essary for evaluation of the clinical usefulness of UDS.
CONFLICT OF INTEREST
None declared.
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