Discussion
This systematic review reports the evidence of
physical therapy interventions for Stress Urinary Incontinence from full
text studies or abstracts published in English
during the last decade. Despite suggestions that the
methodological quality of studies has increased over
time, no correlation was found between a more recent
date of publication and the quality score of the
studies published over the last 10 years and
included in this review. Thus it must be
acknowledged that high quality studies published
prior to 1995 may have been missed by the
limitations on publication date which were set.
The inclusion of both RCTs and non-RCTs dictated the
presentation of results as a narrative summary. The
methodological quality of the studies was variable,
with some RCTs being of lower quality than the lower
level studies. This provides a dilemma for
systematic reviewers, as restriction of study
inclusion to RCTs is considered to ensure
identification of high quality studies [20,63].
However, the possibility of well-designed cohort
studies providing less biased evidence than poorly
designed RCTs has been documented [64].
It is acknowledged that the methodological quality
of the critical review tools themselves may have
incorrectly reflected the quality and ranking of the
included studies [65].
One of the aims of this review was to investigate
outcomes relevant to clinical practice. To this end,
level III and IV studies, not previously reported in
systematic reviews of the literature on Stress Urinary Incontinence, were
included. The inclusion of these studies with lower
levels of evidence provided information about
aspects of physical therapy not obtainable from the
RCTs reviewed, for example, about the different
response rate and the effectiveness of treatment in
the primary care setting.
Question 1: What
is the evidence for PFMT, either alone or in
combination with adjunctive therapies, when
considering all treatment protocols, for the
treatment for Stress Urinary Incontinence in women, immediately and up to 12
months after treatment?
This review found consistent evidence from high
quality level II studies for PFMT alone and in
combination with adjunctive therapies in the
treatment of Stress Urinary Incontinence. Further evidence is presented
about the efficacy of PFM strength training, in
support of previous reports [14,16].
New evidence is provided for the efficacy of
different combinations of PFMT with BF and ES but
the combination of PFMT with BF was shown to be no
more effective than PFMT alone. It is unclear
specifically how the combinations of therapy
contribute to the outcome of any training program
and whether it is more effective to administer
adjunctive therapies in the clinic setting or home
environment.
All of the studies reviewed demonstrated positive
treatment effects for physical therapy, despite a
range of training protocols and combinations of
adjunctive therapies. Studies with a lower quality
score have a greater potential for bias and, with
the plethora of different outcome measures used, it
was not possible to directly compare the
effectiveness of the different protocols. Four
papers were only available as abstracts so that the
assessment of methodological quality in these
studies may be underestimated due to the limited
information available.
Factors Not
Assessed by the Studies Which Could Affect Outcome
This review found that physical therapy is effective
in the treatment of Stress
Urinary Incontinence. However, there were other
factors, common to all studies, which may have
contributed to the differences in outcome. The
expertise of health professionals may vary and also
the quantity and quality of the educational
information about the condition and PFM function.
The impact of these factors on the outcome of
treatment has yet to be evaluated. Furthermore, it
has been well documented that many women depress the
PFM instead of contracting it in a cephalad
direction after brief verbal or written instruction
[66,67]. Thus
assessment for correct action by vaginal examination
should be considered a prerequisite for commencing a
PFMT program. However, correct action was not always
reported and several studies used other methods
(vaginal EMG or pressure BF) which are not
considered to be valid assessment tools [62].
Two studies used perineal ultrasound, which has
demonstrated reliability but is not a readily
available clinical tool [62].
However, the reliability of any method will be
dependent on the experience and expertise of the
user and the results should be interpreted with this
in mind [68].
Outcome Measures
The plethora of outcome measures reported in the
included studies also contributed to the difference
in results and constrained comparisons between
studies. Outcomes measures have been reported here
in terms of their positive and statistically
significant findings and also reported in terms of
the recommended ICS categories. It was notable that
outcomes were reported under every ICS category
except socio-economic outcomes. Previous systematic
reviews [14,16]
have noted the absence of reports on socio-economic
outcomes. This review substantiates this finding for
the past decade.
Not all studies reported their outcomes in terms of
the number of subjects 'cured' or 'improved',
although this would seem to be an important
consideration in determination of the clinical
effectiveness of any intervention for this
condition. Moreover the definition of 'cure' has not
been agreed. Different methods of evaluating 'cure'
eg by pad test and self-report resulted in different
outcomes. This difference may be explained by the
fact that women, who are provoked to leak during a
stress test which involves vigorous jumping, but who
do not normally engage in jumping, may report
satisfaction with treatment outcome. This might
suggest that patient self-report and satisfaction
with treatment are possibly more relevant measures.
However, very different cure rates are obtained if
women are asked to report if they are continent (as
opposed to 'almost continent') or if their
incontinence is 'unproblematic'. This language
difference possibly accounted for the considerable
difference in cure/improvement for two otherwise
similar Pelvic Floor Muscle strength training programs. The use of
common, standardised self-report questionnaires is
recommended in research and clinical practice by the
ICS, and if utilised, will facilitate interpretation
and comparison of future studies.
Reported cure rates were much lower than the
percentages of women 'cured & improved'. This was
also noted by Hay-Smith et al (2001). If the small
percentages of women seeking surgical treatment
after physical therapy for
Stress Urinary Incontinence are considered as a
measure of success, then it would seem that the
greater measure of effect, 'cured & improved', may
be a more valid expression of women's satisfaction
with the outcome. However a validated, ICS-approved
satisfaction score is currently lacking.
There was little evidence about outcomes in the
medium term up to 12 months after the completion of
treatment. It was not the aim of this review to
consider the longer term outcomes of physical
therapy. However, outcomes in the short, medium and
longer term are important information, both for
consumers and for the calculation of the economic
benefits of physical therapy particularly when
compared with alternative treatments.
Question 2: What
is the evidence for different types of Pelvic Floor Muscle Training?
There is strong evidence from a number of high
quality RCTs for specific strength training of the
PFM in effecting change in continence status,
underpinning its theoretical rationale and
confirming previous reports [14,16].
There is evidence that PFM strength continues to
increase over six months with specific strength
training. Changes in bladder neck position as a
result of PFMT have been demonstrated, suggesting
structural changes in the PFM. However, the optimal
training protocol is less clear as different
approaches were effective. Thus the addition of
weekly group exercises or individual sessions with
the therapist may not be essential components of the
training per se but rather the training effect may
be enhanced through regular therapist contact for
motivation.
Despite the number of studies including skill
training in the PFMT protocol, its contribution in
effecting change in health outcomes was not clear.
There was considerable heterogeneity among the
treatment and training protocols, precluding
determination of clear conclusions. However, from
the review, it appears there is sufficient weight of
evidence to recommend a combination of strength and
skill training in the treatment of Stress Urinary Incontinence.
It should be remembered that only studies of PFMT
for women with Stress Urinary Incontinence were included in this review. It
was not the aim of this review to consider the
evidence of all the available literature on the
effect of PFMT on different parameters of PFM
function such as strength, endurance or skill level
for women with other types of PFM dysfunction or for
asymptomatic women. Therefore the effects of the
PFMT protocols described may not be shown in other
populations of women, particularly in those with
other dysfunctions of the PFM such as prolapse and
bowel incontinence.
This review found very different approaches to
training the abdominal wall muscles in conjunction
with the pelvic floor. There were no trials where
deep abdominal training alone was performed as an
intervention for Stress Urinary Incontinence. However, the outcomes of an
effective PFMT program were not improved by the
addition of deep abdominal muscle training, nor by
reduction of rectus abdominis activity by surface
EMG BF.
The evidence from this review, that there is no
benefit in adding BF, ES or deep abdominal muscle
training to a PFMT program, should be considered
from a clinical perspective. There may have been
subgroups of women with different characteristics
who responded differently to the treatment protocol
but who were not identified in the analysis. In
clinical practice, patients have different
characteristics which will demand a reasoned
approach to the choice of treatment at any one time.
Thus it cannot be assumed that additional deep
abdominal muscle training may not be useful for
selected women with Stress Urinary Incontinence who have demonstrated
weakness of their deep abdominal muscles or that BF
may not be beneficial for some women with poor
proprioception of their pelvic floor or low
motivation to exercise. It seems vital for the
clinician to consider all relevant clinical findings
(eg age, baseline pelvic floor muscle strength,
proprioception, motivation, general physical
fitness) when deciding on the best treatment for any
one patient.
Question 3: What
other reported factors could affect outcome of
physical therapy?
Age
This review found evidence for PFMT with and without
adjunctive therapies for women up to the age of 84
who suffer
Stress Urinary Incontinence. There was evidence from a number of
RCTs for the efficacy of a specific training program
with PFMT, BF and ES for younger women after
childbirth. There were a number of RCTs with
consistent reports of efficacy of PFM strength
training in women of mid-age, but limited evidence
for specific PFMT protocols for older women. Given
the demographics in the western world with
increasing numbers of women living longer and the
known association of incontinence with increasing
age, effective training programs for older women are
needed.
Initial Severity
of Incontinence
Previous studies have reported conflicting findings
about the effect of initial incontinence severity on
the outcome of treatment [14,16].
The results of this review suggest that although
fewer women with more severe symptoms may be cured
by physical therapy, there may nevertheless be a
significant improvement in their symptoms. Whether
women with more severe Stress Urinary Incontinence require longer treatment,
different PFMT protocols or different combinations
of therapy remains to be determined.
Compliance with
the Home Training Program
Another factor which may influence outcome is the
degree to which subjects actually comply with the
treatment program prescribed. Compliance with Pelvic Floor Muscle Training
is a complex issue and has been the subject of a
previous review [69]. The
terminology is not agreed as some authors consider
'adherence' to be a more appropriate term implying
voluntary co-operation rather than coercion [69,70].
Subject compliance or adherence was infrequently and
generally poorly reported with no standardised,
validated or reliable approach to its assessment.
However it would appear to be of considerable
importance in any PFMT program which depends on
subjects performing exercise in order to effect
physiological changes. There are complex
psycho-social issues involved in interventions which
demand that women commit time and effort on a
regular basis to training [69,70].
It is likely in the high quality studies with good
outcomes that subjects adhered to the treatment
protocol. However, in studies which reported poorer
outcomes and also did not report subjects'
compliance, it is not possible to say whether an
ineffective intervention or the subjects' lack of
compliance was responsible for the poor result.
Initial PFM Strength
There was evidence from two studies suggesting that
women with weaker PFMs had a greater improvement in
continence symptoms than women with stronger PFM.
Previous reviews have reported conflicting findings
[14,15]. There
were no reports of what strategies were used if
women were unable to contract the PFM at all, even
though this would be likely to have an adverse
effect on outcome.
Question 4: What
is the evidence for the optimal period of treatment
and number of treatments?
We found evidence for the efficacy of shorter
treatment protocols than the 4�6 months recommended
by the ICS. The basis of the ICS recommendation was
to allow time for an increase in PFM hypertrophy and
volume as essential processes for increasing muscle
strength. However, this review has shown that
treatment programmes of less than three months may
result in improved continence status as well as
increased PFM strength. Whether the combination of
PFMT with adjunctive therapy or the actual exercise
dosage is the critical factor is unclear. The
optimal length of treatment and the number of
treatment episodes could be useful information for
the marketing of physical therapy for Stress Urinary Incontinence. Some
women may be deterred from starting a physical
therapy program if told that it is necessary to
commit to six months of intensive training with
weekly classes in order to become dry. This could be
the focus of future research as it seems important
information for consumers not only because of the
implications for their time commitment and
motivation but also because of the cost. More
precise information about the length of treatment
and frequency of therapist contact would underpin
economic evaluations of conservative treatment which
are currently lacking.
Question 5: What
is the evidence for the effectiveness of physical
therapy in clinical practice settings and can the
findings in the research settings be generalised to
clinical practice?
This review sought to determine the effectiveness of
physical therapy in the clinical practice setting
where treatment is administered to a regular
clinical population by continence practitioners.
Only one study clearly took place in a clinical
practice setting but as the inclusion criteria were
not stated in the abstract, it was not possible to
identify the characteristics of the study
population. However, it appears that Pelvic Floor Muscle Training conducted
in a primary care setting may be effective for the
treatment of
Stress
Urinary Incontinence.
The other studies in the review were considered for
the generalisability of their findings to clinical
practice by identifying the patient populations from
which the study samples were drawn, the types of
settings in which treatment was carried out and the
health professional performing the treatment.
However, this information was generally poorly
reported so that only limited conclusions can be
drawn.
Physiotherapists were the only health professionals
stated to be performing the treatment (in 83%
studies), and while continence training can be
assumed for the therapists in these studies, the
level of expertise is likely to be a key factor in
determining success. Expertise in continence
management is likely to be a more important factor
influencing outcome in studies of clinical practice
and should be considered a pre-requisite for health
professionals treating
Stress
Urinary Incontinence.
The effect of selection bias should also be
considered in this context. Bias is potentially
introduced when a study population consists of
volunteers, who may be particularly motivated and
compliant. Volunteers may be well motivated to
succeed, particularly in studies requiring
commitment to a daily exercise program over a
lengthy period of time. Thus the outcomes of studies
with a sample of volunteers may overestimate the
true treatment effect. All three of the highest
quality studies had study populations consisting at
least partly of volunteers. In clinical practice,
women referred for treatment may be variable in
their enthusiasm about committing to a lengthy
exercise program. Thus there may be some limitations
to the generalisability of the results of RCTs
recruiting volunteers and this should be considered
by clinicians when interpreting the results.
Conclusion
Implications for
Practice
-
There was strong evidence that PFMT alone, with BF
and with ES/BF is effective for women with Stress Urinary Incontinence, with
expected rates of cure up to 73% and
cure/improvement up to 97%.
-
There was strong evidence for strength training of
the Pelvic Floor Muscle to reduce symptoms of Stress Urinary Incontinence and to improve PFM
strength.
-
Changes in incontinence outcomes were demonstrated
after treatment duration of one week to six months,
but improvements in PFM strength may require at
least 3 months of specific strength training.
-
No benefit was found in this review in adding BF,
ES or abdominal muscle training to a PFMT protocol.
However, it is likely that these interventions still
have a place in clinical practice as adjuncts to
PFMT in particular populations of women.
-
Strength PFMT protocols were effective in younger
and mid-aged women, but there was scant evidence on
strength training in older women.
-
Evidence for skill training was found, especially
if combined with strength training in women of all
ages, but the optimal specific training protocol for
skill training is unclear.
-
Women with different severity of symptoms and
initial PFM strength require different training
programs and protocols. Women with weaker initial
PFM strength and more severe symptoms may have the
greatest percentage improvement in symptoms.
-
Subjects using BF or ES as home treatment may be
less compliant with a treatment program than women
performing PFMT alone.
-
No serious adverse events have been reported with
physical therapy.
Implications for
Research
Research is needed into:
-
economic outcomes as none have been reported
-
the effectiveness of physical therapy in routine
clinical practice settings
-
the external validity of RCTs. Future studies
should more adequately describe the setting for the
intervention, expertise of person delivering the
treatment, the source and characteristics of
subjects
-
the longer term outcomes of physical therapies
-
programs and protocols appropriate for different
subgroups of women eg women of different ages and
with different severity of incontinence
-
the factors which influence a subject's likelihood
of attending appointments, continuing with treatment
and complying with the home training program
-
the optimal length of an episode of care
-
a more standardised approach to outcome
measurement in research with appropriate outcome
measures reflecting clinical practice requirements
-
an optimal minimum set of common outcome measures
relevant to research and clinical practice settings
Competing
Interests
The author(s) declare that there are no competing
interests.
This study was supported by the Centre for Allied
Health Evidence, University of South Australia.
