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Kari Bø a Norwegian
Centre for Physiotherapy Research and Norwegian University of Sport and
Physical Education, PO Box 4014, Ullevål Stadion, 0806 Oslo, Norway, b National
Hospital of Norway, Oslo, c Norwegian University of Sport and Physical
Education, Oslo
Correspondence to: Professor Bø
karib{at}brage.idrettshs.no
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Abstract |
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Objective:
To compare the effect of pelvic floor
exercises, electrical stimulation, vaginal cones, and no treatment
for genuine stress incontinence.
Design:
Stratified, single blind, randomised
controlled trial.
Setting:
Multicentre.
Participants:
107 women with clinically and
urodynamically proved genuine stress incontinence. Mean (range) age was
49.5 (24-70) years, and mean (range) duration of symptoms 10.8 (1-45) years.
Interventions:
Pelvic floor exercise (n=25)
comprised 8-12 contractions 3 times a day and exercise in groups with
skilled physical therapists once a week. The electrical stimulation
group (n=25) used vaginal intermittent stimulation with the MS 106 Twin at 50 Hz 30 minutes a day. The vaginal cones group (n=27) used cones for 20 minutes a day. The untreated control group (n=30) was
offered the use of a continence guard. Muscle strength was measured by
vaginal squeeze pressure once a month.
Main outcome measures:
Pad test with standardised
bladder volume, and self report of severity.
Results:
Improvement in muscle strength was
significantly greater (P=0.03) after pelvic floor exercises (11.0 cm
H2O (95% confidence interval 7.7 to 14.3) before
v 19.2 cm H2O (15.3 to 23.1) after) than
either electrical stimulation (14.8 cm H2O (10.9 to 18.7)
v 18.6 cm H2O (13.3 to 23.9)) or vaginal
cones (11.8 cm H2O (8.5 to 15.1) v 15.4 cm
H2O (11.1 to 19.7)). Reduction in leakage on pad test was
greater in the exercise group (
30.2 g;
43.3 to 16.9) than in the
electrical stimulation group (
7.4 g;
20.9 to 6.1) and the
vaginal cones group (
14.7 g;
27.6 to
1.8). On completion of
the trial one participant in the control group, 14 in the pelvic floor
exercise group, three in the electrical stimulation group, and two in
the vaginal cones group no longer considered themselves as having a problem.
Conclusion:
Training of the pelvic floor muscles is
superior to electrical stimulation and vaginal cones in the treatment
of genuine stress incontinence.
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Key messages
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Introduction |
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Urinary incontinence is defined by the International Continence Society as "a condition in which involuntary loss of urine is a social or hygienic problem and is objectively demonstrable."1 Urinary incontinence is more common in women than in men and affects women of all ages. Prevalence rates in women between 15 and 64 years of age vary from 10% to 30%.2 Although only a quarter of all women with this problem seek help,2 the approximate annual cost of the condition in the United States has been estimated at $11.2 billion in the community and $5.2 billion in nursing homes.2 The most common type of urinary incontinence in women is stress incontinence, defined as the involuntary loss of urine during coughing, sneezing, or physical exertion such as sporting activities or sudden change in position. Genuine stress incontinence is urodynamically proved involuntary loss of urine when the intravesical pressure exceeds that of the urethra with no simultaneous detrusor contraction.1 Risk factors for genuine stress incontinence are inherently weak connective tissue, vaginal delivery, obesity, strenuous work, and old age.2
Urinary incontinence is a socially embarrassing condition, causing withdrawal from social situations and reduced quality of life. 3 4 Genuine stress incontinence may lead to withdrawal from regular physical and fitness activities. 5 6 This withdrawal may be a threat to women's general health and wellbeing as regular moderate physical activity is important in the prevention of osteoporosis, high blood pressure, coronary heart disease, depression, and anxiety.7
In 1948 Kegel reported a cure rate of 84% after training of the pelvic floor muscles for women with various types of incontinence.8 Surgery soon became the first choice of treatment, however, and not until the 1980s was there renewed interest in physical therapies.9 This renewed interest for conservative treatment may be because of higher awareness among women and cost of and morbidity after surgery. Physical therapies to treat genuine stress incontinence include pelvic floor exercises with or without biofeedback, electrical stimulation, and weighted vaginal cones.9 Pelvic floor exercise is known to be an effective treatment for genuine stress incontinence,2 but randomised controlled trials evaluating electrical stimulation and vaginal cones have given conflicting and inconclusive results, and many of these studies are flawed because of small sample sizes. 9 10 Though neither electrical stimulation nor vaginal cones have been compared with no treatment, they are commonly used.
We compared the effect of pelvic floor exercises, electrical
stimulation, vaginal cones and no treatment in women with genuine stress incontinence.
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Methods |
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This study was a multicentre, single blind, randomised controlled trial with stratified design. Participants were women with genuine stress incontinence who were on the surgical waiting list or women with symptoms of stress incontinence recruited by local newspaper articles. Five centres in southeast Norway participated. A standardised assessment at enrolment included a comprehensive urogynaecological history, urodynamic assessment including uroflowmetry and cystometry, bacteriological examination, and pad test with standardised bladder volume. The study was approved by the local ethics committee, and all women gave written consent.
Inclusion criteria were history of stress urinary incontinence and >4 g of leakage measured by pad test with standardised bladder volume. Exclusion criteria were urinary incontinence other than genuine stress incontinence, involuntary detrusor contractions exceeding 10 cm H2O on cystometry, abnormal bladder function (residual urine >50 ml and maximal uroflow <15 ml/s), previous surgery for genuine stress incontinence, neurological or psychiatric disease, ongoing urinary tract infections, other diseases that could interfere with participation, use of concomitant treatments during the trial, and inability to understand instructions given in Norwegian.
The power calculation of the study was based on the power estimation
and results of a previous study designed to detect differences between
groups of 1 SD with a power of 80% and an
of 5%.11 In the previous study significant differences in the same outcomes after the same training programme were shown in groups of 23 and 29 subjects; therefore 30 participants were recruited for each of the four
groups in this study.
Randomisation procedure
The participants were stratified into two groups (
20 g and
>20 g leakage) according to results of the pad test with standardised
bladder volume. Randomisation schemes stratified by degree of
incontinence were constructed for all sites by using computer generated
random numbers. Participants within each stratum were randomised by
using opaque sealed envelopes to one of the four study groups: pelvic
floor exercises, electrical stimulation, vaginal cones, or untreated
control. Information for decoding randomisation was kept locked in the
statistician's office. The main investigator (KB) was not involved in
any interventions and was blind to group allocation. Physicians
evaluating the effect of the treatments were also blind to allocation
of treatments.
Interventions
Participants were taught about the anatomy of the pelvic
floor and lower urinary tract, physiology, and continence mechanisms by
the local project physical therapist. All were taught to contract the
pelvic floor muscles correctly, and this was assessed by vaginal palpation.
The protocol has been
published previously11 and followed recommendations for
general training to increase strength of skeletal
muscle.13 Participants were asked to conduct 8-12 high
intensity (close to maximum) contractions three times a day at home
with additional training in groups once a week for 45 minutes with a
physical therapist. Group training was performed in lying, standing,
kneeling, and sitting positions with legs apart to emphasise specific
strength training of the pelvic floor muscles and relaxation of other
pelvic muscles. Participants aimed at holding each muscle contraction
for 6-8 seconds, three or four fast contractions were then added. The
rest period was about 6 seconds. A total of eight to 12 contractions
were completed in each position with maximal contraction effort
encouraged. Body awareness, breathing, relaxation exercises, and
strength training for the abdominal, back, and thigh muscles were
performed to music between positions. The participants were encouraged
to use their preferred position and perform equally intensive
contractions at home. An audiotape with verbal guidance for 12 maximum
contractions was available for home training, and a training diary was kept.
Electrical stimulation
An MS 106 Twin (Vitacon AS,
Trondheim, Norway) was used according the manufacturer's recommended
protocol for 30 minutes of intermittent vaginal electrical stimulation
per day. Selected parameters included biphasic intermittent current, frequency 50 Hz, pulse width 0.2 milliseconds, and current intensity between 0-120 mA with individually adapted on-off (duty) cycles on the
basis of each woman's ability to hold a voluntary contraction. On time
ranged from 0.5 seconds to 10 seconds, and off time from 0 seconds to
30 seconds. If ability to hold the contraction improved the duty cycle
was progressed each month. All patients were encouraged to tolerate as
high an intensity as possible to get a contraction. Treatment adherence
was electronically monitored and recorded. At every monthly visit the
physical therapist observed the patients receiving electrical
stimulation from their home stimulators in the clinic.
Vaginal cones
Mabella cones (Vitacon AS, Trondheim,
Norway) were used for 20 minutes a day according to the manufacturer's recommendations. Patients progressed through three cone weights
20, 40, and 70 g
according to their ability to hold the cones. Adherence was noted in a training diary.
Adverse effects and tolerance to treatment
Adverse effects and treatment tolerance were monitored with
a training diary and during monthly clinic visits.
Main outcome measures
Pad test with standardised bladder volume
After the bladder
was emptied by catheter it was refilled with 200 ml saline. Women wore
preweighed pads and ran on the spot for 30 seconds followed by 30 seconds of jumping with legs in subsequent adduction and abduction
(jumping jacks) at a preset metronome rate of 132 beats per minute.
After the test the pad was reweighed.
Women recorded how they perceived the
condition before and after treatment on a 5 point scale (unproblematic, minimal problem, moderate problem, problematic, very
problematic).1
Secondary outcome measures
Three day leakage episodes
The number of episodes of
involuntary leakage in 3 days was recorded in a home voiding diary
before and after the intervention period. Mean number of episodes was calculated.
Twenty four hour pad weighs were
conducted by patients at home before trial entry and after the last
clinic visit. Women chose a typical day that mirrored their average
level of activity.
Leakage index
Patients indicated on a 5 point scale
(5 always, 4 often, 3 sometimes, 2 seldom, 1 never) the frequency of
urinary leakage during sneezing, coughing, laughing, walking, walking
downhill, running, jumping, and lifting. The mean was calculated as an
index of leakage frequency before and after treatment.14
Social activity index
Perceived problems in participating
in nine different social situations were recorded on a 10 cm visual
analogue scale (0 impossible to participate, 10 no problem taking
part). As an overall index of quality of life the mean was calculated before and after treatment.14 After treatment participants
also rated improvement on a 5 point scale (worse, unchanged, improved, almost continent, continent)11 and stated whether they
wanted further treatment.
Muscle function and strength
Pelvic floor muscle function was assessed by the physical
therapist with vaginal evaluation during contraction. Muscle strength
was evaluated by a vaginal balloon catheter (balloon size 6.7×1.7 cm)
connected to a pressure transducer (Camtech AS 1300, Sandvika, Norway).
The middle of the balloon was placed 3.5 cm inside the vaginal
introitus.15 Only contractions with simultaneous
observable inward movement of the perineum were considered valid.16
Statistical methods
The primary analysis was carried on data from treated
participants, with exclusion of data from those without final
evaluation on efficacy variables. Additional intention to treat
analyses were also done for all randomised patients including those who
dropped out. The missing last values were considered as equal to
baseline values. Results are given as mean values with 95% confidence
intervals. As several variables were not normally distributed, however,
the Kruskal-Wallis analysis of variance was chosen as the global test
of differences between groups on visual analogue scales and other
interval scaled variables. Pair-wise comparisons were made with the
Mann-Whitney U test to compare each group with the control and one
intervention group with another. Cochran-Mantel-Haenszel tests or
2 tests were used if data were nominal or categorical.
P values <0.05 were considered significant.
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Results |
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One hundred and twenty two patients were randomised. Three women could not complete the study (asthma, change of work, and death in the family), and two were excluded because they used other treatments during the trial. Ten women dropped out with motivation problems or adverse effects: two from pelvic floor muscle training (one motivation problem, one because of travel time to the training group), seven from electrical stimulation (two because of pain, one for bleeding, and four through lack of motivation), and one from vaginal cones (vaginal bleeding). This left 107 participants: 30 in the control group, 25 in the pelvic floor exercise group, 25 in the electrical stimulation group, and 27 in the vaginal cones group (fig 1).
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At baseline there were no significant differences between the groups in any of the background characteristics such as age, body mass index, duration of symptoms, pelvic floor muscle strength, urodynamic assessment, or degree of leakage (table 1).
Compliance with treatment
Mean (SE) adherence with treatment was 93% (1.5%) for pelvic
floor muscle training, 75% (2.8%) for electrical stimulation, and
78% (4.4%) for vaginal cones. Adherence with pelvic floor muscle
training was significantly greater than with electrical stimulation or
vaginal cones (P<0.001 and <0.002, respectively). The difference
between the electrical stimulation and cone groups was not significant.
Changes after treatment
Figure 2 shows details of the change in strength of the pelvic
floor muscles. There was no significant change in the control group,
but significant improvement was seen after treatment in the other
groups. Only in the pelvic floor exercise group, however, was the
improvement significant when it was compared with the control group
(P<0.01). The change in the strength of pelvic floor muscle was
significantly greater (P=0.03) in the pelvic floor exercise group
(11.0 cm H2O (95% confidence interval 7.7 to 14.3) before
test v 19.2 cm H2O (15.3 to 23.1) after
test) compared with electrical stimulation (14.8 cm H2O
(10.9 to 18.7) v 18.6 cm H2O (13.3 to
23.9)) and vaginal cones (11.8 cm H2O (8.5 to 15.1)
v 15.4 cm H2O (11.1 to 19.7)). There was no
difference in changes of strength between the electrical stimulation
and vaginal cones groups (P=0.90). Intention to treat analyses did not
change the results.
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0.7
(
0.4 to
1.0); P<0.01) and significantly more than the vaginal
cones group in pad test (reduction in urine leaked 30.2 g
v 14.7 g; difference
15.5 (
34.1 to 3.1); P<0.01),
episodes of leakage over 3 days (1.2 fewer v 0.8 more;
difference
2.0 (
41.0 to 0.1); P=0.03), and leakage index (0.9 v 0.3 lower; difference
0.6 (
0.9 to
0.3);
P<0.01). There were no significant differences between the electrical
stimulation and vaginal cones groups in any outcome variable. There
were no significant changes in maximum urethral pressure or maximum
closure pressure for any group.
Objective cure (
2 g leakage on the pad test with standardised
bladder volume) was achieved by two women in the control group, 11 in
the pelvic floor exercise group, seven in the electrical stimulation
group, and four in the vaginal cones group (P=0.02).
Subjective cure (number of women stating that the condition was
"unproblematic" after the treatment) was reported by one woman in
the control group, 14 in the pelvic floor exercise group, three in the
electrical stimulation group, and two in the vaginal cones group. When
corrected for baseline values the change in the pelvic floor exercise
group was significantly greater than the change in the other groups
(P<0.001).
Table 4 shows subjective improvement after intervention. Significantly
more women in the exercise group reported being continent or almost
continent (P<0.001) than in the other groups. Fourteen of the 30 participants in the control group chose to use the continence guard.
Four felt completely dry when wearing the guard, and five felt somewhat
better. Three participants in the control group and two in the
electrical stimulation group considered themselves worse after
treatment.
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Adverse effects and treatment tolerance
There were no side effects reported for pelvic floor exercises. In
the electrical stimulation group two participants reported smarting
(one tenderness and bleeding, one discomfort), and eight women reported
motivation problems and difficulties in using the stimulator. Of those
participants who used vaginal cones, one reported abdominal pain, two
vaginitis, and one bleeding, and 14 reported motivation problems and
trouble in using the cones.
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Discussion |
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To our knowledge, this is the first study to compare three of the most commonly used conservative treatments with no treatment for genuine stress incontinence. We have shown that pelvic floor muscle training was a more effective treatment for genuine stress incontinence than no treatment, electrical stimulation, or vaginal cones. Compared with women in the control group only women in the pelvic floor exercise group increased pelvic floor muscle strength and reduced urinary leakage significantly when it was measured by pad test with standardised bladder volume. In addition, significantly more women in the pelvic floor exercise group stated that after the intervention the condition was no longer a problem.
Pragmatic study
This was a pragmatic study reflecting current practice. The
intention was to give the optimal treatment in each group on the basis
of current theory and recommendations. Because the exercise group met
once a week for training the women had more attention than those in the
the two other treatment groups. Electrical stimulation and vaginal
cones, however, are advertised as treatments that patients can
undertake at home after introduction by health staff. In an attempt to
give equal individual attention and motivation all participants met
once a month for individual follow up by a skilled physical therapist.
On the other hand, both the electrical stimulation group and cone group
spent more time per day with the treatment than the exercise group (30, 20, and less than 10 minutes, respectively). From the present study we
cannot conclude which part of the three treatment packages caused the
results. A decision to exclude the control group from monthly visits to
measure strength of the pelvic floor muscles was taken to prevent this
acting as a stimulus for training
that is, the "avis effect." The
electrical stimulation and vaginal cones groups were not protected from
this effect either, although they were specifically asked not to
undertake pelvic floor exercises during the trial.
Outcome
Lack of reproducible and valid tests to measure urinary leakage
makes the choice of outcome measures difficult. The Urodynamic Society
and the standardisation committee of the International Continence
Society have recommended use of measures for urinary leakage and self
report to evaluate treatment effect,27 although there is
no agreement about the most appropriate measures to date. Because of
the need for inclusion of randomised controlled trials in future
meta-analyses we used a range of outcome measures used in clinical
practice and research that have been previously tested for
reproducibility.
11 14
A pad test with standardised bladder volume was chosen as the primary outcome measure because it has
been shown to be more reproducible than pad tests with no
standardisation.28 The pad test used in our study,
however, entailed movements likely to cause leakage. Some women who
leak urine with this test may consider themselves subjectively cured. Few women may include such rigorous physical activity as part of their
everyday life. Therefore an outcome that assesses how problematic
incontinence is during daily life may be the most appropriate measure
of cure.
Conclusion
Pelvic floor exercises are more effective than electrical
stimulation, vaginal cones, and no treatment for women with genuine
stress incontinence. As such exercise seems to be safe and effective it
should be offered as first choice of treatment for genuine stress incontinence.
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Acknowledgments |
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In addition to the authors the Norwegian Pelvic Floor Study Research Group comprised Ruth Dyresen, Tom Engebretsen, Hanne Borg Finckenhagen, Magne Halvorsen, Anke Helgar, Kjersti Dybvig Jensen, Marit Nicolaisen, Anne Sophie MacLeod, Ann Brit Sangvik, Latis Sadek, Hjalmar Schiøtz, Trine Lise Urnes, and Bjørg Wandås (project secretary). E Jean Hay-Smith has given valuable help with the English revision of the manuscript.
Contributors: KB was the main investigator. She initiated and planned the study, supervised the physicians and physical therapists, administered the whole trial, and wrote the manuscript. TT was in the planning group with KB from the beginning of the study. He was responsible for the planning and administration of the inclusion and exclusion criteria and was head of all urodynamic investigations. He supervised the other physicians in the inclusion and exclusion procedures, urodynamic assessment, and pad testing. In addition, he was the physician in one of the five centres and assessed the patients himself. He has revised the manuscript thoroughly several times, specifically the results from urodynamic investigations. IH advised on the study design and was responsible for stratification and randomisation procedures and planned and supervised all the statistical analysis. He carried out the more advanced statistical analyses, thoroughly revised the manuscript several times, and wrote details on statistical analyses. All participants in the research group contributed throughout the trial period with inclusion, exclusion, assessments, and treatments. KB is the guarantor of the study.
Funding: Norwegian Fund for Postgraduate studies in Physiotherapy and Norwegian Research Council. Coloplast AS provided the continence guards and Vitacon AS provided the electrical stimulators and cones. They also gave financial support to seminars for the research group.
Competing interests: None declared.
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References |
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(Accepted 31 December 1998)
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