The aim of this review was to critically appraise relevant peer-reviewed reports of original investigations of the efficacy or effectiveness of pelvic floor muscle training (PFMT) performed alone and together with other adjunctive physical therapies (eg biofeedback, electrical stimulation, vaginal cones) for stress urinary incontinence in women published in the last decade (1995–2005).

The International Continence Society defines urinary incontinence (UI) as the complaint of any involuntary leakage of urine 1. It is a widespread 2 and prevalent condition affecting an estimated 1.8 million community-dwelling women over the age of 18 years in Australia 3. The personal financial costs for women managing UI in Australia in 1998 were estimated at A$372 million per annum and the total annual costs of treatment at A$339 million 4.

Stress and urge incontinence are the two most common types of UI, which co-exist as mixed incontinence. Urine leakage is classified according to what is reported by the woman (symptoms), what is observed by a clinician (signs) and on the basis of urodynamic studies. Stress urinary incontinence (SUI) is the complaint of involuntary leakage on effort or exertion, sneezing or coughing (symptom) or the observation of urine leakage at the same time as the exertion (sign). SUI is the most common type of UI. Urge urinary incontinence (UUI) is the complaint of involuntary leakage accompanied or immediately preceded by, urgency 1. Both are amenable to conservative therapy but surgery has conventionally been offered for SUI and medication with behavioural methods for UUI. The efficacy of surgery is variable 567. Pharmacotherapy for SUI has also been developed but not extensively prescribed 8. Since 1992, conservative management of UI has been promoted by the US Department of Health and Human Services (AHCPER) as first-line treatment for SUI for its efficacy, low cost and low risk 9.

SUI occurs when intra-vesical pressure exceeds urethral closure pressure in the absence of a detrusor contraction. SUI may be due to bladder neck hyper-mobility or poor urethral closure pressure 1. The pelvic floor muscles (PFM) function to elevate the bladder, preventing descent of the bladder neck during rises in intra-abdominal pressure and to occlude the urethra. The theoretical basis for physical therapy to treat SUI is to improve PFM function by increasing strength, coordination, speed and endurance 10 in order to maintain an elevated position of bladder neck during raised intra-abdominal pressure with adequate urethral closure force 11.

A distinction is to be made between the terms 'efficacy' and 'effectiveness'. Efficacy is defined as "the probability of benefit to individuals in a defined population from a medical technology applied for a given medical problem under ideal conditions of use". By contrast, effectiveness is considered to have all the attributes of efficacy but to reflect "performance under ordinary conditions by the average practitioner for the typical patient" 12.

Pelvic floor muscle training (PFMT) and other physical therapies for the treatment of female SUI 13 and UI 141516 has been the subject of previous systematic reviews. All of these reviews limited their inclusion criteria to randomized controlled trials, because this type of study design is considered to provide the best evidence of efficacy for an intervention by attempting to minimize biases and confounding variables 17.

Because of the very rigor of an RCT, it may not necessarily be appropriate to generalise the results of such a carefully controlled trial into clinical practice. Thus a treatment modality with demonstrated efficacy in an RCT may not be effective when combined with other modalities for a different patient population in clinical practice 121819. Subjects for RCTs are selected according to strict and often limited criteria, health personnel are highly trained and a standardized intervention is applied to all subjects, regardless of individual subject characteristics and clinical presentations (eg severity of incontinence, PFM function (strength, endurance, awareness)2021. In clinical practice, physiotherapists are trained to provide treatment based on individual assessment and clinically reasoned processes, for patients presenting with incontinence and with a range of co-morbidities. Thus different treatment modalities (adjunctive therapies) may be applied to individual patients in conjunction with PFMT in order to activate a weak muscle, to improve sensory feedback, to enhance patient cooperation and compliance with an exercise program 22. Observational studies provide the opportunity to establish the effectiveness of such interventions in routine clinical practice 19. This is difficult to achieve in randomized trials 19 other than pragmatic randomized trials 23.

The effectiveness of physical therapy in clinical practice may thus be assessed from the evidence from lower level studies i.e. levels III & IV according to the Australian National Health and Medical Research Council's hierarchy of evidence 24. These studies would be more likely to report on cohorts or case series of patients, treated under typical clinical conditions. In addition, such studies could also provide other information about clinical practice, such as the responsiveness to treatment (length of time taken to respond) not otherwise available from an RCT. No systematic review on SUI has reported on the generalisability (external validity) of the study findings and their applicability in clinical practice. External validity is an important aspect of methodological quality, but there are few critical review tools to evaluate whether the procedures, hospital characteristics and patient samples reported in the literature are relevant to clinical practice 25.

This systematic literature review evaluated the evidence for the efficacy and effectiveness of physical therapy, described as pelvic floor muscle training with, and without, adjunctive physical therapies such as biofeedback, electrical stimulation or vaginal weights for the treatment of SUI in women.

The review addressed the following research questions:

1. What is the evidence for PFMT, either alone or in combination with adjunctive therapies, when considering all treatment protocols, for the treatment for SUI in women, in the short and medium terms (up to 12 months after treatment)?

2. What is the evidence for different types of PFMT?

3. What other reported factors could affect outcome of physical therapy?

4. What is the optimal period of treatment and number of treatments?

5. What is the effectiveness of physical therapy in clinical practice settings and can the findings in the research settings be generalised to clinical practice?

The methods for conducting this systematic review and for assessing the quality of the evidence are based on the processes outlined by the Joanna Briggs Institute 26 and the Centre for Reviews and Dissemination at the University of York 21.

In order to better understand whether those interventions which have demonstrated efficacy in the research setting are also effective when applied in the clinical setting, prospective research designs other than RCTs were also considered in this review. These included quasi-experimental, controlled clinical trials, observational studies and case studies/series. It was anticipated that these types of research designs may provide information about patient populations more typical of those encountered in primary care settings eg with a broad range of inclusion criteria. This information is needed to underpin estimates of the costs of treatment in the primary care setting.

In this review, experimental studies were classified as RCTs when randomly allocated intervention groups were compared, where a distinct control group could receive either another treatment modality or 'no treatment'. Thus studies were eligible for inclusion if there was at least one arm with a PFMT protocol, alone or together with other adjunctive therapies, compared with either a control group of 'no treatment' or 'usual treatment' or a different PFMT protocol, alone or together with other adjunctive therapies (biofeedback, electrical stimulation or vaginal weights).

Study designs without a control group but with a PFMT protocol, alone or together with other adjunctive therapies were also included. Studies or arms of studies which did not have a PFMT protocol and retrospective analyses or audits, which were unlikely to provide robust evidence of effectiveness because of time-based bias, were excluded.

Only peer-reviewed studies published in English in the last decade (1995–2005) were included in this review. The search was limited to the last decade in order to source the most recent, high-quality evidence 27. This decision was justified on the grounds that systematic reviews evaluating the earlier literature found many of the included studies to be of poor or moderate methodological quality 131415 and based on the findings of Moseley et al (2002), it was assumed that the more recent literature was more likely to be of higher methodolgical quality.

The study populations considered in this review included subjects who were adult females of any age, not pregnant or within six weeks post-partum, with a clinical or urodynamic diagnosis of SUI. Clinical diagnosis could be based on the self-report (symptom) and/or sign of stress incontinence. Studies were excluded if they included subjects with mixed UI or detrusor overactivity because of the assumption of a different underlying pathology and thus rationale of treatment, even if outcomes for subgroups of women with SUI were reported.

Only outcome measures relevant for clinical practice were reported in this review, thus urodynamic study measures were excluded.

The principal measures of effectiveness were considered to be the proportion of women cured (continent/dry), and the proportion of women whose symptoms were improved based on clinical measures such as pad tests, urinary diaries or quality of life scores.

In line with the recommendations of the International Continence Society, outcomes were considered the under the following five categories 29:

To identify all relevant studies for the review, the search strategy comprised searches of the following:

Bibliographic Databases:MEDLINE, CINAHL, AMED, Current Contents, The Cochrane Library, Cochrane Database of Systematic Reviews (CDSR), The Cochrane Controlled Trials Registers (CCTR), SPORTdiscus, CatchWord, AUSTHealth, Academic search elite, Science Direct, PubMed, Ageline, PEDro, OVID

Internet source: http://www.yahoo.com, http://www.google.com

Reference lists of systematic reviews, meta-analyses, reviews and the studies identified by the search strategy above were pearled for additional relevant source material. Their inclusion was validated by checking their key words against the search terms. Hand searching for published and unpublished data was not performed because a systematic and thus reproducible approach could not be guaranteed.

All relevant studies with an English language abstract were located for assessment against the inclusion criteria. Date of the last search was 20 May 2005. Individual strategies were developed for each source searched to accommodate search engine idiosyncrasies. The core terms and search strategies used for each literature source are listed in additional file 1.

The search identified 7760 potentially relevant research reports in the period 1995–2005, of which 24 studies fulfilled the inclusion criteria and hence were considered in this review. Twenty one included studies were English peer-reviewed research reports, three were peer-reviewed conference abstracts with no published full-text report and one was a peer-reviewed foreign language paper with an English language abstract. This English abstract was used for data extraction. There was 100% agreement between the reviewers in terms of study inclusion. Summaries of the studies included in the review are provided in Tables 1 and 2. Studies are presented in order of their quality assessment score with information about the level of evidence, interventions investigated and information to determine the generalisability of the study findings.

Arms of studies were excluded where there was no description of a specific PFMT protocol. Thus the following arm(s) were excluded: Cammu & van Nylen (1997) 32 (VW only), Sung et al (2000) 33 (ES/BF) and Bo et al (1999) 34(ES, VW).

Women were included with a urodynamic diagnosis of SUI, a clinical diagnosis based on signs and/or symptoms, or a combination of the above 1. There was considerable variation in the hormonal status and age (18–84 years) of subjects in this review. Two studies 4156 specifically recruited younger, pre-menopausal women with SUI persisting at least 3 months after the last childbirth. These authors stated that this time was chosen to allow the hormonal changes from pregnancy and parturition to have resolved. Another study 49 also specifically recruited pre-menopausal women. By contrast, Miller et al (1998) recruited older women with a mean age of 68 (range 60–84) and Aksac et al (2003) reported on women with a mean age of 53 (SD 7.2) years who were all using oral hormone replacement therapy. All other studies investigated various combinations of PFMT and adjunctive therapies in women with a mean age 46–56 (range of 18–80). Some of these studies stated that their populations included women who were both pre- and post-menopausal 333438434754. There was therefore considerable heterogeneity in the studies reviewed in terms of possible confounding due to age and hormonal status.

The following confounding variables were controlled by stratification in a number of studies: severity of symptoms 34384147, referral source 34384147 and parity 34.

The initial severity of incontinence was not always reported and methods used to describe severity varied considerably so that any comparisons should be made with caution (Table 3). Two studies included women with a past history of surgery for incontinence 4551. In twelve studies, it was stated that women were excluded if they had prior surgery for incontinence 343841424346474950525354 and it was not reported in nine other studies 323336373940444856.

Recruitment methods varied across the included publications, which potentially influenced subjects' responses to intervention. In three studies, the participants were volunteers who responded to newspaper advertisements 47 or from outpatient hospital populations 4156. In three studies, participants were both volunteers and referred 344344. In ten other studies, they were referred by a medical practitioner or recruited from a tertiary institution clinic population 33373845484950525354 and in the remaining studies the source was not reported 3236394042465155.

The studies were divided into intervention categories and results summarised according to the different interventions reported: 14 studies reported on PFMT alone (Table 4), 11 studies on PFMT with BF (Table 5), three studies on PFMT and ES (Table 6), two studies on PFMT and VW (Table 7), three studies on PFMT with BF and ES (Table 8), one study on PFMT, BF and VW, (Table 9), and one study on PFMT combined with ES, BF and VW (Table 10). Details of the protocols for the interventions for all studies are detailed in Table 11.

A summary of the outcome measures used in terms of the ICS recommendations is presented in Table 12. Outcomes were reported under all categories except socioeconomic variables which were not reported in any study. However, in each category, different instruments were used or modifications of the same instrument. For example, in category 2 (quantification of symptoms by objective measures) the results of 19 pad tests were reported. Two were performed for 48 hours, two for 24 hours, one for 10 hours. In addition, eight different provocative pad tests with standardised bladder filling were performed 3440414547515356 and another four 'standardised' pad tests were reported without details of either bladder filling or provocation 36425254. One test using paper towel instead of a pad to quantify urine loss under coughing provocation was reported 46. This variability precludes precise comparison of outcomes.

A summary of all the positive and statistically significant (p < 0.05) and the non-significant measures of effect for each category of study (PFMT, PFMT/BF etc) is presented in Figure 1. Each measure is displayed for within-group or, if there was a no-treatment control group, also for between group differences.

None of the level III & IV studies and nine of the 16 level II studies included statements about the reliability and validity of the outcome measures used [see additional files 4 &5]. The use of outcome measures which are valid, reliable and sensitive to change is vital when considering the effects of treatment in order to detect valid changes which are greater than measurement error 61. Caution must be exercised when considering the results of studies where valid and reliable outcome measures have not been used.

The definitions used for 'cure' and 'improvement' varied widely and are listed in Table 13. Five studies 3339505153 did not report their outcomes in terms of the numbers (percentages) of subjects who were cured/improved at all. All estimates of 'cured' and 'improved' are expressed as the percentage of subjects who completed treatment compared with the number who started treatment. The number (percent) of withdrawals is presented to permit estimates of bias.

Four studies reported on the numbers of women who had surgery either during the study or after completion of treatment 32474951. Ten studies reported on the occurrence of any adverse events as a result of treatment 34414246474849515455.

This review found consistent evidence from high quality level II studies for PFMT alone and in combination with adjunctive therapies in the treatment of SUI. Further evidence is presented about the efficacy of PFM strength training, in support of previous reports 1416. 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.

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 1416. 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 SUI.

It should be remembered that only studies of PFMT for women with SUI 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 SUI. 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 SUI 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.

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 SUI. 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.

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 PFMT conducted in a primary care setting may be effective for the treatment of SUI.

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 SUI.

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.

• There was strong evidence that PFMT alone, with BF and with ES/BF is effective for women with SUI, with expected rates of cure up to 73% and cure/improvement up to 97%.

• There was strong evidence for strength training of the PFM to reduce symptoms of SUI 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.

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