Introduction and Objectives
According to the 3rd International Consultation on Incontinence (2005), few trials have investigated the association between patient characteristics and outcome of physiotherapy intervention for urinary incontinence.
The aim of this study was to identify predictors of success of a physiotherapy intervention in women with persistent post-partum stress urinary incontinence.
This report is a secondary analysis of data from a single blind randomized control trial comparing two physiotherapy interventions programs for persistent stress urinary incontinence in postpartum women. Fifty-seven women, ages 23 to 39 (35.93 + 3.62), with stress urinary incontinence participated. Twentyeight were randomised to PFM training and 29 to PFM training with abdominal muscle training. Over 8 weeks, both groups followed a PFM or PFM and abdominal exercise program at home, once a day, five days a week. In addition to home exercise program, participants also attended individual weekly physiotherapy sessions throughout the eight week program. Physiotherapy sessions consisted of electrical stimulation and PFM training. The abdominal muscle group had an additional session of deep abdominal muscle exercises. Primary outcome measure consisted of a 20-min pad test with a standardized bladder volume (300 ml). Treatment success was defined as a pad weight gain of less than 2g after the treatment. The result of this study has been previously reported. The relationship between potential predictive variable such as the severity of stress urinary incontinence, age, BMI and pretreatment pelvic floor muscle function measured with a PFM dynamometer (strength at minimum dynamometer opening (19 mm), strength at 24 mm dynamometer opening, endurance, tone, rapidity of contraction) and treatment success was explored using a forward stepwise multivariate logistic regression analyses.
Immediately after the physiotherapy intervention, 42 women (73%) were successful on Pad testing while 15 (26.3%) were not. Interestingly, successful treatment of stress urinary incontinence was associated with pre-treatment pelvic floor muscle function: high pre-intervention PFM endurance OR 1.001 (95% CI on odds ratio [1.000 ; 1.002]) and low PFM strength OR 0.551 (95% CI on odds ratio [0.350 ; 0.868]). The chances of success increased as pre-treatment PFM endurance increased. Inversely, chances of success decreased as pre-treatment PFM strength increased. This model explained between 21% (Cox & Snell R2) and 31% (Nagelkerke R2) of the variability of the outcome. Successful treatment was not associated with severity of urinary incontinence, age or BMI. These results suggest that PFM strength and endurance are predictors of successful outcome of physiotherapy intervention in women with persistent postpartum stress urinary incontinence. Those with low PFM strength seemed to benefit more from a PFM training program than those with high PFM strength. Since postpartum stress urinary incontinence is multifactorial, it is possible that those with higher pre-treatment PFM strength demonstrate other dysfunction such as conjunctive or aponeurotic degradation and are therefore less likely to respond positively to PFMT. In addition, it is possible that the type of PFM program proposed (high intensity strenghtening exercises) targeted those with low strength. Those with low PFM endurance may have had greater chance of successful treatment outcome if an endurance PFM program type was proposed.
The results of this study provide novel information about predictors of physiotherapy treatment for post-partum women with stress urinary incontinence. Pelvic floor muscle strength and endurance were identified as predictors of outcome. Clinicians should assess PFM strength and endurance prior to treatment in order to improve treatment outcomes. More research is needed to study types of PFM training programs and their impact on postpartum stress urinary incontinent women.
pelvic floor, stress urinary incontinence, physiotherapy.