Hypothesis / aims of study
Supine empty bladder stress test (SEST) is a widely used method proposed to measure the severity of urinary incontinence (UI). Subjective and objective measures of SUI severity should correlate with clinical findings. There are some studies evaluating the relationships between urinary incontinence severity indicators and clinical findings as well as urodynamic measurements in the literature. It is generally reported that measurements associated ISD was significantly, worse in patients with a positive SEST, but this difference did not seem clinically meaningful, as well1. We aimed to demonstrate how SEST correlates with clinical and ambulatory urodynamic monitoring (AUM) findings in women with UI.
Study design, materials and methods
Women who underwent AUM in a University Hospital with UI after conservative treatment, were retrospectively reviewed (n=523) and grouped according to SEST (positive, n=140 and negative, n=383). Available data for baseline characteristics, clinical examination findings and voiding diary parameters, validated questionnaires for lower urinary tract symptoms, quality of life and sexual dysfunction and ambulatory urodynamic monitoring records were evaluated retrospectively for all women included to the study. AUM data were obtained from the traces of AUM, performed as described2. After spontaneous micturition and measurement of PVR by catheterization, a 7Fr double lumen air- charged single sensor bladder catheter (T-DOC, Laborietm) and a 7F single lumen air-charged rectal catheter (T-DOC, Laborietm) were inserted to measure intravesical and abdominal pressures, respectively. In case of advanced POP, reduction of prolapse was performed gently by sponges. Both catheters were securely taped adjacent to the external meatus of urethra at 12 cm and to anus at 9 cm to avoid accidental displacements. Then, they were connected to a microcomputer (LUNA, Medical Measurement SystemsTM) worn over the shoulder, allowing patients to move freely. Each transducer was set to zero atmospheric pressure before each investigation with the patient in standing position. Patients and one of their relatives were informed about the use of LUNA event buttons. Urinary leakage during AUM was verified using a pad test. During AUM, all patients were encouraged towards activities or maneuvers they knew to be provocative for their daily urinary symptoms at the special area reserved for AUM in the hospital setting. All women were asked drinking 500 ml of water in 30 min at the beginning of AUM. Monitoring was ended by a pressure-flow study when the patients felt severe bladder fullness and were unable to delay voiding, which was performed by a PC based wireless uroflowmeter (Flowmaster, Medical Measurement SystemsTM) in a special section of the urodynamic room to preserve intimacy and to avoid embarrassment. Continuous variables were presented as mean±SD or median (interquartile ranges) whereas categorical variables were presented as number and percentage. Descriptive statistics of continuous variables were compared between groups using Mann-Whitney or t-test according to their respective distribution properties. Fisher-exact test was used for comparing categorical variables between groups.
Baseline characteristics and clinical findings of women are presented in table 1. Mean age was significantly higher in positive SEST group (55.7±11.9 vs 53.1±10.5, p=0.026). Women with a positive SEST had higher symptom bother for stress, postural, nocturnal and coital urinary incontinence, insensible loss of urine complaints and had worse quality of life. More daily UI episodes in the diary (p<0.001), higher Q-tip positivity (p=0.001), lower residual volume (p=0.04) and lower rate of severe apical prolapse (p<0.001) were demonstrated in women with SEST positive. Valsava leak point pressure (VLPP) was significantly lower in women with SEST positive (71±46 vs 51±39, p=0.031) (table2). Urodynamic SUI and mixed urinary incontinence (MUI) were higher in SEST positive women, while urgency urinary incontinence (UUI) was higher in SEST negative women (Table 2).
Interpretation of results
When comparing subjects with a positive and negative SEST, we demonstrated that VLPP was significantly lower and urodynamic stress urinary incontinence was significantly higher in women with positive SEST. Our data suggests the SEST might be a good indicator of severe stress incontinence, unlike studies suggest that women with demonstrable stress incontinence will not leak with valsalva efforts during conventional urodynamics 3. However SEST positivity seems to be a good indicator for severe stress urinary incontinence, in the group of women with SEST positive; 9% of women was demonstrated urodynamic urgency urinary incontinence, 47% urodynamic mixed urinary incontinence, 52% has detrusor overactivity and 32% women has obstructed voiding pattern during pressure-flow study. Therefore, SEST positive women may be seen as complicated cases and may be candidates for urodynamics.