Hypothesis / aims of study
Urgency urinary incontinence (UUI) and fecal incontinence (FI) are two highly prevalent pelvic floor disorders which negatively impact quality of life (QOL). Among women with UUI, up to 20% also suffer from FI (double incontinence). The primary aim of this study was to characterize change in FI symptom severity using the Vaizey score after 8 weeks of antimuscarinic therapy in patients with double incontinence. Secondary aims were to characterize post-treatment change in FI frequency and QOL, change in overactive bladder (OAB) symptom bother and QOL, and to describe compliance and adverse events of antimuscarinic medication in patients with double incontinence. We hypothesized that in patients with double incontinence, antimuscarinic medication would improve FI symptom severity at 8 weeks.
Study design, materials and methods
This study was a single-arm prospective open label cohort study of women presenting to our clinic with double incontinence, who elected antimuscarinic medication for treatment of UUI. Inclusion criteria were women over the age of 18 years with answer of “moderate” or greater on Urogenital Distress Inventory (UDI) question #2 (Do you usually experience urine leakage associated with a feeling of urgency, that is, a strong sensation of needing to go to the bathroom? If yes, how much does it bother you?), and fecal incontinence of liquid or solid stool with a Vaizey score ≥ 12.
Based on prior data with the minimal clinically important difference (MID) for the Vaizey of -5, with standard deviation (SD) +/-8.5 [1,2], the estimated sample size needed was 30 subjects with 80% power and type I error probability of 0.05, accounting for a 15% lost to follow-up rate.
After informed consent, subjects completed the following baseline questionnaires: Vaizey questionnaire, Fecal Incontinence Quality of Life score (FIQoL), and Overactive Bladder Questionnaire (OAB-Q). After completing a 7-day baseline bowel diary, subjects underwent 8 weeks of treatment with darifenacin 15mg daily. During the 8th week of treatment, a second bowel diary was completed and subjects returned to the clinic to complete post-treatment questionnaires: Vaizey, FIQoL, OAB-Q and Patient Global Impression of Improvement (PGI-I). Adverse events were also recorded. Continuous variables were analyzed using paired t-test or Wilcoxon’s signed rank test, as appropriate.
32 women were recruited with a mean baseline Vaizey score of 17.8 (SD +/-3.0). Mean age was 66.5 (SD +/-10.3) and 84.4% of subjects were post-menopausal. Mean body mass index (BMI) was 30.2 kg/m2 (SD +/-6.4). 34.4% of subjects had a diagnosis of irritable bowel syndrome, and 84.4% of subjects reported baseline fecal urgency. 21.9% of subjects were using fiber supplementation and 15.6% of subjects had undergone prior surgical treatment for FI. Median number of baseline FI episodes per week was 7 (IQR 12) with a median Bristol stool classification of 6 (IQR 1.5).
28 of 32 subjects (87.5%) completed the study. After 8 weeks of antimuscarinic therapy, the mean Vaizey score decreased from 17.8 to 11.0 (95% CI (-8.7, -5.3), p <0.0001), with 67.9% of subjects meeting the MID for this measure (see Table). Median number of FI episodes per week decreased from 7 (IQR 12) to 1 (IQR 9) (p <0.0001). Median number of continent days per week increased from 2 (IQR 5) to 6 (IQR 4) (p <0.0001). Mean percent of continent bowel movements per week increased from 59.8% (SD +/-25.1) to 77.5% (SD +/- 25.1) (p= 0.0014). Each of the four FIQoL subscale scores significantly improved (all p < 0.05, table). Median PGI-I for FI symptoms was 2 (IQR 2) indicating symptoms “much better” than before treatment. Regarding OAB symptoms, each of the OAB-Q subscale scores significantly improved (both p < 0.05, table). Median PGI-I for OAB symptoms was 3 (IQR 2) indicating symptoms that were “a little better.” The most common adverse events were dry mouth (72%), constipation (41.4%) and dry eyes (37.9%), and 27.6% of subjects required a decrease in dosage due to intolerable adverse events.
Interpretation of results
In patients with double incontinence, treatment with an antimuscarinic medication resulted in a clinically and statistically significant improvement in FI symptoms at a short term follow up of 8 weeks. Over 67% of subjects achieved the MID for improvement in FI symptoms measured by the Vaizey scale. Subjects experienced a significant improvement in overall symptom severity and quality of life by questionnaires, as well as significant improvement in number of FI episodes, proportion of continent bowel movements, and median number of continent days per week. Subjects also experienced a significant improvement in OAB symptom severity and quality of life.