Patient Characteristics that May Influence the Effect of Urethral Injection Therapy for Female Stress Urinary Incontinence

Purpose: Urethral injection therapy is a well-known treatment of female stress urinary incontinence but to our knowledge the optimal group of recipients has not been established. In this study we examined which patient characteristics are associated with success after urethral injection therapy. Materials and Methods: This study is a post hoc analysis of a previously published, randomized, 33-center study of the hydrogel bulking agent Bulkamid (R) vs the collagen gel Contigen (R). Regardless of the treatment women were considered cured if there were no stress incontinence episodes in the bladder diary and no stress incontinence symptoms on the ICIQ-UI-SF (International Consultation on Incontinence Questionnaire-Urinary Incontinence-Short Form), improved if there was a 50% or greater reduction in stress incontinence episodes and no effect if there was less than a 50% reduction in stress incontinence episodes 1 year after treatment. Results: Of the 345 women who were initially randomized 291 were included in this study. A total of 191 women received hydrogel and 100 received collagen. At 1 year 74 women (25%) were cured, 164 (56%) were improved and 53 (18%) showed no effect. On multivariate logistic regression analysis age 60 years or greater and fewer than 2.5 daily stress incontinence episodes were associated with cure. In this group 90% of women experienced a treatment effect and 38% were cured compared with a 13% cure rate in those younger than 60 years with 2.5 or more daily stress incontinence episodes. Conclusions: Urethral injection therapy was more effective to treat stress urinary incontinence in women 60 years old or older with fewer than 2.5 daily stress incontinence episodes. It had a 90% success rate in these women.