Efficacy of 100-U Onabotulinumtoxin A Treatment in Female Idiopathic Overactive Bladder-A Prospective Follow-Up Study

Overactive bladder (OAB) affects 11-17% of the female population. First-line treatment with lifestyle modifications and second-line therapy with medications are often limited by inadequate efficacy or pharmacological side effects. This study was aimed at assessing the effect of 100 U onabotulinumtoxin A treatment on idiopathic OAB (iOAB) as a second-line treatment.

This prospective follow-up study involved 94 women who received onabotulinumtoxin A treatment at a dose of 100 U as a second-line treatment for iOAB at the Department of Obstetrics and Gynecology, Oulu University Hospital, Finland, between May 2018 and December 2023. The impact of the treatment on iOAB symptoms was evaluated 3 months after administration using self-reported symptoms and the following internationally validated questionnaires: Visual Analogue Scale (VAS), Incontinence Impact Questionnaire (IIQ-7), and Urogenital Distress Inventory (UDI-6). Postoperative complications were assessed.

The follow-up data were obtained from 74 (78%) patients, of whom 66 (95.7%) reported a good outcome and 3 (4.3%) reported a poor outcome. Incontinence episodes, the number of incontinence pads needed, and daily micturitions were significantly reduced. For all questionnaires, the total scores decreased significantly after the treatment (VAS 8.27 ± 1.78 vs 3.50 ± 3.08, p < 0.001; IIQ-7 72.14 ± 20.55 vs 28.73 ± 29.40, p < 0.001; UDI-6 55.01 ± 18.86 vs 29.66 ± 22.03, p < 0.001). Postoperative urinary tract infection occurred in 9 patients (9.6%), whereas urinary retention occurred in 6 patients (6.4%).

Onabotulinumtoxin A (100 U) demonstrates good effectiveness in the second-line treatment of female iOAB.