Can Baseline Urodynamic Findings Predict the Outcomes and Complications of Intravesical Injections of Onabotulinum Toxin A for Overactive Bladder?

[INTRODUCTION] Intravesical Onabotulinum Toxin A (Botox A) injections are an established minimally invasive therapy option for the treatment of refractory overactive bladder (OAB) symptoms in adults. We have assessed whether baseline urodynamic findings can predict self-reported patient outcomes and posttreatment voiding difficulties.

[METHODS] We have conducted a retrospective review of 407 patients (median age 61 years, range 22-94 years, 286 women) who have received intravesical Botox A injections for refractory non-neurogenic OAB symptoms between 2006 and 2018. Patient outcomes were assessed using the 5-point PGI-I scale and incidence of posttreatment voiding difficulties was noted. Results were correlated with the baseline urodynamic findings.

[RESULTS] Good response to Botox A injections was defined as PGI-I scores of 1 and 2, and was seen in 272 patients overall (67%). Women were significantly more likely to have successful outcomes comparing to men (p = 0.034) and the voiding detrusor contraction duration (DCD) was a further classifier for treatment success. Acute posttreatment voiding difficulties requiring catheterization were observed in 96 patients (24%) and were significantly more likely in those with good response.

[CONCLUSION] Successful outcomes (based on the self-reported PGI-I score) were more likely in women and correlated positively with the increased duration of voiding detrusor contraction, but no other urodynamic parameters. The risk of developing de novo need to catheterize correlated with patient reported benefit, but not with any baseline urodynamic findings. We did not find pre-existing bladder outflow obstruction, concurrent stress urinary incontinence or complex previous surgical history to adversely affect treatment success.