Hypothesis / aims of study
Overactive bladder syndrome (OAB) defined by the presence of urgency, with or without urge urinary incontinence, is considered refractory (ROAB) when it does not respond to hygienic-dietary measures or oral therapy.
Botulinum toxin is indicated in these cases. It is an effective and safe procedure, but not without risks. Nowadays, there is no definitive consensus on the optimal number of recommended intravesical botulinum toxin injections for the management of ROAB. The possibility of reducing the number of injection points, while maintaining a similar efficacy and rate of adverse effects, continues to be the objective of multiple studies
Objectives: To evaluate the effect and complications of a pattern of 10 intravesical injections of botulinum toxin for the management of ROAB.
Study design, materials and methods
Retrospective analytical study that includes all patients with ROAB treated for the first time with intravesical botulinum toxin (100 units divided into 10 injections, without including trigone) between 2019 and 2020 in our center.
We analyzed the pain associated with the procedure using a visual analogue scale (VAS). The response to treatment was evaluated with the OAB-V8, ICIQ-SF questionnaires, whose scores were recorded before and after it. The response perceived by the patient was evaluated using the Treatment Benefit Scale (TBS).
Pathological urine culture, high post-void residue (>100cc), acute urine retention, need for intermittent self-catheterization, or clinically significant hematuria were recorded as possible complications during the first 30 days after treatment.
Data source: Medical history. Statistical analysis: SPSS Statistics (p<0.05). Qualitative variables were expressed as frequencies and percentages. Quantitative variables were expressed as average with standard deviations (SD) and medians with interquartile range (IQR). Chi-square test for qualitative variables. Student's t-test for quantitative variables with normal distribution. Wilcoxon test for quantitative variables with non-normal distribution.
Results
A total of 85 cases were registered, with a predominance of females (85.9%). The mean age is 66.14 years (SD: 15.01).
When evaluating the results in the OAB-V8 questionnaire, we obtain a median of 31 points (IQR: 12) in the pre-treatment version and a median of 17 (IQR: 10) in the post-treatment version, with statistically significant differences (p = 0.01). Regarding the ICIQ-SF questionnaire, we recorded a median of 18 points (IQR: 9) in the pre-treatment version and 5 (IQR: 16) in the post-treatment version, with significant differences between both (p = 0.01).
According to the TBS questionnaire, 75.29% of the patients perceive a symptomatic improvement with the treatment.
Regarding complications, these are present in 16.45% of the procedures, the most frequent being the presence of a positive urine culture (8.23%) and pathological post-void residue (7.05%). Of these, one patient presented acute urinary retention and another the need for self-catheterization. Only one patient (1.17%) presented clinically significant hematuria. No major complications or systemic reactions occurred.
Mean score of 2.02 (SD: 2.03) on the VAS scale of pain associated with the procedure.
Interpretation of results
ROAB is a pathology that predominantly affects the female sex, with a higher prevalence in advanced ages.
The OAB-V8 questionnaire, initially designed to identify those patients with OAB, has proven to be a useful tool in evaluating the severity of symptoms and quality of life of these patients. Similarly, the ICIQ-SF questionnaire makes possible to identify patients with OAB and assess the impact of the treatment they receive. The improvement in the scores of both questionnaires after the treatment evaluated, document the clinical efficacy with the protocol of 10 injections with botulinum toxin.
The results obtained with the TBS questionnaire confirm that the efficacy of this treatment is perceived by patients.
The complications identified in this study have been minor and involved ambulatory management, with positive urine culture and pathological post-void residue standing out due to their frequency. The absence of major complications and low incidence of minor complications reinforce the safety of this strategy.
Finally, this protocol is generally associated with mild pain, which translates into a high rate of tolerance.