OnabotulinumtoxinA has greater 9-month durability for OAB symptoms compared with12 weeks of PTNS
Sherif H, Khalil M, Omar R. Management of refractory idiopathic overactive bladder: intradetrusor injection of botulinum toxin type A versus posterior tibial nerve stimulation. Can J Urol. 2017;24(3):8838-8846.
In this randomized clinical trial, Sherif and colleagues compared the safety and efficacy of a single intradetrusor injection of onabotulinumtoxinA 100 U with that of PTNS for OAB.
Details of the study
Sixty adult men and women with OAB who did not respond to medical therapy were randomly assigned to treatment with either onabotulinumtoxinA 100 U or PTNS. Criteria for exclusion were current UTI, PVR urine volume of more than 150 mL, previous radiation therapy or chemotherapy, previous incontinence surgery or bladder malignancy, or presence of mixed urinary incontinence.
At baseline, participants completed a 3-day bladder diary, an OAB symptom score (OABSS) questionnaire, and urodynamic testing. The OABSS questionnaire included 7 questions (scoring range, 0-28), with higher scores indicating worse symptoms, and included subscales for urgency and quality-of-life measures. Total OABSS, urgency score, quality-of-life score, bladder diary records, and urodynamic testing parameters were assessed at 6, 12, 24, and 36 weeks, along with adverse events.
OnabotulinumtoxinA injections were performed under spinal anesthesia. If PVR urine volume was greater than 200 mL at any follow-up visit, participants were instructed to begin clean intermittent self-catheterization. PTNS was administered as weekly 30-minute sessions for 12 consecutive weeks.
Participants' baseline demographics and symptoms were similar. Average age was 45 years. Averages (SD) for duration of anticholinergic use was 13 (0.8) weeks, UUI episode score was 4.5 (1) on 3-day bladder diary, and OABSS was 22 (2.7). Nine-month data were available for 29 participants in the onabotulinumtoxinA group and for 8 in the PTNS group.
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OnabotulinumtoxinA treatment benefits sustained for 9 months
Through 6 months, compared with baseline assessments, both treatment groups had significant improvements in clinical symptoms and OABSS total score, as well as urgency and quality-of-life subscales. At 3 months, urodynamic study parameters were similarly improved from baseline in both groups.
At 9 months, however, only the onabotulinumtoxinA group, compared with the PTNS group, maintained the significant improvement from baseline in 3-day bladder diary voiding episodes (average [SD], 10.7 [1.01] vs 11.6 [1.09]; P = .009), 3-day bladder diary nocturia episodes (average [SD], 3.8 [1.09] vs 4.4 [0.8]; P = .02), and average [SD] UUI episodes over 3 days (3.5 [1.2] vs 4.2 [1.04]; P = .02). Similarly, onabotulinumtoxinA-treated participants, compared with those treated with PTNS, maintained improvements at 9 months in average (SD): OABSS total score (19.2 [2.4] vs 20.4 [1.7]; P = .03), urgency scores (10.9 [1.3] vs 11.8 [1.4]; P = .009), urine volume at first desire (177.8 [9.2] vs 171.8 [7.7]), maximum cystometric capacity (304 [17.6] vs 290 [13.1]), and Qmax (mL/sec) (20.7 [1.6] vs 22.2 [1.2]).
Adverse events. Average PVR urine volumes were higher in the onabotulinumtoxinA group compared with the PTNS group (36.8 [2.7] vs 32.4 [3.03]; P = .0001) at all time points, and self-catheterization was required in 6.6% of onabotulinumtoxinA-treated participants. Urinary tract infection occurred in 6.6% of participants in the onabotulinumtoxinA group and in none of the PTNS group. In the PTNS group, few experienced pain and minor bleeding at the needle site.
Strengths and limitations. This randomized, open-label trial comparing treatment with onabotulinumtoxinA 100 U and PTNS included both men and women with idiopathic OAB symptoms. The participants were assessed at regular intervals with various measures, and follow-up adherence was good. The sample size was small, so the study may not have been powered to see differences prior to 9 months.
Although at 9 months only the onabotulinumtoxinA group maintained significant improvement over baseline levels, the improvement was diminished, and therefore the clinical meaningfulness is uncertain. Further, participants in the PTNS group did not undergo monthly maintenance therapy after 3 months, which is recommended for those with a 12-week therapeutic response; this may have affected 9-month outcomes in this group. Since the one-time onabotulinumtoxinA 100 U injection was performed under spinal anesthesia, cost comparisons should be considered, since future onabotulinumtoxinA injections would be necessary.
WHAT THIS EVIDENCE MEANS FOR PRACTICE
A one-time onabotulinumtoxinA 100 U injection and 12 weeks of PTNS therapy are reasonable short-term options for symptomatic OAB relief after unsuccessful therapy with medications. OnabotulinumtoxinA injection may provide more durable OAB symptom control at 9 months but with a risk of UTI and need for self-catheterization.
Read about using different doses of onabotulinumtoxinA for OAB.