Elsevier

European Urology

Volume 61, Issue 4, April 2012, Pages 834-839
European Urology

Voiding Dysfunction
Repeated Botulinum Toxin Type A Injections for Refractory Overactive Bladder: Medium-Term Outcomes, Safety Profile, and Discontinuation Rates

https://doi.org/10.1016/j.eururo.2011.12.011Get rights and content

Abstract

Background

Efficacy and safety of botulinum toxin type A (BoNTA) injection is supported by level 1 evidence, but data regarding repeated injections are limited in patients with refractory overactive bladder (OAB) and idiopathic detrusor overactivity (IDO).

Objectives

Describe medium-term outcomes and discontinuation rates for patients adopting repeated BoNTA as a management strategy for IDO.

Design, setting, and participants

Prospective data from a single centre were collected from the first 100 patients.

Intervention

Bladder injection of BoNTA (predominantly 200 U onabotulinumtoxinA; Allergan Ltd., Marlow, Buckinghamshire, UK) in an outpatient setting.

Measurements

OAB symptoms, quality of life, discontinuation rates, interinjection interval, and adverse events were recorded. Data comparisons were performed using a generalised linear model or a chi-square test where appropriate.

Results and limitations

Two hundred seven injections were performed in 100 patients. All patients had 1 injection, 53 had a total of 2, 20 had 3, 13 had 4, 10 had 5, 5 had 6, 3 had 7, 1 had 8, 1 had 9, and 1 had 10 injections. Statistics were applied up to five repeated injections. A statistically significant reduction in frequency, urgency, and urge urinary incontinence were seen following the first BoNTA injection compared to baseline. This improvement was maintained after repeated injections and was not statistically different when comparing differences between injections. Thirty-seven patients stopped treatment after the first two injections; thereafter, dropouts were rare. The most common reasons for discontinuing treatment were poor efficacy (13%) and clean intermittent self-catheterisation (CISC)–related issues (11%). The incidence of CISC after the first injection was 35%. Bacteriuria was detected in 21% of patients. The mean interinjection interval was 322 d. Limitations included the concurrent use of antimuscarinic drugs in some patients.

Conclusions

BoNTA can provide a safe and effective medium-term management option for patients with refractory IDO. The most common reasons cited for stopping treatment were poor efficacy and CISC-related issues.

Introduction

Injections of botulinum toxin type A (BoNTA) into the bladder is an effective treatment for patients with idiopathic detrusor overactivity (IDO) and symptoms of overactive bladder (OAB). Over the last 5 yr, data from several randomised, double-blind, placebo-controlled trials have demonstrated its safety and efficacy after one injection [1], [2], [3]. A large, phase 2, dose-escalation, industry-sponsored study confirmed its efficacy in doses of ≥100 U compared with placebo, with significant improvement in OAB symptoms, urodynamic parameters, and quality of life (QoL) [4], [5]. A European consensus group gave a grade A recommendation for BoNTA use in IDO and a recent systematic review suggested its use for refractory OAB is well justified [6], [7].

Many patients have come to rely on repeated injections for continued control of OAB symptoms. To date there have only been few small series reporting the outcomes of repeated injections in patients with IDO [8], [9]. In this study we seek to expand on our previous work by reporting outcomes in our first 100 patients with a particular focus on efficacy, safety, and the proportion of patients who chose to discontinue BoNTA injections as a long-term strategy and the reasons for their choice.

Section snippets

Patients and methods

Patients were adults (>18 yr) of both sexes who had OAB symptoms and IDO. All patients had failed treatment with at least one antimuscarinic medication (often multiple antimuscarinics had been tried for at least 4–6 wk unless there were tolerability issues) and had urodynamics performed within 12 mo of injection. All urodynamic procedures were performed as recommended by the International Continence Society [10]. OnabotulinumtoxinA injections were first offered in our unit as part of a clinical

Results

Between 2004 and 2010, 207 injections were performed in 100 patients. Median age at first injection was 55 yr (range: 22–85 yr); 76 patients were female. Table 1 outlines the number of injections each patient received, the number of patients who chose to discontinue injections, and the reasons they gave for stopping. After the first and second injections, 25 patients (25%) and 12 patients (22%), respectively, did not undergo further injections at our institution. Subsequently, the vast majority

Discussion

In this study we have reported our clinical experience of onabotulinumtoxinA as a medium-term management strategy for IDO. Our data reflect the outcomes for 100 patients who commenced their therapy with onabotulinumtoxinA in a staggered fashion over a reporting period of approximately 6 yr. Therefore, one would not expect all 100 patients to have had the same number of repeat injections and thus we saw a decreasing number of patients at each stage. The key question is whether this represents a

Conclusions

To our knowledge, this is the largest series to date reporting on repeated onabotulinumtoxinA injections in patients with refractory IDO. The data suggest that the toxin can provide an efficacious and safe repeated therapy for managing refractory OAB symptoms in the medium term. Discontinuation rates are most likely related to poor efficacy and the need to perform CISC. Further research into optimum delivery and dosage according to individual patient information may improve the number of

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