2 Research recommendations

The Guideline Development Group has made the following recommendations for research, based on its review of evidence, to improve NICE guidance and patient care in the future. The Guideline Development Group's full set of research recommendations is detailed in the full guideline.

2.1 Pelvic floor muscle training

How effective are different pelvic floor muscle training regimens in the management of women with overactive bladder (OAB) symptoms and to whom should it be offered?

Why this is important

For many women with urinary incontinence symptoms, management of their condition will take place predominantly in primary and community care. Pelvic floor muscle training may be their only experience of therapeutic intervention. It is not currently known whether different pelvic floor muscle training regimens have an impact on treatment outcomes. It is also not known whether other factors also have an impact on its effectiveness. These factors include the way that the training is offered, the technique that is taught, the intensity and frequency of training, and the length of time that pelvic floor muscle training is continued. Because pelvic floor muscle training is widely used in clinical practice, robust evaluation is needed to identify whether these or other factors have an important impact on patient‑centred outcomes.

2.2 Neurostimulation

What is the comparative effectiveness and cost‑effectiveness of transcutaneous stimulation of the sacral nerve roots, and transcutaneous and percutaneous posterior tibial nerve stimulation for the treatment of OAB?

Why this is important

Transcutaneous neurostimulation can be applied either over the sacrum or over the posterior tibial nerve to modulate the sacral nerve supply to the bladder. The treatment uses surface electrodes and the woman can carry it out in her own home. Percutaneous posterior tibial nerve stimulation involves the introduction of a needle in the region of the posterior tibial nerve near the ankle, and at present is carried out in clinics in secondary care. Currently, it is offered widely as a conservative treatment for OAB without adequate evidence that it is effective. Although this is a relatively low cost treatment, both the equipment and staff time have a cost implication, and because it has been widely used in conservative management this has large resource consequences for the NHS. Robust evidence is needed to establish whether it is a cost‑effective option relative to other conservative therapies for all women or for a selected group of patients who are unsuitable for or have unsuccessful botulinum toxin A, percutaneous sacral nerve stimulation or OAB drug treatment.

2.3 Botulinum toxin A

What is the long‑term effectiveness, optimal dose and optimal frequency of repeat therapy of botulinum toxin A in women with OAB based on detrusor overactivity including risk of adverse events such as urinary infection and intermittent catheterisation?

Why is this important

There are currently no trials looking at long‑term outcomes, quality of life, satisfaction, optimal dose, optimal frequency and long‑term adverse effects of botulinum toxin A for women with OAB. Further research into these outcomes will have an impact on future updates of key recommendations within the guideline and would impact on how resources are used within urinary incontinence services. Effective treatment with botulinum toxin A may need repeated injections to remain effective but the frequency of these is not reported in the current evidence. Botulinum toxin A has the potential to cause incomplete bladder emptying resulting in the need for women to perform catheterisation indefinitely. This not only has financial implications but catheterisation and the morbidity associated with it will not always be acceptable to women. Additionally, there are currently no data on whether repeated botulinum toxin A injections alter bladder function.

2.4 Sequence of invasive OAB procedures

What is the effectiveness and optimum sequence of treatment with botulinum toxin A and percutaneous sacral nerve stimulation for the treatment of OAB after failed conservative (including drug) management?

Why is this important

It is not currently known which treatment option, either botulinum toxin A or percutaneous sacral nerve stimulation, is the most effective in the medium‑ and long‑term for women with OAB in whom initial treatment, including OAB drugs, has failed. The initial outlay for percutaneous sacral nerve stimulation is high but when successful it appears to be effective. Botulinum toxin A also has a high failure rate but a lower outlay and it is not yet understood the cost threshold (in terms of treatment cycles or length of follow‑up) at which botulinum toxin A is likely to be the less cost‑effective option compared with percutaneous sacral nerve stimulation. Currently, funding for percutaneous sacral nerve stimulation is on an individual basis because of its high cost, leading to geographical inequalities in access. A head‑to‑head longitudinal study of these 2 treatments would determine both which should be offered first and at what point in the treatment pathway. Such studies have not been done. This evidence could reduce inequalities in access to treatment. In subsequent NICE guidance, evidence would be available to inform recommendations on the treatment pathway and at which point in the treatment pathway for OAB each of these options should be offered. It would also provide more robust information to patients about the risk of adverse events and support women's choice about whether to proceed with treatment.

2.5 Predictors of tape failure

What are the effects of the following predictors on tape failure?

  • Age per decade

  • Lower maximum urethral closure pressure

  • Secondary surgery versus primary surgery

  • Higher maximal flow rate

  • Concurrent pelvic organ prolapse surgery

  • Nocturia versus no nocturia

  • Urgency versus no urgency

  • Pad weight (per 10 g)

  • Previous urinary incontinence surgery versus no surgery

  • Q‑tip maximum straining less than 30 degrees, yes versus no

  • Urge score (per 10 points)

  • Urgency symptoms versus no urgency symptoms

  • More than 20 procedures for each surgeon versus first 10 procedures for each surgeon

  • General anaesthesia versus local anaesthesia

  • BMI over 35 versus 30 or less

  • Maximum urethral closure pressure of 31 or more versus 30 or less

  • Primary surgery versus secondary surgery

  • Preoperative anticholinergic medication use versus no use

Why is this important

The factors identified for this research question are thought anecdotally by surgeons to have an impact on the outcome of tape surgery but there is little robust evidence in the literature. Certain patient factors such as older age and increased weight are thought to produce a higher chance of recurrent symptoms. Similarly, the effect of previous incontinence surgery, concomitant prolapse surgery and the 'learning curve' of the surgeon are all thought to have adverse effects on outcome (including an increased chance of urgency incontinence). In addition there is little robust evidence regarding the effect of previous urgency incontinence, higher maximum flow rates, nocturia or preoperative use of anticholinergics on the occurrence of post‑operative urgency and bladder overactivity. It would be useful to be able to individualise treatment by understanding these risks in more detail.

  • National Institute for Health and Care Excellence (NICE)