Description of the condition
As the world's population ages, more and more people will develop lower urinary tract symptoms (LUTS), which will diminish their quality of life. LUTS can be classified into three types: storage, voiding, and post-micturition symptoms (Abrams 2003). According to the International Urogynecological Association and the International Continence Society, voiding dysfunction is defined as abnormally slow and/or incomplete micturition based on symptoms and/or urodynamic investigations (Haylen 2010).
The prevalence of female voiding dysfunction is various, from 2.7 to 23 % (Choi 2013). A large survey in Canada, Germany, Italy, Sweden and the United Kingdom showed that men (25.7%) reported voiding symptoms more than women (19.5%) (Irwin 2006). Pelvic floor disorders, urogenital prolapse > stage II, symptoms of voiding difficulty, age > 55 years, prior incontinence surgery, a history of multiple sclerosis and the absence of stress urinary incontinence are risk factors for voiding dysfunction (Robinson 2012).
Patients with voiding dysfunction comprise a significant proportion of people with complicated urinary tract infections (Neal 2008). An increase in postvoid residual urinary volume (for example, > 50 mL) is an independent risk factor for recurrent urinary tract infections in postmenopausal women (Kodner 2010). Furthermore, insufficient bladder voiding can lead to renal damage, for example in caudal regression syndrome patients (Torre 2011).
Voiding dysfunction can manifest as a broad spectrum of symptoms including urinary hesitancy, slow stream, intermittency, straining to void, spraying, incomplete bladder emptying, need to immediately re-void, post-micturition leakage, position-dependent micturition and dysuria (Robinson 2012). Voiding dysfunction can be caused by either detrusor underactivity and/or bladder outlet obstruction (Raheem 2013).
The common causes of female detrusor underactivity include the following:
neurogenic (cerebral, spinal sacral and subsacral lesions);
myogenic (aging and acute prolonged bladder overdistension); and
mixed other risk factors (e.g. diabetic cystopathy).
The pathogenesis of female bladder outlet obstruction can be anatomical (for example, pelvic organ prolapse) or functional (for example, dysfunctional voiding) (Raheem 2013).
Description of the intervention
For therapy, it might not be possible to achieve a complete cure for patients with voiding dysfunction. Therefore, the goal of symptom relief may be acceptable.
Women with an acontractile bladder detrusor muscle (detrusor underactivity) can be offered the below treatment options:
intravesical electrical stimulation;
clean intermittent self-catheterisation;
For women with mechanical bladder outlet obstruction, clean intermittent catheterisation or a suprapubic catheter can be offered if it is not possible to correct the cause of the obstruction, for example with surgery for pelvic organ prolapse (Raheem 2013).
The availability of effective pharmacological treatment, direct-to-consumer outreach by pharmaceutical industries, the relative frequency of side effects with surgery, and an increasing focus on quality of life have all led to a steady decrease in the number of surgical procedures performed and an increase in the use of drugs (pharmacological treatment) for voiding dysfunction in the US, Europe, and other parts of the world (Chapple 2012).
Drug treatment for female voiding dysfunction
The pharmacological treatment of female voiding dysfunction varies depending on the underlying pathophysiology. Pharmacological intervention for women with detrusor underactivity focus on increasing bladder contractility by increasing detrusor strength, decreasing outflow resistance, or both.
How the intervention might work
Voiding dysfunction may be treated by drugs that either increase the detrusor contractile force and/or decrease outflow resistance, thereby restoring an appropriate balance between detrusor strength and urethral resistance.
Increasing detrusor strength
Muscarinic receptor agonists and choline esterase inhibitors have been found to enhance detrusor strength (Raheem 2013). Muscarinic receptor agonists (for example, bethanechol and carbachol) may stimulate the detrusor cells causing an increase in bladder contractility. Moreover, choline esterase inhibitors (for example, distigmine, pyridostigmine and neostigmineacetyl) can activate the endogenous agonist acetylcholinesterase to provide additional stimulation of muscarinic receptors on the detrusor cells (Barendrecht 2007).
Decreasing outflow resistance
Female bladder outlet obstruction is relatively uncommon, but the condition may coexist with detrusor underactivity. Drugs that decrease outflow resistance (for example, alpha-1-adrenoreceptor antagonists) may restore the balance between detrusor strength and urethral resistance (Koeveringe 2011). Alpha-1-adrenoreceptor antagonists can increase smooth muscle relaxation and improve urinary flow by blocking noradrenaline from binding to and stimulating alpha1-adrenoreceptors in the bladder neck (as well as the prostate and prostatic urethra) so as to relieve bladder outlet obstruction (Meyer 2012). Thus, while alpha-1-adrenoreceptor antagonists might be efficacious for primary bladder outlet obstruction, they may also increase the risk of stress urinary incontinence by reducing urethral resistance (Raheem 2013).
Why it is important to do this review
The above interventions are currently used for the treatment of voiding dysfunction, but few studies on their effectiveness and safety have been conducted, resulting in a lack of evidence and hence uncertain recommendations for clinicians and patients.
A search of The Cochrane Library revealed no published systematic reviews of drug treatment for LUTS in women with voiding dysfunction. If there is evidence that pharmacological treatment is effective, this could add an important treatment modality to the overall management of voiding dysfunction. Furthermore, the best available evidence on the cost-effectiveness of alternative treatment strategies will be summarised and the findings will help decision makers to consider the maximisation of health benefit within the confines of scarce healthcare budgets.
We are aware of a Cochrane protocol covering non-drug treatment for lower urinary tract symptoms in women with voiding dysfunction, which is currently being developed (Hajebrahimi ongoing). Other related reviews that may be of interest to the reader include:
urinary diversion for intractable incontinence or after cystectomy (Cody 2012);
surgical management of bladder outlet obstruction in neurogenic bladder dysfunction (Utomo 2011).