Urodynamic verification of an overactive bladder is not a prerequisite for antimuscarinic treatment response

The puzzle of overactive bladder: controversies, inconsistencies, and insights

Overactive bladder (OAB) affects millions of individuals and may severely impair the quality of life of those affected. The contribution of human behavior to manifestations of this symptom complex remains poorly understood. Continued evolution of our understanding of the pathophysiology of OAB has identified contributory mechanisms, which in turn may open new therapeutic avenues. Recent improvements in drug delivery systems represent advances in the management of OAB. However, more complete symptom control with greater tolerability is desirable; this awaits the development of agents specific for newly emerging and as yet unidentified pathophysiologic pathways. Importantly, as understanding of outcomes assessment in OAB matures, refined assessments of disease severity, response to intervention, and patient preference should be possible.

¿Es necesario realizar estudio urodinámico en el diagnóstico de la incontinencia urinaria?

Urinary incontinence is a dysfunction that affects 20%-50% of the women in Spain, depending on age. Even though it does not involve a prognosis of severity, it reduces self-esteem, limits independence and clear deteriorates quality of life. The diagnosis is generally made following the international criteria collected in the clinical practice guidelines. Even if it is true that the symptoms make it possible to suspect the nature of the functional disorder, this is not always sufficient or conclusive and there may be errors even in the clearest cases. Even so, the need to conduct a urodynamic study in the assessment of women with urinary incontinence diagnosed according to the symptoms mentioned continues to be debatable and there are no unified and defined criteria in our setting in regards to when it is necessary to request urodynamic tests.

A double-blind, randomized controlled trial of cystometry using saline versus 0.3 M potassium chloride infusion in women with overactive bladder syndrome

AIM

To evaluate the effect of 0.3 M potassium chloride on cystometric parameters by comparing it with normal saline as a filling solution in women with overactive bladder (OAB).

PATIENTS AND METHODS

Twenty-three women with significant OAB symptoms underwent consecutive cystometrograms (CMGs) using 0.9% normal saline (NS) and 0.3 M potassium chloride (KCl), the order of which was randomized for each patient. Individual CMGs were performed by separate investigators and both patients and investigators were blinded to the order in which each solution was given and to the results of the other CMG.

RESULTS

Regardless of the nature of the filling solution, the order in which the CMGs were performed had little influence on either first desire to void (FDV, mean 83.5 ml vs. 117.8 ml for first and second CMGs respectively, P = 0.10) or on maximum cystometric capacity (Cmax, mean 265.0 ml vs. 264.4 ml, P = 0.98). KCl produced a significant (24%) reduction in mean Cmax compared to NS (mean 228.6 ml vs. 300.8 ml, P = 0.001), irrespective of the order of infusion.

CONCLUSION

This comparative study using 0.3 M KCl versus NS as filling solutions suggests that intravesical potassium may not simply act on urothelial sensory nerve endings; it may also stimulate detrusor muscle contraction. These findings may influence the interpretation of the potassium sensitivity test in patients with OAB symptoms, particularly in those suspected of having interstitial cystitis.

Secondary-care treatment patterns in the UK for women with urinary incontinence

OBJECTIVES

To describe the treatment trends for women with urinary incontinence (UI) after their referral from primary to secondary care, as despite the high prevalence of UI within the female population, relatively few women actively seek treatment for their UI and fewer reach secondary care.

PATIENTS AND METHODS

We retrospectively reviewed the notes of patients attending in two randomly selected months in five hospital sites in the UK. Records were identified through outpatient clinic lists, surgery lists, nursing and physiotherapy lists. Data were collated and analysed for trends.

RESULTS

In all, 412 women (mean age 54.6 years, SD 12.6) covering 1406 visits to secondary care were covered by the study. Most women had a symptomatic diagnosis of mixed UI and mild to moderate UI, as defined by their physician. Most women had conservative therapies by either continence nurses or physiotherapists, regardless of the severity of their condition; 73% had cystometry and 39% were recommended for surgical intervention.

CONCLUSIONS

Women largely undergo similar procedures in secondary care. Most present with mixed UI. The perceived severity of disease did not preclude a trial of conservative therapies.

Overactive Bladder in the Elderly

Overactive bladder (OAB) is a common condition characterised by the symptoms of urinary frequency and urgency, with or without urge incontinence and nocturia. The prevalence of OAB increases markedly with age in both men and women. OAB can have a detrimental effect on physical functioning and psychological well-being, as well as significantly reducing quality of life. Antimuscarinic therapy -- with or without behavioural therapy -- represents the most common treatment for patients with OAB. Several antimuscarinic agents are currently available for the treatment of OAB in adults, including oxybutynin, tolterodine, trospium chloride, darifenacin and solifenacin. The antimuscarinics all appear to exert their clinical effect through inhibition of the bladder muscarinic receptors, but they vary both in structure and in their functional profile. While efficacy has been demonstrated in adult populations (including patients >65 years of age), few studies have been reported specifically in a geriatric population, and antimuscarinics are often underutilised in the elderly despite the marked increase in the prevalence of OAB in this age group. One explanation for this apparent underuse of an effective treatment option may be concerns about the frequency of anticholinergic adverse events, such as dry mouth; the likelihood of detrimental CNS effects, including cognitive impairment and sleep disturbances; and the potential for harmful interactions with existing pharmacotherapy. When selecting an antimuscarinic agent for the management of an elderly patient presenting with OAB, in addition to considering evidence of clinical efficacy and tolerability, issues of safety specific to an older population should be borne in mind. In particular, the likelihood of detrimental CNS effects should be considered, including cognitive impairment and sleep disturbances, secondary to anticholinergic load. Oxybutynin and tolterodine have both been associated with cognitive adverse events and effects on sleep architecture and quality. In contrast, trospium chloride and darifenacin do not appear to be associated with cognitive adverse events and trospium chloride does not negatively affect sleep architecture or quality. Biotransformation by the cytochrome P450 (CYP450) system is an important step in the activation or elimination of a large number of drugs, including oxybutynin, tolterodine, darifenacin and solifenacin, raising the possibility of clinically relevant and potentially serious drug interactions. In elderly patients, such interactions are of particular relevance given the potential for declining activity of certain members of the CYP450 family combined with decreased hepatic blood flow, which can reduce first-pass metabolism and thus the bioavailability of drugs metabolised via this route. Of the antimuscarinic agents used to treat OAB, only trospium chloride is not extensively metabolised in the liver by the CYP450 system and is excreted largely as the active parent compound in the urine. This paper provides an overview of the pathophysiology of OAB and reviews current approaches to achieving a differential diagnosis and selecting appropriate treatment for the older patient. The pharmacology and clinical effects of current medication for the treatment of OAB symptoms in patients defined by the OAB pharmacology literature as 'elderly' are also reviewed.