Clonidine and botulinum toxin: a tale of two treatments

Endpoints for therapeutic interventions in faecal incontinence: small step or game changer

Faecal incontinence (FI) is common and its pathophysiology and treatments continue to evolve. However, a standard measure(s) for assessing its clinical outcome has been elusive. Consequently, over 100 measures and scoring systems, each with intrinsic biases have been reported. These include adequate relief or global satisfaction, ≥50% reduction in episodes or days without FI, quality of life (QOL), FI severity scales and composite indices. Earlier scales relied on the frequency and type of solid, liquid or flatus incontinence and effects on life style whereas newer scales have incorporated urgency, use of pads, antidiarrhoeals and amount of leakage, using prospective daily stool diaries or retrospective weekly or single point assessments. Such a plethora of measures have negatively impacted the assessment and outcome of clinical trials, and have made comparisons difficult. So, how does one sort out the grain from the chaff? In a provocative, post-hoc analysis published in this issue, the minimal clinically important difference, i.e. the smallest change detected by an instrument that is associated with a clinically meaningful change was used to assess FI endpoint. Based on this a ≥50% reduction in FI episodes is recommended as a clinically meaningful outcome measure when assessed by prospective stool diary, and it correlates with symptoms and severity. However, this requires further validation in multi-centre, longer duration and therapeutically effective clinical trial(s). Simultaneous assessment of coping strategies, QOL and psychosocial domains can provide further insights regarding the overall impact of treatments. This mini-review discusses the advances and controversies in defining meaningful FI endpoints.

Validating endpoints for therapeutic trials in fecal incontinence

BACKGROUND

A 50% or greater reduction in the frequency of fecal incontinence (FI) recorded with daily bowel diaries is the primary endpoint in clinical trials of FI. Whether this difference is clinically important is unknown. The relationship between FI symptoms recorded with daily and weekly instruments is unknown. The contribution of psychological factors to quality of life (QOL) in FI is unclear.

METHODS

Fecal incontinence severity was assessed with daily bowel diaries and periodic questionnaires (fecal incontinence severity score [FISS], FIQOL, 36-Item Short Form Health Survey [SF-36], and hospital anxiety and depression scales) for 4 weeks before and during double-blind randomization to placebo or clonidine in 44 women with FI. The reduction in FI frequency was compared to the minimal clinically important difference (MCID) computed from the FISS. Endpoints of FI were compared between daily and weekly diaries.

KEY RESULTS

The FISS exceeded the MCID in 75% and 83% of patients in whom the FI frequency declined by 50-74% and ≥75% respectively. Parameters of FI measured with daily and weekly instruments were significantly correlated. The daily parameters explained 71% of the inter-patient variation in the FISS. The SF-36 health scores, rather than the FISS rating, explained a majority of the inter-subject variation in FIQOL.

CONCLUSIONS & INFERENCES

Most patients who report a ≥50% reduction in FI frequency experience a clinically important improvement. Weekly questionnaires accurately assess the severity of FI. Self-reported physical and mental health explained a greater proportion of the variance in FIQOL than FI symptom severity.

Functional Anorectal Disorders

This report defines criteria and reviews the epidemiology, pathophysiology, and management of common anorectal disorders: fecal incontinence (FI), functional anorectal pain and functional defecation disorders. FI is defined as the recurrent uncontrolled passage of fecal material for at least 3 months. The clinical features of FI are useful for guiding diagnostic testing and therapy. Anorectal manometry and imaging are useful for evaluating anal and pelvic floor structure and function. Education, antidiarrheals and biofeedback therapy are the mainstay of management; surgery may be useful in refractory cases. Functional anorectal pain syndromes are defined by clinical features and categorized into three subtypes. In proctalgia fugax, the pain is typically fleeting and lasts for seconds to minutes. In levator ani syndrome (LAS) and unspecified anorectal pain the pain lasts more than 30 minutes, but in LAS there is puborectalis tenderness. Functional defecation disorders are defined by >2 symptoms of chronic constipation or irritable bowel syndrome with constipation, and with >2 features of impaired evacuation i.e., abnormal evacuation pattern on manometry, abnormal balloon expulsion test or impaired rectal evacuation by imaging. It includes two subtypes; dyssynergic defecation and inadequate defecatory propulsion. Pelvic floor biofeedback therapy is effective for treating LAS and defecatory disorders.

Functional Anorectal Disorders

This report defines criteria and reviews the epidemiology, pathophysiology, and management of common anorectal disorders: fecal incontinence (FI), functional anorectal pain and functional defecation disorders. FI is defined as the recurrent uncontrolled passage of fecal material for at least 3 months. The clinical features of FI are useful for guiding diagnostic testing and therapy. Anorectal manometry and imaging are useful for evaluating anal and pelvic floor structure and function. Education, antidiarrheals and biofeedback therapy are the mainstay of management; surgery may be useful in refractory cases. Functional anorectal pain syndromes are defined by clinical features and categorized into three subtypes. In proctalgia fugax, the pain is typically fleeting and lasts for seconds to minutes. In levator ani syndrome (LAS) and unspecified anorectal pain the pain lasts more than 30 minutes, but in LAS there is puborectalis tenderness. Functional defecation disorders are defined by >2 symptoms of chronic constipation or irritable bowel syndrome with constipation, and with >2 features of impaired evacuation i.e., abnormal evacuation pattern on manometry, abnormal balloon expulsion test or impaired rectal evacuation by imaging. It includes two subtypes; dyssynergic defecation and inadequate defecatory propulsion. Pelvic floor biofeedback therapy is effective for treating LAS and defecatory disorders.

New treatments for fecal incontinence: update for the gastroenterologist

Fecal incontinence is one of the most emotionally devastating of all nonfatal conditions. Many patients do not respond satisfactorily to conservative measures, and there is a need for new and effective strategies when medical therapy fails. The development of sacral nerve stimulation and other forms of neuromodulation and the injection of biologically compatible substances into the anal sphincter complex have brought renewed enthusiasm for using these novel treatments in this underserved population. Because injectable bulking agents such as dextranomer in stabilized hyaluronic acid can be administered in an outpatient setting, this procedure is being marketed to both gastroenterologists and surgeons. This article reviews both sacral nerve stimulation and dextranomer bulking agents and compares their strengths and potential limitations in patients with fecal incontinence.