Background

Fecal incontinence (FI) is the recurrent involuntary loss of feces,^1,2 which is defined by the frequency of episodes (such as daily or weekly episode counts) and by the consistency of the feces (solid, liquid, or mucus).^1,3 FI severity varies widely and the amount of leakage can vary across episodes. The negative psychological effects, social stigma, and reduced quality of life surrounding FI can be devastating.³ Severe skin breakdown and ulceration can result from FI, particularly in nursing home residents and immobile adults.

FI prevalence increases with age and varies by sex, but prevalence estimates vary widely across patient populations and by the FI definition used. More recent terminology aimed at minimizing social stigma (accidental bowel leakage [ABL]), may further compound the discrepancies around FI prevalence estimates, because adults can have ABL (a symptom) for many reasons, not just FI (a chronic condition). Among community-dwelling adults, the prevalence of monthly bowel leakage is reported as 8.3 percent,² with slightly higher prevalence in women (9%) than men (7.7%).² FI affects less than 3 percent of young adults age 20 to 29 but more than 15 percent of adults age 70 and older.² Women over age 40 are disproportionately affected due to pelvic floor dysfunction after childbirth and obstetrical trauma. At least half of all nursing home residents and 83 percent of residents with severe cognitive impairment have experienced bowel leakage.⁴ Approximately 3 percent of adults have FI at least weekly.² Among community-dwelling adults with at least monthly bowel leakage, 6.2 percent experience leakage as liquid stool, 1.6 percent as solid stool, and 3.1 percent as mucus.²

FI etiologies fall into two broad categories: non-neurological or neurological. Non-neurological causes of FI may be structural (e.g., muscle damage from episiotomy or surgery), functional (e.g., post-radiation or muscle atrophy), due to an underlying gastrointestinal (GI) disorder (e.g., inflammatory bowel disease), from stool consistency problems, or from other factors. Neurological causes of FI include damage to the nervous system or advanced cognitive impairment. Multiple causes of FI in individual adults are common and a dominant etiology may not be sought or determinable. Risk factors for FI include increasing age, female sex, chronic diarrhea, nerve damage (from injury, multiple sclerosis, or chronic diabetes), obstetrical trauma, postsurgical or postradiation complications, anal sphincter injury, cognitive impairment, or other factors such as severe constipation.^4,5

Treatment goals are to decrease the frequency and severity of FI episodes. Treatments for FI are imperfect and are often delivered in combination. Most treatments are aimed at symptom reduction; few treatments, if any, afford long-term cures for FI. FI treatments typically follow a progression from nonsurgical to surgical, and from easy to implement (dietary fiber, drugs) to more intensive nonsurgical (pelvic floor muscle training with biofeedback [PFMT-BF]), to more invasive nonsurgical (anal sphincter tissue bulking injections) or surgical treatments. However, nonsurgical treatments may also be used to complement surgical treatment. As a result, the nature of patients offered different types of FI treatment can vary widely.

Nonsurgical treatments include dietary fiber supplementation,⁵ bowel schedules, stool-modifying drugs,⁶ PFMT-BF,^7,8 anal plugs,^9,10 rectal irrigation,^10,11 or combinations thereof.^5,7 A new vaginal bowel control device received Food and Drug Administration (FDA) approval in February 2015,¹² and other interventions, such as percutaneous posterior tibial nerve stimulation are emerging. Injections of biocompatible tissue-bulking agents into the anal canal walls are a newer, more invasive nonsurgical procedure.¹³ Surgical procedures used to treat FI in the United States include implanted sacral nerve stimulation (SNS), radiofrequency anal sphincter remodeling (SECCA), antegrade colonic enema (ACE), anal sphincter repair (sphincteroplasty), sphincter replacement (artificial anal sphincter), surgical correction of conditions that can result in FI (rectal prolapse, hemorrhoids, or rectocele), or, when all other treatments fail, colostomy.^1,5,14,15

FI etiologies and other patient factors dictate feasible treatment options.¹ For example, the range of treatment approaches used for FI in adults with spinal cord (neurologic) injury would differ from those used to treat pelvic floor muscle atrophy (weakness) or anal sphincter injury. However, etiologic differentiation can be clinically challenging.

Although many recent systematic reviews have assessed the effectiveness of component treatments for FI,^6-9,13-22 none has yet examined the collective evidence for FI treatment effectiveness, reported overall treatment effects and those within subgroups of adults defined by their FI etiologies (when available), or examined the long-term treatment effects across all FI treatments. Given the heterogeneous population of adults afflicted with FI, information on subgroup treatment outcomes across that range of available FI treatments would advance knowledge and possibly improve patient care and outcomes.³

This systematic review synthesizes the available evidence on FI treatment outcomes across FI etiologies and treatments to provide current and potentially better information to aid decisionmaking for both patients and physicians and identifies gaps in the evidence base for treatment-subgroup combinations. When possible, we addressed additional information on baseline patient factors that could modify treatment effects, such as age, sex, FI severity, comorbidities, and prior FI treatments.

Our findings should inform FI treatment guidelines and clinical decisions in general.

Scope and Key Questions