Incontinence: An Underappreciated Problem in Obesity and Bariatric Surgery

Abstract

Driven by the obesity epidemic, the number of bariatric operations performed in the United States has increased markedly, by one estimate from *20,000 in 1998 to 140,000 in 2004, and plateaued thereafter [1]. While diarrhea is a recognized consequence of intestinal bypass procedures, Roberson and colleagues in this issue of the journal highlight, for the first time, that fecal incontinence (FI) may begin or worsen after bariatric surgery [2]. Of note, 48% of women and 42% of men reported FI for liquid stools while 21% of women and 30% of men reported solid FI after surgery. Moreover, 55% of women and 31% of men reported their symptoms were worse after surgery. While these figures may be affected by response rates (48%) or, since surveys were only conducted after surgery, by recall bias, they draw attention for the first time to an underappreciated and significant problem since FI can be a devastating symptom which can substantially impair quality of life [3,4].Consistent with studies in the general population, diarrhea, cholecystectomy, stress, and mixed urinary incontinence were risk factors for FI by univariate analysis [5,6]. However, only diarrhea remained a significant risk factor in multivariate analysis. The high prevalence of FI, not only in women but also in men, who are less prone to pelvic floor injury, also underscores the contribution of diarrhea. Stool consistency is a critical factor affecting fecal continence. Indeed, even healthy subjects find it harder to retain continence for low-viscosity (i.e., 100 cPois) than highviscosity material (10,000 cPois) in the rectum, particularly when anal sphincter endurance is reduced [7]. In addition to fat malabsorption resulting from biliopancreatic diversion, an alteration in intestinal and colonic bacterial flora after bariatric surgery may also contribute to diarrhea [8].Obesity is a risk factor for urinary incontinence [9]. Moreover, in a large trial of 338 obese women with urinary incontinence, a 6-month structured weight loss program was more effective than education alone for weight loss (i.e., average weight loss of 8% body weight for treatment versus 1.6% for control group) and reducing the frequency of urinary incontinence (47.4 vs. 28.1%) [10]. This benefit was more pronounced for stress than urge urinary incontinence and supports the concept that obesity predisposes one to urinary incontinence. In the Roberson study, urinary incontinence improved in one-third of patients after bariatric surgery; whether this improvement was related to actual weight loss is unclear. In contrast to urinary incontinence, the relationship between obesity per se (i.e., before bariatric surgery) and FI is less clearly defined. In one study of 256 morbidly obese (BMI C 35 kg/m 2 ) women, the prevalence of anal incontinence (i.e., gas and stool) was 67%, which seems very high [11]. The BMI was not a risk factor for anal incontinence in that study, perhaps because all women were morbidly obese. However, it is difficult to compare this figure to population-based estimates,...

Validating endpoints for therapeutic trials in fecal incontinence

“…Among 44 subjects, 27% had a normal BMI, 30% were overweight, 25% were obese, and 18% were severely obese. Obesity and bariatric surgery are risk factors for FI . Obesity is associated with faster colonic transit and diarrhea as also with greater intra‐abdominal pressure, all of which may predispose to FI …”

Bowel Disturbances Are the Most Important Risk Factors for Late Onset Fecal Incontinence: A Population-Based Case-Control Study in Women

“…The association between obesity and FI is underappreciated and significant, particularly given the alarming increase in the prevalence of obesity and because bariatric surgery (e.g., intestinal bypass procedures) can aggravate diarrhea and FI. 44, 45…”

Epidemiology, Pathophysiology, and Classification of Fecal Incontinence: State of the Science Summary for the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Workshop

“…A history of smoking and obesity are emerging and potentially modifiable risk factors (9, 11, 17, 60, 61); smoking is also a risk factor for external sphincter atrophy by MRI (61). The mechanisms by which obesity predisposes to FI are incompletely understood (62). Other conditions associated with FI include advanced age, disease burden (co-morbidity count, diabetes), anal sphincter trauma (obstetrical injury, prior surgery), and decreased physical activity (3, 9, 13, 17, 63).…”