Bowel Habits After Bariatric Surgery

Disordered bowel habits might influence quality of life after bariatric surgery. Different types of bariatric operations—gastric banding (AGB), Roux-en-Y gastric bypass (RYGB), or biliopancreatic diversion (BPD)—might alter bowel habits as a consequence of the surgical procedure used. Whether change in bowel habits affects quality of life after AGB, RYGB, or BPD differently is unknown.

The study group contained 290 severely obese patients undergoing bariatric surgery between August 1996 and September 2004 [BPD: n = 103, 64.1% women, age 43 ± 1 years (mean ± SEM), BMI 53.9 ± 0.9 kg/m², weight 153.4 ± 2.9 kg; Roux-en-Y gastric bypass: n = 126, 73.0% women, age 43 ± 1 years, BMI 44.2 ± 0.3 kg/m², weight 123.8 ± 1.5 kg; adjustable gastric banding (AGB): n = 61, 57.4% women, age 44 ± 1 years, BMI 49.9 ± 0.5 kg/m², weight 146.1 ± 2.0 kg). Changes in bowel habits, flatulence, flatus odor, and effects on social life were estimated at least 4 months after surgery using a self-administered questionnaire.

Fecal consistency changed significantly after surgery. Loose stools and diarrhea were more frequent after BPD and RYGB (P < 0.001) but more so after BPD than after either RYGB or AGB (P < 0.002). Constipation was more likely after AGB (P = 0.03). In addition, malodorous flatus affecting social life was more frequent after BPD than after either RYGB or AGB (P < 0.003). Furthermore, flatus frequency increased after BPD and RYGB, and patients were more bothered by their malodorous flatus than after AGB (all P < 0.001). Flatus severity score was highest in BPD, intermediate in RYGB, and lowest in AGB patients (all P < 0.001), a difference that was not influenced by frequency of metabolic syndrome before and after surgery. Moreover, observation period after surgery had no influence on overall results of bowel habits. Subsore quality of life bariatric analysis and reporting outcome system (BAROS) scores were largely similar between all three groups. However, flatulence severity score correlated inversely with quality of life estimated by BAROS in BPD and RYGB, but not in AGB patients.

The type of bariatric surgery affects bowel habits in an operation-specific manner, resulting mainly in diarrhea after BPD and RYGB, and constipation after AGB. Flatulence severity impairs quality of life most in BPD, is intermediate in RYGB, and is only minor after AGB, a phenomenon that was only partially mirrored in quality-of-life measures of BAROS.