Changes in Gastrointestinal Function and Patient-scored Symptoms after Bariatric Surgery

Abstract: The obesity pandemic is rapidly increasing. Individuals with obesity are affected by obesity-related comorbidities, reduced life expectancy, and reduced quality of life. The most effective treatment for obesity and its comorbidities is bariatric surgery, restoring the physical component of quality of life. These procedures change bowel anatomy and physiology, giving rise to different gastrointestinal symptoms.In the first paper, we used data on quality of life from the Scandinavian Obesity Surgery Registry (SOReg) together with two validated disease-specific questionnaires to study bowel function and fecal incontinence after Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion with duodenal switch (BPD/DS). In the second paper, we collected SOReg data on acid-related symptoms and diarrhea before and up to 5 years after RYGB, sleeve gastrectomy (SG) and BPD/DS. The association between the two symptoms and postoperative complications was studied. In the third paper, we studied bowel transit times and intraluminal pressure with a wireless motility capsule (WMC) before and after BPD/DS, comparing the result to lean controls. In the fourth paper, we analyzed gut peptide profiles before and after BPD/DS.In Paper I, RYGB resulted in reduced bowel motions but increased problems with abdominal pain, whereas BPD/DS resulted in increased number of bowel motions and more problems with flatus. General quality of life was improved after both operations. Paper II showed that the presence of acid-related symptoms and diarrhea was associated with increased risk for postoperative complications. RYGB relieved acid-related symptoms, but SG worsened them. Diarrhea increased 6-fold after BPD/DS. In Paper III, small bowel transit time was shortened, and motility was decreased in the distal small bowel after BPD/DS. Paper IV showed a clear reduction in postprandial levels of glucose and insulin and described in detail gut peptide profiles.In conclusion, general quality of life was improved after bariatric procedures although BPD/DS negatively affected bowel habits. The presence of acid-related symptoms and diarrhea increased the risk of postoperative complications. The novel use of WMC was safe, allowing future use for evaluation of bowel motility, both pre- and postoperatively. Glucose homeostasis was improved after BPD/DS with resolved insulin resistance. Postoperative hormone profiles will aid in maintaining weight loss.