Exocrine Pancreatic Function and Dynamic of Digestion After Restrictive and Malabsorptive Bariatric Surgery: a Prospective, Cross-sectional, and Comparative Study

Background: Gastrointestinal anatomical changes after restrictive and malabsorptive bariatric surgery lead to important disturbances in the process of digestion and absorption of nutrients and could lead to exocrine pancreatic insufficiency (EPI).

Objective: The aim of the present study was to evaluate and to compare pancreatic function and the dynamic of digestion and absorption of nutrients after restrictive and malabsorptive bariatric surgical procedures.

Setting: University Hospital of Santiago de Compostela, Santiago de Compostela, Spain.

Methods: A prospective, observational, cross-sectional, comparative study of patients after sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and biliopancreatic diversion with duodenal switch (BPD/DS) was carried out. Patients with obesity who did not undergo surgery were included as control group. Pancreatic function and the dynamic of digestion and absorption of nutrients were evaluated by the C-mixed triglyceride (C-MTG) breath test. Six-hour C-cumulative recovery rate (C-CRR), C exhalation peak, and 1-hour maximal C-CRR were calculated.

Results: One-hundred five patients were included (mean age, 49.8 yr; 84 women). Six-hour C-CRR was significantly reduced after BPD/DS (P < .001) but not after SG and RYGB. EPI was present in 75% of patients after BPD/DS, 8.3% of patients after RYGB, and 4.3% of patients after SG. Compared with the control group who did not undergo surgery, digestion and absorption of nutrients tended to occur earlier after SG, whereas it was delayed after RYGB and mainly after BPD/DS (P < .001).

Conclusion: Bariatric surgery significantly alters the dynamic of the digestive process. EPI is very common after BPD/DS, frequent after RYGB, and less frequent after SG. This information is clinically relevant since EPI is a treatable condition associated with symptoms, nutritional deficiencies, and complications.