Bariatric Surgery Is Associated With Increased Risk of Acute Pancreatitis in the First 90 Days After Surgery: 2017 Category Award (Obesity): 2017 Presidential Poster Award

Abstract

Introduction: Acute pancreatitis (AP) is the most common single cause of gastrointestinal admissions in the USA. Obesity, an increasing health care burden, is associated with an elevated risk of AP incidence and severity. While bariatric surgery may alleviate the adverse effect of obesity on AP outcomes, the post-operative impact of bariatric surgery on AP incidence has not been investigated. The objective of this study was to determine the short term impact of Roux-en-Y gastric bypass surgery (RYGB) and vertical sleeve gastrectomy (VSG) on rates of AP. Methods: This is a retrospective study using the 2013 National Readmission Database (NRD), a database representing all USA hospital discharges and readmissions in 2013. Obese patients that had RYGB or VSG from 04/01/2013 to 09/31/2013 were used as their own control and followed for 90 days before and 90 days after surgery. We also compared rates of AP among obese control patients that had ventral hernia repair surgery without bowel resection (VHR) at the same time period. Exclusions included: age < 18 years old, pregnancy, prior bariatric surgery, AP or mortality on index surgery, history of pancreatic cyst, chronic pancreatitis or abdominal neoplasm. We used the McNemar's test that matches patients as their own controls pre and post-surgery. Results: Our cohort included 29,462 RYGB, 37,401 VSG and 8,084 VHR patients. VHR patients were older, had more comorbidities and a longer length of stay when compared to bariatric surgery patients as shown in table 1 (P < 0.05). The incidence of AP before surgery was very low in RYGB and VSG and none in VHR (0.02% vs 0.04% vs 0.0%). Post-surgery, there was a 7 fold increase in AP in RYGB and 4 fold increase in VSG patients while no significant increase was seen after VHR as described in table 2 (P < 0.05). Conclusion: The increased AP risk in the 90 day postoperative period of bariatric surgery, irrespective of surgery type, is alarming and requires attention. This increase in AP rates could be due to the rapid weight loss induced gallstones formation after bariatric surgery. Further studies validating this risk including mechanistic explanations are warranted.Table: Table. Acute pancreatitis admissions before and after bariatric surgeryTable: Table. Demographic and hospital characteristics of RYGB, VSG and VHR patients at the time of surgery (discharge months April through September)