Original article| Volume 17, ISSUE 6, P1117-1124, June 2021

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program bariatric surgical risk/benefit calculator: 30-day risk

Published:February 10, 2021DOI:


      • The Bariatric Surgical Risk/Benefit Calculator estimates 30-day post-op event risk
      • Predictive models for each of nine outcomes are accurate and well calibrated
      • The tool supports surgical decision-making, communication, and informed consent
      • The Risk/Benefit Calculator also estimates 1-Year BMI and comorbidity remission



      There is increasing demand for data-driven tools that provide accurate and clearly communicated patient-specific information. These can aid discussions between practitioners and patients, promote shared decision-making, and enhance informed consent. The American College of Surgeons Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) sought to create a risk calculator for adult patients considering primary metabolic and bariatric surgery, with multiple prediction features: (1) 30-day risk; (2) 1-year body mass index projections; and (3) 1-year co-morbidity remission.


      To evaluate the 30-day risk estimation feature of this tool.


      Not-for-profit organization, international bariatric surgery clinical data registry.


      MBSAQIP data across 5.5 years, 925 hospitals, and 775,291 cases were used to develop the 30-day risk feature. Logistic regression models were employed to estimate postoperative risks for 9 outcomes across 4 procedures: laparoscopic Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, laparoscopic adjustable gastric band, and biliopancreatic diversion with duodenal switch.


      The tool showed good discrimination for mortality and surgical site infection models (c-statistics, .80 and .70, respectively), and was slightly less accurate for the 7 other complications (.62–.69). Graphical representations showed excellent calibration for all 9 outcomes.


      Overall, the 30-day risk models were accurate and well calibrated, with acceptable discrimination. The MBSAQIP bariatric surgical risk/benefit calculator is publicly available, with the intent to be integrated into healthcare practice to guide bariatric surgical decision-making and care planning, and to enhance communication between patients and their surgical care team.


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