American College Of Surgeons - Inspiring Quality: Highest Standards, Better Outcomes

Bariatric Surgical Risk/Benefit Calculator

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) surgical risk/benefit calculator provides metabolic and bariatric surgeons and their patients with accurate, patient-specific information to guide surgical decision making and informed consent.

The Bariatric Surgical Risk/Benefit Calculator was built using data collected from more than 775,000 operations from 925 centers participating in MBSAQIP from January 1, 2013, through June 30, 2018. For 30-day outcomes, the calculator uses 20 patient predictors, such as age, American Society of Anesthesiologists Physical Status classification, and preoperative body mass index (BMI) to predict the likelihood that patients will experience any of nine different outcomes within the first 30 days after an operation. Examples of these outcomes include surgical site infections, unplanned reoperations, and death.

The calculator can predict the patient’s body mass index (BMI), weight, and total weight change percentage trajectories up to one year after a surgical procedure. To assist with patients’ understanding of the predictions, the calculator provides a summary report designed for patients to share the information with their families and other multidisciplinary team members involved in their care.

Access the Bariatric Surgical Risk/Benefit Calculator


The MBSAQIP Bariatric Surgical Risk/Benefit Calculator estimates the chance of an unfavorable outcome (such as a complication or death), the chance of remission of weight-related comorbidities, and the patient's BMI, weight change, and percent total weight change after surgery. These quantities are estimated based upon information the patient gives the healthcare provider about prior health history. The estimates are calculated using data from a large number of patients who had a primary bariatric surgical procedure similar to the one the patient may have.

Please note the risk percentages, remission percentages, BMI, weight change, and percent total weight change provided to you by the risk/benefit calculator are only estimates. These estimates only take certain information into account. There may be other factors that are not included in the estimate which may increase or decrease the risk of a complication, the chance of remission of a weight-related comorbidity, or the amount of weight the patient loses. These estimates are not a guarantee of results. A complication after surgery may happen even if the risk is low, a weight-related comorbidity may not go into remission even if the chances are high, and a patient may lose more or less weight than predicted. This information is not intended to replace the advice of a doctor or healthcare provider about the diagnosis, treatment, or potential outcomes. MBSAQIP is not responsible for medical decisions that may be made based on the risk/benefit calculator estimates, since these estimates are provided for informational purposes. Patients should always consult their doctor or other health care provider before deciding on a treatment plan.

Risk/Benefit Calculator Permitted Use

An external platform (for example, an electronic health record) may open the web address of the risk/benefit calculator in a new browser window. However, we do not permit the calculator to appear as an integrated feature of any external platform, nor do we permit the functionality of the calculator to be automated in any way. The calculator must be presented in its original, unaltered form, maintaining all MBSAQIP branding and copyright information.