The Risks of Bariatric Surgery

Low level view of surgical team operating
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A number of surgical weight-loss procedures are available for the treatment of certain patients with obesity. Although these procedures have many benefits, they also carry risks.

What Is Bariatric Surgery?

The term “bariatric surgery” applies to a number of surgical procedures that have been developed to treat obesity and surgically induce weight loss. These include gastric bypass, gastric banding, and gastric sleeve (sleeve gastrectomy) procedures, among others, which have been developed for the surgical treatment of obesity.

Who Is a Candidate for Bariatric Surgery?

According to the latest obesity guidelines released by the American Heart Association (AHA), the American College of Cardiology (ACC), and The Obesity Society (TOS), bariatric surgery may be an option for adult patients who meet certain criteria.

These criteria include a body mass index (BMI) of 40 or greater, or a BMI of 35 or greater in a patient who has other medical conditions (known as “comorbid conditions”) caused by obesity. The obesity guideline writing committee did not find sufficient evidence to recommend bariatric surgery for patients who have BMIs that fall below these cutpoints.

The guideline further advises primary care doctors and others caring for patients with obesity with high BMI to try “behavioral treatment with or without pharmacotherapy” first, and then if this has not worked along with other diet and lifestyle measures to achieve sufficient weight loss, bariatric surgery may be considered.

What Are the Risks?

Bariatric surgery, in general, has been found to be slightly more risky than cholecystectomy, but less risky than appendectomy, colon surgery, small bowel surgery and stomach (gastric) surgery.

Bariatric surgery has also been found to be much less risky than pancreatic, liver (hepatic) or esophageal surgery.

Specifically, for elective surgical weight-loss procedures, mortality falls in the 0.05% - 0.2% range, way below 1%.

Certain risks are common to all surgical operations that require anesthesia, such as the possibility for heart or lung problems and even death (which is rare). For bariatric surgery, in particular, there are complications that can develop over the longer term, such as bowel obstruction, gallstones, hernias, stomach perforation, ulcers, malnutrition, vomiting and dumping syndrome (in which food empties into the small intestine too quickly, resulting in diarrhea, nausea, and vomiting).

As with most bariatric surgery procedures, patients will need to be followed closely for the rest of their lives to monitor for vitamin and mineral deficiencies. Most patients will require vitamin supplementation and laboratory (blood test) monitoring on a regular basis, as many if not all of the bariatric surgery procedures cause changes in how the body absorbs certain vitamins and nutrients.

Patients who have had bariatric surgery must still be strict about their diet and lifestyle habits, as it is not uncommon to gain weight once more even after the surgery if the recommended lifestyle changes, which include both diet and exercise, are not followed vigilantly.


Jensen MD, Ryan DH, Apovian CM, et al. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society [published online November 27, 2013]. J Am Coll Cardiol.

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Schauer PR, Bhatt DL, Kirwan JP, Wolski K, et al. Bariatric surgery versus intensive medical therapy for diabetes—3-year outcomes. N Engl J Med 2014; 370:2002-13.

Puzziferri N, Roshek TB, Mayo HG, et al. Long-term follow-up after bariatric surgery: a systematic review. JAMA 2014;312:934-942.

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