Gastric Bypass Mortality

Dying from Gastric Bypass Surgery (it’s very unlikely!) – All You Need to Know

Dying as a result of having gastric bypass surgery is extremely rare. The procedure has a 99.8% survival rate. In fact, the chances of dying early from an obesity-related health issue are much greater.

Read the sections below for everything you need to know about gastric bypass mortality rates and how to further minimize your risks.


Click on any of the topics below to jump directly to that section

  1. General Safety
  2. Vs. Remaining Obese
  3. Causes of Death
  4. How to Minimize risk

General Safety of Gastric Bypass Surgery


  • Gastric bypass surgery is very safe - the survival rate is 99.8%

Compare the 0.22% mortality rate (99.8% survival rate) of gastric bypass surgery to other well-known procedures:

  • Gallbladder removal: 0.15% mortality rate (1)
  • Hip replacement: 0.29% mortality rate (2)
  • Cesarean section (“C-Section”): 0.40% mortality rate (3)

In other words, gastric bypass is about as risky as gallbladder surgery and a lot less risky than a hip replacement or a C-section.

Typical gastric sleeve results include:

  • 1-year weight loss: 65% of excess weight, on average
  • 5-year weight loss: 60% of excess weight, on average, after weight regain
  • Complete resolution or significant improvement for at least 15 obesity-related health conditions, including diabetes, hypertension, and sleep apnea

See our Gastric Bypass Results section for more information about weight loss and health benefits to expect.

Tap here to view Gastric Bypass Mortality Rate Studies

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Study# of gastric bypass
Patients in study
Mortality RateYear
Study A64,4940.22%2016
Study B1,3640.15%2008
Study C1110.9%2007
Study D4940.6%2006
Study E700%2006
Study F25,7590.25%2006
Study G5,6440.5%2004

The Risk of Death from Having Gastric Bypass Surgery Vs. The Risk of Remaining Obese


  • Early death as a result of an obesity-related health issue is much more likely than dying from undergoing gastric bypass surgery

It’s one thing to worry about the likelihood of dying during surgery, but what about the likelihood of dying if you don’t have surgery? And how do the two compare?

“…a morbidly obese person is much more likely to die from not having bariatric surgery than from having it.”

Two studies explored these questions directly and found that…

  1. Bariatric surgery patients were 29% less likely to die than morbidly obese people who didn’t have surgery. Cancer and cardiovascular disease were the main killers of those who didn’t have surgery, both of which were less prevalent in the bariatric surgery group (4).
  2. Mortality rate decreases by 40% following bariatric surgery. Those having bariatric surgery were 56% less likely to die from coronary artery disease, 92% less likely from diabetes and 60% less likely to die from cancer (5).

So we now understand that gastric bypass surgery deaths are in the “middle of the road” among other bariatric procedures and that a morbidly obese person (body mass index of 35 or more) is much more likely to die over the long-term from not having surgery than from having it.

But bariatric surgery does carry a risk, so next we will review the causes and how to minimize your chances of experiencing them.


Causes of Gastric Bypass Deaths


  • Read the 3 most common issues below
  • Each are very rare (99.8% of patients not affected)

In a meta-analysis (a study that combines many previous studies) done by the University of Iowa, 93 patients died within 30 days of surgery out of 38,501 bariatric surgery patients studied).4 The 3 leading culprits of gastric bypass surgery deaths were…

  1. Pulmonary embolism (0.078% of patients from the study) is an embolism (the sudden obstruction of a blood vessel by an abnormal particle, such as a bubble, circulating in the blood) of a pulmonary artery or one of its branches that is produced by foreign matter and most often a blood clot originating in a vein of the leg or pelvis. Its symptoms/effects include labored breathing, chest pain, fainting, rapid heart rate, cyanosis, shock and sometimes gastric bypass surgery deaths.
  2. Leaks (0.036% of patients from the study) happen when the surgical connections or staple lines made during gastric bypass surgery leak digestive contents into the abdomen. This can cause infection and abscess. This serious complication is usually repaired as long as it is caught early. Symptoms include fever, severe pain and a high heart rate. In order to prevent leaks, your surgeon should check the surgical connections made during surgery a number of different ways, including (1) blowing air into the connection and observing whether any gets through and (2) using a dye to check for a leak. Leaks not discovered right away are usually treated by resting the stomach (being fed through an IV), but sometimes surgery is required fix them.
  3. Small bowel obstruction (0.02% of patients from the study) also called an “internal hernia”, can happen anywhere from 1 to 7 years following surgery and occurs when the intestines twist and prevent the flow of food and digestive fluids. Patients with this condition usually experience abdominal pain, abdominal swelling or vomiting. A doctor will confirm the diagnosis with a CAT scan or through surgery, and surgery may or may not be needed to treat it.

Additional risks of gastric bypass include…

  • Bleeding
  • Blood clots
  • Gallstones
  • Gastroesophageal Reflux Disease (GERD)
  • Hypoglycemia
  • Stenosis/Stricture
  • Ulcers
  • Vitamin and mineral deficiency

For more on the above along with a full list of gastric bypass complications, definitions, treatments and how they compare to other procedures, see our Bariatric Surgery Complications page.


How to Minimize Your Risk of Death from Gastric Bypass Surgery


  • Read the 10 steps to a successful gastric bypass procedure below

There are 10 important steps you should take to improve your chances for a successful surgery. Click the following links for more information about each step…

  1. Educate yourself about all angles of bariatric treatment. Be mentally prepared by knowing exactly what to expect before, during and after surgery.
  2. Educate your family and close friends with a summary of your research. If they are uneducated, they are more likely to steer you off-course before or after surgery (i.e. eating tempting foods around you, not encouraging you when you need it, etc.) which can lead to complications.

    If you find that anyone is vehemently opposed to your decision, it is best to distance yourself from them, at least temporarily. Their negative influence could lead you down the wrong path during the all-important preparation, recovery and post-surgery-routine-developing stages.
  3. Lose as much weight as possible prior to surgery. The lower your body mass index before surgery, the lower your risks. (See our BMI Formula page for more about body mass index.)
  4. Eat a healthy bariatric diet both after surgery and in the months prior to surgery.

***Most Important Step***

  1. Choose a good bariatric doctors and a good bariatric weight loss clinic by finding the right candidates and interviewing them with the right questions. This is the most important step by far. In fact, there is evidence that a surgeon’s reoperation and rate of conversions to an open (and more dangerous) procedure drops as his total number of surgeries performed increases…
    1. Click here to find a qualified surgeon in your area
    2. Click here to learn how to evaluate and interview your bariatric doctors
  1. Stay close to your bariatric surgery center and surgeon for at least 10 days (preferably 2 weeks) after surgery. (Especially applies if you don’t have surgery near your home.)
  2. Exercise after gastric bypass surgery. Start walking as soon as possible and as your fitness level improves, work your way towards a more robust program that incorporates strength, flexibility and endurance routines.
  3. Use tools and/or medication to keep the blood flowing in your legs. See our Blood Clot Symptoms page for more details.
  4. Follow your doctor and nutritionist’s/dietitian’s advice to the letter.
  5. Have and use an effective support system before and after surgery.  In addition to friends and family, working with a good in-person weight loss surgery support group and the right online weight loss support is essential.

Go to our Complications to Bariatric Surgery page to learn more about these factors along with the ones that may be out of your control.



  1. National Institutes of Health Press Release: NIH Study Finds Low Short-term Risks After Bariatric Surgery for Extreme Obesity. July 2009. Available at:
  2. Sjöström L, Narbro K, Sjöström CD, Karason K, Larsson B, Wedel H, Lystig T, Sullivan M, Bouchard C, Carlsson B, Bengtsson C, Dahlgren S, Gummesson A, Jacobson P, Karlsson J, Lindroos AK, Lönroth H, Näslund I, Olbers T, Stenlöf K, Torgerson J, Agren G, Carlsson LM; Swedish Obese Subjects Study.
  3. Effects of bariatric surgery on mortality in Swedish obese subjects. N Engl J Med. 2007 Aug 23;357(8):741-52.
  4. Adams TD, Gress RE, Smith SC, Halverson RC, Simper SC, Rosamond WD, Lamonte MJ, Stroup AM, Hunt SC. Long-term mortality after gastric bypass surgery.
  5. N Engl J Med. 2007 Aug 23;357(8):753-61.
  6. Mason EE, Renquist KE, Huang YH, Jamal M, Samuel I. Causes of 30-day bariatric surgery mortality: with emphasis on bypass obstruction.
  7. Obes Surg. 2007 Jan;17(1):9-14.

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