We know that gastric bypass surgery is a powerful tool in the management of obesity and metabolic syndrome.  However, there is not a lot of data available following patients out over the very long term.  A recent study is the first prospective study looking only at Roux-en-Y gastric bypass surgery, to give us data out as far as 12 years.
The study, published by Adams and colleagues in the New England Journal of Medicine,enrolled 418 patients in Utah, USA who underwent gastric bypass surgery, and compared them over the long term to 417 patients who wanted surgery but did not have surgery (primarily because of lack of financial insurance coverage), and a third group of 321 patients with obesity who were not interested in surgery. They had an excellent rate of follow up of over 90% of patients at 12 years.
Here are some of the key findings: (skip to take home messages below for the short version)
1.  Weight loss:
  • Two years after gastric bypass surgery, the mean weight loss was 45 kg. 
  • At 6 years postop, the mean weight loss was 36.3kg (so there was about 20% weight regain, which is very consistent across studies).
  • At 12 years postop, the mean weight loss was 35kg – so weight was overall stable from 6 years to 12 years after surgery.

 

 [At 12 years, people who wanted surgery but didn’t have it had lost 2.9 kg (probably because they were part of this study), and people with obesity who did not want surgery had lost 0 kg (also notable for no weight gain over the long term).]
2.  Type 2 diabetes:
Among patients in the surgery group who had type 2 diabetes before surgery:
  • At 2 years postop, 75% of diabetes had gone into remission.
  • At 6 years postop, 62% of diabetes cases were in remission
  • At 12 years postop, 51% of diabetes cases were in remission.
  • The likelihood of diabetes being in diabetes remission at 12 years was 8.9 times higher for those who had had surgery compared to those who wanted but did not get surgery, and 14.8 times higher than those who did not want surgery in the first place.
  • At 12 years, the likelihood of being in diabetes remission was highest in people who had diet controlled diabetes before surgery (remission rate 73%), less for people who needed pills to treat their diabetes before surgery (remission rate 56%), and
    lowest for people who required insulin to treat their diabetes before surgery (remission rate 16%). 
  • At 12 years, there was a 91-92% lower risk of having new type 2 diabetes develop in patients who had had bariatric surgery, compared to the non surgery groups.

 

 
3.  Mortality rates:
 
At 12 years, mortality in people who had gastric bypass surgery was lower than those who wanted surgery but didn’t get it, but there no different between those who had gastric bypass surgery than those who didn’t want surgery in the first place, likely because the group not wanting surgery was healthier at baseline. There were 5 suicides in the group that had bariatric surgery, compared to 2 suicides in the non surgical group.  (see here and here and here for discussion of suicide risk after bariatric surgery ) 
 
Take home messages from this study:
  • On average, weight loss is stable over the long term after gastric bypass surgery – though the results can be different for different people, and certainly lifelong dedication to permanent lifestyle changes are essential for continued success.
  • Gastric bypass surgery can be a powerful tool to not only put diabetes into remission, but also to decrease the risk of developing diabetes later on.  Earlier intervention is better, because the longer a person has diabetes, the more tired their pancreas gets (ie decreased beta cell function, which are the cells that produce insulin), and a tired pancreas may be too tired to control blood sugars after bariatric surgery without help from medication.  Thus, considering bariatric surgery early in the course of diabetes, or even in the prediabetes phase, may have the most powerful impact.
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