Does Weight Loss Surgery Keep Working for Diabetes Management?
If your weight makes it difficult to manage your diabetes, bariatric surgery will help you to lose many pounds. But how well will it help you manage your diabetes over the long term?
Until now, nobody knew the answer to this question. That’s why researchers have been studying a group of 120 adults with Type 2 diabetes at three teaching hospitals in the U.S. and one in Taiwan. Half of them got bariatric surgery, the other half got intensive lifestyle medical management.
The bariatric surgery used is one of the most common ones, Roux-en-Y gastric bypass, named after the Swiss surgeon who pioneered the procedure and the resulting vague Y-shape of the intestines. It was done laparoscopically, which is safer than gastric bypass surgery done with an open incision.
Side effects are a concern. The American Diabetes Association says that they can include dumping syndrome (nausea, colic, diarrhea), vitamin and mineral deficiencies, and osteoporosis.
The intensive management had two goals. One was for the people in this arm of the study to lose about 7 percent of their body weight through a low-fat diet of 1,200 to 1,800 calories per day, depending on their weight. The other was for them to get about 175 minutes a week of moderately intense physical activity. The researchers used lots of group sessions and individual meetings to give the participants the encouragement they needed.
This June, the researchers reported how well each group was doing after three years. The professional journal Diabetes Care published a randomized controlled study online before it was printed. Only the abstract of the study is free, but a friend of mine who is an endocrinologist gave me a copy of the full text.
The people in the study who got the surgery lost a mean of 25.5 percent of their weight after one year. By the end of the third year, they had typically succeeded in keeping off 21 percent of those pounds.
By comparison, the intensive management group lost only 7.3 percent of their weight after a year. After three years, they kept off 6.3 percent of it. No big surprises here.
But how well does bariatric surgery compare with this intensive management in helping to manage diabetes?
To find the answers to this question, the researchers looked at not only the A1C levels of the people in the two groups but also at their blood pressure and LDL cholesterol levels. They followed the American Diabetes Association’s “Standards of Medical Care in Diabetes.” When they began the study, these standards were A1C levels of less than 7 percent, LDL cholesterol values of less than 100 mg/dL, and systolic blood pressure goals of less than 130 mmHg. Subsequently, the ADA relaxed this blood pressure goal to less than 140 mmHg.
Much better A1C levels
Starting with a mean A1C level of 9.6 in each group, those who got surgery typically were below the goal of 7 after both one and three years, but the intensive management group weren’t. The surgery group was down to a mean of 6.4 after a year, rising slightly to 6.7 after three years. Those who had intensive management brought down their A1C to 7.8 after a year, but it was up considerably to 8.6 after three years. The difference between the two groups after three years was statistically significant.
For blood pressure, the results weren’t so dramatic, but they didn’t need to be. Even at the start of the study, each group was within range of the current standard of 140, with the surgery group at a mean of 127 and the intensive management group at 132. After three years, the surgery group had a mean of 123 with the intensive management group at 130, which was in fact a statistically significant difference between the two groups.
The results for LDL cholesterol weren’t statistically significant. But at the start of the study, the mean of each group was close to the goal of 100. Those in the surgery group had a level of 103; those in the intensive group were 105. After three years, their levels had fallen a bit to 90 and 103, respectively.
Surgery for people with a lower BMI?
Clearly, bariatric surgery works not only for weight loss but also for diabetes management. The study also addresses another gap in our knowledge.
The bariatric surgery guidelines of the American Diabetes Association set the body mass index, or BMI cutoff point at 35 because “there isn't enough evidence for people with BMIs lower than 35.” But 59 percent of the people in the new study had a BMI of 30 to 35.
Bariatric surgery isn’t for everyone. But it’s certainly something you ought to consider if you weigh far too much.
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David Mendosa is a journalist who learned in 1994 that he has Type 2 diabetes, which he now writes about exclusively. He has written thousands of diabetes articles, two books about it, created one of the first diabetes websites, and publishes the monthly newsletter, “Diabetes Update.” His very low-carbohydrate diet, current A1C level of 5.5, and BMI of 19.8 keeps his diabetes in remission without any drugs.