However, the effects of gastric bypass surgery on diabetes have not received much attention, writes lead researcher Philip R. Schauer, MD, director of bariatric surgery at the University of Pittsburgh Medical Center. His report appears in the current issue of Annals of Surgery.
'Very Dramatic' Diabetes Results
But his study showed the procedure can actually "cure" diabetes, Schauer tells WebMD. "Overall, after surgery these patients had complete resolution of diabetes -- very dramatic."
Jennifer Marks, MD, a diabetes specialist at the University of Miami School of Medicine, has counseled a number of gastric bypass patients. "Gastric surgery is a technique for people have tried everything else to lose weight and not been successful," Marks tells WebMD. "I recommend it as an option. It can work." She, too, has seen remarkable effects on diabetes.
However, if patients regain weight, "it also means their diabetes could come back," Suzanne Gebhart, MD, a diabetes expert with Emory University School of Medicine in Atlanta, tells WebMD.
The surgery involves restricting the size of the stomach by stapling most of it shut, so that patients feel satisfied with small amounts of food. And some of the food isn't absorbed. These two mechanisms allow patients to lose weight.
The study's patients all had some degree or risk of type 2 diabetes, ranging from very mild to moderate to severe, he says. Some were taking no diabetes medications; others were taking several prescriptions plus insulin. Some patients had had diabetes for less than five years, some for more than 10 years.
Normal Blood Sugar, Fewer Meds
Schauer tracked the patients' weight loss and their diabetes during the five years after gastric bypass surgery. Overall, they lost about 60% of their body fat -- nearly 100 pounds apiece.
The women's fasting glucose levels, an indicator for diabetes, got much better:
- For 83% of the women, glucose levels returned to normal levels; for 17%, there was marked improvement.
- 80% of patients reduced the amount of diabetes medications and 79% required less insulin.
"Even patients with very severe disease, who required more than 100 units of insulin every day for more than 10 years, were cured," Schauer tells WebMD.
In fact, 30% of patients could quit diabetes medications immediately after hospital discharge, even before they lost much weight.
The most dramatic changes in improvement in their diabetes was seen in patients who had had diabetes for shorter periods or less severe diabetes.
Diabetes-related complications also improved significantly: Nerve damage was present in 47 patients prior to surgery, after surgery 50% of patients reported improvement of symptoms; 18% of the men with erectile dysfunction had improvements.
Other health improvements: 89% had improved blood pressure; 78% had better cholesterol; 80% got better sleep because their obstructive sleep apnea improved. The sleep-related condition occurs when breathing temporarily -- and frequently -- stops because neck structures around the breathing pipe collapse, usually because of excess weight.
Gastric Bypass Surgery: Truly a Cure?
"One of the big messages here -- the major message -- is that early surgical intervention in these patients is most important," he tells WebMD. "If we catch them early, almost all of them will be cured."
Also, patients who lost a modest amount of weight did quite well, he points out. "This brings up a very interesting question, is it the weight loss or something else that's going on?"
The findings add insight to the insulin-production process, Schauer says. "We're still very early in understanding role the gut plays in glucose metabolism and onset of diabetes."
Here's what may be happening: After gastric bypass surgery, food bypasses the stomach and upper intestine. This bypass seems to affect hormones produced by the upper intestines and islet cells produced by the pancreas, which is key in producing insulin. All these mechanisms play into onset of diabetes, Schauer explains.
These factors also affect the amount of diabetes medication patients are taking, he adds. "Some were taking 100 units insulin a day, and taking three to five oral medications," he tells WebMD.
"After surgery, there was a dramatic reduction in the number of medications they were taking. The vast majority was able to get rid of all their medications."
In the five-year follow-up, some patients had "a modest regain of weight, which is typical," Schauer admits. However, other studies of gastric bypass studies have shown that 15 years down the road, patients will keep most the weight off, he adds.
"Most patients do quite well with gastric bypass surgery, Marks tells WebMD. "Even those people who had not yet developed diabetes improved. That's very important, that even when blood sugars are within the normal range, there can be some improvement."
In dollars-and-cents terms, it makes sense, she adds. "The decreased use of diabetes medications may make the surgery a cost-effective intervention."
SOURCES: Schauer, P. Annals of Surgery, Oct. 2003; vol 238: pp 467-485. Philip R. Schauer, MD, director, bariatric surgery, University of Pittsburgh Medical Center. Suzanne Gebhart, MD, Emory University School of Medicine, Atlanta. Jennifer Marks, MD, endocrinologist, University of Miami School of Medicine.