GRAPEVINE, TEX. — Greater initial weight loss following surgery and the ability to keep much of that excess weight off over time distinguished patients who achieved long-term remission of their type 2 diabetes after bariatric surgery.
Severely obese patients with type 2 diabetes had a 40% diabetes remission rate at 5 years after laparoscopic adjustable gastric banding, in one large retrospective study presented at the annual meeting of the American Society for Metabolic and Bariatric Surgery. In a second study, those who had gastric bypass surgery maintained a 57% diabetes remission rate at median of 8.6 years.
Samuel Sultan reported on 95 type 2 diabetic patients who underwent laparoscopic adjustable gastric banding (LAGB). They went from a mean preoperative body mass index of 46.3 kg/m2 to a mean BMI of 35.0 kg/m2 at 5 years, with a resultant mean 48% excess weight loss.
At 5 years follow-up, 40% of patients were off all diabetes medications and had a hemoglobin A1c level below 6.0% or fasting blood glucose of less than 100 mg/dL. In 80% of patients, diabetes was either in remission or improved as defined by reduced need for diabetes medications and fasting blood glucose of 100-125 mg/dL, said Mr. Sultan, a medical student at New York University.
The 5-year excess weight loss in the group with long-term diabetes remission was 57%, compared with 38% in those with recurrence. There was a trend toward a higher remission rate in patients whose presurgical duration of diabetes was shorter: The remission group had a mean 4.7-year history of diabetes, whereas those not in remission had a mean 7.3-year history. Viewed another way, the 5-year remission rate in patients with less than a 7-year history of type 2 diabetes was 44%, compared with 27% in those with diabetes for more than 7 years.
Mean fasting blood glucose in the overall study population was 146 mg/dL preoperatively and 118.5 mg/dL at 5 years. Mean HbA1c was 7.5% before LAGB and 6.6% after 5 years.
In a separate presentation, Dr. Silas M. Chikunguwo reported on 177 type 2 diabetes patients who underwent open or laparoscopic gastric bypass for morbid obesity and were followed for a mean of 8.6 years and up to 16 years. Their mean BMI went from 50 to 31 kg/m2.
Postoperatively, 89% of patients had complete remission of their diabetes. The remission proved durable in 57%, said Dr. Chikunguwo of Virginia Commonwealth University, Richmond.
Factors associated with durable remissions included limb bypass length greater than 100 cm, male sex, younger age, greater mean percent excess weight loss, and less weight regain.
Another predictor of durable remission was less severe preoperative diabetes: The recurrence rate was 72% in patients on preoperative insulin, 34% in those on oral agents, and 24% in those on dietary control alone.
The studies presented by Dr. Chikunguwo and Mr. Sultan are among the largest and longest follow-ups to date examining bariatric surgery's impact on diabetes. The increase in recurrences over time noted in Dr. Chikunguwo's study is consistent with the results of a landmark recent systematic review and meta-analysis led by Dr. Henry Buchwald, professor of surgery and biomedical engineering at the University of Minnesota, Minneapolis.
The meta-analysis included 621 published studies in more than 135,000 morbidly obese patients, 22% of them with type 2 diabetes, who underwent various forms of bariatric surgery. Eighty-two percent of the diabetics experienced complete resolution of the clinical and laboratory manifestations of diabetes in the first 2 years post surgery, dropping off to a 62% resolution rate after 2 years.
The diabetes remission rates ranged from a high of 95% for patients undergoing biliopancreatic diversion/duodenal switch, to 80% for gastric bypass, 80% for gastroplasty, and 57% for LAGB. Those resolution rates paralleled weight loss, which was greatest in recipients of biliopancreatic diversion/duodenal switch and least with LAGB (Am. J. Med. 2009;122:248-56.e5)
But weight loss can't be the whole explanation for postsurgical remission of diabetes. It's likely that surgically induced changes in the gut hormonal milieu are involved. As Dr. Buchwald noted, diabetes can go into remission within days after bariatric surgery, before major weight loss has occurred.
Dr. Chikunguwo and Mr. Sultan reported having no conflicts of interest, although Mr. Sultan noted that his coinvestigators serve as consultants to Allergan, which markets the LAP-BAND system.
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