RNY, Sleeve & Band only Mediocre at Rx Diabetes
Bariatric surgery has offered patients hope of a cure for their type 2 diabetes mellitus, but what constitutes remission from diabetes? In the November 2009 issue of Diabetes Care, Buse and colleagues provide a consensus definition of remission of diabetes. Partial remission was defined as a hemoglobin A1c (HbA1c) level of less than 6.5%, along with a fasting serum glucose level between 100 and 125 mg/dL. Complete remission was defined as an HbA1c level of less than 6% and a fasting glucose level of less than 100 mg/dL. These values should be sustained for at least 1 year after bariatric surgery without pharmacologic therapy.
The current study by Pournaras and colleagues uses these criteria to examine the effect of bariatric surgery in promoting remission of diabetes.
Study Synopsis and Perspective
Bariatric surgery (gastric bypass, sleeve gastrectomy, or gastric banding) leads to complete remission in only about one third of patients with type 2 diabetes, and should be viewed as a means for improving glycemic control, not as a cure, Dimitrios J. Pournaras, MD, and colleagues report in an article published online October 21, 2011, and in the January 2012 print issue of the British Journal of Surgery.
Using the recently updated American Diabetes Association (ADA) standard, which defined diabetes remission as HbA1c levels below 6% and fasting glucose levels less than 5.6 mmol/L at least 1 year after bariatric surgery without hypoglycemic medication, the researchers found remission to be substantially lower than had been reported with earlier criteria.
Using data from 1006 patients, 209 of whom had type 2 diabetes at the time of gastric surgery, and a median follow-up of 23 months postsurgery, complete remission rates, using the new ADA standard, were 40.6% after gastric bypass (65/160 patients), 26% after sleeve gastrectomy (5/19 patients), and 7% after gastric banding (2/30 patients). However, the authors explain, “[t]he remission rate for gastric bypass was significantly lower with the new definition than with the previously used definition (40.6 versus 57.5 per cent; P = 0.003).” Remission rates for the other 2 procedures were not significantly different according to the new vs the old criteria.
The data, which were collected prospectively in 2 bariatric surgery centers in the United Kingdom and 1 center in Norway, also showed that on average, patients remained obese after surgery (preoperative body mass index [BMI], 48 kg/m2 vs postoperative BMI, 35 kg/m2). After surgery, oral hypoglycemic medications were still used by 29.4% of gastric bypass patients, 63% of sleeve gastrectomy patients, and 83% of gastric banding patients.
HbA1c levels were significantly lower after surgery in all 3 surgical groups, with mean levels of 6.2% (compared with 8.1% before gastric bypass), 6.8% (compared with 7.5% before sleeve gastrectomy), and 6.3% (compared with 7.7% before gastric banding; P < .001 for each comparison).
Study limitations include the small number of patients with type 2 diabetes in the gastric banding and sleeve gastrectomy groups, as well as lack of data regarding the duration of diabetes.
The authors note that these findings are important for “[e]stablishing realistic expectations among patients, clinicians, and policy-makers” regarding bariatric surgery in the management of type 2 diabetes. They suggest that emphasis should shift to bariatric surgery as an aid in achieving glycemic control, rather than as a tool for achieving remission.
The authors conclude, “The principal benefit of surgery, however, would not be to improve glycemic control per se but rather to reduce microvascular and macrovascular complications associated with diabetes. The findings of this study emphasize the need for intensive follow-up of patients with type II diabetes following bariatric surgery, in order to review pharmacological treatment, monitor for complications of diabetes, and ensure that adequate glycemic control is achieved.”
The study was supported by funding from the National Institute of Health Research Biomedical Research Center to Imperial College London. One author received a National Institute of Health Clinician Scientist award for work involving the trial. The authors have disclosed no relevant financial relationships.
Br J Surg. 2012:88:100-103. Abstract
- Researchers focused on 209 patients with type 2 diabetes who underwent laparoscopic bariatric surgery in one of 3 centers between 2004 and 2009.
- Patients were seen at 6 weeks, 6 months, and 12 months after surgery. The main study outcome was partial and complete remission from diabetes, as defined by the criteria described in the Clinical Context section.
- The mean age of participants was 48 years, and 65.6% were women. The mean BMI values before and after surgery were 48 kg/m2 and 35 kg/m2, respectively.
- The mean HbA1c level before surgery was 8.0%, and 30% of participants used insulin.
- 160 participants underwent gastric bypass, 19 completed sleeve gastrectomy, and 30 participants had gastric banding.
- Participants were observed for a median of 23 months after surgery. Overall, the rate of complete remission of diabetes was 34.4%. Use of older, more liberal criteria for the remission of diabetes yielded higher rates of complete remission (49.3%).
- In comparison of the different bariatric procedures, the remission rates were 40.6% after gastric bypass, 26% after sleeve gastrectomy, and 7% after gastric banding. The respective rates of use of oral hypoglycemic medications after surgery were 29.4%, 63%, and 83%, and the respective mean HbA1c levels after each procedure were 6.2%, 6.8%, and 6.3%.
- The rates of partial remission of diabetes with gastric bypass, sleeve gastrectomy, and gastric banding were 15.6%, 5%, and 7%, respectively.
- Preoperative insulin use was associated with a lower remission rate after surgery.
- In a consensus statement by Buse and colleagues, complete remission of type 2 diabetes was defined as an HbA1c level of less than 6% and a fasting glucose level of less than 100 mg/dL. For complete remission, these values should be maintained for at least 1 year after bariatric surgery without pharmacologic therapy.
- The current study by Pournaras and colleagues demonstrates that the rate of remission of diabetes after gastric bypass was 40.6%, whereas the respective remission rates after sleeve gastrectomy and gastric banding were 26% and 7%.