Choosing The Best Bariatric Procedure For Long-term Type 2 Diabetes Remission

A team of researchers from Cleveland Clinic and several universities around the world have created the first online tool to help physicians make evidence-based recommendations for the appropriate bariatric surgery for long-term remission of type 2 diabetes mellitus. They recently presented the tool and the study behind it at the 2017 American Surgical Association’s Annual Meeting in Philadelphia.

The online calculator, which can be found here, asks doctors to input four independent criteria: how long the patient has had diabetes, the number of diabetes medications they are taking, whether they are taking insulin, and whether their HbA1C is less than or greater than 7 percent.

From there, it creates an Individual Metabolic Surgery (IMS) score for the patient that grades their diabetes as either mild, moderate or severe and recommends either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG).

“Several high-quality studies, including randomized clinical trials, have shown that bariatric surgery is more effective than medical therapy in achieving glucose control in patients with type 2 diabetes,” says Cleveland Clinic general surgeon Ali Aminian, MD, of Cleveland Clinic Bariatric and Metabolic Institute and lead author on the study. “So the next question that needed to be answered was, ‘What procedure would be more appropriate in each individual patient?’”

Long-term remission depends on diabetes severity

Dr. Aminian and his colleagues first analyzed data from 659 Cleveland Clinic patients who had type 2 diabetes, underwent either RYGB or SG between 2004 and 2011 and had at least five years of postoperative glycemic follow-up. They externally validated their findings by comparing them to 241 patients with similar criteria from Hospital Clínic Universitari, Barcelona, Spain.

Their analysis revealed four predictors of long-term remission: preoperative duration of diabetes, preoperative number of diabetes medications, insulin use and glycemic control (HbA1C less than 7 percent). Using these parameters, they then developed an IMS scoring system that led to three patient categories: mild for those with an IMS score of 25 or less, moderate for those with an IMS between 25 and 95 and severe for those with an IMS of more than 95.

“Our analysis showed that long-term response after bariatric surgery in patients with type 2 diabetes significantly differs according to the severity of the disease at the baseline,” Dr. Aminian says. “For example, a patient who has had diabetes for two years and is taking just one medication would have a significantly different outcome compared to a person who has had diabetes for 15 years, and is taking three medications including insulin.”

Recommendations based on efficacy and risk

The investigators then analyzed which procedure would be best for patients in a particular IMS category based on the procedure’s risk-benefit ratio.

They found both procedures were very beneficial for the mild patients (IMS score less than or equal to 25) — RYGB was associated with 92 per and SG with 74 percent long-term remission in Cleveland Clinic’s cohort. Because the data also showed RYGB was associated with a great reduction in diabetes medications, they suggest it over SG for patients with mild disease.

The opposite was true for the severe patients (IMS score greater than 95); whether they received RYGB or SG, only 12 percent achieved long-term remission. Dr. Aminian says the low efficacy for such patients is most likely due to their limited functional pancreatic ß-cell reserves; ß-cells produce and secrete insulin. Because of the low success rate in achieving diabetes remission with these patients, they suggest the less-invasive SG in patients with severe disease.

For the moderate patients (IMS score between 25 and 95), the analysis showed RYGB was more effective than SG with 60 percent of RYGB patients achieving long-term remission versus 25 percent of SG patients. Dr Aminian says this is likely due to RYGB’s more pronounced effects on neurohormonal mechanisms that can improve diabetes status.

Data indicate early intervention is best

Dr. Aminian says other considerations — outside the realm of the study — may also affect which procedure is best for a particular patient. Research shows, for example, that RYGB is better for patients suffering from gastroesophageal reflux disorder and that SG would be more appropriate for patients with Crohn’s disease.

In addition, he says, the study’s findings highlight that physicians should consider bariatric surgery in patients with type 2 diabetes while they are still in the early stages of the disease. “If we want to treat type 2 diabetes effectively and achieve long-term remission,” he says, “We shouldn’t wait too long.”