Sleeve or Bypass? That is the Question.New Scoring System Helps Guide Surgical Choice
for Patients with Obesity and Diabetes


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Published in June Issue             

Cleveland Clinic researchers unveiled the Individualized Metabolic Surgery Score (IMS) or nomogram at the American Surgical Association annual meeting in April. The score is based on an analysis of data from the longest and largest study of patients with obesity and type 2 diabetes who underwent either Roux-en-Y gastric bypass or sleeve gastrectomy at the Cleveland Clinic, Ohio, USA and Hospital Clínic Universitari, Barcelona, Spain.

connect recently talked to Ali Aminian, MD, Associate Professor of Surgery at the Cleveland Clinic, Ohio, who presented the findings at ASA and was co-author of the study.

Our Q&A follows:

What is the significance of your study on the Individualized Metabolic
Surgery score?

This is the largest reported cohort with long-term glycemic follow-up after bariatric and metabolic surgery, which for the first time categorizes type 2 diabetes into three validated stages of severity to guide procedure selection.

Why were the four preoperative factors selected for the nomogram?

Our model was constructed based on four independent predictors of long-term diabetes remission including preoperative number of diabetes medications, insulin use, preoperative duration of diabetes in years, and glycemic control (HbA1C< 7%) which allow for classification of diabetes severity. These factors are readily available in clinical practice and can serve as a proxy to the functional pancreatic ß-cell reserve.

How do long term surgical outcomes differ in relation to diabetes severity?

In mild diabetes (IMS Score<=25), both procedures significantly improve diabetes, yet if risk-benefit ratio permits, we suggest RYGB since it leads to higher long-term remission. For patients with severe diabetes (IMS Score>95), when there is limited functional pancreatic ß-cell reserve, both procedures have similarly low efficacy for diabetes remission. Thus, we suggest sleeve gastrectomy as the metabolic procedure of choice given better risk-benefit ratio. There is an intermediate group, for whom RYGB is significantly more effective than sleeve gastrectomy in achieving long-term diabetes remission, which is likely related to its more pronounced neurohormonal effects.

Considering gastric bypass seemed to outperform sleeve, why not just use gastric bypass for all patients with severe obesity and diabetes?

Patients with an IMS score >95 points are considered to have severe diabetes. Long-term diabetes remission for those with severe disease was only a low estimate of 12% after both RYGB and sleeve gastrectomy. Given the similarly low long-term diabetes remission, along with comparable changes in HbA1C and diabetes medications, we suggest sleeve gastrectomy (less risky procedure) to be the metabolic surgery of choice in patients with severe diabetes. However, in patients with mild diabetes and particularly in patients with moderate diabetes, RYGB outperforms sleeve gastrectomy.

How do you see the score being adopted in clinical practice? What more must
be done?

The IMS nomogram and its online version (accessible at: http://riskcalc.org/Metabolic_Surgery_Score) can assist in decision making. Surgeons, endocrinologists, general practitioners, and even patients with obesity and type 2 diabetes can use it for evidence-based procedure selection. For example, a patient on 3 diabetes medications, using insulin, with a duration of diabetes for 11 years whose HbA1C is 6.8% who is considering bariatric surgery would have an IMS score of 106 which classifies this patient in severe group. Since the glycemic outcomes after RYGB and sleeve gastrectomy in this group are comparable, sleeve gastrectomy (less risky procedure) is suggested for surgical management of type 2 diabetes, if there is no other reason to favor RYGB.