Bariatric Surgery: Many Can Come Off Insulin Long Term

Miriam E Tucker

November 06, 2017

WASHINTON, DC — Bariatric surgery can produce significant long-term metabolic benefits for insulin-treated patients with type 2 diabetes, new research indicates.

Findings from the retrospective analysis of data for over 250 patients, which represents the largest series with the longest follow-up time to date, were presented November 2 here at Obesity Week 2017 by Ali Aminian, MD, associate professor of surgery at the Cleveland Clinic, Ohio.

"Seven years after bariatric surgery, 44% of patients could come off insulin with their glycemic control at the target. Discontinuation of insulin can have significant impact on quality of life and healthcare costs," Dr Aminian told Medscape Medical News.

For the 194 patients who underwent Roux-en-Y gastric bypass and 58 given sleeve gastrectomy, the surgeries also produced significant improvements in blood pressure and lipid profiles. And while gastric bypass was associated with more weight loss, less weight regain, and better short-term diabetes control, long-term diabetes control was similar between the two procedures.

Asked to comment, session moderator Shanu N Kothari, MD, director of the minimally invasive bariatric surgery program at Gundersen Health System, La Crosse, Wisconsin, told Medscape Medical News that the new data "add to our body of literature that we have a metabolic intervention that's underutilized that gives far more durable and successful outcomes than medications."

Dr Kothari added, "One message from this is that we should be intervening sooner. We know the chances of remission are much higher when we intervene with either procedure sooner as opposed to later…preferably for patients with type 2 diabetes before they get to the point where they're on insulin, because as the diabetes duration and severity increases over years, the pancreatic reserve goes down."

Greater Weight Loss With Bypass vs Sleeve

Dr Aminian and colleagues examined data for 252 patients with type 2 diabetes who were treated with insulin prior to undergoing bariatric surgery at Cleveland Clinic between 2004 and June 2012 and for whom at least 5 years of follow-up data were available. The median follow-up time was 7 years overall.

The primary outcome was glycemic control, defined as HbA1c less than 7% without insulin use. Secondary outcomes were HbA1c <7% irrespective of medications and diabetes remission, defined as HbA1c below 6.5% and fasting blood glucose less than 126 mg/dL in the absence of any diabetes medications.

"Short-term" and "long-term" follow-up were defined as 1 to 2 years and 5 or more years postsurgery, respectively. Late weight regain was defined as a gain in body mass index (BMI) of more than 5 kg/m2 from the lowest weight postsurgery.

The patients were 64% female with a mean age of 52 years, mean BMI  46 kg/m2, and diabetes duration of 11 years. Average HbA1c at baseline was 8.5%, and 82% had an HbA1c of 7.0% or greater.

At long-term follow-up, the sleeve-gastrectomy group had experienced a 7.8-kg/mdrop in BMI  compared with a 12.2-kg/m2 reduction for gastric bypass, a significant 4.4-point difference at both the short- and long-term points (< .001).

Total weight loss at 7 years was 17% after sleeve vs 26% after bypass, percent excess weight loss was 44% vs 62%, respectively, and late weight regain was 31% vs 20%, respectively (< .001 for all three comparisons).

"Remarkable" Results for Glycemic Control

Both procedures significantly reduced HbA1c levels, but the improvement was greater for bypass in the short term — from 8.4% to 6.5% vs 8.8% to 7.1% for sleeve gastrectomy. At 7 years, HbA1c was reduced by 1.4 percentage points for bypass and by 1.6 for sleeve, both significant (< .001) with no difference between the two procedures (= .05).

For the entire cohort, 51% met the primary outcome of HbA1c <7% without insulin use in the short term and 44% met it in the long term, "which is remarkable," Dr Aminian commented during his presentation.

Whereas only 18% had an HbA1c of less than 7.0% prior to surgery, 70% achieved that level of control short term and 59% remained there beyond 5 years.

Diabetes remission was achieved by 29% in the short term and 15% long term.

 "Interestingly," Dr Aminian said, "type of procedure didn't predict any study outcomes, nor did baseline BMI, number of diabetes drugs, or gender."

Other overall improvements included reductions in LDL cholesterol (from 92.8 mg/dL at baseline to 85.2 mg/dL at long-term follow-up, = .001), triglycerides (165 to 107 mg/dL, < .001), systolic blood pressure (140.5 to 123.2 mm Hg, < 0.001) and diastolic blood pressure (77.1 vs 70.6, < .001), and increased HDL cholesterol (41 to 50 mg/dL, <0.001).

Percentage of Patients Meeting the ADA Goal for Cardiometabolic Outcomes

Outcomes Baseline (%) Short term (%) Long term (%) P, short term vs baseline P, long term vs baseline
HbA1c <7% 18 70 59 <0.001 <0.001
BP <140/90 mm Hg 44 82 86 <0.001 <0.001
LDL <100 mg/dL 61 74 70 0.004 0.06
All three parameters 3 39 32 <0.001 <0.001

"Both gastric bypass and sleeve gastrectomy induce a significant and sustainable improvement in cardiometabolic risk factors and glycemic status in patients with insulin-treated type 2 diabetes," Dr Aminian said.

Benefits and Risks Will Help Match Procedure to Patient

Given that glycemic outcomes were comparable for the two procedures in the long term, Dr Aminian advised that "other factors, including BMI, surgical risk, and presence of comorbidities should be considered in choosing bariatric procedure in patients with insulin-treated type 2 diabetes."

Indeed, Dr Kothari said, "I think we need to get to the point where we can look at the profile of a patient and the profile of what our operations offer and weigh the risks and benefits and match the right procedure to the right patient based on their metabolic severity."

Of course, he added, the patient's preferences and goals should be primary considerations.

"Is their goal to be off insulin? Off all meds? To lose weight and if their diabetes gets better that's a bonus? Ultimately we need to be able to metabolically profile the patient, match it to our operation, and then match that with the goals and expectations of the patient."

Dr Aminian has no relevant financial relationships. Dr Kothari is a consultant for Lexington Medical and a speaker for Ethicon and Gore.

Obesity Week 2017. November 2, 2017; Washington, DC. Abstract A110.

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