Bariatric Surgery Tied to Less MACE in Obesity, Diabetes

Marlene Busko

September 13, 2019

PARIS — Obese patients with type 2 diabetes who underwent bariatric (metabolic) surgery were less likely than similar patients who received medical treatment to experience one of six major adverse cardiovascular events (MACE), findings of a new observational study show.

Compared with obese patients with type 2 diabetes who received medical treatment, those who underwent bariatric surgery were 39% less likely to die from any cause or to develop heart failure, coronary artery events, cerebrovascular events, atrial fibrillation, or nephropathy in the following 8 years, Ali Aminian MD, bariatric surgeon at the Cleveland Clinic, in Ohio, reported here in a late-breaking science session of the European Society of Cardiology (ESC) Congress 2019, World Congress of Cardiology.

The study was simultaneously published online September 2 in JAMA.

For patients in the surgery group, there was a 38% lower risk for three-point MACE (myocardial infarction, ischemic stroke, and mortality), and the incidence of each component of the six-point MACE was lower, Ali noted.

The patients in the nonsurgery group were not receiving any of the newer diabetes drugs that yield cardiovascular benefits, Aminian acknowledged to theheart.org | Medscape Cardiology, but the "magnitude of the effect of surgery was so striking [that] I don't think that even if we use a new drug, that it's going to wash out the findings," he said.

He agreed, however, that the patients who underwent bariatric surgery may have been more motivated to adhere to a healthy lifestyle, and "so we need a prospective clinical trial."

In the meantime, "primary care physicians, endocrinologists, and cardiologists could consider bariatric surgery when they see patients with cardiovascular risk factors and obesity, and talk about that with the patient and refer a patient to the bariatric surgery program," he suggested. He noted that "not all patients would be good candidates for [this surgery], but at least that would be an option for some patients."

RCT Needed

In an accompanying editorial, JAMA Deputy Editor and bariatric surgeon Edward H. Livingston, MD, University of California, Los Angeles, writes that these study results should be interpreted with caution because the study was observational and that the two patient groups were similar rather than closely matched.

However, it builds on other studies that have shown that "by inducing substantial weight loss, bariatric surgery not only treats diabetes but also improves hypertension, lipid levels, and sleep apnea; reduces osteoarthritis; and improves many other weight related problems," he noted.

Livingston writes, "the many benefits associated with bariatric surgery–induced weight loss suggest that it should be the preferred treatment option for carefully selected, motivated patients who are obese and have diabetes and cannot lose weight by other means."

The results were "impressive," session co-chair Maryam Kavousi, MD, PhD, Erasmus University, Rotterdam, the Netherlands, told theheart.org | Medscape Cardiology, especially that bariatric surgery was associated with better outcomes for all six measures and, notably, heart failure and nephropathy.

More research is needed, she said, to detect any sex differences and uncover the underlying pathophysiology.

An increasing amount of data supports bariatric surgery for obese patients with type 2 diabetes, "particularly fairly soon after diagnosis, before people are on multiple drugs and insulin," Robert H. Eckel, MD, University of Colorado, Denver, who is the incoming co-president of the American Diabetes Association, told theheart.org | Medscape Cardiology.

Bariatric surgery performed early — when beta cells may be able to recover function — is very effective for sustained diabetes remission, he noted.

Regarding the current study, Eckel said, "Now we have data in terms of cardiovascular disease outcomes and nephropathy and all-cause mortality that really reflect the need for a randomized controlled trial."

In the meantime, cardiologists "should be in a position to think about patients with diabetes not only being on one of these new agents that's shown benefit in terms of cardiovascular disease but also, very importantly, considering surgeons and a surgical approach."

However, he cautioned, they need to "pick the right surgeons," meaning those who have a lot of experience with Roux-en-Y bypass or sleeve gastrectomy.

"I think that this is a way to take care of a disease that's very weight related," Eckel said. "If you look at the impact of BMI [body mass index] or obesity on type 2 diabetes incidence and prevalence, it's incredible."

Case-Control, Observational Study

It is difficult for patients with obesity and type 2 diabetes to achieve weight and glycemic goals through lifestyle modification and pharmacotherapies, Aminian and colleagues write.

Previous studies have reported that metabolic surgery is associated with lasting weight loss and even remission of diabetes in some patients, but there is limited evidence about long-term cardiovascular outcomes.

To investigate this, the researchers identified 2287 patients who had diabetes and had undergone bariatric surgery in the Cleveland Clinic Health System from 1998 to 2017.

Each patient was matched with five patients in the healthcare system who had diabetes and a BMI ≥30 kg/m2 and who underwent follow-up through December 2018.

In the bariatric surgery group, almost two thirds of the patients (63%) had Roux-en-Y gastric bypass, about a third had sleeve gastrectomy (32%), and a few underwent adjustable gastric banding (5%) or duodenal switch (<1%).

For the patients in the surgery and nonsurgery groups, the percentage of women was similar (65.5% and 64.2%, respectively), as was median age (52.5 vs 54.8 years), mean BMI (45.1 vs 42.6 kg/m2), and mean HbA1C level (7.1% vs 7.1%).

The primary endpoint was a composite of all-cause mortality, diabetic nephropathy, coronary artery events (unstable angina, myocardial infarction, or coronary intervention/surgery), cerebrovascular events (ischemic stroke, hemorrhagic stroke, or carotid intervention/surgery), atrial fibrillation, and heart failure.

For the groups that underwent surgery vs medical management, the 8-year cumulative incidence of six-component MACE was 31% vs 48%.

All of the individual components of this outcome were also lower in the surgery group. Notably, the 8-year cumulative incidence of nephropathy was 6.1% in the bariatric surgery group vs 16.3% in the nonsurgery group, and the rate of heart failure was 6.8% in the surgery group vs 18.9% in the nonsurgical group.

During the study period, all-cause mortality was 10.0% in the bariatric surgery group vs 17.8% in the nonsurgery group, a 41% lower risk.

Mean body weight was reduced by 29.1 kg in the surgery group vs 8.7 kg in the nonsurgery group, and mean HbA1C level was reduced by 1% more in the surgery group than in the nonsurgery group.

The study was partially funded by an unrestricted grant from Medtronic. A coauthor was supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases. Aminian receives grants from Medtronic. The disclosures of the other authors are listed in the original article.

European Society of Cardiology (ESC) Congress 2019, World Congress of Cardiology: Presented September 2, 2019.

JAMA. Published online September 2, 2019. Abstract, Editorial

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