Metabolic surgery improves health in obese diabetics

By Dr. Liji Thomas, MDSep 3 2019

Paris is hosting the European Society of Cardiology Congress (ESC) meet this year where on the 2nd of September researchers from the Cleveland Clinic reveal that weight loss surgeries in patients with obesity and type 2 diabetes could reduce the risk of death and major untoward heart or cardiovascular events or major adverse cardiovascular events (MACE).

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This large study also reveals that persons undergoing these surgeries have a better diabetes control or blood glucose control and needed less medication for their diabetes control and heart health. The study titled, “Association of Metabolic Surgery With Major Adverse Cardiovascular Outcomes in Patients With Type 2 Diabetes and Obesity” was published in the September issue of the Journal of the American Medical Association (JAMA).

Four in ten Americans suffer from diabetes and heart disease and research has shown that 40 percent of the patients with diabetes are at risk of dying due to heart disease and its complications. The research question the authors of the study posed was, “Is there an association between metabolic surgery and major adverse cardiovascular events (all-cause mortality, coronary artery events, cerebrovascular events, heart failure, nephropathy, and atrial fibrillation) in patients with type 2 diabetes and obesity?”

The team of researchers included 2,287 patients who underwent one of the four types of metabolic surgeries - gastric bypass, sleeve gastrectomy, adjustable gastric banding, or duodenal switch surgery. These patients were then compared to 11,435 matched patients who did not undergo the surgeries but were provided standard medical care. Thus each of the participant who underwent surgery was matched in a 1:5 ratio with a control. The study took place between 1998 and 2017. All participants were followed up until December 2018. There were around 65 percent females in either group and the average age of the participants at recruitment was around 53 years. The data was obtained from the Cleveland Clinic Electronic Health Record (EHR).

The team was looking at deaths or any of the five major events associated with cardiovascular disease, obesity and diabetes among the participants. The five events they recorded as untoward were coronary artery events such as heart attacks or angina, cerebrovascular events such as strokes, heart failure, abnormal heart rhythm or atrial fibrillation or kidney disease. The authors wrote describing their study population, “Metabolic surgical procedures included Roux-en-Y gastric bypass (n = 1443 [63%]), sleeve gastrectomy (n = 730 [32%]), adjustable gastric banding (n = 109 [5%]), and duodenal switch (n = 5). In the surgical group, 1713 patients (75%) had a BMI of 40 or greater, 465 patients (20%) had a BMI between 35 and 39.9, and 109 patients (5%) had a BMI between 30 and 34.9.”

Results revealed that over a course of eight year of follow up of the patients and the controls, those that underwent the metabolic surgeries had a 40 percent lowered risk of getting one of the five adverse cardiovascular events compared to those who were on standard medical care. These patients who underwent surgery were also 41 percent less likely to die compared to their counterparts who were provided medical care alone. The researchers wrote, “All-cause mortality occurred in 112 patients in the metabolic surgery group and 1111 patients in the nonsurgical group.” Further those who underwent the surgery also had a 15 percent more weight loss and lowered blood glucose levels. Consequently their requirement of blood sugar lowering medications, insulin and heart medications (including medications to lower blood pressure or cholesterol levels) were also lowered significantly write the researchers.

Ali Aminian, M.D., a bariatric surgeon at Cleveland Clinic and lead author of the study, in a statement said, “The striking results that we saw after metabolic surgery may be related to the patients' substantial and sustained weight loss. However, there is a growing body of evidence to suggest that there are beneficial metabolic and hormonal changes after these surgical procedures that are independent of weight loss.”

The team concluded, “Among patients with type 2 diabetes and obesity, metabolic surgery, compared with nonsurgical management, was associated with a significantly lower risk of incident MACE. The findings from this observational study must be confirmed in randomized clinical trials.”

Steven Nissen, M.D., Chief Academic Officer of the Heart & Vascular Institute at Cleveland Clinic and the study's senior author, said in his statement, “Cardiovascular complications from obesity and diabetes can be devastating. Now that we've seen these remarkable results, a well-designed randomized controlled trial is needed to definitively determine whether metabolic surgery can reduce the incidence of major heart problems in patients with type 2 diabetes and obesity.”

The study received partial funding from Medtronic as declared by the researchers.