Gastric Bypass May Confer Survival, Comorbidity Benefits

Marlene Busko

November 07, 2016

NEW ORLEANS — Patients who had Roux-en-Y gastric-bypass surgery were less likely to die of all causes during an average 6-year follow-up than patients of the same gender, age, body mass index (BMI), and diabetes status, a new study indicates.

A second study showed that many patients have durable weight loss and fewer obesity-related comorbidities 10 years after this surgery. Both studies were presented at Obesity Week 2016.

"We speculate that the improvements that we see after bariatric surgery in [terms of] survival benefits really relate to changes in metabolic risk," since HDL cholesterol, total cholesterol, and systolic blood pressure improved after the surgery, and some patients had diabetes remission, said Michelle R Lent, PhD, a clinical psychologist at the Geisinger Obesity Research Center, in Danville, Pennsylvania, who presented the mortality findings from the study at her center.

This type of long-term data show that bariatric-surgery benefits are durable and can be used to inform payers, she noted.

Session comoderator and presenter of the other study, Shanu N Kothari, MD, director of the minimally invasive bariatric surgery fellowship at Gunderson Health System, in La Crosse, Wisconsin, told Medscape Medical News that bariatric surgery sets a patient on a different course for weight loss and reduced comorbidities.

But the question remains, "Can we move the survival curve, or has the damage been done to the joints, bones, heart, lungs, and kidneys, even though [the patient] may have lost 100 pounds?"

Does bariatric surgery confer similar benefits as stopping smoking; for example — a smoker who smokes for 30 years and then quits for a year has a diminished risk of lung cancer. Related to this, it will be important to understand the cause of death of these bariatric surgery patients — whether they are dying from suicide or from cardiac, pulmonary, or oncologic causes, according to Dr Kothari.

"That is where we are going to have to mine larger databases; but this is a good start," he said. Dr Lent said she and her colleagues plan to investigate this question further.

Six-Year Survival Advantage; Biggest Benefit Seen in Those > 60 Years or With Diabetes

In their study, Dr Lent and colleagues identified 3490 patients who underwent Roux-en-Y gastric bypass from 2004 to 2014, and they matched 2696 of these patients with control patients of the same sex, age range (< 40, 40–49, 50–59, > 60), BMI (< 40, 40–49, 50–59, > 60), and diabetes status (present or absent).

The patients had a mean age of 46 and mean BMI of 47, and 30% had diabetes. Almost all of the patients were white (97%) and most (83%) were women.

During a median follow-up of 6.4 years, 94 surgery patients and 133 control patients died.

By year 2, survival curves for the two patient groups began to diverge. At 39 months, mortality was significantly lower in the surgery patients than in the control patients (1.3% vs 2.4%, respectively).

During a median follow-up of 6.4 years, patients in the surgery group were 48% less likely to die from all causes than were patients in the control group (hazard ratio [HR] for death in the control group, 1.48).

When stratified by selected patient characteristics, the largest reduction in death was observed among patients age 60 years or older and those with diabetes, with those who had had surgery being about 50% less likely to have died than controls (HR, 0.50; P = .0048 for > 60 years; HR, 0.48; P = .0001 for those with diabetes).

"While bariatric surgery provides significant health benefits to most patients, it is important to note that in our study some of the strongest mortality risk reductions following gastric bypass were found in older adults," noted Dr Lent.

"Until recently, older age was viewed as a relative contraindication to bariatric surgery, as the benefits were less clear. Our findings help to challenge that myth and instead support offering the surgery to older patients."

Durable Weight Loss, Improved Comorbidities in Long-term Study

To Medscape Medical News, Dr Kothari said that two of the criticisms of bariatric surgery are 'you don't have enough long-term data' or 'the outcomes are variable.' " His group addressed both of these.

They performed a retrospective review of 1402 patients who had laparoscopic Roux-en-Y gastric bypass at their healthcare system from September 2001 through June 2015.

They used standardized outcome reporting as described by the American Society for Metabolic and Bariatric Surgery (ASMBS) in 2015 (Surg Obes Relat Dis. 2015;11:489-506), which specifies standard definitions for remission or improvement of comorbidities such as type 2 diabetes, hypertension, and dyslipidemia.

"This is the first longitudinal report to apply these standardized definitions to this patient population to get real-world data," Dr Kothari noted.

The population was very stable, and although patients did not return for follow-up in the bariatric clinic, they visited other healthcare facilities, and this study was able to capture that data.

The patients had a mean BMI of 47.5 kg/m2 and a mean age of 47.5, and 81% were female.

Follow-up weight data were available for > 70% of patients throughout 12 years postsurgery.

The highest mean percent excess weight loss and lowest mean BMI were reached at 18 months postoperation, at 79% and 30.1 kg/m2, respectively.

Mean percent excess weight loss remained high throughout follow-up, and many patients had improvement in or remission of type 2 diabetes, dyslipidemia, and hypertension.

Laparoscopic Roux-en-Y gastric-bypass results in durable improvement and resolution of obesity-related comorbidities, Dr Kothari concluded, adding that integrated healthcare systems provide an optimal environment for data collection and long-term follow-up.

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Obesity Week 2016: The American Society for Metabolic and Bariatric Surgery and the Obesity Society Joint Annual Scientific Meeting; November 2, 2016; New Orleans, Louisiana. Abstracts A110, A10.

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