Weight loss surgery linked to reduced mortality 5-10 years after procedure

Obese individuals who undergo weight loss surgery may have lower risk of death in the 5-10 years following the procedure than those who do not have the surgery, according to new research published in JAMA.

Researchers say obese individuals who undergo weight loss surgery may have better long-term survival than those who do not have the procedure.

Weight loss surgery, or bariatric surgery, is used as a weight-loss aid for individuals who are obese. It primarily involves one of three procedures: gastric bypass, gastric banding or sleeve gastrectomy.

During a gastric bypass - the most common of the three procedures - the stomach is divided into a small upper section and large bottom section. The small intestine is then rerouted to the small upper section, meaning the patient will eat less.

Gastric banding involves the placement of an inflatable band around the top portion of the stomach, creating a smaller stomach, while sleeve gastrectomy involves the removal of around 80% of the stomach.

Past studies have associated weight loss surgery with improved weight, quality of life and reduced risk of obesity-related conditions. 

What is more, there is an increasing amount of research indicating that bariatric surgery may reduce mortality among individuals who are severely obese.

However, according to the researchers of this latest study at the Group Health Research Institute in Seattle, WA; many of these studies have involved participants with few obesity-related diseases and the majority have been female. As such, the researchers say "the long-term outcomes of bariatric patients with substantial comorbid disease are not known."

Results 'may have broader implications for encouraging weight loss in general'

With this in mind, the researchers set out to assess the long-term survival of 2,500 patients - of whom 74% were men - who underwent bariatric surgery in Veteran Affairs bariatric centers between 2000 and 2011.

Fast facts about obesity

• Around one third (78.6 million) of adults in the US are obese
• Obesity is more common among middle-aged adults aged 40-59 years
• In 2008, the estimated annual medical cost of obesity in the US was $147 billion.

These patients were an average age of 52 years and had an average body mass index (BMI) of 47. They underwent either gastric bypass (74%), gastric banding (10%), sleeve gastrectomy (1%) or another bariatric procedure (1%).

To act as controls, the team compared the long-term survival of bariatric surgery patients with those of 7,642 individuals who did not undergo weight loss surgery. These patients were an average age of 52 years and had an average BMI of 46.

Around 55% of study participants had diabetes, the researchers note, while many of the participants had other obesity-related conditions, such as heart disease, high blood pressure and arthritis.

During the 14-year follow-up, there were 263 deaths among patients who had bariatric surgery and 1,277 deaths in the control group.

At 1 year, the estimated mortality rate for patients who underwent bariatric surgery was 2.4%, compared with 1.7% in the control group, indicating that weight loss surgery does not improve survival in the first year following the procedure.

However, mortality rates for bariatric surgery patients at 5 and 10 years were 6.4% and 13.8%, respectively, compared with mortality rates of 10.4% at 5 years and 23.9% at 10 years in the control group. This suggests that weight loss surgery may improve long-term survival.

These results may have broader implications for encouraging weight loss in general. Despite the studies showing that patients with lower BMIs live longer, not much evidence has linked intentional weight loss - from surgery, medication or diet and exercise - with longer survival. But these results, combined with other studies of bariatric surgery, may help to make that case.

Although many studies have associated weight loss surgery with health benefits, a study published in the journal Neurology last October linked surgical weight loss procedures to increased risk of spontaneous intracranial hypotension, which causes severe headaches.

References:

1.  Association between bariatric surgery and long-term survival, David E. Arterburn, et al., JAMA, doi:10.1001/jama.2014.16968, published online 6 January 2015, abstract.
2.  JAMA news release, accessed 5 January 2015.
3.  Group Health Research Institute news release, accessed 5 January 2015.
4.  Additional source: Centers for Disease Control and Prevention, adult obesity facts, accessed 5 January 2015.