Weight of evidence favours bariatric surgery

Research shows surgical interventions are the proven best treatments we have for severe obesity

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Patients with severe obesity are more likely to be alive four years later if they are given bariatric surgery instead of usual care, the latest evidence shows.

Researchers tracked mortality rates in more than 8000 Israeli patients who received bariatric surgery to treat obesity.

After four years, around 100 patients had died, compared with more than 580 in a matched cohort with obesity that were given dietary counselling and behaviour-modification treatment instead.

The patients that underwent bariatric surgery were more likely to show a reduction in BMI, remission of diabetes, and reduction of incident hypertension than the matched non-surgical patients. Surgical procedures included laparoscopic banding, Roux-en-Y gastric bypass, and laparoscopic sleeve gastrectomy.

“This study, along with the existing evidence … is certainly going to strengthen the case for this sort of management for the really obese subset,” Professor Bruce Neal, an epidemiologist and the deputy executive director of the cardio-metabolic group at the George Institute for Global Health, said.

There were relatively few studies that reported long-term outcomes for bariatric surgery, the authors said.

The Swedish Obese Subjects study found 2010 patients who underwent bariatric surgery were more likely to survive over a 10-year period than those who received standard obesity treatment.

The same pattern was observed in a decade-long study from the US Veterans Affairs system, which included around 2500 bariatric surgery patients.

“This [latest paper] fits very nicely with that pattern,” Professor John Dixon, an academic general practitioner and the head of clinical obesity research at the Baker Heart and Diabetes Institute, said.

Prior to this research, very little was known about the long-term benefits of sleeve gastrectomy, which recently had become very popular, the authors said.

“The latest kid on the block, as far as (bariatric) surgery is concerned, is the sleeve gastrectomy,” said Professor Dixon.

“Until this data came out we didn’t know anything about this from a mortality point of view. But it does appear that … it is also associated with that reduction in mortality.”

Previous studies were also hampered by a loss to follow up; around one-quarter of patients dropped out at four years in the US Veterans study. This study was also limited to men.

The Israeli study benefited from a nearly complete follow up, an equal mix of men and women, and a dataset that included half the country’s population. The mortality advantage identified in the study did not necessarily extend to people with a BMI lower than 35, Professor Dixon said.

“All of these studies are done in people with a BMI over 35 with complications, or a BMI over 40,” he said. “We can’t say surgery is going to save lives in overweight or class one people. It is likely to in class one, [but] we just don’t know.”

However, there was clear evidence that surgical interventions in people with a BMI between 30 and 35 improved their quality of life, improved diabetes and reduced cardiovascular risk, he said.

The NHMRC guidelines recommend bariatric surgery for the management of morbid obesity (BMI>40) or a BMI over 35 in the presence of co-morbid conditions.

But many Australians with morbid obesity faced barriers to access, particularly those lacking private health insurance. Bariatric surgery costs between $12,000 and $25,000. Even with private health insurance, the out-of-pocket fees can range between $3000 to $7000.

“The three people I saw this morning desperately need, and would be high priorities for, bariatric surgery,” Professor Dixon said. “They are unemployed, are very large and have serious complications.”

Their only hope was waiting to be seen through the public hospital system.

“I can’t tell you whether they will live to make that,” Professor Dixon said.