Best results seen for those with pre-op BMI of less than 40, study says

July 26, 2017

WEDNESDAY, July 26, 2017 (HealthDay News) -- Having weight-loss surgery before you become severely obese tends to achieve better results, a new study finds.

Researchers found that people who underwent bariatric surgery when their body mass index (BMI) was less than 40 were more likely to achieve a BMI below 30 (overweight but not obese) compared to those with a higher body mass index, researchers.

A BMI of 30 or more is considered obese. For example, a 5-foot-5 woman weighing around 180 pounds has a BMI of 30. A BMI of over 40 (for example, the same woman weighing 240 pounds or more) is extremely obese.

"Bariatric surgery is extremely safe and effective and should be considered as first-line therapy for patients with a BMI between 35 and 40," said lead researcher Dr. Oliver Varban. He's director of bariatric surgery of the University of Michigan Health Systems.

"Waiting to reach a BMI of 50 or more only serves to limit the benefits of bariatric surgery," he said.

More than one-third of American adults are classified as obese. Besides weight loss, bariatric surgery can improve obesity-related conditions such as diabetes, high blood pressure, high cholesterol and sleep apnea. Obese people also have a higher risk for premature death, the researchers said in background notes.

"With obesity, just like any chronic progressive disease, the earlier you intervene the better your outcomes will be," said Dr. Stacy Brethauer, president of the American Society for Metabolic and Bariatric Surgery.

People for whom bariatric surgery is an option have a BMI of 35 or higher plus diabetes or another obesity-related disease, or a BMI over 40 without another condition, said Brethauer, a bariatric surgeon at the Cleveland Clinic.

"I would tell patients, if your BMI is over 30, you need to ask your physician to help manage your obesity," Brethauer said. "If your BMI is over 35, you need to start having discussions about effective treatment, which right now is bariatric surgery."

Currently, only about 1 percent of people eligible for bariatric surgery get the operation, he said.

"There is a fear of surgery and a reluctance of physicians to refer patients for surgery," Brethauer said. "But there is ample evidence that bariatric surgery is safe and effective."

For the study, Varban and colleagues collected data on more than 27,000 patients who had bariatric surgery in Michigan between 2006 and 2015.

A year after surgery, 36 percent of patients had a BMI of less than 30, which is considered an important goal.

Those patients were more likely than others to have had a pre-operative BMI of less than 40.

With a final BMI of less than 30, patients had a better chance of discontinuing medications for diabetes, high blood pressure and high cholesterol. They were also more likely be cured of sleep apnea, a sleep disorder related to obesity, the study found.

The type of surgery also made a difference. Procedures that permanently reduced the size of the stomach or bypassed it -- sleeve gastrectomy, gastric bypass or duodenal switch -- were more likely to result in the healthier BMI compared with adjustable gastric banding, a reversible procedure, Varban said.

Less than 9 percent of patients with a BMI above 50 achieved the below-30 BMI goal, he said.

The report appears online July 26 in the journal JAMA Surgery.

Dr. Mitchell Roslin is chief of obesity surgery at Lenox Hill Hospital in New York City. He agreed that earlier surgery often pays bigger dividends in terms of weight loss and related medical problems.

But Roslin cautioned that having surgery doesn't mean you will achieve a normal weight.

Also, patients have to consider the benefits and risks of each procedure, he said.

The more aggressive the procedure, the greater the weight loss -- but there's also a higher risk for side effects, Roslin said.

"The more we change the stomach and intestine, the more the weight loss and the lower the odds of regaining weight," he said. "But the odds are higher of frequent bowel movements and the need to take micronutrient supplements."

Another specialist stressed that losing weight at any level of obesity is beneficial.

"Weight loss at whatever point you start is good," said Dr. Bruce Wolfe, a professor in the division of bariatric surgery at Oregon Health and Science University.

Everybody who has a BMI of 50 or 60 at one point had a BMI of 40, said Wolfe, co-author of an accompanying journal editorial.

Getting bariatric surgery earlier might prevent patients from reaching a BMI of 50 or more, but even those who are severely obese can benefit from weight-loss surgery, Wolfe said.

More information

For more about bariatric surgery, visit the American Society for Metabolic and Bariatric Surgery.

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