Weight loss surgery does not lower health costs over the long run for people who are obese, according to a new study.
Some researchers had suggested that the initial costs of surgery may pay off down the road, when people who've dropped the extra weight need fewer medications and less care in general.
The new report joins other recent studies challenging that theory.
"No way does this study say you shouldn't do bariatric surgery," said Jonathan Weiner from the Johns Hopkins Bloomberg School of Public Health in Baltimore, who led the new research.
But, he added, "We need to view this as the serious, expensive surgery that it is, that for some people can almost save their lives, but for others is a more complex decision."
According to the American Society for Metabolic and Bariatric Surgery, about 200,000 people have weight loss surgery every year.
Surgery is typically recommended for people with a body mass index (BMI) - a measure of weight in relation to height - of at least 40, or at least 35 if they also have co-occurring health problems such as diabetes or severe sleep apnea.
A five-foot, eight-inch person weighing 263 pounds has a BMI of 40, for example.
For their study, Weiner and his colleagues tracked health insurance claims for almost 30,000 people who underwent weight loss surgery between 2002 and 2008. They compared those with claims from an equal number of obese people who had a similar set of health problems but didn't get surgery.
As expected, the surgery group had a higher up-front cost of care, with the average procedure running about $29,500.
In each of the six years after that, health care costs were either the same among people who had or hadn't had surgery or slightly higher in the bariatric surgery group, according to findings published Wednesday in JAMA Surgery.
Average annual claims ranged between $8,700 and $9,900 per patient.
Weiner's team did see a drop in medication costs for surgery patients in the years following their procedures. But those people also received more inpatient care during that span - cancelling out any financial benefits tied to weight loss surgery.
One limitation of the study was that only a small proportion of the patients - less than seven percent - were tracked for a full six years. Others had their procedures more recently.
The study was partially funded by surgical product manufacturers and pharmaceutical companies, including Johnson & Johnson and Pfizer. Claims data came from BlueCross BlueShield.
It's clear that surgery can help people lose weight and sometimes even cures diabetes, Weiner told Reuters Health. But it might not be worthwhile, or cost-effective, for everyone who is obese.
That means policymakers and companies will have to decide who should get insurance coverage for the procedure and who shouldn't.
"It's showing that bariatric surgery is not reducing overall health care costs, in at least a three- to six-year time frame," said Matthew Maciejewski, who has studied that topic at the Center for Health Services Research in Primary Care at the Durham VA Medical Center in North Carolina, but wasn't involved in the new study.
"What is unknown is whether there's some subgroup of patients who seem to have cost reductions," he told Reuters Health.
In the meantime, whether or not to have weight loss surgery is still a personal decision for people who are very obese, Weiner said.
"Every patient needs to talk it through with their doctor," he said. "It obviously shouldn't be taken lightly, but shouldn't be avoided either."
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