Bariatric surgery is the most effective treatment for people who are morbidly obese, but the procedure tends to be most successful when done before patients gain too much weight, researchers reported Wednesday.
That means that policies and practices that delay operations lead to poorer health outcomes, the researchers argued in their study, published Wednesday in the journal JAMA Surgery.
Relying on records from thousands of bariatric surgeries performed over a decade in Michigan, researchers found that patients’ body mass index at the time of the procedure was a key predictor of their weight later on — and that those with a BMI of less than 40 when undergoing surgery were much more likely to have a BMI of less than 30 about 12 months later.
“Patients with BMIs of 55 or 60 once had BMIs of 35,” said Dr. Oliver Varban, the lead author of the study and a bariatric surgeon at the University of Michigan. “We’re truly missing the boat on those patients.”
Having a BMI of more than 30 is defined as being obese, which is also associated with an array of health problems. In the study, patients who had conditions including diabetes, hyperlipidemia, and sleep apnea and whose BMI dropped below 30 after surgery were more likely to see improvements in their symptoms.
For a number of reasons — from insurance policies to personal preferences — many patients do not have surgery until their BMIs reach higher levels. The average pre-surgery BMI for the 27,000 patients studied, for example, was 48.
Varban said he and his colleagues conducted the study because patients had been asking how effective the surgery was at getting people to BMIs below obesity levels. Did it matter if someone had a BMI of 45 versus a BMI of 65?
The analysis only looked at outcomes one year after the surgery, and some outside experts said they were curious if the results would hold after a longer follow-up. Some researchers not involved with the study also suggested that by focusing on BMI, the new paper was giving short shrift to the benefits of surgery-induced weight loss overall, even if it did not pull BMI below 30.
In a commentary also published Wednesday, Dr. Bruce Wolfe and Elizaveta Walker of Oregon Health and Science University highlighted other studies that found improvements in comorbidities — those related health problems like diabetes — were more correlated with overall weight loss than decreases in BMI. The new study and similar findings, Wolfe and Walker wrote, “do not refute the importance of weight loss in achieving important clinical benefit among patients.”
Dr. Guilherme Campos, the director of Virginia Commonwealth University’s bariatric surgery program, who was not involved with the study, similarly said that patients with higher BMIs should still be offered surgery because of the benefits of weight loss. But he said he hoped the study would encourage more patients to consider surgery at lower BMIs and more doctors to discuss surgical treatments earlier with patients.
“There are a lot of patients out there who do not have or are not offered a surgery for a variety of reasons,” he said. “We need to improve utilization of these procedures.”
In most cases, patients are required to have a BMI of at least 40 or a BMI of at least 35 with a related illness before they can qualify for the surgery, according to the American Society for Metabolic and Bariatric Surgery. But insurers will often require patients to undergo several months of medically supervised weight loss before agreeing to cover a surgery, and many patients themselves view surgery as a last-ditch effort, only consenting once they develop other health issues, Varban and his colleagues wrote.
Varban said he was not suggesting that patients with BMIs in the 50s and 60s avoid bariatric surgery; rather, doctors, patients, and insurers should also consider moving ahead with surgery sooner.
“The only thing we have to change as physicians is capture these people at an earlier time when their BMI is a little lower,” he said.