Earlier intervention may boost bariatric surgery effectiveness
medwireNews: A study suggests that obese patients may improve their chances of becoming non-obese and reversing comorbidities such as diabetes if they undergo bariatric surgery before their body mass index (BMI) reaches 40 kg/m2.
The study “highlights the advantages of early surgical management of obesity in that smaller amounts of weight loss are required to achieve the desired effect,” say Oliver Varban (University of Michigan Health Systems, Ann Arbor, USA) and co-researchers.
They note in JAMA Surgery that although “it stands to reason that patients with the highest BMI benefit the most from bariatric surgery,” such patients may still be severely obese even after achieving excellent weight loss, making their obesity-related comorbidities less likely to resolve.
The team used data from 27,320 patients included in the Michigan Bariatric Surgery Collaborative registry who had surgery between June 2006 and May 2015 and their weight recorded 1 year later, which amounted to half of all patients who underwent surgery. The patients’ average preoperative BMI was 42.7 kg/m2, and 36% achieved a BMI below 30 kg/m2 when assessed 1 year later.
More than 4000 patients had a baseline BMI below 40 kg/m2, and nearly three-quarters of these were non-obese 1 year after surgery, making this outcome 12.9 times more likely than for patients with higher starting BMIs. Indeed, only 8.5% of patients achieving this target had a starting BMI of 50 kg/m2 or above.
Patients who did achieve a non-obese BMI had an increased likelihood of no longer requiring oral antidiabetes medications or insulin, compared with patients who remained obese, at 78.5% versus 64.3% and 67.7% versus 50.0%, respectively. This equated to a twofold increased likelihood, which was also seen for discontinuation of cholesterol medication, antihypertensives, and of continuous positive airway pressure for obstructive sleep apnea.
The authors of an accompanying commentary, Bruce Wolfe and Elizaveta Walker, both from the Oregon Health & Science University in Portland, USA, note that the findings run counter to previous studies in which baseline BMI did not predict resolution of comorbidities.
They suggest this could be because of the very recent setting of the current study, or because it included a higher proportion of patients with BMIs below 40 kg/m2 than the older studies did.
A finding in line with previous studies, however, was that patients had better outcomes if they underwent procedures such as sleeve gastrectomy, gastric bypass, or duodenal switch, rather than gastric banding.
The commentators stress that although the present results support referral for surgery at a relatively low BMI, they “do not refute the importance of weight loss in achieving important clinical benefit” for patients with obesity-related comorbidities irrespective of BMI.
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