In adults with obesity, metabolic–bariatric surgery vs. usual care is associated with lower all-cause mortality

A meta-analysis of 16 matched cohort studies and one nonrandomized controlled trial comprising 174,772 participants who received or did not receive metabolic-bariatric surgery found that the procedure is associated with lower all-cause mortality compared with usual obesity management. It was also associated with longer life expectancy. Survival benefits were much more pronounced for patients with pre-existing diabetes than those without.

The study was published May 6 by The Lancet. The following commentary by Scott Kahan, MD, MPH, and Adriana Williams, MD, appeared in the ACP Journal Club section of the September Annals of Internal Medicine.

In the 1990s, bariatric surgery was dismissed as barbaric and a quick fix. Within a decade, prospective trials showed long-term durability of weight loss, Medicare initiated coverage, and several celebrities publicly revealed large surgical weight losses, contributing to increased use of surgery. By the 2010s, evidence of long-term safety and benefits mounted, including resolution of diabetes (prompting reframing as “metabolic surgery”) and improved cardiovascular outcomes and mortality.

The meta-analysis by Syn and colleagues leaves little question that metabolic surgery is lifesaving compared with usual care. Unfortunately, usual care is usually only self-directed diet and exercise. For example, controls in the Swedish Obese Subjects study were offered dietary treatment with their primary care providers. However, providers struggled to address obesity: Almost 25% of controls reported no weight loss attempt, >50% reported they simply followed their own regimen, and the control group gained weight. Pontiroli and colleagues' study offered only diet and exercise advice and treatment for diabetes and hypertension (but not antiobesity drug treatment). No trial has used a comparator of guideline-based nonsurgical treatment, such as intensive behavioral counseling and obesity pharmacotherapy, which achieve weight loss similar to gastric banding.

Metabolic surgery is incontrovertibly valuable, yet progress must occur outside the operating room: Only 1% of those eligible are treated with surgery. Coordinated education, provider training, and policy intervention are needed to bust myths, minimize insurance hurdles, and counter pervasive weight and antisurgery stigma. And when will we have surgery-in-a-pill? Medications in the pipeline (guided by advances in gastrointestinal physiology from studies of metabolic surgery) will probably achieve weight losses approaching sleeve gastrectomy. Still, the same challenges of misunderstandings and myths, inconsistent insurance coverage or under-coverage, and weight stigma must be tackled for widespread use.