Semaglutide could nearly halve obesity prevalence in US

Key takeaways:

• About 93 million adults in the U.S. could be eligible for semaglutide 2.4 mg for weight loss.
• Approximately 50.5% of them could lose at least 15% of body weight after treatment.

Researchers estimated that semaglutide could cut the obesity prevalence in the United States by about 46% and prevent more than 1.5 million CVD events over 10 years when given to eligible patients with overweight or obesity.

The FDA approved weekly injectable semaglutide 2.4 mg (Wegovy, Novo Nordisk) in 2021 for chronic weight management in adults with overweight or obesity. In 2017, the agency approved weekly injections of semaglutide 0.5 mg and 1 mg (Ozempic, Novo Nordisk) for glycemic control in adults with type 2 diabetes, and it also approved a 2 mg formulation of the drug last year for patients with type 2 diabetes who did not respond to the lower doses.

Nathan D. Wong, PhD, MPH, a professor of medicine at the University of California, Irvine School of Medicine, and colleagues noted that the impact glucagon-like peptide 1 (GLP-1) receptor agonists have on weight loss have recently generated “interest and investigation.”

“Semaglutide activates GLP-1 receptors, improving incretin function and insulin secretion (glucose-dependent), inhibiting glucagon release and suppressing hepatic gluconeogenesis, resulting in reductions in both fasting as well as postprandial glucose,” they wrote in Cardiovascular Drugs and Therapy.

In the STEP 1 trial, researchers found that a weekly 2.4 mg dose of semaglutide was associated with a 14.9% reduction in body weight among participants with overweight or obesity vs. a 2.4% reduction with placebo. It was also associated with improvements in BP, fasting plasma glucose and lipids, according to Wong and colleagues.

For the current study, the researchers used treatment eligibility criteria and treatment effects from the STEP 1 trial to estimate the impact of semaglutide treatment on obesity prevalence and CVD events within the U.S. population. The analysis included data on 19,225 participants from the 2015 to 2018 U.S. National Health and Nutrition Examination Survey (NHANES).

Overall, 3,999 participants fit the STEP 1 eligibility criteria for treatment, translating to a population size of 93 million, or 38% of U.S. adults, according to the researchers.

Among the 3,999 participants, 3,493 had no prior CVD and were eligible for a 10-year CVD risk estimation.

The researchers found that applying STEP 1 treatment effects resulted in:

• 86.4% of adults losing 5% or more body weight;
• 69.1% losing 10% or more body weight; and
• 50.5% losing 15% or more body weight.

Based on this, the researchers estimated that semaglutide could reduce the obesity prevalence by 46.1% in the U.S., leading to 43 million fewer people with obesity. In addition, 16.8% of the study cohort would be reverted to the normal weight category, representing 17.5 million U.S. adults.

Meanwhile, the estimated 10-year risk for CVD was reduced from 10.15% to 8.34% following treatment, amounting to a 1.81% overall risk reduction and 17.8% relative risk reduction. This translates to 1.5 million fewer CVD events over 10 years, with most preventable cases among men (2.2%) and white individuals (2.01%).

The study had several limitations, according to the researchers. For example, because STEP 1 trial eligibility criteria was used to identify NHANES participants, there may have been differences between the current study participants and STEP 1 participants, “and therefore the weight loss and cardiovascular risk factor changes observed in STEP 1 may not be entirely translatable to our NHANES sample,” Wong and colleagues wrote. They were also unable to determine whether CVD reductions were due to semaglutide treatment or from other risk factor interventions.

Still, Wong and colleagues concluded that semaglutide “could have a significant impact on reducing health care costs associated with obesity and CVD.”

“The ongoing SELECT trial will document the actual impact of semaglutide treatment on cardiovascular outcomes in high-risk adults and established CVD and without diabetes,” they wrote.