Medscape Diabetes & Endocrinology
COMMENTARY
Kevin Fernando, MBChB, MSc Diabetes, BSc
DISCLOSURES | June 03, 2024
There has been much hyperbole since the presentation of results from the SELECT cardiovascular outcomes trial (CVOT) at this year’s European Congress on Obesity, which led many to herald semaglutide as the “new statin.”
In the SELECT CVOT, participants with overweight or obesity (body mass index [BMI] ≥ 27), established cardiovascular disease (CVD), and no history of type 2 diabetes were administered the injectable glucagon-like peptide 1 (GLP-1) receptor agonist semaglutide (Wegovy) at a 2.4-mg dose weekly. Treatment resulted in a significant 20% relative risk reduction in major adverse CV events (a composite endpoint comprising CV death, nonfatal myocardial infarction, or nonfatal stroke). Importantly, SELECT was a trial on secondary prevention of CVD.
The CV benefits of semaglutide were notably independent of baseline weight or amount of weight lost. This suggests that the underlying driver of improved CV outcomes with semaglutide extends beyond simple reduction in obesity and perhaps indicates a direct effect on vasculature and reduction in atherosclerosis, although this remains unproven.
Not All Risk Reduction Is Equal
Much of the sensationalist coverage in the lay press focused on the 20% relative risk reduction figure. This endpoint is often more impressive and headline-grabbing than the absolute risk reduction, which provides a clearer view of a treatment’s real-world impact.
In SELECT, the absolute risk reduction was 1.5 percentage points, which translated into a number needed to treat (NNT) of 67 over 34 months to prevent one primary outcome of a major adverse CV event.
Lower NNTs suggest more effective treatments because fewer people need to be treated to prevent one clinical event, such as the major adverse CV events used in SELECT.
Semaglutide vs Statins
How does the clinical effectiveness observed in the SELECT trial compare with that observed in statin trials when it comes to the secondary prevention of CVD?
The seminal 4S study published in 1994 explored the impact of simvastatin on all-cause mortality among people with previous myocardial infarction or angina and hyperlipidemia (mean baseline BMI, 26). After 5.4 years of follow-up, the trial was stopped early owing to a 3.3–percentage point absolute risk reduction in all-cause mortality (NNT, 30; relative risk reduction, 28%). The NNT to prevent one death from CV causes was 31, and the NNT to prevent one major coronary event was lower, at 15.
Other statin secondary prevention trials, such as the LIPID and MIRACL studies, demonstrated similarly low NNTs.
So, you can see that the NNTs for statins in secondary prevention are much lower than with semaglutide in SELECT. Furthermore, the benefits of semaglutide in preventing CVD in people living with overweight/obesity have yet to be elucidated.
In contrast, we already have published evidence showing the benefits of statins in the primary prevention of CVD, albeit with higher and more variable NNTs than in the statin secondary prevention studies.
The benefits of statins are also postulated to extend beyond their impact on lowering low-density lipoprotein cholesterol. Statins have been suggested to have anti-inflammatory and plaque-stabilizing effects, among other pleiotropic benefits.
We also currently lack evidence for the cost-effectiveness of semaglutide for CV risk reduction. Assessing economic viability and use in healthcare systems, such as the UK’s National Health Service, involves comparing the cost of semaglutide against the healthcare savings from prevented CV events. Health economic studies are vital to determine whether the benefits justify the expense. In contrast, the cost-effectiveness of statins is well established, particularly for high-risk individuals.
Advantages of GLP-1s Should Not Be Overlooked
Of course, statins don’t provide the significant weight loss benefits of semaglutide.
Additional data from SELECT presented at the 2024 European Congress on Obesity demonstrated that participants lost a mean of 10.2% body weight and 7.7 cm from their waist circumference after 4 years. Moreover, after 2 years, 12% of individuals randomized to semaglutide had returned to a normal BMI, and nearly half were no longer were living with obesity.
Although the CV benefits of semaglutide were independent of weight reduction, this level of weight loss is clinically meaningful and will reduce the risk of many other cardiometabolic conditions including type 2 diabetes, metabolic dysfunction–associated steatotic liver disease, and obstructive sleep apnea/hypopnea syndrome, as well as improve low mood, depression, and overall quality of life. Additionally, obesity is now a risk factor for 13 different types of cancer, including bowel, breast, and pancreatic cancer, so facilitating a return to a healthier body weight will also mitigate future risk for cancer.
Sticking With Our Cornerstone Therapy, For Now
In conclusion, I do not believe that semaglutide is the “new statin.” Statins are the cornerstone of primary and secondary prevention of CVD in a wide range of comorbidities, as evidenced in multiple large and high-quality trials dating back over 30 years.
However, there is no doubt that the GLP-1 receptor agonist class is the most significant therapeutic advance for the management of obesity and comorbidities to date.
The SELECT CVOT data uniquely position semaglutide as a secondary CVD prevention agent on top of guideline-driven management for people living with overweight/obesity and established CVD. Additionally, the clinically meaningful weight loss achieved with semaglutide will impact the risk of developing many other cardiometabolic conditions, as well as improve mental health and overall quality of life.
Dr Kevin Fernando creates concise clinical aide-mémoire for primary and secondary care to make life easier for healthcare professionals and ultimately to improve the lives of patients. He is very active on social media (X handle @drkevinfernando), where he posts hot topics in type 2 diabetes and CVRM. He recently has forayed into YouTube (@DrKevinFernando) and TikTok (@drkevinfernando) with patient-facing video content. Kevin has been elected to Fellowship of the Royal College of General Practitioners, the Royal College of Physicians of Edinburgh, and the Academy of Medical Educators for his work in diabetes and medical education.
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