Semaglutide and cardiovascular outcomes by baseline and changes in adiposity measurements: a prespecified analysis of the SELECT trial

Background: The SELECT trial found semaglutide reduced major adverse cardiovascular events (MACE) in patients with overweight or obesity with cardiovascular disease but without diabetes. We report a prespecified analysis of the SELECT trial on the relationships between baseline adiposity measures, treatment-induced adiposity changes, and subsequent MACE risk. Methods: Patients aged at least 45 years, with a BMI of at least 27 kg/m2 were enrolled in 41 countries (804 sites) and randomised 1:1 to once-weekly semaglutide 2·4 mg or placebo. The primary outcome was time to first MACE (composite of cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke). Adiposity measures included weight and waist circumference. In this analysis, risk of MACE occurring after 20 weeks was assessed between patients by adiposity changes in the first 20 weeks and, in a separate analysis, all in-trial MACE were assessed between patients by adiposity changes over 104 weeks. This trial is registered with ClinicalTrials.gov, NCT03574597. Findings: Semaglutide significantly reduced MACE incidence compared with placebo among 17 604 patients enrolled in SELECT, with consistent benefits across all baseline weight and waist circumference categories. In the semaglutide group, analyses for linear trends showed lower baseline bodyweight and waist circumference were associated with lower incidence of MACE-an average 4% reduction in risk per 5 kg lower bodyweight (hazard ratio [HR] 0·96 [95% CI 0·94-0·99]; p=0·001) and per 5 cm smaller waist circumference (0·96 [0·93-0·99]; p=0·004). In the placebo group, lower baseline waist circumference (0·96 [0·94-0·99]; p=0·007), but not bodyweight (0·99 [0·97-1·01]; p=0·28), was associated with a lower MACE risk and weight loss was paradoxically associated with increased MACE risk. In those receiving semaglutide there was no linear trend linking weight loss at week 20 to subsequent MACE risk, but greater waist circumference reduction at week 20 was associated with lower subsequent MACE risk, and waist circumference reduction by week 104 was associated with lower in-trial risk of MACE. An estimated 33% of the observed benefit on MACE was mediated through waist circumference reduction (HR 0·86 [95% CI 0·77-0·97] after adjustment for time-varying changes in waist circumference). Interpretation: The cardioprotective effects of semaglutide were independent of baseline adiposity and weight loss and had only a small association with waist circumference, suggesting some mechanisms for benefit beyond adiposity reduction. Funding: Novo Nordisk.