Semaglutide & heart disease

Executive summary

* A recent obesity Congress generated headlines about the 'weight loss jab' cutting heart disease. Two papers were referenced in a press release from the Congress – one has been published.

* The weight loss jab refers to the drug semaglutide, which has the brand names Ozempic and Wegovy. These brands have been in the news a lot over recent years, as celebrities have been taking them with noticeable effects (not all good).

* This week's note looks at three papers on semaglutide:

i) The 2021 publication reporting the outcomes from the semaglutide and weight loss trial (called the STEP 1 trial).

ii) The 2023 publication reporting the outcomes from the semaglutide and cardiovascular events trial (called the SELECT trial).

iii) The recent publication from the Congress. This was also focused on the SELECT trial and cardiovascular events. It grouped participants by BMI level to make claims for people with different starting weights.

* The weight loss achieved with semaglutide is striking. The side effects are striking too – from pancreatitis and retinopathy (reported as serious and common) to hair loss and gastritis (reported as less serious but still common). The FDA approval of semaglutide warned about thyroid cancer.

* The cardiovascular events claims are less robust. The relative difference was small and could be explained by double the number of drop outs in the semaglutide group, meaning that fewer participants remained available to have cardiac events counted. Analysis of particular groups (women, certain age groups, certain BMI groups, certain ethnic groups etc) found no significant results.

* Notwithstanding the weak results, there is a logical mechanism by which semaglutide could improve heart health. It has an amusing twist, however.

* Novo Nordisk makes semaglutide. Novo Nordisk is omnipresent in semaglutide research. The papers reported in the Congress press release were led by two professors with Novo Nordisk conflicts. The claims that they made for semaglutide would have delighted Novo Nordisk.