Semaglutide's CRP fall starts before the weight comes off

Design

prespecified secondary analysis of a randomised, double-blind, placebo-controlled trial

Population

17,604 adults with atherosclerotic cardiovascular disease and overweight or obesity, without diabetes

Primary outcome

change in high-sensitivity CRP and its relation to time to first MACE

Effect

hsCRP −37.8% with semaglutide at 104 weeks; MACE reduced across all baseline hsCRP subgroups; hsCRP fall evident by weeks 4–8

This prespecified secondary analysis of SELECT examined high-sensitivity CRP (hsCRP) in 17,604 patients with established atherosclerotic cardiovascular disease and overweight or obesity but without diabetes. Baseline hsCRP was similar in both arms (geometric mean 1.96 mg/L on semaglutide, 1.91 mg/L on placebo) and predicted future major adverse cardiovascular events, with risk rising across the <2, 2 to <10 and at least 10 mg/L strata, including cardiovascular and all-cause death.

Semaglutide lowered hsCRP by 37.8% at 104 weeks and reduced MACE across every hsCRP subgroup. The timing is the interesting part: larger falls in hsCRP went with larger weight loss, but the reduction was already evident at 4 and 8 weeks, before major weight loss, and was seen in patients who lost no weight at all. It was independent of LDL cholesterol, statin use and the entry cardiovascular criterion.

That pattern is hard to explain as a consequence of adiposity alone, and the authors' modelling suggests reduced inflammation contributes in part to the benefit seen in SELECT. For practice it is a reason to stop describing GLP-1 receptor agonist cardiovascular benefit as a weight-loss effect, and to be less quick to assume a patient whose weight has plateaued is getting nothing.

• Do not use hsCRP to select patients for a GLP-1 receptor agonist — benefit was seen across all strata
• A patient losing little weight on semaglutide may still be deriving cardiovascular benefit
• Keep statin and LDL targets unchanged; this effect was independent of both
• Record baseline weight and follow-up weight, but do not treat weight as the only marker of response

Why it matters

It challenges the assumption that these drugs work on the heart because they take weight off.

Don't overread it

This is a biomarker substudy with modelling — it does not establish that lowering inflammation is what prevented the events.

The statistics, in plain English

A 37.8% fall in hsCRP is a within-arm change over 104 weeks, not a head-to-head effect on an outcome. hsCRP was prognostic in both groups, meaning it identifies risk; that it fell with treatment and that the fall tracked lower MACE risk is consistent with inflammation mediating part of the benefit, but mediation analyses cannot prove the pathway. The clinically meaningful finding is the reduction in MACE already established by the main trial.

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