GLP-1 drugs cut deaths and heart attacks even without diabetes

GLP-1 receptor agonists have well documented protective effects on the heart in people with diabetes, where most of the landmark trials were run. But a growing share of the people now taking these drugs have obesity without diabetes, and whether the cardiovascular protection carries over to them has remained under debate. Obesity itself raises the risk of heart disease and early death, so the answer matters well beyond blood sugar. This review set out to settle whether the heart benefits belong to the drug or to the diabetic populations it was first tested in.

The researchers systematically searched PubMed, Web of Science, Scopus and Cochrane databases through December 26, 2023 for randomised controlled trials comparing GLP-1 receptor agonists with placebo in adults with obesity and no diabetes. They found 19 eligible trials totalling 32,884 patients and pooled the results, using risk ratios for event outcomes and mean differences for continuous ones. Study quality was assessed with the Cochrane risk of bias method: 15 trials had a low overall risk of bias, two raised concerns and two were rated high risk. The protocol was registered in advance on PROSPERO.

Compared with placebo, GLP-1 drugs reduced death from any cause (risk ratio 0.82), non-cardiovascular death (0.77) and myocardial infarction (0.73). Cardiovascular death on its own did not reach statistical significance (risk ratio 0.85). Patients on the drugs lost an average of 8.53 kg and showed improvements in total cholesterol, triglycerides and low-density lipoproteins. The cost was side effects: any adverse event was more common (risk ratio 1.11), with gut problems leading the list, including nausea (2.70), vomiting (3.85), diarrhoea (1.97) and constipation (2.35). Serious adverse events, however, were no more frequent than with placebo.

This analysis extends the cardioprotective story of GLP-1 drugs from diabetic populations into obesity without diabetes, which had been the open question. It largely confirms what the drug class showed in diabetes, though with a complication: the drop in cardiovascular death specifically fell short of significance, even as overall death and heart attacks clearly declined. The authors also note heterogeneity in outcomes across trials, which argues for individualised rather than blanket use. How the benefits distribute across different degrees of obesity, and over longer horizons, remains open.

If you have obesity but not diabetes, this is a reason to see GLP-1 drugs as more than cosmetic weight loss tools: in pooled trial data they were linked to fewer deaths and fewer heart attacks in people like this. It is equally a reason to take the side effect profile seriously, since gut complaints were markedly more common, even though serious harms were not. The mixed result on heart-specific deaths is a reminder that the evidence is strong but not tidy. Any decision about these drugs sits with a prescriber, but the case for them no longer rests on the scale alone.