Tirzepatide benefits people living with obesity and heart failure, regardless of type 2 diabetes, study finds
A new study has shown that the weight-loss drug tirzepatide significantly improves health outcomes in people living with obesity and heart failure, even when type 2 diabetes limits the extent of weight loss.
The findings, from the SUMMIT trial, offer fresh evidence that the benefits of incretin-based therapies may go beyond weight reduction alone.
Obesity is a major risk factor for heart failure with preserved ejection fraction (HFpEF), a condition that affects the heart’s ability to relax and fill properly. People living with type 2 diabetes are at especially high risk and while incretin-based drugs such as tirzepatide are known to promote weight loss, diabetes has been shown to reduce how much weight patients lose.
Researchers set out to test whether this reduced weight loss would affect the drug’s overall benefits in people with both obesity and HFpEF.
In this double-blind trial, 731 adults with HFpEF and a body mass index of at least 30 kilograms per square metre were randomly assigned to receive weekly injections of tirzepatide (up to 15 milligrams) or a placebo. Participants were followed for a median of 104 weeks.
The two main outcomes were the time to first cardiovascular death or worsening heart failure event and the change in health status at 52 weeks, measured using the Kansas City Cardiomyopathy Questionnaire.
Patients given tirzepatide were less likely to die from cardiovascular causes or experience worsening heart failure than those on placebo, representing a 38 per cent reduction in risk (hazard ratio 0.62; 95 per cent confidence interval 0.41–0.95; P = 0.026).
Crucially, these benefits were consistent in people living with and without diabetes. Improvements in symptoms, physical function and quality of life were also statistically significant in both groups.
After one year, participants living with diabetes lost an average of 10.4 per cent (95 per cent confidence interval 8.7–12.2 per cent) of their body weight, while those without diabetes lost 12.9 per cent (95 per cent confidence interval 11.2–14.6 per cent). Despite this difference, both groups experienced similar reductions in visceral fat around the heart and in left ventricular mass, indicators of improved cardiac health.
The findings suggest that tirzepatide’s benefits in heart failure extend well beyond its impact on body weight and that people living with obesity can expect meaningful improvements even if diabetes modestly limits their weight loss.
Researchers said the results highlight the complex relationship between obesity, diabetes and cardiovascular health and suggest that targeting obesity pharmacologically could improve outcomes for a broad range of people living with heart failure.
The study authors concluded that the heart failure benefits of incretin-based therapies “may not be fully captured by the degree of weight loss alone”.