Metabolically healthy obese people have some CV risk

Individuals who are obese but without metabolic abnormalities (metabolically healthy obese [MHO]) have an elevated risk of developing MACE-HF*, new-onset heart failure (HF), and new-onset atrial fibrillation (AF), according to a French study presented at EASD 2021.

“Individuals with metabolically healthy obesity do not have a higher risk of myocardial infarction (MI), ischaemic stroke, or cardiovascular (CV) death than metabolically healthy non-obese individuals,” said study lead author Dr Laurent Fauchier from Centre Hospitalier Universitaire Trousseau, Tours, France.

“By contrast, they have a higher risk of new-onset HF and new-onset AF. Even individuals who are non-obese can have metabolic abnormalities and be at high risk of CV disease events,” he pointed out.

Using the French national hospitalization discharge database, the researchers identified adults discharged from French hospitals in 2013 (n=2,953,816). To be included, patients needed to have ≥5 years of complete follow-up, not have a history of MACE-HF, and not be underweight or malnourished. Of these, 9.5 percent (n=272,838) were obese, of whom 32.8 percent (n=89,414) were metabolically healthy. They were categorized according to obesity and the presence of three metabolic abnormalities (hypertension, hyperlipidaemia, and diabetes mellitus) and were followed up for a mean 4.9 years.

Compared with metabolically healthy non-obese individuals, MHO individuals had an increased risk of MACE-HF (adjusted hazard ratio [adjHR], 1.22, 95 percent confidence interval [CI], 1.19–1.24), new-onset HF (adjHR, 1.34, 95 percent CI, 1.31–1.37), and new-onset AF (adjHR, 1.33, 95 percent CI, 1.30–1.37). [EASD 2021, presentation 64; Diabetes Obes Metab 2021;23:2492-2501]

Conversely, MHO individuals did not have a higher risk of MI, ischaemic stroke, or CV death compared with metabolically healthy non-obese individuals (adjHR, 0.92, 95 percent CI, 0.87–0.98, adjHR, 0.93, 95 percent CI, 0.88–0.98, and adjHR, 0.99, 95 percent CI, 0.93–1.04, respectively).

The increased CV disease risk was particularly evident among MHO men who had elevated risks of MACE-HF, CV death, MI, ischaemic stroke, new-onset HF, and new-onset AF (HRs, 1.61, 1.14, 1.47, 1.12, 1.74, and 1.80, respectively). In contrast, the risks were not raised, and in some cases were reduced, among MHO women (HRs, 0.89, 0.80, 0.49, 0.77, 0.99, and 0.95, respectively).

After adjusting for baseline characteristics, obesity was an independent risk factor for MACE-HF (HR, 1.13, 95 percent CI, 1.12–1.14), new-onset HF (HR, 1.19, 95 percent CI, 1.18–1.20), and new-onset AF (HR, 1.29, 95 percent CI, 1.28–1.31), but not MI (HR, 0.93, 95 percent CI, 0.91–0.95), ischaemic stroke (HR, 0.93, 95 percent CI, 0.91–0.96), or CV death (HR, 0.96, 95 percent CI, 0.94–0.98).

“Metabolic abnormalities such as hypertension, dyslipidaemia, and diabetes mellitus are commonly associated with obesity and may mediate some of its deleterious effects,” said Fauchier.

“This new and best available evidence tells us that on a population level, the idea that large numbers of people can be obese but metabolically healthy is simply untrue,” he highlighted.

The authors noted several limitations with the study including the observational design, largely Caucasian population, and relatively short follow-up period.

“Our observations suggest that specific studies investigating different aggressive preventive measures in specific subgroups of patients are warranted,” noted Fauchier.

“[All-in-all,] encouraging weight loss in people with obesity, regardless of whether or not they are metabolically healthy, will help prevent AF and HF. Our findings also highlight the importance of preventing poor metabolic health and suggest that even normal weight individuals may benefit from early behavioural and medical management to improve their diet and increase physical activity in order to guard against stroke,” he concluded.