‘Metabolically Healthy Obesity’ Has Heart Risks, Is it a Misnomer?
Carrying excess weight is associated with an increased risk for certain heart problems even when there are no metabolic disturbances, data from a large French longitudinal study have shown.
In an analysis of almost 3 million people with no prior heart issues, there was a 34% increased risk for developing heart failure and a 33% increased risk for developing atrial fibrillation, it was reported at the annual meeting of the European Association for the Study of Diabetes.
There appeared to be no increase in the risk for heart attacks, ischemic stroke, or cardiovascular death, but the study’s 5-year follow-up period may have been too short to see such differences.
“Our findings highlight the importance of preventing poor metabolic health,” study investigator Laurent Fauchier, MD, PhD, of Centre Hospitalier Universitaire Trousseau (France), observed in a press release that highlighted his EASD presentation.
“Encouraging weight loss in people with obesity, regardless of whether or not they are ‘metabolically healthy,’ will help prevent atrial fibrillation and heart failure,” he suggested.
‘Metabolically Healthy Obesity’ a Misnomer?
‘Metabolically healthy obesity’, or MHO, has been suggested as a term to describe those who have a body mass index greater than 30 mg/m2 but no obvious metabolic abnormalities, such as hypertension, dyslipidemia, or diabetes. It’s a term that could cover around a third of people with obesity, but it’s one that not everyone agrees with.
“I don’t feel the label ‘MHO’ is useful,” Frederick Ho, PhD, who is part of team at the University of Glasgow (Scotland) that has done similar research in a U.K. population, said in an interview.
“Even if – and this is a big if – [people with obesity] are at no higher risk of heart attack or stroke, they are still at higher risk of many other diseases, including heart failure and respiratory diseases. The term ‘healthy’ is sometimes interpreted as no additional health risk at all, which is not true,” Ho, a research fellow in public health, qualified.
Hospital Discharge Records Checked
For their analysis Fauchier and coinvestigators obtained the medical records of all patients who had been discharged from French hospitals in 2013 and who had at least 5 years’ worth of follow-up data. For inclusion, there had to be no prior history of major cardiovascular events (MACE), which included myocardial infarction (MI), heart failure, and ischemic stroke. Patients who were underweight or malnourished were excluded.
In all, around 2.8 million patients were included for the analysis, of whom 9.5% (n = 272,838) were classified as being obese and the remainder as ‘nonobese’ (n = 2,600,201). Patients were then subdivided according to whether they had diabetes, hypertension, and hyperlipidemia, with those who did not have any of these conditions being classified as ‘metabolically healthy’ and those who had all three as ‘metabolically unhealthy.’
The results, published in Diabetes, Obesity and Metabolism, showed that just under a third (32.8%) of the obese patients were ‘metabolically healthy,’ compared with 72.7% of those who were not obese.
The adjusted hazard ratio (aHR) for experiencing MACE with heart failure was 1.22 comparing those who were obese and ‘metabolically healthy’ with those who were not obese and had no metabolic abnormalities (95% confidence interval, 1.19-1.24). Corresponding aHRs for new-onset heart failure and new-onset atrial fibrillation were 1.34 (CI, 1.31-1.37) and 1.33 (CI, 1.30-1.37). For MI, ischemic stroke, and cardiovascular death aHRs were a respective 0.92 (CI, 0.87-0.98), 0.93 (CI, 0.88-0.98), and 0.99 (CI, 0.93-1.0).
Findings Consistent With UK Biobank Data
While these are observational associations that do not show cause and effect, they do agree with other recently published data from the UK Biobank as Ho pointed out. These data are “quite interesting and partly consistent with what we found previously, e.g., a higher heart failure risk,” he said.
“We’d expect people with ‘metabolically healthy’ obesity to develop heart attack and stroke a little later than those who were initially metabolically unhealthy,” Ho noted, observing that the study was very large, but it does has a relatively short period of follow up.
“This is partly because quite a few of those with ‘MHO’ would become metabolically unhealthy after a few years,” Ho added.
Importantly, he noted, “this study has omitted several important confounders, such as physical activity and diet, which are both strong predictors of MHO and cardiovascular outcomes.”
Naveed Sattar, FMedSci, FRCPath, FRCPGlas, FRSE, professor and honorary consultant in cardiovascular and medical sciences at the University of Glasgow, with whom Ho has collaborated, gave his thoughts on the topic in an interview.
“Carrying excess weight can give considerable risks for conditions such as heart failure or respiratory disease in ways (not yet fully understood) that are not captured by metabolic health factors,” he said.
“This means that even if someone were to be labeled as living with metabolically healthy obesity, losing weight may still benefit that individual in many ways and reduce their risk of several other important health outcomes. They may also feel better.”
Furthermore, he added: “Our Glasgow team has therefore strongly cautioned on the use of the term metabolically healthy obesity, and these new data do not change our view.”
Fauchier has acted as a speaker or consultant for AstraZeneca, Bayer, Bristol Myers Squibb Pfizer, Boehringer Ingelheim, Medtronic, Novartis, and XO. Ho had no relevant conflicts of interest. Sattar has received grants and personal fees from Boehringer Ingelheim, and personal fees from Amgen, AstraZeneca, Eli Lilly, Merck Sharp & Dohme, Novartis, Novo Nordisk, Pfizer, and Sanofi.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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