Slim Is Not Necessarily Always Healthy in Heart Failure Risk

September 13, 2011

September 12, 2011 (Athens, Greece) — Greek researchers have demonstrated, for the first time, that normal-weight individuals with metabolic syndrome had an increased risk of developing heart failure compared with obese people who were metabolically healthy [1]. They report their findings in the September 20, 2011 issue of the Journal of the American College of Cardiology.

Lead author Dr Christine Voulgari (Athens University Medical School, Greece) told heartwire : "A lot has been written about the 'obesity paradox.' What makes our study unique is that we have shown the clinical translation of this in our prospective, but observational, study." But she adds that "a lot of work still needs to be done in order to explain what makes this phenotype--obese but metabolically healthy--unique."

In an accompanying editorial [2], Dr Eileen Hsich (Cleveland Clinic, OH) says, "The paper by Voulgari et al nicely demonstrates that metabolic syndrome better correlates with the development of heart failure than body-mass index [BMI]."

Presence of Metabolic Syndrome Ups HF Risk by More Than Twofold

Voulgari said she was inspired to conduct her study because normal-weight patients with heart failure would ask her why they were suffering with heart problems despite being a healthy size, when some obese people did not have any cardiac concerns.

She and her colleagues studied 550 individuals without diabetes or baseline macrovascular complications for a median of six years. Participants were classified by the presence (n=271) or absence (n=279) of metabolic syndrome and by BMI. A BMI of 25 kg/m2 or less was classified as normal weight (n=177), a BMI of 25 to 29 kg/m2 was overweight (n=234), and a BMI of >30 kg/m2 was categorized as obese (n=139).

The researchers showed that, after adjustment for other well-known cardiovascular risk factors, BMI was not associated with increased heart-failure risk. The presence of metabolic syndrome did confer around a 2-to 2.5-fold higher HF risk, however.

Compared with normal-weight individuals without metabolic syndrome, overweight and obese individuals without metabolic syndrome had the lowest six-year risk of HF (hazard ratio 1.12 and 0.41, respectively) while normal-weight people with the metabolic syndrome had one of the highest risks of HF (HR 2.33; p<0.001).

The Presence of Metabolic Syndrome, BMI, and HF Incidence During Six Years of Follow-Up

BMI group Metabolic syndrome n Pre-incidence of HF (%) Adjusted HR* p
Normal No 109 15.6 1.00 -
Normal Yes 68 63.2 2.33 0.007
Overweight No 127 14.2 1.12 0.36
Overweight Yes 107 47.7 2.66 <0.001
Obese No 43 9.3 0.41 0.49
Obese Yes 96 54.2 2.13 0.002

*Adjusted for all factors associated with HF incidence: age, sex, impaired glucose tolerance, dyslipidemia, current cigarette smoking, physical inactivity, left ventricular hypertrophy and function on echo, high fasting glucose (>100 mg/dL), high BP (>130/85 mm Hg), waist circumference >102 cm in men or >88 cm in women, low HDL cholesterol (<40 mg/dL in men and <50 mg/dL in women), high triglyceride level (>150 mg/dL), and microalbuminuria

It's Not Okay to Be Fat, But Don't Be Complacent if You're Slim

Voulgari stressed to heartwire that she didn't want patients "to get the wrong impression. We showed that obese patients with metabolic syndrome also had an increased incidence of heart failure," and in fact those who were overweight with metabolic syndrome had the highest risk of developing HF.

Thus, it's only the "specific phenotype" of the obese individual without metabolic syndrome who appears to have a lower risk of HF. "These overweight or obese people without metabolic syndrome managed to exercise more and probably had better diet profiles [than the normal-weight people with metabolic syndrome], and they didn't have hypertension, dyslipidemia, or prediabetes," she observes.

In her editorial, Hsich questions how the information from this new study should be incorporated into daily medical practice. She wonders whether doctors should tell obese people that eating cheeseburgers and french fries is okay as long as they don't meet the criteria for metabolic syndrome, for example.

She thinks not, observing that while middle-aged obese people may often be comparatively healthy, this phenomenon does not appear to translate into old age, it being rare to see healthy elderly obese men and women.

Not that it's okay to be fat, but if you are slim, you should still take care of your health.

Voulgari says: "The important message here is not just to concentrate on losing weight but to see the whole picture. Our study addresses the contemporary question, 'You are slim, but is your heart fat?' Not that it's okay to be fat, but if you are slim, you should still take care of your health."

And the findings, she stresses, indicate the importance of the metabolic syndrome "as a highly prognostic marker of future HF risk, whereas obesity alone appears to confer little independent value in cardiovascular risk stratification."

"Appropriate medical treatment of hypertension, dyslipidemia, and hyperglycemia in those at risk of HF is an essential component of prevention," she and her colleagues conclude.

Neither the authors nor the editorialist have conflicts of interest.

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