BMI called into question as a measure of risk in heart failure

Nothing works without the heart: the approximately fist-sized organ located within our chest beats around 100,000 times a day and pumps roughly 10,000 liters of blood around the body. This organ ensures that nutrients and oxygen are distributed throughout the body and waste materials are removed. When the heart does not perform as well as it used to, the consequences can be far-reaching. This is referred to as heart failure. The causes of heart failure can be diverse, yet obesity plays an important role in most cases, especially in heart failure with preserved ejection fraction (HFpEF, approximately half of all cases of heart failure). In the past, BMI has often been used as the basis for assessment, but now Alexander Peikert of Med Uni Graz has explored another parameter that is more suitable for evaluating HFpEF risk. The cardiologist has received the renowned Desmond Julian Award, one of the most prestigious international prizes for cardiology research.

The problem with BMI

Until now, obesity has mainly been assessed in clinical practice using BMI. BMI compares body weight and height yet says very little about how fat is distributed throughout the body. For example, it does not differentiate between adipose tissue, muscle and bone mass, and it cannot adequately record belly fat accumulation, which has a particular impact on health.

"A modern alternative that is easy to determine is waist-to-height ratio (WHtR). It compares waist circumference to height and provides an indication of how much fat is concentrated in the belly," explains Alexander Peikert. The goal of Peikert's study was to investigate how BMI and WHtR are associated with further disease progression and especially with heart failure-related hospitalizations.

Wide-ranging analysis

Peikert examined 4,796 patients with heart failure with preserved ejection fraction from the international PARAGON-HF study. Based on BMI, 49 percent of the patients were obese. However, if central fat distribution based on WHtR was considered, 96 percent exhibited central obesity, or accumulation of body fat around the belly. "Especially remarkable was that of the patients not considered obese according to their BMI, 37 percent had significant belly fat and thus a higher risk of heart failure. WHtR was more strongly associated with the risk of hospitalization due to heart failure than BMI. In addition, the so-called "obesity paradox" is not apparent with WHtR, which can be observed when BMI is used," says Peikert, summarizing the findings. The obesity paradox is a phenomenon observed in epidemiological studies that may falsely suggest that people who are overweight based on their BMI have a higher survival rate than patients whose weight is normal with regard to certain diseases.

"The findings question the previous heavy emphasis on BMI. When obesity and cardiovascular risk are assessed in HFpEF patients, the focus should no longer be exclusively on how much a person weighs but on where fat is located in the body. WHtR might be a simple and more meaningful measure here," concludes Peikert.

Furthermore, the study indicated that nearly all patients with HFpEF had central obesity. This calls into question the previous idea that belly fat is only significant in a certain subgroup of HFpEF patients. Instead, central obesity might be a fundamental feature of this type of heart failure.

International recognition

For this publication, Alexander Peikert received the renowned Desmond Julian Award from the European Heart Journal, the flagship journal of the European Society of Cardiology. The editor-in-chief and executive editors made the selection based on criteria such as originality, scientific quality, methodological excellence, clinical relevance and scientific influence. One of the most internationally acclaimed honors for a single original scientific paper in cardiology, the award recognizes papers that have made a special contribution to the advancement of the specialty area.

Profile: Alexander Peikert

Alexander Peikert is a specialist in internal medicine and cardiology. He works at the Med Uni Graz Division of Cardiology in clinical care and research with a focus on heart failure and cardiometabolic disease. The cardiology outpatient clinic and its associated research programs are points of contact and counseling centers for patients with cardiovascular and cardiometabolic risk factors.

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