CARDIOMETABOLIC CHRONICLE: Could some of the obesity paradox then be attributed to heavily relying on BMI to evaluate obesity?
DR. CARBONE: At a population level, BMI remains a very good marker of adiposity and it still remains a strong predictor for the development of cardiometabolic disease.10 However, in some conditions BMI is just not enough. Patients with heart failure for instance, have continuous changes in fluid status, which is unfortunately part of the pathophysiology of the disease which ultimately leads to increased risk for hospitalizations, and using BMI may often misclassify a patient as overweight or obese. Those are the setting in which I strongly believe we should really start looking at body composition, quality of the weight, how much of weight is fat, how much is fluid, and how much is muscle mass, rather than just focusing on total body weight and calculated BMI. To do this, however, you need some relatively sophisticated tools that not everybody has available in their practice, including devices to measure body composition, like bioelectrical impedance analysis (BIA), which is frequently being used in research and more recently also in clinical practice. Other tools involve dual-energy X-ray absorptiometry (DEXA), which is mostly used in research to estimate total body composition and segmental body composition (i.e., appendicular lean mass), and more sophisticated tools like magnetic resonance imaging (MRI) or computed tomography (CT) scans.