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If we were sitting with two patients who had coronary heart disease (CHD), possibly post myocardial infarction, 20 years ago, and one had a body mass index (BMI) of 23 kg/m2, or ‘normal’ BMI, and the other had a BMI of 32 kg/m2, or class I obesity, we would have likely been much more concerned about the short-term and long-term prognosis in the heavier patient. However, during the past 15 years, considerable evidence from our own studies and meta-analyses tell us that we were not just incorrect, but actually flat out wrong regarding our prognostication in these two patients!1–3 Using a meta-analysis of 89 studies in over 1.3 million patients with established CHD, by far the largest of such studies, Wang et al4 confirmed the information from prior studies, and provided several important new observations on this interesting and controversial topic.
How can obesity be protective?
When we (CJL, RVM) and others first made these observations 15 years ago, about the obesity paradox in heart failure (HF), there were concerns that there may be fatal flaws in our data. Certainly, excess body weight is associated with adverse effects on cardiovascular (CV) risk factors, including hypertension (HTN), lipids, glucose and inflammation, and is associated with an increased risk of almost all CV diseases (CVD), including HTN, CHD, HF and atrial fibrillation.1–3 Therefore, no expert to our knowledge is suggesting that obesity is a ‘good thing’, and support for the obesity paradox does not make this claim. However, 15 years later, it is hard to deny the fact that at least mild increases in BMI in patients with CVD appear to be associated with a better prognosis than noted in patients with low BMI.
Is BMI the problem?
As Wang et al4 alluded to, some have suggested that since BMI includes total …