Is There an Obesity Paradox in Cardiogenic Shock?

Abstract

Obesity has reached epidemic levels in the United States and in much of the Westernized world.1– 3 The majority of the US population is now either overweight or obese (75%), and 42% meet the current body mass index criteria (BMI ≥30 kg/m2) for obesity, with 9% meeting criteria for severe, class III obesity (formerly called morbid obesity with a BMI ≥40 kg/ m2 or a BMI of 35 kg/m2 or higher and experiencing obesityrelated health conditions).1 Obesity adversely influences cardiovascular diseases (CVD) by its intersection with major CVD risk factors, including worsening of arterial pressure and glucose intolerance, thus leading to metabolic syndrome and diabetes and worsening lipids, especially triglyceride levels. Not only is obesity associated with worsening inflammation, but it also increases the prevalence of hypertension and coronary heart disease, all of which conspire to cause heart failure (HF). Thus, obesity increases the risk of HF, especially HF with preserved ejection fraction (EF) more so than HF with reduced EF. As reviewed elsewhere3,4 obesity is associated with development of atrial fibrillation, worsened renal function, venous thromboembolism, and respiratory illness, all of which alone and together can worsen HF prognosis. Despite the increased health risks associated with obesity, considerable focus has centered on the “obesity paradox” (wherein individuals with overweight or obesity and CVD have a better shortand mediumterm prognosis than do leaner patients with the same degree of disease) among patients with CVD, endstage renal disease, pulmonary diseases (including chronic obstructive pulmonary disease), and complications from infections.2,3,5– 8 Particularly, an obesity paradox has been noted with both HF with reduced EF and HF with preserved EF, manifest by a lower overall and CVDmortality in people who are overweight or mildly obese, whereas hospitalizations seem to be increased as obesity progresses to severe.9,10 In advanced stages of HF and especially in states of therapy for such a condition such as use of left ventricular assist devices or heart transplantation, the presence of obesity perpetuates complications and worsens survival.11,12 Similarly, an obesity paradox has not been demonstrated in cardiogenic shock. Recently, Sreenivasan and colleagues13 did not find an obesity paradox in a large US population of cardiogenic shock (CS) compared with those who were nonobese, and moderate and severe obesity had progressively higher mortality.13,14 In this issue of the Journal of the American Heart Association (JAHA), Kwon and colleagues15 studied 1227 patients with CS from a South Korean registry and classified patients as obese (BMI ≥25 kg/m2 based