The obesity factor in critical illness: Between consensus and controversy

The prevalence of obesity has increased starkly during the last decades, and this trend includes every age, sex, race and socioeconomic group.(1,2) According to the most recent epidemiologic data,(1,2) approximately two thirds of the US population are either overweight or obese, of whom approximately 30% are obese and more than 5% are morbidly obese. Although some reports suggest that the trend of obesity may have begun to stabilize within some segments of the US population,(3) other studies project that obesity prevalence will continue to worsen, with as many as 50% of Americans potentially being obese by the year 2030.(4) Obesity has been linked to increased mortality resulting from acute and chronic comorbidities including diabetes, stroke, and cardiovascular diseases (CVDs).(5) The epidemic of obesity also has reached the intensive care unit (ICU), such that 33% of ICU patients are obese and 7% are morbidly obese.(6) Consequently, obesity complicates all aspects of health care in the ICU by increasing the complexity of management, nutritional support, and changes in the pattern of comorbidities.(7) Furthermore, obesity induces anatomic and physiologic changes that may interfere with the body response to injury and complicate any hospitalization.(7) In this article, we will review recent studies that have examined the impact of obesity in critical illness.