Is Obesity Critical in Critical Care?

Although obesity is now well-recognized as a risk factor for the development of many chronic diseases, its role in acute situations is less clear.

So while one might assume that severe obesity in critical ill patients is a predictor of poor outcomes, this hypothesis was not confirmed in a recent meta-analysis of studies comparing outcomes in obese (BMI > 30 kg/m2) critically ill patients in intensive care settings published by Akinnusi and colleagues from the University of Buffalo School of Medicine in the January issue of Critical Care Medicine (for Abstract click here).

Fourteen studies with 15,347 obese patients met inclusion criteria. Surprisingly, obesity was not associated with an increased risk of intensive care unit mortality, albeit duration of mechanical ventilation and intensive care unit length of stay were statistically but not remarkably longer in the obese group.

Interestingly, in a subgroup analysis, an improved survival was observed in obese patients with body mass index ranging between 30 and 39.9 compared with nonobese patients (relative risk, 0.86; 95% Cl, 0.81-0.91; p < .001). This latter finding is reminiscent of the "obesity survival paradox” alluded to in previous blogs.

Clearly, obesity is not a significant risk factor for poor survival outcomes in critical care. Whether or not this also applies to the subset of extremely obese patients that are now increasingly seen in hospital settings remains to be seen.