Obesity and the ICU with Mike Margarson

Mike Margarson, from St Richard’s Hospital in Chichester opens his talk with a reflection of our appetite at lunchtime!

First point… obesity takes years off an individuals life in the long term. But does it cause short term problems?

“Watch out for the apples”. Central obesity is much more harmful than peripheral “pear” obesity. Central obesity is a pro-thrombotic and pro-inflammatory condition, which isn’t necessarily seen in peripheral obesity. The difficulty of obesity research is that it hasn’t discriminated between these two different obesity states.

Is there a link between BMI and mortality?

Mike presents various scientific papers with the summary that there is a survival benefit from being slightly overweight: the Obesity Paradox.

Bochiccio has demonstrated a 7-fold increase in risk of hospital mortality in trauma patients with BMI > 30.

Straw poll of the audience… how many actually weigh and measure height of our patients? Just a scattering of hands go up. Any yet this data is entered into ICNARC. Are our estimates good enough?

ICNARC shows that a higher BMI is associated with a lower APACHE 2 – obese admissions are less sick. As expected, higher BMI is associated with longer mechanical ventilation duration. And again, the lowest (crude) mortality is seen in BMI 40–49.9 cohort. When this data is subgrouped by age, we see that youth does not protect: being underweight increases mortality risk regardless of age.


  • Moderate obesity is protective in Critical Illness
  • Being underweight is bad
  • Outcomes of those over BMI 50 is not clear, and existing data do not take into account the different fat distributions

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