Neville et al evaluated risk factors associated with mortality in patients with blunt trauma. They were able to demonstrate that obesity impacts on outcome. The authors are from the University of Southern California in Los Angeles.


Patient selection: blunt trauma, apparently in adults


body mass index in kg per square meter =

= (body weight in kilograms) / ((body height in meters)^2)


Independent risk factors for mortality:

(1) severe head injury (approximate mean odds ratio 35)

(2) pulmonary contusion (approximate mean odds ratio 10)

(3) obesity (defined as BMI >= 30 kg per square meter) (approximate mean odds ratio 6)

(4) injury severity score > 20 (approximate mean odds ratio 5)

(5) age > 55 years (approximate mean odds ratio 1.6)



• 37% of patients were from automobile accidents. Pulmonary contusions would indicate significant blunt trauma to the thorax.

• It would be interesting to see if there are higher risk subgroups associated with age, such as > 70 years of age.

• The odds ratio of mortality for moderate head injury might be helpful in using the data.

• The mortality rate for entire population was 20%.

• Multiple organ failure is at least 2 times more common in an obese patient vs a nonobese one.


One possible way to use this information is the following untested table:

Possible Combinations

Mortality Risk

severe head injury and any other risk factor

very high

pulmonary contusion and 3 of items #3 to #5

very high

severe head injury


pulmonary contusion and 2 of items #3 to #5


all 3 items #3 to #5


pulmonary contusion and 1 item from #3 to #5

moderate to high

2 items from #3 to #5


pulmonary contusion alone


1 item from #3 to #5

low to moderate


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