The effects of body mass index on complications and mortality after emergency abdominal operations: The obesity paradox

Am J Surg. 2017 Nov;214(5):899-903. doi: 10.1016/j.amjsurg.2017.01.023. Epub 2017 Feb 13.


Background: Recent literature suggests that obesity is protective in critically illness. This study addresses the effect of BMI on outcomes after emergency abdominal surgery (EAS).

Methods: Retrospective, ACS-NSQIP analysis. All patients that underwent EAS were included. The study population was divided into five groups based on BMI; regression models were used to evaluate the role of obesity in morbidity and mortality.

Results: 101,078 patients underwent EAS; morbidity and mortality were 19.5% and 4.5%, respectively. Adjusted mortality was higher in underweight patients (AOR 1.92), but significantly lower in all obesity groups (AOR's 0.73, 0.66, 0.70, 0.70 respectively). Underweight and class III obesity was associated with increased complications (AOR 1.47 and 1.30), while mild obesity was protective (AOR 0.92).

Conclusions: Underweight patients undergoing EAS have increased morbidity and mortality. Although class III obesity is associated with increased morbidity, overweight and class I obesity were protective. All grades of obesity may be protective against mortality after EAS relative to normal weight patients.

Keywords: Body mass index; Emergency abdominal surgery; Obesity.

MeSH terms

  • Abdomen / surgery*
  • Body Mass Index*
  • Emergency Treatment*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Obesity / classification
  • Obesity / complications*
  • Postoperative Complications / epidemiology*
  • Postoperative Complications / etiology*
  • Postoperative Complications / mortality
  • Retrospective Studies
  • Thinness / complications*