The impact of BMI on morbidity and mortality after femoral fractures

Femur fractures are the result of high energy injury and are associated with life-threatening complications. Therefore, we studied how body mass index (BMI) contributes to complications after femoral fractures.

Using the 2016 American College of Surgeons Trauma Quality Improvement Program (ACS TQIP) database, we stratified 41,362 patients into groups based on their BMI: Normal Weight (NW), Overweight (OW), Obese (OB), Severely Obese (SO), and Morbidly Obese (MO). We compared each BMI group to the NW cohort for differences in demographic factors, comorbidities, complications, and mechanism of injury.

OB, SO, and MO patients sustained higher rates of traumatic injury from high energy mechanisms, such as motor vehicle trauma, in comparison to NW patients, who sustained more injuries from falls (p < 0.05). Correspondingly, obese patients were more likely than NW patients to sustain shaft and distal end fractures (p < 0.05). At hospital admission, obese patients presented with more comorbidities, such as bleeding disorders, congestive heart failure, diabetes mellitus, and hypertension (p < 0.05). Despite these individual findings, patients with OB, SO, and MO BMI, as opposed to NW BMI, were independently associated with a higher probability of developing at least one post-trauma complication. More specifically, MO patients were associated with a 45% higher odds of developing a complication (p < 0.05).

Irrespective of presenting with more comorbidities and sustaining high energy injuries, OB, SO, and MO patients were independently associated with having a higher risk of developing complications following a femoral fracture. Overall, better clinical outcomes are observed among patients with no underlying conditions and normal BMI.