A study from Brigham and Women’s hospital in Boston in the April issue of The Journal of the American College of Surgeons demonstrated that body fat percentage (BF %) as measured by bioelectrical impedance, markedly outperformed body mass index (BMI) as a predictor of postoperative surgical site infections. Obesity measured by BF% was associated with five times the risk of surgical site infections postoperatively compared to non-obese patients. BMI measurements of obesity were unable to accurately predict an increased risk of postoperative infections. BF% also identified almost twice as many patients as obese, therefore at greater risk, compared to BMI measurements.
Dr. Blackshear’s Comment:
This study demonstrates once again that BF% is a much more sensitive clinical tool for identifying patients who are at increased risk from obesity. It has long been recognized that BMI can be elevated for reasons other than obesity. For example, individuals with significant muscularity may be identified as obese by BMI when in fact their body fat percentage is low. We have long relied upon BF%, as measured by bioelectrical impedance, to identify patients who will benefit from significant weight loss.