High BMI Is Associated with Greater Postoperative Infection Risk after Open GI Surgery

Researchers have been interested for quite some time in the influence of high body mass index (BMI) on the risk for postsurgical complications following open gastrointestinal (GI) surgery. A leading concern is that open GI surgery usually interferes with patients' nutritional intake, since vomiting, diarrhea, and malabsorption before the operation (and insufficient nutrition after) are common. This symptom constellation might also weaken the immune system and increase the risk of postoperative complications. In addition, obese patients usually have thick abdominal fat. After surgery, sagging skin and fat liquefaction create new problems, and complications increase as visceral fat increases. Subsequent postoperative infectious complications would also increase the length of the hospital stay.

Studies have reported mixed results about postoperative outcomes in patients with high BMI. The American Journal of Infection Control has published a meta-analysis designed to resolve this controversy.

The inclusion criteria defined high and normal BMIs as ≥25 and 18.5-24.99, respectively. These analysts identified mortality as their primary outcome measures and infectious outcomes (surgical site, pulmonary, and urinary tract) as the secondary outcome.

They ultimately found 11 studies eligible for meta-analysis that had enrolled 51,307.

High BMI did not increase the risk of 30-day mortality. Previous studies that looked at hepatic resection reported similar results−no increased mortality.

The likelihood of infection was significantly higher, however, in patients who were obese. High-BMI patients were 1.7 times more likely to develop and infections of the surgical site and 1.2 times more likely to develop a pulmonary infection. Urinary tract infections occurred at the same rate regardless of BMI. The analysts report that in high-BMI patients, surgery usually took longer and this in itself may have contributed to increased risk of infection.

The analysts recommend using preventive measures and monitoring high BMI patients closely after surgery.