Effect of body mass index on short-term outcomes after colectomy for cancer

Obesity is associated with an increased risk of postoperative complications after colectomy for cancer, but it is unclear which specific complications occur more frequently in obese patients. Our objective was to assess the association of body mass index (BMI) on short-term outcomes after colectomy for cancer.

Using the American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) dataset, we identified patients who underwent colectomy for malignancy at 121 hospitals. Logistic regression models were developed to assess risk-adjusted 30-day outcomes by BMI while adjusting for preoperative risk factors.

There were 3,202 patients identified: 33.4% normal weight (BMI 18.5 to 24 kg/m(2)), 35.1% overweight (BMI 25 to 29 kg/m(2)), 19.0% obese (BMI 30 to 34 kg/m(2)), and 12.4% morbidly obese (BMI>/=35 kg/m(2)). Compared with normal weight patients, complications occurred more frequently in the morbidly obese (31.8% versus 20.5%, odds ratio [OR] 1.75, 95% CI 1.33 to 2.31). Specifically, the morbidly obese had a higher risk of surgical site infection (20.7% versus 9.0%; OR 2.66, 95% CI 1.91 to 3.73), dehiscence (3.3% versus 1.1%; OR 3.51, 95% CI 1.55 to 7.95), pulmonary embolism (1.3% versus 0.3%; OR 6.98, 95% CI 1.62 to 30.06), and renal failure (3.0% versus 1.5%; OR 2.75, 95% CI 1.21 to 6.26). Pneumonia, urinary tract infection, stroke, cardiac arrest, myocardial infarction, deep venous thrombosis, length of stay, sepsis, and 30-day mortality did not differ significantly by BMI.

Compared with normal weight patients, morbidly obese patients had a higher risk of surgical site infection, dehiscence, pulmonary embolism, and renal failure, but not other complications or mortality. Quality initiatives should include these specific complications.