Effect of Body Mass Index on Short-Term Outcomes after Colectomy for Cancer Ryan P Merkow, MD, Karl Y Bilimoria, MD, MS, Martin D McCarter, MD, FACS, David J Bentrem, MD, FACS BACKGROUND: 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. STUDY DESIGN: 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. RESULTS: 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. CONCLUSIONS: 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. (J Am Coll Surg 2009;208:53–61. © 2008 by the American College of Surgeons) Obesity is a growing worldwide epidemic. Compared with nonobese patients, obese patients are more likely to de- velop and die from colon cancer. 1 In the US, colon cancer is the fourth most commonly diagnosed cancer and is the second leading cause of cancer death. Surgical intervention remains the primary treatment modality, but resection con- tinues to be associated with appreciable morbidity and mortality. 2 Reports have suggested that obese patients undergoing colectomy have higher postoperative morbidity and mor- tality. 3,4 But most of these studies have been unable to examine differences in the frequency of specific complica- tions based on body mass index (BMI), primarily because of small sample sizes and inconsistent definitions. Quality initiatives focused on complications for obese patients after bariatric surgery are being considered, but they may not be applicable to obese patients undergoing colectomy for cancer. 5 The objective of this study was to assess the impact of BMI with short-term outcomes after colectomy for cancer using the American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) database, which provides a large sample of prospectively collected data from 121 hospitals in the US. Specifically, we sought to identify complications that occur more frequently in obese patients to identify specific target areas for quality Disclosure Information: Nothing to disclose. Supported in part by a grant from the American Cancer Society, Illinois Division, Inc, to Dr Bentrem. Abstract presented at the American College of Surgeons 94th Annual Clinical Congress, Surgical Forum, San Francisco, CA, October 2008. Received June 24, 2008; Revised August 27, 2008; Accepted August 27, 2008. From the Departments of Surgery, University of Colorado Denver School of Medicine, Aurora, CO (Merkow, McCarter) and Northwestern University, Feinberg School of Medicine, Chicago, IL (Bilimoria, Bentrem). Correspondence address: Karl Y Bilimoria, MD, MS, Department of Surgery, Feinberg School of Medicine, Northwestern University, 251 E Huron St, Galter 3–150, Chicago, IL 60611. 53 © 2008 by the American College of Surgeons ISSN 1072-7515/09/$36.00 Published by Elsevier Inc. doi:10.1016/j.jamcollsurg.2008.08.032