Impact of BMI on Postoperative Outcomes in Patients Undergoing Proctectomy for Rectal Cancer: A National Surgical Quality Improvement Program Analysis

BACKGROUND: There is a mounting body of evidence that suggests worsened postoperative outcomes at the extremes of BMI, yet few studies investigate this relationship in patients undergoing proctectomy for rectal cancer. OBJECTIVE: We aimed to examine the relationship between BMI and short-term outcomes after proctectomy for cancer. DESIGN: This was a retrospective study comparing the outcomes of patients undergoing proctectomy for rectal cancer as they relate to BMI. SETTINGS: The American College of Surgeons-National Surgical Quality Improvement Program database was queried for this study. PATIENTS: Patients included were those who underwent proctectomy for rectal neoplasm between 2005 and 2011. MAIN OUTCOME MEASURES: Study end points included 30-day mortality and overall morbidity, including the receipt of blood transfusion, venous thromboembolic disease, wound dehiscence, renal failure, reintubation, cardiac complications, readmission, reoperation, and infectious complications (surgical site infection, intra-abdominal abscess, pneumonia, and urinary tract infection). Univariate logistic regression was used to analyze differences among patients of varying BMI ranges (kg/m(2); 20, 20-24, 25-29, 30-34, and 35). When significant differences were found, multivariable logistic regression, adjusting for preoperative demographic and clinical variables, was performed. RESULTS: A total of 11,995 patients were analyzed in this study. The incidences of overall morbidity, wound infection, urinary tract infection, venous thromboembolic event, and sepsis were highest in those patients with a BMI of 35 kg/m(2) (OR, 1.63, 3.42, 1.47, 1.64, and 1.50). Wound dehiscence was also significantly more common in heavier patients. Patients with a BMI <20 kg/m(2) had significantly increased rates of mortality (OR, 1.72) and sepsis (OR, 1.30). LIMITATIONS: This study was limited by its retrospective design. Furthermore, it only includes patients from the American College of Surgeons-National Surgical Quality Improvement Program database, limiting its generalizability to nonparticipating hospitals. CONCLUSIONS: Obese and underweight patients undergoing proctectomy for neoplasm are at a higher risk for postoperative complications and death.