Body Mass Index Significantly Impacts Outcomes of Colorectal Surgery.

There are limited data regarding the association between body mass index (BMI) and colorectal surgery outcomes. We sought to evaluate the effect of BMI on short-term surgical outcomes in colon and rectal surgery patients in the United States. The American College of Surgeons National Surgery Quality Improvement Project database was used to identify all patients who underwent colon or rectal resection from 2005 to 2013. Multivariate regression analysis was used to assess the independent effect of BMI on outcomes. A total of 206,360 patients underwent colorectal resection during the study period. Of these, 3.2 per cent of patients were underweight (BMI < 18.5), 23.8 per cent patients were normal weight (18.5 ≤ BMI < 25), 26.5 per cent were overweight (25 ≤ BMI < 30), 25.2 per cent were obese (30 ≤ BMI < 40), and 5.3 per cent were morbidly obese (BMI ≥ 40). Underweight patients had longer length of stay (confidence interval: 2.70-3.49, P < 0.001) and higher mortality (adjusted odds ratio: 1.45, P < 0.01) compared with patients with a normal BMI. Morbidly obese patients had the highest overall morbidity rate compared with normal BMI patients (adjusted odds ratio: 1.53, confidence interval: 1.42-1.64, P < 0.01). BMI is associated with outcomes in colon and rectal surgery patients. Underweight and morbidly obese patients have a significantly increased risk of postsurgical complications compared with those with normal BMI.