Background: As the impact of obesity on surgical outcomes after colorectal resection is not well known, this study was designed to compare the results of colorectal resection in obese and nonobese patients.

Methods: From 1990 to 1997, 584 consecutive patients underwent elective colorectal resection in our department. Of these, 158 (27%) were obese (body mass index >27). Obese and nonobese patients were well matched for demographic data and surgical procedures.

Results: After right or left colectomy, no difference was noted between obese and nonobese patients for overall mortality, morbidity, or leakage rates. However, after left colectomy, postoperative intra-abdominal collections requiring treatment were significantly more frequent in obese than in nonobese patients (10% versus 2%; P <0.05). After proctectomy, the mortality rate was 5% (3 of 61) among obese patients and 0.5% (1 of 185) among nonobese patients (P <0.02). The anastomotic leakage rate was 16% (5 of 58) for obese patients and 6% (11 of 169) for nonobese patients (P <0.05), and the corresponding proportions of transfused patients were 43% and 19%, respectively (P <0.02). After proctectomy, multivariate analysis showed that for obese patients, diabetes mellitus (P <0.05) and American Society of Anesthesiologists (ASA) status >2 (P <0.05) were significant risk factors for anastomotic leakage; age >60 years (P <0.01) and ASA status >2 (P <0.05) were significant risk factors for perioperative blood transfusions.

Conclusions: Our study suggested that, for obese patients, (1) right colectomy can be performed in the same manner as for nonobese patients; (2) after left colectomy, abdominal drainage may be indicated, and (3) after proctectomy, a defunctioning stoma should be recommended when diabetes mellitus or ASA status >2 is present, and an autologous blood transfusion could be discussed for patients >60 years old or with ASA status >2.