Obesity in general elective surgery

Obese patients are generally believed to be at a higher risk for surgery than those who are not obese, although convincing data are lacking. Methods We prospectively investigated a cohort of 6336 patients undergoing general elective surgery at our institution to assess whether obesity affects the outcome of surgery. Exclusion criteria were emergency, vascular, thoracic, and bariatric operations; transplantation procedures; patients under immunosuppression; and operations done under local anaesthesia. Postoperative morbidity was analysed for non-obese and obese patients (body-mass index <30 kg/m2 vs 3=30 kg/m2). Obesity was further stratified into mild obesity (30•0–34•9 kg/m2) and severe obesity ( 35kg/m2). Risk factors were analysed with univariate and multivariate models. Findings The cohort consisted of 6336 patients, of whom 808 (13%) were obese, 569 (9%) were mildly obese, and 239 (4%) had severe obesity. The morbidity rates in patients who were obese compared with those who were not were much the same (122 [15•1%] of 808 vs 901 [16•3%] of 5528; p=0•26), with the exception of an increased incidence of wound infections after open surgery in patients who were obese (17 [4%] of 431 vs 92 [3%] of 3555, p=0•03). Incidence of complications did not differ between patients who were mildly obese (91 [16•0%] of 569), severely obese (36 [15•1%] of 239), and non-obese (901 [16•3%] of 5528; p=0•19). In multivariate regression analyses, obesity was not a risk factor for development of postoperative complications. Of note, the additional medical resource use as estimated by a new classification of complications showed no differences between patients who were and were not obese. Interpretation Obesity alone is not a risk factor for postoperative complications. The regressive attitude towards general surgery in obese patients is no longer justified.