Weight Loss Before Bariatric Surgery
We read with great interest the study by Anderin et al1 in the December 2014 issue of Annals of Surgery. However, we believe that external validity of those findings is questionable, and we warn readers against an over-interpretation of these data. Indeed, the influence of nutritional status on postoperative morbidity and mortality has been well documented for years in both retrospective and prospective studies and decreased weight loss before a surgical procedure has been considered to be associated with a higher postoperative mortality rate.2–5 Consequently, the Anderin et al study conclusions are in full contradiction with all current recommendations endorsed by European and American6–9 guidelines based on an updated literature review.
In nonbariatric patients, Mullen et al10 have shown in a prospective, multi-institutional, risk-adjusted cohort study of 118,707 patients that patients undergoing general surgical procedures have paradoxically “lower” crude and adjusted risks of mortality compared with patients with “normal” preoperative weight. This study confirmed the existence of an “obesity paradox” in this subset of patient population. More recently, Khan et al11 showed in 44,408 patients from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database that independent predictive factors associated with significantly increased postoperative mortality included 10% weight loss during the 6 months before bariatric procedure (AOR,13.5). Furthermore, an important proportion of obese surgical patients have sarcopenic obesity at operation, with relative low levels of lean body mass despite a large body habitus. This means that those patients are at higher risk of major perioperative complications and mortality.12 In conclusion, we believe that systematic preoperative weight loss before bariatric surgery could lead to an increased postoperative mortality rate and could end up with a counter-intuitive postoperative effect.