Elective surgery in adult patients with excess weight: Can preoperative dietary interventions improve surgical outcomes?

Abstract

Background: Excess fat can complicate surgery and is a risk factor for postoperative complications, and dietitians are being asked to assist patients to lose weight preoperatively. Aim: To summarise the literature regarding the impact of preoperative dietary interventions on non-bariatric surgery outcomes for patients with excess weight or obesity. Methods: PRISMA guidelines were followed, and four electronic databases were searched for non-bariatric surgery studies, which evaluated surgical outcomes resulting from a preoperative dietary intervention that focused on weight loss, fat loss, or improvement of liver steatosis. Results: Fourteen studies, including five randomised controlled trials, were selected. Laparoscopic cholecystectomy, hernia repair, and liver resection were most studied. Diet duration was 1–68 weeks (median 9 weeks). Weight loss ranged from 1.4 to 25 kg. Preoperative very low calorie diet (≤800 kcal) or low calorie diet (≤900 kcal) for one to 3 weeks resulted in: reduction in blood loss for two liver resection and one gastrectomy study (−27 to −411 ml, p < 0.05), and for laparoscopic cholecystectomy, reduction of 6 min in operating time (p < 0.05) and reduced difficulty of aspects of procedure (p < 0.05). There was no difference in length of stay (n = 7 studies). No consensus was found regarding other surgical outcomes, as studies examining the same surgery types were too few and reporting of outcomes too inconsistent. Conclusions: Preoperative ≤900 kcal diets for one to three weeks could improve surgical outcomes for laparoscopic cholecystectomy, liver resection, and gastrectomy. Multiple randomised controlled trials with common surgical outcomes are required to establish impact on other surgeries.