Effects of preoperative weight loss with a very low calorie diet (VLCD) on weight loss after biliopancreatic diversion in patients with severe obesity

Abstract

Weight loss before bariatric surgery, achieved by means of a very low calorie diet (VLCD) has been recently reported to be related to a lower rate of postoperative complications. However, it is controversial if preoperative weight loss after VLCD could improve postoperative weight loss. To assess the effectiveness of a preoperative VLCD for 6 weeks in weight loss one year after bariatric surgery. To evaluate the changes obtained in anthropometric measures and biochemical parameters after VLCD. Prospective uncontrolled study including severely obese patients undergoing biliopancreatic diversion in our Obesity Unit in 2008-2010. Patients included followed a VLCD providing 840 kcal and 60 g of protein (Optisource®). Descriptive data are presented as mean (standard deviation) and after checking a normal distribution is followed, they were analyzed by Student s T test, ANOVA or Pearson correlation. We evaluated 107 obese patients, 43.5 (10.2) years-old, 72% women, with initial weight 122.4 (18.6) Kg and BMI 46.8 (5.5) kg/m(2). 24.5% of them lost more than 10 % of initial weight and 73.5% more than 5% after following VLCD. Mean percentage of excess weight loss (% PSP) one year after surgery was 59.6 (13.4)%, and although it was higher for those patients losing more weight after VLCD, a significant correlation was not found: those who lost more than 5% showed %PSP 59.5 (13.8) % after twelve months and 68.4 (16.2) % of percentage of excess BMI loss (%PEIMC), vs 57,9 (13,1) % and 68.5 (16.6) % if they didn t lose that amount of weight. Those patients losing more than 10% achieved %PSP 63.3 (13.7) and %PEIMC 70.9 (14.7) vs 58.2 (14.0) y 67.7 (16.7) vs those not losing that amount. Significant correlations between preoperative loss with VLCD and %PSP or %PEIMC at 3,6,9 and 12 months were not found, and only %PSP 1 month after surgery correlated with %PSP after VLCD (r = 0.454, p = 0.003). Preoperative weight loss with VLCD in severely obese patients did not show to improve either %PSP or %PEIMC one year after bariatric surgery.