The Time to Weight-Loss Steady State After Gastric Bypass Predicts Weight-Loss Success.

Abstract

There is marked variability in weight loss achieved after laparoscopic Roux-en-Y gastric bypass (LRYGB) with little ability to predict pre-operatively poor weight-loss outcomes. In this study, we categorize the patterns of post-operative weight loss after LRYGB by using a novel method of measurement based on the time to weight-loss steady state (SS). A bariatric database was retrospectively reviewed for patients who underwent a LRYGB from 01/2001-12/2010. SS was defined as the month when the patient had ≤3% excess weight loss (%EWL) or weight gain from the prior visit. Percent total weight loss (%TWL) and %EWL were compared based on time to SS. The average time to SS was 15.5 months (n = 178). A percentage of 7.3 of patients lost >5%EWL after achieving their SS weight. Patients with SS <12 months (n = 47) had a significantly lower %TWL and %EWL at SS and a 3-4-year follow-up compared to SS ≥12 months (n = 131, p < 0.05 for all). Initial weight loss velocity (IWLV) and body mass index (BMI) were not significantly associated with the time to SS. Patients with a SS <12 months were significantly older than patients with SS ≥months (42.7 ± 10.5 versus 46.5 ± 11.8 years, p = 0.05). Few patients achieve meaningful weight loss after SS. The time to SS varies significantly among LRYGB patients and is not predicted by the IWLV or BMI. Achievement of SS within the first year after surgery is more common with increasing age and may represent rapid physiologic adaptation with significantly lower %TWL and %EWL.