Predictors of Inadequate Weight Loss After Laparoscopic Gastric Bypass for Morbid Obesity

Laparoscopic Roux-en-Y gastric bypass (LRYGB) is an effective treatment for morbid obesity resulting in approx. 70% excess weight loss (EWL) at 1-2 years. The aim of this study was to identify factors predictive of inadequate EWL following primary LRYGB.

Data on consecutive patients who underwent primary LRYGB between September 2009 and March 2013 were collected prospectively. The effects of age, gender, baseline body mass index (BMI), preoperative EWL, length of time between initial consultation and surgery (TtS), presence of diabetes mellitus (DM), arthritis, obstructive sleep apnea (OSA) and postoperative length of hospital stay (LOS) on EWL at 12 months were studied. General linear regression models were used to evaluate group differences in EWL and to assess independent associations between baseline variables and EWL at 12 months. Stepwise regression analyses were used to estimate individual contributions of independent variables to the variance in EWL at 12 months. In this study, inadequate EWL was defined as <50% EWL at 12 months.

LRYGB was performed in 227 patients with a mean ± SD age and BMI of 48.6 ± 11 years and 53.6 ± 7.1 kg/m², respectively. Female to male ratio was 3:1. EWL at 12 months had an inverse correlation with age (p = 0.01), baseline BMI (p < 0.001), TtS (p = 0.001), OSA (p = 0.039) and DM (p = 0.039). Conversely, there was a significant positive association between preoperative EWL and that at 12 months (p = 0.009). There was no effect of gender, arthritis or LOS on EWL at 12 months. Multiple regression analysis demonstrated inadequate EWL at 12 months to be predicted by older age (>60 years), patients with diabetes, higher baseline BMI (>60), those who gained weight preoperatively and in patients who waited longer than 18 months for surgery (p = 0.027).

Preoperative factors that predict inadequate EWL at 12 months following primary LRYGB include higher initial BMI, older age, presence of DM and preoperative weight gain. Identification of these factors preoperatively should aid in providing intensive support to these at-risk patient groups.