Baseline Anthropometric and Metabolic Parameters Correlate with Weight Loss in Women 1-Year After Laparoscopic Roux-En-Y Gastric Bypass.

BACKGROUND: In this study, we explored in a prospective cohort of morbidly obese women undergoing laparoscopic Roux-en-Y gastric bypass (LRYGP) correlations between baseline anthropometrics, metabolic parameters, resting energy expenditure (REE), body composition, and 1-year % excess body mass index loss (%EBMIL). We also investigated risk factors for insufficient %EBMIL.
METHODS: One hundred three consecutive women were prospectively evaluated at baseline (age 40.6 ± 11.2, weight 113.9 kg ± 15.3, BMI 43.3 ± 4.9 kg/m2) and 1 year after LRYGP. Weight, excess weight, brachial circumference, waist circumference, fat mass (FM) and fat-free mass (FFM) (measured with bioelectrical impedance analysis), REE, inflammation, insulin resistance, and lipid disturbances were determined before and 1 year after LRYGP.
RESULTS: At 1 year, mean weight loss was 39.8 kg ± 11.7 and mean EBMIL was 15.2 kg/m2 ± 4.2. Mean %EBMIL was 86% ± 21% (range 30-146%). Baseline brachial circumference, waist circumference and triceps skinfold thickness decreased significantly at 1 year (P < 0.001). Blood glucose and insulin levels, HDL cholesterol, LDL cholesterol, triglycerides, and CRP also decreased significantly (P < 0.001). The mean loss of initial FFM and FM was 9.1 kg ± 8.2 (15%) and 30.7 kg ± 11.8 (53%), respectively. REE on body weight ratio (REE/BW) increased from 15.3 kcal/kg ± 2.8 to 18.4 kcal/kg ± 2.5 (p < 0.0001) and REE on FFM ratio decreased from 31.2 to 28.7 kcal/day/kg (p < 0.001). Preoperative waist circumference (r = -0.3; P < 0.001), blood glucose level (r = -0.37; P < 0.001), and CRP (r = -0.28; P = 0.004) were negatively correlated with EBMIL% 1 year after surgery. Among baseline body composition parameters, only preoperative FM was negatively correlated with %EBMIL (r = -0.23; p = 0.02). One year after surgery FM change was negatively correlated with EBMIL% (r = -0.49; P < 0.001) while FFM/BW ratio was positively correlated with %EBMIL (r = 0.71; P < 0.001). Increase in REE/BW at 1 year was positively correlated with %EBMIL (r = 0.47; p < 0.001). On multivariate analysis, baseline blood glucose level (OR = 1.77; CI 95%: [1.3-2.4]) was the only predictive factor of EBMIL <60% at 1 year.
CONCLUSION: LRYGB has beneficial effects on clinical, biological parameters, and body composition. Increasing the proportion of FFM on total BW and REE/BW is associated with better results in terms of weight loss. Baseline glucose level may be helpful in identifying poor responders to LRYGBP. TRIAL REGISTRATION: NCT02820285y ( https://clinicaltrials.gov/ct2/show/NCT02820285?term=Characterization+of+Immune+Semaphorin+in+Non-Alcoholic+Fatty+Liver+Disease+and+NASH&rank=1 ).