Fasting glycemia: a good predictor of weight loss after RYGB.

BACKGROUND: Preoperative prediction of weight loss after Roux-en-Y gastric bypass (RYGB) could help surgeons in managing surgical lists and patients' expectations. The objective of this study was to understand if preoperative metabolic control might improve surgical results.

METHODS: Prospective cohort of 163 consecutive patients who underwent RYGB with at least 1 year of follow-up.

RESULTS: Most patients were female (90.2%), with a mean age of 38 (19-60) and a BMI of 46.0 (34.3-59.9) kg/m(2). After 12 months, the mean body mass index (BMI) was 29.7 kg/m(2) (21.5-39.9) with a corresponding percentage of excess weight lost (%EWL) of 78.8% and a percentage of weight loss (%WL) of 35.1%. Patients with the highest preoperative fasting blood glucose (FBG) were older (42 versus 36; P<.001); were more likely to have type 2 diabetes (T2 DM, 40% versus 6.8%; P<.001) and metabolic syndrome (89% versus 25%; P<.001), had a slightly higher BMI (30.8 versus 29.3 kg/m(2); P = .03), and had achieved a significantly lower %EWL and %WL at 12 months (72.5% versus 81.2%; P = .004; 33.2 versus 35.9%; P = .03, respectively). We observed a dose-response effect with increasing FBG (<85 mg/dL, 85-100 mg/dL, and ≥ 100 mg/dL, respectively), with 83.5%, 80.0%, and 72.5% (P = .009) of %EWL at 12 months. By multivariate logistic regression, initial BMI and FBG>100, were the only variables related (inversely) with the probability of achieving a %EWL>80 or %WL>35. This effect was not detected in patients receiving oral antidiabetic medications.

CONCLUSION: Higher preoperative FBG is independently related to a poorer weight loss 12 months after RYGB; this suggests the need to offer earlier surgical intervention for severely obese patients with impairment of glucose metabolism. The potential for less weight loss in patients with a higher FBG should not discourage RYGB, given the significant metabolic improvement after surgery.