Fasting glycemia: a good predictor of weight loss after RYGB

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.

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

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.

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.