Pre- and Post-prandial Plasma Ghrelin Levels Do Not Correlate with Satiety or Failure to Achieve a Successful Outcome after Roux-en-Y Gastric Bypass

Background: We tested the hypothesis that the amount of weight lost after Roux-en-Y gastric bypass (RYGBP) correlates with plasma ghrelin levels. Methods: 36 morbidly obese patients were studied 3 years after RYGBP (6 men, 30 women) with mean initial BMI 51 kg/m² and 8 healthy controls (2 men, 6 women) with mean BMI 25 kg/m². Subjects consumed a light breakfast, and the first blood sample was drawn at 1200 hrs immediately before lunch and the second sample at 1400 hrs. Satiety was assessed using a Visual Analog Scale (VAS). Patients were stratified as success (current BMI <35) or failures (current BMI ≥35). Results: Plasma ghrelin levels were significantly lower in patients after RYGBP (269 ± 66 pcg/ml) compared with lean controls (616 ± 112 pcg/ml, P<0.001). Ghrelin levels pre or post meals were not different between patients who had a successful weight loss (preoperative BMI 47, current BMI 29, 72% EWL) or those who achieved a less then ideal weight loss (preoperative BMI 48, current BMI 41, 29% EWL). There was no correlation between any of the VAS scores and plasma ghrelin. There was a strong inverse correlation between pre-prandial ghrelin levels and the preoperative or current BMI. Conclusion: Failure to lose weight after RYGBP does not correlate with pre- or post-prandial ghrelin plasma levels. Ghrelin levels were inversely proportional to BMI and did not correlate with satiety. These data do not support a role for higher plasma ghrelin levels for inadequate weight loss after RYGBP.